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[v6,00/10] Introduce VDUSE - vDPA Device in Userspace

Message ID 20210331080519.172-1-xieyongji@bytedance.com
Headers show
Series Introduce VDUSE - vDPA Device in Userspace | expand

Message

Yongji Xie March 31, 2021, 8:05 a.m. UTC
This series introduces a framework, which can be used to implement
vDPA Devices in a userspace program. The work consist of two parts:
control path forwarding and data path offloading.

In the control path, the VDUSE driver will make use of message
mechnism to forward the config operation from vdpa bus driver
to userspace. Userspace can use read()/write() to receive/reply
those control messages.

In the data path, the core is mapping dma buffer into VDUSE
daemon's address space, which can be implemented in different ways
depending on the vdpa bus to which the vDPA device is attached.

In virtio-vdpa case, we implements a MMU-based on-chip IOMMU driver with
bounce-buffering mechanism to achieve that. And in vhost-vdpa case, the dma
buffer is reside in a userspace memory region which can be shared to the
VDUSE userspace processs via transferring the shmfd.

The details and our user case is shown below:

------------------------    -------------------------   ----------------------------------------------
|            Container |    |              QEMU(VM) |   |                               VDUSE daemon |
|       ---------      |    |  -------------------  |   | ------------------------- ---------------- |
|       |dev/vdx|      |    |  |/dev/vhost-vdpa-x|  |   | | vDPA device emulation | | block driver | |
------------+-----------     -----------+------------   -------------+----------------------+---------
            |                           |                            |                      |
            |                           |                            |                      |
------------+---------------------------+----------------------------+----------------------+---------
|    | block device |           |  vhost device |            | vduse driver |          | TCP/IP |    |
|    -------+--------           --------+--------            -------+--------          -----+----    |
|           |                           |                           |                       |        |
| ----------+----------       ----------+-----------         -------+-------                |        |
| | virtio-blk driver |       |  vhost-vdpa driver |         | vdpa device |                |        |
| ----------+----------       ----------+-----------         -------+-------                |        |
|           |      virtio bus           |                           |                       |        |
|   --------+----+-----------           |                           |                       |        |
|                |                      |                           |                       |        |
|      ----------+----------            |                           |                       |        |
|      | virtio-blk device |            |                           |                       |        |
|      ----------+----------            |                           |                       |        |
|                |                      |                           |                       |        |
|     -----------+-----------           |                           |                       |        |
|     |  virtio-vdpa driver |           |                           |                       |        |
|     -----------+-----------           |                           |                       |        |
|                |                      |                           |    vdpa bus           |        |
|     -----------+----------------------+---------------------------+------------           |        |
|                                                                                        ---+---     |
-----------------------------------------------------------------------------------------| NIC |------
                                                                                         ---+---
                                                                                            |
                                                                                   ---------+---------
                                                                                   | Remote Storages |
                                                                                   -------------------

We make use of it to implement a block device connecting to
our distributed storage, which can be used both in containers and
VMs. Thus, we can have an unified technology stack in this two cases.

To test it with null-blk:

  $ qemu-storage-daemon \
      --chardev socket,id=charmonitor,path=/tmp/qmp.sock,server,nowait \
      --monitor chardev=charmonitor \
      --blockdev driver=host_device,cache.direct=on,aio=native,filename=/dev/nullb0,node-name=disk0 \
      --export type=vduse-blk,id=test,node-name=disk0,writable=on,name=vduse-null,num-queues=16,queue-size=128

The qemu-storage-daemon can be found at https://github.com/bytedance/qemu/tree/vduse

Future work:
  - Improve performance
  - Userspace library (find a way to reuse device emulation code in qemu/rust-vmm)

V5 to V6:
- Export receive_fd() instead of __receive_fd()
- Factor out the unmapping logic of pa and va separatedly
- Remove the logic of bounce page allocation in page fault handler
- Use PAGE_SIZE as IOVA allocation granule
- Add EPOLLOUT support
- Enable setting API version in userspace
- Fix some bugs

V4 to V5:
- Remove the patch for irq binding
- Use a single IOTLB for all types of mapping
- Factor out vhost_vdpa_pa_map()
- Add some sample codes in document
- Use receice_fd_user() to pass file descriptor
- Fix some bugs

V3 to V4:
- Rebase to vhost.git
- Split some patches
- Add some documents
- Use ioctl to inject interrupt rather than eventfd
- Enable config interrupt support
- Support binding irq to the specified cpu
- Add two module parameter to limit bounce/iova size
- Create char device rather than anon inode per vduse
- Reuse vhost IOTLB for iova domain
- Rework the message mechnism in control path

V2 to V3:
- Rework the MMU-based IOMMU driver
- Use the iova domain as iova allocator instead of genpool
- Support transferring vma->vm_file in vhost-vdpa
- Add SVA support in vhost-vdpa
- Remove the patches on bounce pages reclaim

V1 to V2:
- Add vhost-vdpa support
- Add some documents
- Based on the vdpa management tool
- Introduce a workqueue for irq injection
- Replace interval tree with array map to store the iova_map

Xie Yongji (10):
  file: Export receive_fd() to modules
  eventfd: Increase the recursion depth of eventfd_signal()
  vhost-vdpa: protect concurrent access to vhost device iotlb
  vhost-iotlb: Add an opaque pointer for vhost IOTLB
  vdpa: Add an opaque pointer for vdpa_config_ops.dma_map()
  vdpa: factor out vhost_vdpa_pa_map() and vhost_vdpa_pa_unmap()
  vdpa: Support transferring virtual addressing during DMA mapping
  vduse: Implement an MMU-based IOMMU driver
  vduse: Introduce VDUSE - vDPA Device in Userspace
  Documentation: Add documentation for VDUSE

 Documentation/userspace-api/index.rst              |    1 +
 Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +
 Documentation/userspace-api/vduse.rst              |  212 +++
 drivers/vdpa/Kconfig                               |   10 +
 drivers/vdpa/Makefile                              |    1 +
 drivers/vdpa/ifcvf/ifcvf_main.c                    |    2 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c                  |    2 +-
 drivers/vdpa/vdpa.c                                |    9 +-
 drivers/vdpa/vdpa_sim/vdpa_sim.c                   |    8 +-
 drivers/vdpa/vdpa_user/Makefile                    |    5 +
 drivers/vdpa/vdpa_user/iova_domain.c               |  521 ++++++++
 drivers/vdpa/vdpa_user/iova_domain.h               |   70 +
 drivers/vdpa/vdpa_user/vduse_dev.c                 | 1362 ++++++++++++++++++++
 drivers/vdpa/virtio_pci/vp_vdpa.c                  |    2 +-
 drivers/vhost/iotlb.c                              |   20 +-
 drivers/vhost/vdpa.c                               |  154 ++-
 fs/eventfd.c                                       |    2 +-
 fs/file.c                                          |    6 +
 include/linux/eventfd.h                            |    5 +-
 include/linux/file.h                               |    7 +-
 include/linux/vdpa.h                               |   21 +-
 include/linux/vhost_iotlb.h                        |    3 +
 include/uapi/linux/vduse.h                         |  175 +++
 23 files changed, 2548 insertions(+), 51 deletions(-)
 create mode 100644 Documentation/userspace-api/vduse.rst
 create mode 100644 drivers/vdpa/vdpa_user/Makefile
 create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c
 create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h
 create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
 create mode 100644 include/uapi/linux/vduse.h

Comments

Jason Wang April 8, 2021, 3:25 a.m. UTC | #1
在 2021/3/31 下午4:05, Xie Yongji 写道:
> This implements an MMU-based IOMMU driver to support mapping

> kernel dma buffer into userspace. The basic idea behind it is

> treating MMU (VA->PA) as IOMMU (IOVA->PA). The driver will set

> up MMU mapping instead of IOMMU mapping for the DMA transfer so

> that the userspace process is able to use its virtual address to

> access the dma buffer in kernel.

>

> And to avoid security issue, a bounce-buffering mechanism is

> introduced to prevent userspace accessing the original buffer

> directly.

>

> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>



Acked-by: Jason Wang <jasowang@redhat.com>


With some nits:


> ---

>   drivers/vdpa/vdpa_user/iova_domain.c | 521 +++++++++++++++++++++++++++++++++++

>   drivers/vdpa/vdpa_user/iova_domain.h |  70 +++++

>   2 files changed, 591 insertions(+)

>   create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c

>   create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h



[...]


> +static void vduse_domain_bounce(struct vduse_iova_domain *domain,

> +				dma_addr_t iova, size_t size,

> +				enum dma_data_direction dir)

> +{

> +	struct vduse_bounce_map *map;

> +	unsigned int offset;

> +	void *addr;

> +	size_t sz;

> +

> +	while (size) {

> +		map = &domain->bounce_maps[iova >> PAGE_SHIFT];

> +		offset = offset_in_page(iova);

> +		sz = min_t(size_t, PAGE_SIZE - offset, size);

> +

> +		if (WARN_ON(!map->bounce_page ||

> +			    map->orig_phys == INVALID_PHYS_ADDR))

> +			return;

> +

> +		addr = page_address(map->bounce_page) + offset;

> +		do_bounce(map->orig_phys + offset, addr, sz, dir);

> +		size -= sz;

> +		iova += sz;

> +	}

> +}

> +

> +static struct page *

> +vduse_domain_get_mapping_page(struct vduse_iova_domain *domain, u64 iova)



It's better to rename this as "vduse_domain_get_coherent_page?".


> +{

> +	u64 start = iova & PAGE_MASK;

> +	u64 last = start + PAGE_SIZE - 1;

> +	struct vhost_iotlb_map *map;

> +	struct page *page = NULL;

> +

> +	spin_lock(&domain->iotlb_lock);

> +	map = vhost_iotlb_itree_first(domain->iotlb, start, last);

> +	if (!map)

> +		goto out;

> +

> +	page = pfn_to_page((map->addr + iova - map->start) >> PAGE_SHIFT);

> +	get_page(page);

> +out:

> +	spin_unlock(&domain->iotlb_lock);

> +

> +	return page;

> +}

> +



[...]


> +

> +static dma_addr_t

> +vduse_domain_alloc_iova(struct iova_domain *iovad,

> +			unsigned long size, unsigned long limit)

> +{

> +	unsigned long shift = iova_shift(iovad);

> +	unsigned long iova_len = iova_align(iovad, size) >> shift;

> +	unsigned long iova_pfn;

> +

> +	if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))

> +		iova_len = roundup_pow_of_two(iova_len);



Let's add a comment as what has been done in dma-iommu.c?

(In the future, it looks to me it's better to move them to 
alloc_iova_fast()).

Thanks
Yongji Xie April 8, 2021, 5:27 a.m. UTC | #2
On Thu, Apr 8, 2021 at 11:26 AM Jason Wang <jasowang@redhat.com> wrote:
>

>

> 在 2021/3/31 下午4:05, Xie Yongji 写道:

> > This implements an MMU-based IOMMU driver to support mapping

> > kernel dma buffer into userspace. The basic idea behind it is

> > treating MMU (VA->PA) as IOMMU (IOVA->PA). The driver will set

> > up MMU mapping instead of IOMMU mapping for the DMA transfer so

> > that the userspace process is able to use its virtual address to

> > access the dma buffer in kernel.

> >

> > And to avoid security issue, a bounce-buffering mechanism is

> > introduced to prevent userspace accessing the original buffer

> > directly.

> >

> > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>

>

>

> Acked-by: Jason Wang <jasowang@redhat.com>

>

> With some nits:

>

>

> > ---

> >   drivers/vdpa/vdpa_user/iova_domain.c | 521 +++++++++++++++++++++++++++++++++++

> >   drivers/vdpa/vdpa_user/iova_domain.h |  70 +++++

> >   2 files changed, 591 insertions(+)

> >   create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c

> >   create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h

>

>

> [...]

>

>

> > +static void vduse_domain_bounce(struct vduse_iova_domain *domain,

> > +                             dma_addr_t iova, size_t size,

> > +                             enum dma_data_direction dir)

> > +{

> > +     struct vduse_bounce_map *map;

> > +     unsigned int offset;

> > +     void *addr;

> > +     size_t sz;

> > +

> > +     while (size) {

> > +             map = &domain->bounce_maps[iova >> PAGE_SHIFT];

> > +             offset = offset_in_page(iova);

> > +             sz = min_t(size_t, PAGE_SIZE - offset, size);

> > +

> > +             if (WARN_ON(!map->bounce_page ||

> > +                         map->orig_phys == INVALID_PHYS_ADDR))

> > +                     return;

> > +

> > +             addr = page_address(map->bounce_page) + offset;

> > +             do_bounce(map->orig_phys + offset, addr, sz, dir);

> > +             size -= sz;

> > +             iova += sz;

> > +     }

> > +}

> > +

> > +static struct page *

> > +vduse_domain_get_mapping_page(struct vduse_iova_domain *domain, u64 iova)

>

>

> It's better to rename this as "vduse_domain_get_coherent_page?".

>


OK.

>

> > +{

> > +     u64 start = iova & PAGE_MASK;

> > +     u64 last = start + PAGE_SIZE - 1;

> > +     struct vhost_iotlb_map *map;

> > +     struct page *page = NULL;

> > +

> > +     spin_lock(&domain->iotlb_lock);

> > +     map = vhost_iotlb_itree_first(domain->iotlb, start, last);

> > +     if (!map)

> > +             goto out;

> > +

> > +     page = pfn_to_page((map->addr + iova - map->start) >> PAGE_SHIFT);

> > +     get_page(page);

> > +out:

> > +     spin_unlock(&domain->iotlb_lock);

> > +

> > +     return page;

> > +}

> > +

>

>

> [...]

>

>

> > +

> > +static dma_addr_t

> > +vduse_domain_alloc_iova(struct iova_domain *iovad,

> > +                     unsigned long size, unsigned long limit)

> > +{

> > +     unsigned long shift = iova_shift(iovad);

> > +     unsigned long iova_len = iova_align(iovad, size) >> shift;

> > +     unsigned long iova_pfn;

> > +

> > +     if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))

> > +             iova_len = roundup_pow_of_two(iova_len);

>

>

> Let's add a comment as what has been done in dma-iommu.c?

>


Fine.

> (In the future, it looks to me it's better to move them to

> alloc_iova_fast()).

>


Agree.

Thanks,
Yongji
Jason Wang April 8, 2021, 6:57 a.m. UTC | #3
在 2021/3/31 下午4:05, Xie Yongji 写道:
> This VDUSE driver enables implementing vDPA devices in userspace.

> Both control path and data path of vDPA devices will be able to

> be handled in userspace.

>

> In the control path, the VDUSE driver will make use of message

> mechnism to forward the config operation from vdpa bus driver

> to userspace. Userspace can use read()/write() to receive/reply

> those control messages.

>

> In the data path, VDUSE_IOTLB_GET_FD ioctl will be used to get

> the file descriptors referring to vDPA device's iova regions. Then

> userspace can use mmap() to access those iova regions. Besides,

> userspace can use ioctl() to inject interrupt and use the eventfd

> mechanism to receive virtqueue kicks.

>

> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>

> ---

>   Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +

>   drivers/vdpa/Kconfig                               |   10 +

>   drivers/vdpa/Makefile                              |    1 +

>   drivers/vdpa/vdpa_user/Makefile                    |    5 +

>   drivers/vdpa/vdpa_user/vduse_dev.c                 | 1362 ++++++++++++++++++++

>   include/uapi/linux/vduse.h                         |  175 +++

>   6 files changed, 1554 insertions(+)

>   create mode 100644 drivers/vdpa/vdpa_user/Makefile

>   create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c

>   create mode 100644 include/uapi/linux/vduse.h

>

> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst

> index a4c75a28c839..71722e6f8f23 100644

> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst

> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst

> @@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments

>   'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!

>   '|'   00-7F  linux/media.h

>   0x80  00-1F  linux/fb.h

> +0x81  00-1F  linux/vduse.h

>   0x89  00-06  arch/x86/include/asm/sockios.h

>   0x89  0B-DF  linux/sockios.h

>   0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range

> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig

> index a245809c99d0..77a1da522c21 100644

> --- a/drivers/vdpa/Kconfig

> +++ b/drivers/vdpa/Kconfig

> @@ -25,6 +25,16 @@ config VDPA_SIM_NET

>   	help

>   	  vDPA networking device simulator which loops TX traffic back to RX.

>   

> +config VDPA_USER

> +	tristate "VDUSE (vDPA Device in Userspace) support"

> +	depends on EVENTFD && MMU && HAS_DMA

> +	select DMA_OPS

> +	select VHOST_IOTLB

> +	select IOMMU_IOVA

> +	help

> +	  With VDUSE it is possible to emulate a vDPA Device

> +	  in a userspace program.

> +

>   config IFCVF

>   	tristate "Intel IFC VF vDPA driver"

>   	depends on PCI_MSI

> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile

> index 67fe7f3d6943..f02ebed33f19 100644

> --- a/drivers/vdpa/Makefile

> +++ b/drivers/vdpa/Makefile

> @@ -1,6 +1,7 @@

>   # SPDX-License-Identifier: GPL-2.0

>   obj-$(CONFIG_VDPA) += vdpa.o

>   obj-$(CONFIG_VDPA_SIM) += vdpa_sim/

> +obj-$(CONFIG_VDPA_USER) += vdpa_user/

>   obj-$(CONFIG_IFCVF)    += ifcvf/

>   obj-$(CONFIG_MLX5_VDPA) += mlx5/

>   obj-$(CONFIG_VP_VDPA)    += virtio_pci/

> diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile

> new file mode 100644

> index 000000000000..260e0b26af99

> --- /dev/null

> +++ b/drivers/vdpa/vdpa_user/Makefile

> @@ -0,0 +1,5 @@

> +# SPDX-License-Identifier: GPL-2.0

> +

> +vduse-y := vduse_dev.o iova_domain.o

> +

> +obj-$(CONFIG_VDPA_USER) += vduse.o

> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c

> new file mode 100644

> index 000000000000..51ca73464d0d

> --- /dev/null

> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c

> @@ -0,0 +1,1362 @@

> +// SPDX-License-Identifier: GPL-2.0-only

> +/*

> + * VDUSE: vDPA Device in Userspace

> + *

> + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.

> + *

> + * Author: Xie Yongji <xieyongji@bytedance.com>

> + *

> + */

> +

> +#include <linux/init.h>

> +#include <linux/module.h>

> +#include <linux/miscdevice.h>

> +#include <linux/cdev.h>

> +#include <linux/device.h>

> +#include <linux/eventfd.h>

> +#include <linux/slab.h>

> +#include <linux/wait.h>

> +#include <linux/dma-map-ops.h>

> +#include <linux/poll.h>

> +#include <linux/file.h>

> +#include <linux/uio.h>

> +#include <linux/vdpa.h>

> +#include <uapi/linux/vduse.h>

> +#include <uapi/linux/vdpa.h>

> +#include <uapi/linux/virtio_config.h>

> +#include <linux/mod_devicetable.h>

> +

> +#include "iova_domain.h"

> +

> +#define DRV_VERSION  "1.0"

> +#define DRV_AUTHOR   "Yongji Xie <xieyongji@bytedance.com>"

> +#define DRV_DESC     "vDPA Device in Userspace"

> +#define DRV_LICENSE  "GPL v2"

> +

> +#define VDUSE_DEV_MAX (1U << MINORBITS)

> +

> +struct vduse_virtqueue {

> +	u16 index;

> +	bool ready;

> +	spinlock_t kick_lock;

> +	spinlock_t irq_lock;

> +	struct eventfd_ctx *kickfd;

> +	struct vdpa_callback cb;

> +	struct work_struct inject;

> +};

> +

> +struct vduse_dev;

> +

> +struct vduse_vdpa {

> +	struct vdpa_device vdpa;

> +	struct vduse_dev *dev;

> +};

> +

> +struct vduse_dev {

> +	struct vduse_vdpa *vdev;

> +	struct device dev;

> +	struct cdev cdev;

> +	struct vduse_virtqueue *vqs;

> +	struct vduse_iova_domain *domain;

> +	struct mutex lock;

> +	spinlock_t msg_lock;

> +	atomic64_t msg_unique;

> +	wait_queue_head_t waitq;

> +	struct list_head send_list;

> +	struct list_head recv_list;

> +	struct list_head list;

> +	struct vdpa_callback config_cb;

> +	spinlock_t irq_lock;

> +	unsigned long api_version;

> +	bool connected;

> +	int minor;

> +	u16 vq_size_max;

> +	u16 vq_num;

> +	u32 vq_align;

> +	u32 device_id;

> +	u32 vendor_id;

> +};

> +

> +struct vduse_dev_msg {

> +	struct vduse_dev_request req;

> +	struct vduse_dev_response resp;

> +	struct list_head list;

> +	wait_queue_head_t waitq;

> +	bool completed;

> +};

> +

> +struct vduse_control {

> +	unsigned long api_version;

> +};

> +

> +static unsigned long max_bounce_size = (64 * 1024 * 1024);

> +module_param(max_bounce_size, ulong, 0444);

> +MODULE_PARM_DESC(max_bounce_size, "Maximum bounce buffer size. (default: 64M)");

> +

> +static unsigned long max_iova_size = (128 * 1024 * 1024);

> +module_param(max_iova_size, ulong, 0444);

> +MODULE_PARM_DESC(max_iova_size, "Maximum iova space size (default: 128M)");

> +

> +static DEFINE_MUTEX(vduse_lock);

> +static LIST_HEAD(vduse_devs);

> +static DEFINE_IDA(vduse_ida);

> +

> +static dev_t vduse_major;

> +static struct class *vduse_class;

> +static struct workqueue_struct *vduse_irq_wq;

> +

> +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)

> +{

> +	struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);

> +

> +	return vdev->dev;

> +}

> +

> +static inline struct vduse_dev *dev_to_vduse(struct device *dev)

> +{

> +	struct vdpa_device *vdpa = dev_to_vdpa(dev);

> +

> +	return vdpa_to_vduse(vdpa);

> +}

> +

> +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,

> +					    uint32_t request_id)

> +{

> +	struct vduse_dev_msg *tmp, *msg = NULL;

> +

> +	list_for_each_entry(tmp, head, list) {

> +		if (tmp->req.request_id == request_id) {

> +			msg = tmp;

> +			list_del(&tmp->list);

> +			break;

> +		}

> +	}

> +

> +	return msg;

> +}

> +

> +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)

> +{

> +	struct vduse_dev_msg *msg = NULL;

> +

> +	if (!list_empty(head)) {

> +		msg = list_first_entry(head, struct vduse_dev_msg, list);

> +		list_del(&msg->list);

> +	}

> +

> +	return msg;

> +}

> +

> +static void vduse_enqueue_msg(struct list_head *head,

> +			      struct vduse_dev_msg *msg)

> +{

> +	list_add_tail(&msg->list, head);

> +}

> +

> +static int vduse_dev_msg_sync(struct vduse_dev *dev,

> +			      struct vduse_dev_msg *msg)

> +{

> +	init_waitqueue_head(&msg->waitq);

> +	spin_lock(&dev->msg_lock);

> +	vduse_enqueue_msg(&dev->send_list, msg);

> +	wake_up(&dev->waitq);

> +	spin_unlock(&dev->msg_lock);

> +	wait_event_interruptible(msg->waitq, msg->completed);

> +	spin_lock(&dev->msg_lock);

> +	if (!msg->completed)

> +		list_del(&msg->list);

> +	spin_unlock(&dev->msg_lock);

> +

> +	return (msg->resp.result == VDUSE_REQUEST_OK) ? 0 : -1;

> +}

> +

> +static u32 vduse_dev_get_request_id(struct vduse_dev *dev)

> +{

> +	return atomic64_fetch_inc(&dev->msg_unique);

> +}

> +

> +static u64 vduse_dev_get_features(struct vduse_dev *dev)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_GET_FEATURES;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +

> +	return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.f.features;

> +}

> +

> +static int vduse_dev_set_features(struct vduse_dev *dev, u64 features)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_SET_FEATURES;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.f.features = features;

> +

> +	return vduse_dev_msg_sync(dev, &msg);

> +}

> +

> +static u8 vduse_dev_get_status(struct vduse_dev *dev)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_GET_STATUS;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +

> +	return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.s.status;

> +}

> +

> +static void vduse_dev_set_status(struct vduse_dev *dev, u8 status)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_SET_STATUS;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.s.status = status;

> +

> +	vduse_dev_msg_sync(dev, &msg);

> +}

> +

> +static void vduse_dev_get_config(struct vduse_dev *dev, unsigned int offset,

> +				 void *buf, unsigned int len)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +	unsigned int sz;

> +

> +	while (len) {

> +		sz = min_t(unsigned int, len, sizeof(msg.req.config.data));

> +		msg.req.type = VDUSE_GET_CONFIG;

> +		msg.req.request_id = vduse_dev_get_request_id(dev);

> +		msg.req.config.offset = offset;

> +		msg.req.config.len = sz;

> +		vduse_dev_msg_sync(dev, &msg);

> +		memcpy(buf, msg.resp.config.data, sz);

> +		buf += sz;

> +		offset += sz;

> +		len -= sz;

> +	}

> +}

> +

> +static void vduse_dev_set_config(struct vduse_dev *dev, unsigned int offset,

> +				 const void *buf, unsigned int len)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +	unsigned int sz;

> +

> +	while (len) {

> +		sz = min_t(unsigned int, len, sizeof(msg.req.config.data));

> +		msg.req.type = VDUSE_SET_CONFIG;

> +		msg.req.request_id = vduse_dev_get_request_id(dev);

> +		msg.req.config.offset = offset;

> +		msg.req.config.len = sz;

> +		memcpy(msg.req.config.data, buf, sz);

> +		vduse_dev_msg_sync(dev, &msg);

> +		buf += sz;

> +		offset += sz;

> +		len -= sz;

> +	}

> +}

> +

> +static void vduse_dev_set_vq_num(struct vduse_dev *dev,

> +				 struct vduse_virtqueue *vq, u32 num)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_SET_VQ_NUM;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.vq_num.index = vq->index;

> +	msg.req.vq_num.num = num;

> +

> +	vduse_dev_msg_sync(dev, &msg);

> +}

> +

> +static int vduse_dev_set_vq_addr(struct vduse_dev *dev,

> +				 struct vduse_virtqueue *vq, u64 desc_addr,

> +				 u64 driver_addr, u64 device_addr)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_SET_VQ_ADDR;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.vq_addr.index = vq->index;

> +	msg.req.vq_addr.desc_addr = desc_addr;

> +	msg.req.vq_addr.driver_addr = driver_addr;

> +	msg.req.vq_addr.device_addr = device_addr;

> +

> +	return vduse_dev_msg_sync(dev, &msg);

> +}

> +

> +static void vduse_dev_set_vq_ready(struct vduse_dev *dev,

> +				struct vduse_virtqueue *vq, bool ready)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_SET_VQ_READY;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.vq_ready.index = vq->index;

> +	msg.req.vq_ready.ready = ready;

> +

> +	vduse_dev_msg_sync(dev, &msg);

> +}

> +

> +static bool vduse_dev_get_vq_ready(struct vduse_dev *dev,

> +				   struct vduse_virtqueue *vq)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_GET_VQ_READY;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.vq_ready.index = vq->index;

> +

> +	return vduse_dev_msg_sync(dev, &msg) ? false : msg.resp.vq_ready.ready;

> +}

> +

> +static int vduse_dev_get_vq_state(struct vduse_dev *dev,

> +				struct vduse_virtqueue *vq,

> +				struct vdpa_vq_state *state)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +	int ret;

> +

> +	msg.req.type = VDUSE_GET_VQ_STATE;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.vq_state.index = vq->index;

> +

> +	ret = vduse_dev_msg_sync(dev, &msg);

> +	if (!ret)

> +		state->avail_index = msg.resp.vq_state.avail_idx;

> +

> +	return ret;

> +}

> +

> +static int vduse_dev_set_vq_state(struct vduse_dev *dev,

> +				struct vduse_virtqueue *vq,

> +				const struct vdpa_vq_state *state)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	msg.req.type = VDUSE_SET_VQ_STATE;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.vq_state.index = vq->index;

> +	msg.req.vq_state.avail_idx = state->avail_index;

> +

> +	return vduse_dev_msg_sync(dev, &msg);

> +}

> +

> +static int vduse_dev_update_iotlb(struct vduse_dev *dev,

> +				u64 start, u64 last)

> +{

> +	struct vduse_dev_msg msg = { 0 };

> +

> +	if (last < start)

> +		return -EINVAL;

> +

> +	msg.req.type = VDUSE_UPDATE_IOTLB;

> +	msg.req.request_id = vduse_dev_get_request_id(dev);

> +	msg.req.iova.start = start;

> +	msg.req.iova.last = last;

> +

> +	return vduse_dev_msg_sync(dev, &msg);

> +}

> +

> +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)

> +{

> +	struct file *file = iocb->ki_filp;

> +	struct vduse_dev *dev = file->private_data;

> +	struct vduse_dev_msg *msg;

> +	int size = sizeof(struct vduse_dev_request);

> +	ssize_t ret = 0;

> +

> +	if (iov_iter_count(to) < size)

> +		return 0;

> +

> +	spin_lock(&dev->msg_lock);

> +	while (1) {

> +		msg = vduse_dequeue_msg(&dev->send_list);

> +		if (msg)

> +			break;

> +

> +		ret = -EAGAIN;

> +		if (file->f_flags & O_NONBLOCK)

> +			goto unlock;

> +

> +		spin_unlock(&dev->msg_lock);

> +		ret = wait_event_interruptible_exclusive(dev->waitq,

> +					!list_empty(&dev->send_list));

> +		if (ret)

> +			return ret;

> +

> +		spin_lock(&dev->msg_lock);

> +	}

> +	spin_unlock(&dev->msg_lock);

> +	ret = copy_to_iter(&msg->req, size, to);

> +	spin_lock(&dev->msg_lock);

> +	if (ret != size) {

> +		ret = -EFAULT;

> +		vduse_enqueue_msg(&dev->send_list, msg);

> +		goto unlock;

> +	}

> +	vduse_enqueue_msg(&dev->recv_list, msg);

> +	wake_up(&dev->waitq);

> +unlock:

> +	spin_unlock(&dev->msg_lock);

> +

> +	return ret;

> +}

> +

> +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)

> +{

> +	struct file *file = iocb->ki_filp;

> +	struct vduse_dev *dev = file->private_data;

> +	struct vduse_dev_response resp;

> +	struct vduse_dev_msg *msg;

> +	size_t ret;

> +

> +	ret = copy_from_iter(&resp, sizeof(resp), from);

> +	if (ret != sizeof(resp))

> +		return -EINVAL;

> +

> +	spin_lock(&dev->msg_lock);

> +	msg = vduse_find_msg(&dev->recv_list, resp.request_id);

> +	if (!msg) {

> +		ret = -EINVAL;

> +		goto unlock;

> +	}

> +

> +	memcpy(&msg->resp, &resp, sizeof(resp));

> +	msg->completed = 1;

> +	wake_up(&msg->waitq);

> +unlock:

> +	spin_unlock(&dev->msg_lock);

> +

> +	return ret;

> +}

> +

> +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)

> +{

> +	struct vduse_dev *dev = file->private_data;

> +	__poll_t mask = 0;

> +

> +	poll_wait(file, &dev->waitq, wait);

> +

> +	if (!list_empty(&dev->send_list))

> +		mask |= EPOLLIN | EPOLLRDNORM;

> +	if (!list_empty(&dev->recv_list))

> +		mask |= EPOLLOUT;

> +

> +	return mask;

> +}

> +

> +static void vduse_dev_reset(struct vduse_dev *dev)

> +{

> +	int i;

> +

> +	/* The coherent mappings are handled in vduse_dev_free_coherent() */

> +	vduse_domain_reset_bounce_map(dev->domain);

> +	vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);

> +

> +	spin_lock(&dev->irq_lock);

> +	dev->config_cb.callback = NULL;

> +	dev->config_cb.private = NULL;

> +	spin_unlock(&dev->irq_lock);

> +

> +	for (i = 0; i < dev->vq_num; i++) {

> +		struct vduse_virtqueue *vq = &dev->vqs[i];

> +

> +		spin_lock(&vq->irq_lock);

> +		vq->ready = false;

> +		vq->cb.callback = NULL;

> +		vq->cb.private = NULL;

> +		spin_unlock(&vq->irq_lock);

> +	}

> +}

> +

> +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,

> +				u64 desc_area, u64 driver_area,

> +				u64 device_area)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	struct vduse_virtqueue *vq = &dev->vqs[idx];

> +

> +	return vduse_dev_set_vq_addr(dev, vq, desc_area,

> +					driver_area, device_area);

> +}

> +

> +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	struct vduse_virtqueue *vq = &dev->vqs[idx];

> +

> +	spin_lock(&vq->kick_lock);

> +	if (vq->ready && vq->kickfd)

> +		eventfd_signal(vq->kickfd, 1);

> +	spin_unlock(&vq->kick_lock);

> +}

> +

> +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,

> +			      struct vdpa_callback *cb)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	struct vduse_virtqueue *vq = &dev->vqs[idx];

> +

> +	spin_lock(&vq->irq_lock);

> +	vq->cb.callback = cb->callback;

> +	vq->cb.private = cb->private;

> +	spin_unlock(&vq->irq_lock);

> +}

> +

> +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	struct vduse_virtqueue *vq = &dev->vqs[idx];

> +

> +	vduse_dev_set_vq_num(dev, vq, num);

> +}

> +

> +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,

> +					u16 idx, bool ready)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	struct vduse_virtqueue *vq = &dev->vqs[idx];

> +

> +	vduse_dev_set_vq_ready(dev, vq, ready);

> +	vq->ready = ready;

> +}

> +

> +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	struct vduse_virtqueue *vq = &dev->vqs[idx];

> +

> +	vq->ready = vduse_dev_get_vq_ready(dev, vq);

> +

> +	return vq->ready;

> +}

> +

> +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,

> +				const struct vdpa_vq_state *state)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	struct vduse_virtqueue *vq = &dev->vqs[idx];

> +

> +	return vduse_dev_set_vq_state(dev, vq, state);

> +}

> +

> +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,

> +				struct vdpa_vq_state *state)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	struct vduse_virtqueue *vq = &dev->vqs[idx];

> +

> +	return vduse_dev_get_vq_state(dev, vq, state);

> +}

> +

> +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	return dev->vq_align;

> +}

> +

> +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	return vduse_dev_get_features(dev);

> +}

> +

> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))

> +		return -EINVAL;

> +

> +	return vduse_dev_set_features(dev, features);

> +}

> +

> +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,

> +				  struct vdpa_callback *cb)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	spin_lock(&dev->irq_lock);

> +	dev->config_cb.callback = cb->callback;

> +	dev->config_cb.private = cb->private;

> +	spin_unlock(&dev->irq_lock);

> +}

> +

> +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	return dev->vq_size_max;

> +}

> +

> +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	return dev->device_id;

> +}

> +

> +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	return dev->vendor_id;

> +}

> +

> +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	return vduse_dev_get_status(dev);

> +}

> +

> +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	vduse_dev_set_status(dev, status);

> +

> +	if (status == 0)

> +		vduse_dev_reset(dev);

> +}

> +

> +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,

> +			     void *buf, unsigned int len)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	vduse_dev_get_config(dev, offset, buf, len);

> +}

> +

> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,

> +			const void *buf, unsigned int len)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	vduse_dev_set_config(dev, offset, buf, len);

> +}

> +

> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,

> +				struct vhost_iotlb *iotlb)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +	int ret;

> +

> +	ret = vduse_domain_set_map(dev->domain, iotlb);

> +	vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);

> +

> +	return ret;

> +}

> +

> +static void vduse_vdpa_free(struct vdpa_device *vdpa)

> +{

> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> +

> +	WARN_ON(!list_empty(&dev->send_list));

> +	WARN_ON(!list_empty(&dev->recv_list));

> +	dev->vdev = NULL;

> +}

> +

> +static const struct vdpa_config_ops vduse_vdpa_config_ops = {

> +	.set_vq_address		= vduse_vdpa_set_vq_address,

> +	.kick_vq		= vduse_vdpa_kick_vq,

> +	.set_vq_cb		= vduse_vdpa_set_vq_cb,

> +	.set_vq_num             = vduse_vdpa_set_vq_num,

> +	.set_vq_ready		= vduse_vdpa_set_vq_ready,

> +	.get_vq_ready		= vduse_vdpa_get_vq_ready,

> +	.set_vq_state		= vduse_vdpa_set_vq_state,

> +	.get_vq_state		= vduse_vdpa_get_vq_state,

> +	.get_vq_align		= vduse_vdpa_get_vq_align,

> +	.get_features		= vduse_vdpa_get_features,

> +	.set_features		= vduse_vdpa_set_features,

> +	.set_config_cb		= vduse_vdpa_set_config_cb,

> +	.get_vq_num_max		= vduse_vdpa_get_vq_num_max,

> +	.get_device_id		= vduse_vdpa_get_device_id,

> +	.get_vendor_id		= vduse_vdpa_get_vendor_id,

> +	.get_status		= vduse_vdpa_get_status,

> +	.set_status		= vduse_vdpa_set_status,

> +	.get_config		= vduse_vdpa_get_config,

> +	.set_config		= vduse_vdpa_set_config,

> +	.set_map		= vduse_vdpa_set_map,

> +	.free			= vduse_vdpa_free,

> +};

> +

> +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,

> +				     unsigned long offset, size_t size,

> +				     enum dma_data_direction dir,

> +				     unsigned long attrs)

> +{

> +	struct vduse_dev *vdev = dev_to_vduse(dev);

> +	struct vduse_iova_domain *domain = vdev->domain;

> +

> +	return vduse_domain_map_page(domain, page, offset, size, dir, attrs);

> +}

> +

> +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,

> +				size_t size, enum dma_data_direction dir,

> +				unsigned long attrs)

> +{

> +	struct vduse_dev *vdev = dev_to_vduse(dev);

> +	struct vduse_iova_domain *domain = vdev->domain;

> +

> +	return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);

> +}

> +

> +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,

> +					dma_addr_t *dma_addr, gfp_t flag,

> +					unsigned long attrs)

> +{

> +	struct vduse_dev *vdev = dev_to_vduse(dev);

> +	struct vduse_iova_domain *domain = vdev->domain;

> +	unsigned long iova;

> +	void *addr;

> +

> +	*dma_addr = DMA_MAPPING_ERROR;

> +	addr = vduse_domain_alloc_coherent(domain, size,

> +				(dma_addr_t *)&iova, flag, attrs);

> +	if (!addr)

> +		return NULL;

> +

> +	*dma_addr = (dma_addr_t)iova;

> +	vduse_dev_update_iotlb(vdev, iova, iova + size - 1);

> +

> +	return addr;

> +}

> +

> +static void vduse_dev_free_coherent(struct device *dev, size_t size,

> +					void *vaddr, dma_addr_t dma_addr,

> +					unsigned long attrs)

> +{

> +	struct vduse_dev *vdev = dev_to_vduse(dev);

> +	struct vduse_iova_domain *domain = vdev->domain;

> +	unsigned long start = (unsigned long)dma_addr;

> +	unsigned long last = start + size - 1;

> +

> +	vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);

> +	vduse_dev_update_iotlb(vdev, start, last);

> +}

> +

> +static const struct dma_map_ops vduse_dev_dma_ops = {

> +	.map_page = vduse_dev_map_page,

> +	.unmap_page = vduse_dev_unmap_page,

> +	.alloc = vduse_dev_alloc_coherent,

> +	.free = vduse_dev_free_coherent,

> +};

> +

> +static unsigned int perm_to_file_flags(u8 perm)

> +{

> +	unsigned int flags = 0;

> +

> +	switch (perm) {

> +	case VDUSE_ACCESS_WO:

> +		flags |= O_WRONLY;

> +		break;

> +	case VDUSE_ACCESS_RO:

> +		flags |= O_RDONLY;

> +		break;

> +	case VDUSE_ACCESS_RW:

> +		flags |= O_RDWR;

> +		break;

> +	default:

> +		WARN(1, "invalidate vhost IOTLB permission\n");

> +		break;

> +	}

> +

> +	return flags;

> +}

> +

> +static int vduse_kickfd_setup(struct vduse_dev *dev,

> +			struct vduse_vq_eventfd *eventfd)

> +{

> +	struct eventfd_ctx *ctx = NULL;

> +	struct vduse_virtqueue *vq;

> +

> +	if (eventfd->index >= dev->vq_num)

> +		return -EINVAL;

> +

> +	vq = &dev->vqs[eventfd->index];

> +	if (eventfd->fd > 0) {

> +		ctx = eventfd_ctx_fdget(eventfd->fd);

> +		if (IS_ERR(ctx))

> +			return PTR_ERR(ctx);

> +	} else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)

> +		return 0;



Do we allow the userspace to switch kickfd here? If yes, we need to deal 
with that.


> +

> +	spin_lock(&vq->kick_lock);

> +	if (vq->kickfd)

> +		eventfd_ctx_put(vq->kickfd);

> +	vq->kickfd = ctx;

> +	spin_unlock(&vq->kick_lock);

> +

> +	return 0;

> +}

> +

> +static void vduse_vq_irq_inject(struct work_struct *work)

> +{

> +	struct vduse_virtqueue *vq = container_of(work,

> +					struct vduse_virtqueue, inject);

> +

> +	spin_lock_irq(&vq->irq_lock);

> +	if (vq->ready && vq->cb.callback)

> +		vq->cb.callback(vq->cb.private);

> +	spin_unlock_irq(&vq->irq_lock);

> +}

> +

> +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,

> +			    unsigned long arg)

> +{

> +	struct vduse_dev *dev = file->private_data;

> +	void __user *argp = (void __user *)arg;

> +	int ret;

> +

> +	switch (cmd) {

> +	case VDUSE_IOTLB_GET_FD: {

> +		struct vduse_iotlb_entry entry;

> +		struct vhost_iotlb_map *map;

> +		struct vdpa_map_file *map_file;

> +		struct vduse_iova_domain *domain = dev->domain;

> +		struct file *f = NULL;

> +

> +		ret = -EFAULT;

> +		if (copy_from_user(&entry, argp, sizeof(entry)))

> +			break;

> +

> +		ret = -EINVAL;

> +		if (entry.start > entry.last)

> +			break;

> +

> +		spin_lock(&domain->iotlb_lock);

> +		map = vhost_iotlb_itree_first(domain->iotlb,

> +					      entry.start, entry.last);

> +		if (map) {

> +			map_file = (struct vdpa_map_file *)map->opaque;

> +			f = get_file(map_file->file);

> +			entry.offset = map_file->offset;

> +			entry.start = map->start;

> +			entry.last = map->last;

> +			entry.perm = map->perm;

> +		}

> +		spin_unlock(&domain->iotlb_lock);

> +		ret = -EINVAL;

> +		if (!f)

> +			break;

> +

> +		ret = -EFAULT;

> +		if (copy_to_user(argp, &entry, sizeof(entry))) {

> +			fput(f);

> +			break;

> +		}

> +		ret = receive_fd(f, perm_to_file_flags(entry.perm));

> +		fput(f);



Any reason to drop the refcnt here?


> +		break;

> +	}

> +	case VDUSE_VQ_SETUP_KICKFD: {

> +		struct vduse_vq_eventfd eventfd;

> +

> +		ret = -EFAULT;

> +		if (copy_from_user(&eventfd, argp, sizeof(eventfd)))

> +			break;

> +

> +		ret = vduse_kickfd_setup(dev, &eventfd);

> +		break;

> +	}

> +	case VDUSE_INJECT_VQ_IRQ:

> +		ret = -EINVAL;

> +		if (arg >= dev->vq_num)

> +			break;

> +

> +		ret = 0;

> +		queue_work(vduse_irq_wq, &dev->vqs[arg].inject);

> +		break;

> +	case VDUSE_INJECT_CONFIG_IRQ:

> +		ret = -EINVAL;

> +		spin_lock_irq(&dev->irq_lock);

> +		if (dev->config_cb.callback) {

> +			dev->config_cb.callback(dev->config_cb.private);

> +			ret = 0;

> +		}

> +		spin_unlock_irq(&dev->irq_lock);



For consistency, is it better to use vduse_irq_wq here?


> +		break;

> +	default:

> +		ret = -ENOIOCTLCMD;

> +		break;

> +	}

> +

> +	return ret;

> +}

> +

> +static int vduse_dev_release(struct inode *inode, struct file *file)

> +{

> +	struct vduse_dev *dev = file->private_data;

> +	struct vduse_dev_msg *msg;

> +	int i;

> +

> +	for (i = 0; i < dev->vq_num; i++) {

> +		struct vduse_virtqueue *vq = &dev->vqs[i];

> +

> +		spin_lock(&vq->kick_lock);

> +		if (vq->kickfd)

> +			eventfd_ctx_put(vq->kickfd);

> +		vq->kickfd = NULL;

> +		spin_unlock(&vq->kick_lock);

> +	}

> +

> +	spin_lock(&dev->msg_lock);

> +	/*  Make sure the inflight messages can processed */



This might be better:

/*  Make sure the inflight messages can processed after reconncection */

> +	while ((msg = vduse_dequeue_msg(&dev->recv_list)))

> +		vduse_enqueue_msg(&dev->send_list, msg);

> +	spin_unlock(&dev->msg_lock);

> +

> +	dev->connected = false;

> +

> +	return 0;

> +}

> +

> +static int vduse_dev_open(struct inode *inode, struct file *file)

> +{

> +	struct vduse_dev *dev = container_of(inode->i_cdev,

> +					struct vduse_dev, cdev);

> +	int ret = -EBUSY;

> +

> +	mutex_lock(&dev->lock);

> +	if (dev->connected)

> +		goto unlock;

> +

> +	ret = 0;

> +	dev->connected = true;

> +	file->private_data = dev;

> +unlock:

> +	mutex_unlock(&dev->lock);

> +

> +	return ret;

> +}

> +

> +static const struct file_operations vduse_dev_fops = {

> +	.owner		= THIS_MODULE,

> +	.open		= vduse_dev_open,

> +	.release	= vduse_dev_release,

> +	.read_iter	= vduse_dev_read_iter,

> +	.write_iter	= vduse_dev_write_iter,

> +	.poll		= vduse_dev_poll,

> +	.unlocked_ioctl	= vduse_dev_ioctl,

> +	.compat_ioctl	= compat_ptr_ioctl,

> +	.llseek		= noop_llseek,

> +};

> +

> +static struct vduse_dev *vduse_dev_create(void)

> +{

> +	struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);

> +

> +	if (!dev)

> +		return NULL;

> +

> +	mutex_init(&dev->lock);

> +	spin_lock_init(&dev->msg_lock);

> +	INIT_LIST_HEAD(&dev->send_list);

> +	INIT_LIST_HEAD(&dev->recv_list);

> +	atomic64_set(&dev->msg_unique, 0);

> +	spin_lock_init(&dev->irq_lock);

> +

> +	init_waitqueue_head(&dev->waitq);

> +

> +	return dev;

> +}

> +

> +static void vduse_dev_destroy(struct vduse_dev *dev)

> +{

> +	kfree(dev);

> +}

> +

> +static struct vduse_dev *vduse_find_dev(const char *name)

> +{

> +	struct vduse_dev *tmp, *dev = NULL;

> +

> +	list_for_each_entry(tmp, &vduse_devs, list) {

> +		if (!strcmp(dev_name(&tmp->dev), name)) {

> +			dev = tmp;

> +			break;

> +		}

> +	}

> +	return dev;

> +}

> +

> +static int vduse_destroy_dev(char *name)

> +{

> +	struct vduse_dev *dev = vduse_find_dev(name);

> +

> +	if (!dev)

> +		return -EINVAL;

> +

> +	mutex_lock(&dev->lock);

> +	if (dev->vdev || dev->connected) {

> +		mutex_unlock(&dev->lock);

> +		return -EBUSY;

> +	}

> +	dev->connected = true;

> +	mutex_unlock(&dev->lock);

> +

> +	list_del(&dev->list);

> +	cdev_device_del(&dev->cdev, &dev->dev);

> +	put_device(&dev->dev);

> +	module_put(THIS_MODULE);

> +

> +	return 0;

> +}

> +

> +static void vduse_release_dev(struct device *device)

> +{

> +	struct vduse_dev *dev =

> +		container_of(device, struct vduse_dev, dev);

> +

> +	ida_simple_remove(&vduse_ida, dev->minor);

> +	kfree(dev->vqs);

> +	vduse_domain_destroy(dev->domain);

> +	vduse_dev_destroy(dev);

> +}

> +

> +static int vduse_create_dev(struct vduse_dev_config *config,

> +			    unsigned long api_version)

> +{

> +	int i, ret = -ENOMEM;

> +	struct vduse_dev *dev;

> +

> +	if (config->bounce_size > max_bounce_size)

> +		return -EINVAL;

> +

> +	if (config->bounce_size > max_iova_size)

> +		return -EINVAL;

> +

> +	if (vduse_find_dev(config->name))

> +		return -EEXIST;

> +

> +	dev = vduse_dev_create();

> +	if (!dev)

> +		return -ENOMEM;

> +

> +	dev->api_version = api_version;

> +	dev->device_id = config->device_id;

> +	dev->vendor_id = config->vendor_id;

> +	dev->domain = vduse_domain_create(max_iova_size - 1,

> +					config->bounce_size);

> +	if (!dev->domain)

> +		goto err_domain;

> +

> +	dev->vq_align = config->vq_align;

> +	dev->vq_size_max = config->vq_size_max;

> +	dev->vq_num = config->vq_num;

> +	dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);

> +	if (!dev->vqs)

> +		goto err_vqs;

> +

> +	for (i = 0; i < dev->vq_num; i++) {

> +		dev->vqs[i].index = i;

> +		INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);

> +		spin_lock_init(&dev->vqs[i].kick_lock);

> +		spin_lock_init(&dev->vqs[i].irq_lock);

> +	}

> +

> +	ret = ida_simple_get(&vduse_ida, 0, VDUSE_DEV_MAX, GFP_KERNEL);

> +	if (ret < 0)

> +		goto err_ida;

> +

> +	dev->minor = ret;

> +	device_initialize(&dev->dev);

> +	dev->dev.release = vduse_release_dev;

> +	dev->dev.class = vduse_class;

> +	dev->dev.devt = MKDEV(MAJOR(vduse_major), dev->minor);

> +	ret = dev_set_name(&dev->dev, "%s", config->name);

> +	if (ret) {

> +		put_device(&dev->dev);

> +		return ret;

> +	}

> +	cdev_init(&dev->cdev, &vduse_dev_fops);

> +	dev->cdev.owner = THIS_MODULE;

> +

> +	ret = cdev_device_add(&dev->cdev, &dev->dev);

> +	if (ret) {

> +		put_device(&dev->dev);

> +		return ret;



Let's introduce an error label for this.


> +	}

> +	list_add(&dev->list, &vduse_devs);

> +	__module_get(THIS_MODULE);

> +

> +	return 0;

> +err_ida:

> +	kfree(dev->vqs);

> +err_vqs:

> +	vduse_domain_destroy(dev->domain);

> +err_domain:

> +	vduse_dev_destroy(dev);

> +	return ret;

> +}

> +

> +static long vduse_ioctl(struct file *file, unsigned int cmd,

> +			unsigned long arg)

> +{

> +	int ret;

> +	void __user *argp = (void __user *)arg;

> +	struct vduse_control *control = file->private_data;

> +

> +	mutex_lock(&vduse_lock);

> +	switch (cmd) {

> +	case VDUSE_GET_API_VERSION:

> +		ret = control->api_version;

> +		break;

> +	case VDUSE_SET_API_VERSION:

> +		ret = -EINVAL;

> +		if (arg > VDUSE_API_VERSION)

> +			break;

> +

> +		ret = 0;

> +		control->api_version = arg;

> +		break;

> +	case VDUSE_CREATE_DEV: {

> +		struct vduse_dev_config config;

> +

> +		ret = -EFAULT;

> +		if (copy_from_user(&config, argp, sizeof(config)))

> +			break;

> +

> +		ret = vduse_create_dev(&config, control->api_version);

> +		break;

> +	}

> +	case VDUSE_DESTROY_DEV: {

> +		char name[VDUSE_NAME_MAX];

> +

> +		ret = -EFAULT;

> +		if (copy_from_user(name, argp, VDUSE_NAME_MAX))

> +			break;

> +

> +		ret = vduse_destroy_dev(name);

> +		break;

> +	}

> +	default:

> +		ret = -EINVAL;

> +		break;

> +	}

> +	mutex_unlock(&vduse_lock);

> +

> +	return ret;

> +}

> +

> +static int vduse_release(struct inode *inode, struct file *file)

> +{

> +	struct vduse_control *control = file->private_data;

> +

> +	kfree(control);

> +	return 0;

> +}

> +

> +static int vduse_open(struct inode *inode, struct file *file)

> +{

> +	struct vduse_control *control;

> +

> +	control = kmalloc(sizeof(struct vduse_control), GFP_KERNEL);

> +	if (!control)

> +		return -ENOMEM;

> +

> +	control->api_version = VDUSE_API_VERSION;

> +	file->private_data = control;

> +

> +	return 0;

> +}

> +

> +static const struct file_operations vduse_fops = {

> +	.owner		= THIS_MODULE,

> +	.open		= vduse_open,

> +	.release	= vduse_release,

> +	.unlocked_ioctl	= vduse_ioctl,

> +	.compat_ioctl	= compat_ptr_ioctl,

> +	.llseek		= noop_llseek,

> +};

> +

> +static char *vduse_devnode(struct device *dev, umode_t *mode)

> +{

> +	return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));

> +}

> +

> +static struct miscdevice vduse_misc = {

> +	.fops = &vduse_fops,

> +	.minor = MISC_DYNAMIC_MINOR,

> +	.name = "vduse",

> +	.nodename = "vduse/control",

> +};

> +

> +static void vduse_mgmtdev_release(struct device *dev)

> +{

> +}

> +

> +static struct device vduse_mgmtdev = {

> +	.init_name = "vduse",

> +	.release = vduse_mgmtdev_release,

> +};

> +

> +static struct vdpa_mgmt_dev mgmt_dev;

> +

> +static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)

> +{

> +	struct vduse_vdpa *vdev;

> +	int ret;

> +

> +	if (dev->vdev)

> +		return -EEXIST;

> +

> +	vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, &dev->dev,

> +				 &vduse_vdpa_config_ops, name, true);

> +	if (!vdev)

> +		return -ENOMEM;

> +

> +	dev->vdev = vdev;

> +	vdev->dev = dev;

> +	vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;

> +	ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));

> +	if (ret) {

> +		put_device(&vdev->vdpa.dev);

> +		return ret;

> +	}

> +	set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);

> +	vdev->vdpa.dma_dev = &vdev->vdpa.dev;

> +	vdev->vdpa.mdev = &mgmt_dev;

> +

> +	return 0;

> +}

> +

> +static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)

> +{

> +	struct vduse_dev *dev;

> +	int ret = -EINVAL;

> +

> +	mutex_lock(&vduse_lock);

> +	dev = vduse_find_dev(name);

> +	if (!dev) {

> +		mutex_unlock(&vduse_lock);

> +		return -EINVAL;

> +	}

> +	ret = vduse_dev_init_vdpa(dev, name);

> +	mutex_unlock(&vduse_lock);

> +	if (ret)

> +		return ret;

> +

> +	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);

> +	if (ret) {

> +		put_device(&dev->vdev->vdpa.dev);

> +		return ret;

> +	}

> +

> +	return 0;

> +}

> +

> +static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)

> +{

> +	_vdpa_unregister_device(dev);

> +}

> +

> +static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {

> +	.dev_add = vdpa_dev_add,

> +	.dev_del = vdpa_dev_del,

> +};

> +

> +static struct virtio_device_id id_table[] = {

> +	{ VIRTIO_DEV_ANY_ID, VIRTIO_DEV_ANY_ID },

> +	{ 0 },

> +};

> +

> +static struct vdpa_mgmt_dev mgmt_dev = {

> +	.device = &vduse_mgmtdev,

> +	.id_table = id_table,

> +	.ops = &vdpa_dev_mgmtdev_ops,

> +};

> +

> +static int vduse_mgmtdev_init(void)

> +{

> +	int ret;

> +

> +	ret = device_register(&vduse_mgmtdev);

> +	if (ret)

> +		return ret;

> +

> +	ret = vdpa_mgmtdev_register(&mgmt_dev);

> +	if (ret)

> +		goto err;

> +

> +	return 0;

> +err:

> +	device_unregister(&vduse_mgmtdev);

> +	return ret;

> +}

> +

> +static void vduse_mgmtdev_exit(void)

> +{

> +	vdpa_mgmtdev_unregister(&mgmt_dev);

> +	device_unregister(&vduse_mgmtdev);

> +}

> +

> +static int vduse_init(void)

> +{

> +	int ret;

> +

> +	if (max_bounce_size >= max_iova_size)

> +		return -EINVAL;

> +

> +	ret = misc_register(&vduse_misc);

> +	if (ret)

> +		return ret;

> +

> +	vduse_class = class_create(THIS_MODULE, "vduse");

> +	if (IS_ERR(vduse_class)) {

> +		ret = PTR_ERR(vduse_class);

> +		goto err_class;

> +	}

> +	vduse_class->devnode = vduse_devnode;

> +

> +	ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");

> +	if (ret)

> +		goto err_chardev;

> +

> +	vduse_irq_wq = alloc_workqueue("vduse-irq",

> +				WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);

> +	if (!vduse_irq_wq)

> +		goto err_wq;

> +

> +	ret = vduse_domain_init();

> +	if (ret)

> +		goto err_domain;

> +

> +	ret = vduse_mgmtdev_init();

> +	if (ret)

> +		goto err_mgmtdev;

> +

> +	return 0;

> +err_mgmtdev:

> +	vduse_domain_exit();

> +err_domain:

> +	destroy_workqueue(vduse_irq_wq);

> +err_wq:

> +	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);

> +err_chardev:

> +	class_destroy(vduse_class);

> +err_class:

> +	misc_deregister(&vduse_misc);

> +	return ret;

> +}

> +module_init(vduse_init);

> +

> +static void vduse_exit(void)

> +{

> +	misc_deregister(&vduse_misc);

> +	class_destroy(vduse_class);

> +	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);

> +	destroy_workqueue(vduse_irq_wq);

> +	vduse_domain_exit();

> +	vduse_mgmtdev_exit();

> +}

> +module_exit(vduse_exit);

> +

> +MODULE_VERSION(DRV_VERSION);

> +MODULE_LICENSE(DRV_LICENSE);

> +MODULE_AUTHOR(DRV_AUTHOR);

> +MODULE_DESCRIPTION(DRV_DESC);

> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h

> new file mode 100644

> index 000000000000..66a6e5212226

> --- /dev/null

> +++ b/include/uapi/linux/vduse.h

> @@ -0,0 +1,175 @@

> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */

> +#ifndef _UAPI_VDUSE_H_

> +#define _UAPI_VDUSE_H_

> +

> +#include <linux/types.h>

> +

> +#define VDUSE_API_VERSION	0

> +

> +#define VDUSE_CONFIG_DATA_LEN	256

> +#define VDUSE_NAME_MAX	256

> +

> +/* the control messages definition for read/write */

> +

> +enum vduse_req_type {

> +	/* Set the vring address of virtqueue. */

> +	VDUSE_SET_VQ_NUM,

> +	/* Set the vring address of virtqueue. */

> +	VDUSE_SET_VQ_ADDR,

> +	/* Set ready status of virtqueue */

> +	VDUSE_SET_VQ_READY,

> +	/* Get ready status of virtqueue */

> +	VDUSE_GET_VQ_READY,

> +	/* Set the state for virtqueue */

> +	VDUSE_SET_VQ_STATE,

> +	/* Get the state for virtqueue */

> +	VDUSE_GET_VQ_STATE,

> +	/* Set virtio features supported by the driver */

> +	VDUSE_SET_FEATURES,

> +	/* Get virtio features supported by the device */

> +	VDUSE_GET_FEATURES,

> +	/* Set the device status */

> +	VDUSE_SET_STATUS,

> +	/* Get the device status */

> +	VDUSE_GET_STATUS,

> +	/* Write to device specific configuration space */

> +	VDUSE_SET_CONFIG,

> +	/* Read from device specific configuration space */

> +	VDUSE_GET_CONFIG,

> +	/* Notify userspace to update the memory mapping in device IOTLB */

> +	VDUSE_UPDATE_IOTLB,

> +};

> +

> +struct vduse_vq_num {

> +	__u32 index; /* virtqueue index */



I think it's better to have a consistent style of the doc/comment. If 
yes, let's move those comment above the field.


> +	__u32 num; /* the size of virtqueue */

> +};

> +

> +struct vduse_vq_addr {

> +	__u32 index; /* virtqueue index */

> +	__u64 desc_addr; /* address of desc area */

> +	__u64 driver_addr; /* address of driver area */

> +	__u64 device_addr; /* address of device area */

> +};

> +

> +struct vduse_vq_ready {

> +	__u32 index; /* virtqueue index */

> +	__u8 ready; /* ready status of virtqueue */

> +};

> +

> +struct vduse_vq_state {

> +	__u32 index; /* virtqueue index */

> +	__u16 avail_idx; /* virtqueue state (last_avail_idx) */



Let's use __u64 here to be consistent with get_vq_state(). The idea is 
to support packed virtqueue.


> +};

> +

> +struct vduse_dev_config_data {

> +	__u32 offset; /* offset from the beginning of config space */

> +	__u32 len; /* the length to read/write */

> +	__u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */



Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can 
not change it in the future.

So this might suffcient for future features or all type of virtio devices.


> +};

> +

> +struct vduse_iova_range {

> +	__u64 start; /* start of the IOVA range */

> +	__u64 last; /* end of the IOVA range */

> +};

> +

> +struct vduse_features {

> +	__u64 features; /* virtio features */

> +};

> +

> +struct vduse_status {

> +	__u8 status; /* device status */

> +};

> +

> +struct vduse_dev_request {

> +	__u32 type; /* request type */

> +	__u32 request_id; /* request id */

> +	__u32 reserved[2]; /* for future use */

> +	union {

> +		struct vduse_vq_num vq_num; /* virtqueue num */

> +		struct vduse_vq_addr vq_addr; /* virtqueue address */

> +		struct vduse_vq_ready vq_ready; /* virtqueue ready status */

> +		struct vduse_vq_state vq_state; /* virtqueue state */

> +		struct vduse_dev_config_data config; /* virtio device config space */

> +		struct vduse_iova_range iova; /* iova range for updating */

> +		struct vduse_features f; /* virtio features */

> +		struct vduse_status s; /* device status */

> +		__u32 padding[16]; /* padding */

> +	};

> +};

> +

> +struct vduse_dev_response {

> +	__u32 request_id; /* corresponding request id */

> +#define VDUSE_REQUEST_OK	0x00

> +#define VDUSE_REQUEST_FAILED	0x01

> +	__u32 result; /* the result of request */

> +	__u32 reserved[2]; /* for future use */

> +	union {

> +		struct vduse_vq_ready vq_ready; /* virtqueue ready status */

> +		struct vduse_vq_state vq_state; /* virtqueue state */

> +		struct vduse_dev_config_data config; /* virtio device config space */

> +		struct vduse_features f; /* virtio features */

> +		struct vduse_status s; /* device status */

> +		__u32 padding[16]; /* padding */



So it looks to me this padding doesn't work since vduse_dev_config_data 
is larger than it.


> +	};

> +};

> +

> +/* ioctls */

> +

> +struct vduse_dev_config {

> +	char name[VDUSE_NAME_MAX]; /* vduse device name */

> +	__u32 vendor_id; /* virtio vendor id */

> +	__u32 device_id; /* virtio device id */

> +	__u64 bounce_size; /* bounce buffer size for iommu */

> +	__u16 vq_num; /* the number of virtqueues */

> +	__u16 vq_size_max; /* the max size of virtqueue */

> +	__u32 vq_align; /* the allocation alignment of virtqueue's metadata */

> +	__u32 reserved[8]; /* for future use */



Is there a hole before reserved?


> +};

> +

> +struct vduse_iotlb_entry {

> +	__u64 offset; /* the mmap offset on fd */

> +	__u64 start; /* start of the IOVA range */

> +	__u64 last; /* last of the IOVA range */

> +#define VDUSE_ACCESS_RO 0x1

> +#define VDUSE_ACCESS_WO 0x2

> +#define VDUSE_ACCESS_RW 0x3

> +	__u8 perm; /* access permission of this range */

> +};

> +

> +struct vduse_vq_eventfd {

> +	__u32 index; /* virtqueue index */

> +#define VDUSE_EVENTFD_DEASSIGN -1

> +	int fd; /* eventfd, -1 means de-assigning the eventfd */

> +};

> +

> +#define VDUSE_BASE	0x81

> +

> +/* Get the version of VDUSE API. This is used for future extension */

> +#define VDUSE_GET_API_VERSION	_IO(VDUSE_BASE, 0x00)

> +

> +/* Set the version of VDUSE API. */

> +#define VDUSE_SET_API_VERSION	_IO(VDUSE_BASE, 0x01)

> +

> +/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */

> +#define VDUSE_CREATE_DEV	_IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)

> +

> +/* Destroy a vduse device. Make sure there are no references to the char device */

> +#define VDUSE_DESTROY_DEV	_IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])

> +

> +/*

> + * Get a file descriptor for the first overlapped iova region,

> + * -EINVAL means the iova region doesn't exist.

> + */

> +#define VDUSE_IOTLB_GET_FD	_IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)

> +

> +/* Setup an eventfd to receive kick for virtqueue */

> +#define VDUSE_VQ_SETUP_KICKFD	_IOW(VDUSE_BASE, 0x05, struct vduse_vq_eventfd)

> +

> +/* Inject an interrupt for specific virtqueue */

> +#define VDUSE_INJECT_VQ_IRQ	_IO(VDUSE_BASE, 0x06)



Missing parameter?

Thanks


> +

> +/* Inject a config interrupt */

> +#define VDUSE_INJECT_CONFIG_IRQ	_IO(VDUSE_BASE, 0x07)

> +

> +#endif /* _UAPI_VDUSE_H_ */
Yongji Xie April 8, 2021, 9:36 a.m. UTC | #4
On Thu, Apr 8, 2021 at 2:57 PM Jason Wang <jasowang@redhat.com> wrote:
>

>

> 在 2021/3/31 下午4:05, Xie Yongji 写道:

> > This VDUSE driver enables implementing vDPA devices in userspace.

> > Both control path and data path of vDPA devices will be able to

> > be handled in userspace.

> >

> > In the control path, the VDUSE driver will make use of message

> > mechnism to forward the config operation from vdpa bus driver

> > to userspace. Userspace can use read()/write() to receive/reply

> > those control messages.

> >

> > In the data path, VDUSE_IOTLB_GET_FD ioctl will be used to get

> > the file descriptors referring to vDPA device's iova regions. Then

> > userspace can use mmap() to access those iova regions. Besides,

> > userspace can use ioctl() to inject interrupt and use the eventfd

> > mechanism to receive virtqueue kicks.

> >

> > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>

> > ---

> >   Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +

> >   drivers/vdpa/Kconfig                               |   10 +

> >   drivers/vdpa/Makefile                              |    1 +

> >   drivers/vdpa/vdpa_user/Makefile                    |    5 +

> >   drivers/vdpa/vdpa_user/vduse_dev.c                 | 1362 ++++++++++++++++++++

> >   include/uapi/linux/vduse.h                         |  175 +++

> >   6 files changed, 1554 insertions(+)

> >   create mode 100644 drivers/vdpa/vdpa_user/Makefile

> >   create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c

> >   create mode 100644 include/uapi/linux/vduse.h

> >

> > diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst

> > index a4c75a28c839..71722e6f8f23 100644

> > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst

> > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst

> > @@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments

> >   'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!

> >   '|'   00-7F  linux/media.h

> >   0x80  00-1F  linux/fb.h

> > +0x81  00-1F  linux/vduse.h

> >   0x89  00-06  arch/x86/include/asm/sockios.h

> >   0x89  0B-DF  linux/sockios.h

> >   0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range

> > diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig

> > index a245809c99d0..77a1da522c21 100644

> > --- a/drivers/vdpa/Kconfig

> > +++ b/drivers/vdpa/Kconfig

> > @@ -25,6 +25,16 @@ config VDPA_SIM_NET

> >       help

> >         vDPA networking device simulator which loops TX traffic back to RX.

> >

> > +config VDPA_USER

> > +     tristate "VDUSE (vDPA Device in Userspace) support"

> > +     depends on EVENTFD && MMU && HAS_DMA

> > +     select DMA_OPS

> > +     select VHOST_IOTLB

> > +     select IOMMU_IOVA

> > +     help

> > +       With VDUSE it is possible to emulate a vDPA Device

> > +       in a userspace program.

> > +

> >   config IFCVF

> >       tristate "Intel IFC VF vDPA driver"

> >       depends on PCI_MSI

> > diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile

> > index 67fe7f3d6943..f02ebed33f19 100644

> > --- a/drivers/vdpa/Makefile

> > +++ b/drivers/vdpa/Makefile

> > @@ -1,6 +1,7 @@

> >   # SPDX-License-Identifier: GPL-2.0

> >   obj-$(CONFIG_VDPA) += vdpa.o

> >   obj-$(CONFIG_VDPA_SIM) += vdpa_sim/

> > +obj-$(CONFIG_VDPA_USER) += vdpa_user/

> >   obj-$(CONFIG_IFCVF)    += ifcvf/

> >   obj-$(CONFIG_MLX5_VDPA) += mlx5/

> >   obj-$(CONFIG_VP_VDPA)    += virtio_pci/

> > diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile

> > new file mode 100644

> > index 000000000000..260e0b26af99

> > --- /dev/null

> > +++ b/drivers/vdpa/vdpa_user/Makefile

> > @@ -0,0 +1,5 @@

> > +# SPDX-License-Identifier: GPL-2.0

> > +

> > +vduse-y := vduse_dev.o iova_domain.o

> > +

> > +obj-$(CONFIG_VDPA_USER) += vduse.o

> > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c

> > new file mode 100644

> > index 000000000000..51ca73464d0d

> > --- /dev/null

> > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c

> > @@ -0,0 +1,1362 @@

> > +// SPDX-License-Identifier: GPL-2.0-only

> > +/*

> > + * VDUSE: vDPA Device in Userspace

> > + *

> > + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.

> > + *

> > + * Author: Xie Yongji <xieyongji@bytedance.com>

> > + *

> > + */

> > +

> > +#include <linux/init.h>

> > +#include <linux/module.h>

> > +#include <linux/miscdevice.h>

> > +#include <linux/cdev.h>

> > +#include <linux/device.h>

> > +#include <linux/eventfd.h>

> > +#include <linux/slab.h>

> > +#include <linux/wait.h>

> > +#include <linux/dma-map-ops.h>

> > +#include <linux/poll.h>

> > +#include <linux/file.h>

> > +#include <linux/uio.h>

> > +#include <linux/vdpa.h>

> > +#include <uapi/linux/vduse.h>

> > +#include <uapi/linux/vdpa.h>

> > +#include <uapi/linux/virtio_config.h>

> > +#include <linux/mod_devicetable.h>

> > +

> > +#include "iova_domain.h"

> > +

> > +#define DRV_VERSION  "1.0"

> > +#define DRV_AUTHOR   "Yongji Xie <xieyongji@bytedance.com>"

> > +#define DRV_DESC     "vDPA Device in Userspace"

> > +#define DRV_LICENSE  "GPL v2"

> > +

> > +#define VDUSE_DEV_MAX (1U << MINORBITS)

> > +

> > +struct vduse_virtqueue {

> > +     u16 index;

> > +     bool ready;

> > +     spinlock_t kick_lock;

> > +     spinlock_t irq_lock;

> > +     struct eventfd_ctx *kickfd;

> > +     struct vdpa_callback cb;

> > +     struct work_struct inject;

> > +};

> > +

> > +struct vduse_dev;

> > +

> > +struct vduse_vdpa {

> > +     struct vdpa_device vdpa;

> > +     struct vduse_dev *dev;

> > +};

> > +

> > +struct vduse_dev {

> > +     struct vduse_vdpa *vdev;

> > +     struct device dev;

> > +     struct cdev cdev;

> > +     struct vduse_virtqueue *vqs;

> > +     struct vduse_iova_domain *domain;

> > +     struct mutex lock;

> > +     spinlock_t msg_lock;

> > +     atomic64_t msg_unique;

> > +     wait_queue_head_t waitq;

> > +     struct list_head send_list;

> > +     struct list_head recv_list;

> > +     struct list_head list;

> > +     struct vdpa_callback config_cb;

> > +     spinlock_t irq_lock;

> > +     unsigned long api_version;

> > +     bool connected;

> > +     int minor;

> > +     u16 vq_size_max;

> > +     u16 vq_num;

> > +     u32 vq_align;

> > +     u32 device_id;

> > +     u32 vendor_id;

> > +};

> > +

> > +struct vduse_dev_msg {

> > +     struct vduse_dev_request req;

> > +     struct vduse_dev_response resp;

> > +     struct list_head list;

> > +     wait_queue_head_t waitq;

> > +     bool completed;

> > +};

> > +

> > +struct vduse_control {

> > +     unsigned long api_version;

> > +};

> > +

> > +static unsigned long max_bounce_size = (64 * 1024 * 1024);

> > +module_param(max_bounce_size, ulong, 0444);

> > +MODULE_PARM_DESC(max_bounce_size, "Maximum bounce buffer size. (default: 64M)");

> > +

> > +static unsigned long max_iova_size = (128 * 1024 * 1024);

> > +module_param(max_iova_size, ulong, 0444);

> > +MODULE_PARM_DESC(max_iova_size, "Maximum iova space size (default: 128M)");

> > +

> > +static DEFINE_MUTEX(vduse_lock);

> > +static LIST_HEAD(vduse_devs);

> > +static DEFINE_IDA(vduse_ida);

> > +

> > +static dev_t vduse_major;

> > +static struct class *vduse_class;

> > +static struct workqueue_struct *vduse_irq_wq;

> > +

> > +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)

> > +{

> > +     struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);

> > +

> > +     return vdev->dev;

> > +}

> > +

> > +static inline struct vduse_dev *dev_to_vduse(struct device *dev)

> > +{

> > +     struct vdpa_device *vdpa = dev_to_vdpa(dev);

> > +

> > +     return vdpa_to_vduse(vdpa);

> > +}

> > +

> > +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,

> > +                                         uint32_t request_id)

> > +{

> > +     struct vduse_dev_msg *tmp, *msg = NULL;

> > +

> > +     list_for_each_entry(tmp, head, list) {

> > +             if (tmp->req.request_id == request_id) {

> > +                     msg = tmp;

> > +                     list_del(&tmp->list);

> > +                     break;

> > +             }

> > +     }

> > +

> > +     return msg;

> > +}

> > +

> > +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)

> > +{

> > +     struct vduse_dev_msg *msg = NULL;

> > +

> > +     if (!list_empty(head)) {

> > +             msg = list_first_entry(head, struct vduse_dev_msg, list);

> > +             list_del(&msg->list);

> > +     }

> > +

> > +     return msg;

> > +}

> > +

> > +static void vduse_enqueue_msg(struct list_head *head,

> > +                           struct vduse_dev_msg *msg)

> > +{

> > +     list_add_tail(&msg->list, head);

> > +}

> > +

> > +static int vduse_dev_msg_sync(struct vduse_dev *dev,

> > +                           struct vduse_dev_msg *msg)

> > +{

> > +     init_waitqueue_head(&msg->waitq);

> > +     spin_lock(&dev->msg_lock);

> > +     vduse_enqueue_msg(&dev->send_list, msg);

> > +     wake_up(&dev->waitq);

> > +     spin_unlock(&dev->msg_lock);

> > +     wait_event_interruptible(msg->waitq, msg->completed);

> > +     spin_lock(&dev->msg_lock);

> > +     if (!msg->completed)

> > +             list_del(&msg->list);

> > +     spin_unlock(&dev->msg_lock);

> > +

> > +     return (msg->resp.result == VDUSE_REQUEST_OK) ? 0 : -1;

> > +}

> > +

> > +static u32 vduse_dev_get_request_id(struct vduse_dev *dev)

> > +{

> > +     return atomic64_fetch_inc(&dev->msg_unique);

> > +}

> > +

> > +static u64 vduse_dev_get_features(struct vduse_dev *dev)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_GET_FEATURES;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +

> > +     return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.f.features;

> > +}

> > +

> > +static int vduse_dev_set_features(struct vduse_dev *dev, u64 features)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_SET_FEATURES;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.f.features = features;

> > +

> > +     return vduse_dev_msg_sync(dev, &msg);

> > +}

> > +

> > +static u8 vduse_dev_get_status(struct vduse_dev *dev)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_GET_STATUS;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +

> > +     return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.s.status;

> > +}

> > +

> > +static void vduse_dev_set_status(struct vduse_dev *dev, u8 status)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_SET_STATUS;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.s.status = status;

> > +

> > +     vduse_dev_msg_sync(dev, &msg);

> > +}

> > +

> > +static void vduse_dev_get_config(struct vduse_dev *dev, unsigned int offset,

> > +                              void *buf, unsigned int len)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +     unsigned int sz;

> > +

> > +     while (len) {

> > +             sz = min_t(unsigned int, len, sizeof(msg.req.config.data));

> > +             msg.req.type = VDUSE_GET_CONFIG;

> > +             msg.req.request_id = vduse_dev_get_request_id(dev);

> > +             msg.req.config.offset = offset;

> > +             msg.req.config.len = sz;

> > +             vduse_dev_msg_sync(dev, &msg);

> > +             memcpy(buf, msg.resp.config.data, sz);

> > +             buf += sz;

> > +             offset += sz;

> > +             len -= sz;

> > +     }

> > +}

> > +

> > +static void vduse_dev_set_config(struct vduse_dev *dev, unsigned int offset,

> > +                              const void *buf, unsigned int len)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +     unsigned int sz;

> > +

> > +     while (len) {

> > +             sz = min_t(unsigned int, len, sizeof(msg.req.config.data));

> > +             msg.req.type = VDUSE_SET_CONFIG;

> > +             msg.req.request_id = vduse_dev_get_request_id(dev);

> > +             msg.req.config.offset = offset;

> > +             msg.req.config.len = sz;

> > +             memcpy(msg.req.config.data, buf, sz);

> > +             vduse_dev_msg_sync(dev, &msg);

> > +             buf += sz;

> > +             offset += sz;

> > +             len -= sz;

> > +     }

> > +}

> > +

> > +static void vduse_dev_set_vq_num(struct vduse_dev *dev,

> > +                              struct vduse_virtqueue *vq, u32 num)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_SET_VQ_NUM;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.vq_num.index = vq->index;

> > +     msg.req.vq_num.num = num;

> > +

> > +     vduse_dev_msg_sync(dev, &msg);

> > +}

> > +

> > +static int vduse_dev_set_vq_addr(struct vduse_dev *dev,

> > +                              struct vduse_virtqueue *vq, u64 desc_addr,

> > +                              u64 driver_addr, u64 device_addr)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_SET_VQ_ADDR;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.vq_addr.index = vq->index;

> > +     msg.req.vq_addr.desc_addr = desc_addr;

> > +     msg.req.vq_addr.driver_addr = driver_addr;

> > +     msg.req.vq_addr.device_addr = device_addr;

> > +

> > +     return vduse_dev_msg_sync(dev, &msg);

> > +}

> > +

> > +static void vduse_dev_set_vq_ready(struct vduse_dev *dev,

> > +                             struct vduse_virtqueue *vq, bool ready)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_SET_VQ_READY;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.vq_ready.index = vq->index;

> > +     msg.req.vq_ready.ready = ready;

> > +

> > +     vduse_dev_msg_sync(dev, &msg);

> > +}

> > +

> > +static bool vduse_dev_get_vq_ready(struct vduse_dev *dev,

> > +                                struct vduse_virtqueue *vq)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_GET_VQ_READY;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.vq_ready.index = vq->index;

> > +

> > +     return vduse_dev_msg_sync(dev, &msg) ? false : msg.resp.vq_ready.ready;

> > +}

> > +

> > +static int vduse_dev_get_vq_state(struct vduse_dev *dev,

> > +                             struct vduse_virtqueue *vq,

> > +                             struct vdpa_vq_state *state)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +     int ret;

> > +

> > +     msg.req.type = VDUSE_GET_VQ_STATE;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.vq_state.index = vq->index;

> > +

> > +     ret = vduse_dev_msg_sync(dev, &msg);

> > +     if (!ret)

> > +             state->avail_index = msg.resp.vq_state.avail_idx;

> > +

> > +     return ret;

> > +}

> > +

> > +static int vduse_dev_set_vq_state(struct vduse_dev *dev,

> > +                             struct vduse_virtqueue *vq,

> > +                             const struct vdpa_vq_state *state)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     msg.req.type = VDUSE_SET_VQ_STATE;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.vq_state.index = vq->index;

> > +     msg.req.vq_state.avail_idx = state->avail_index;

> > +

> > +     return vduse_dev_msg_sync(dev, &msg);

> > +}

> > +

> > +static int vduse_dev_update_iotlb(struct vduse_dev *dev,

> > +                             u64 start, u64 last)

> > +{

> > +     struct vduse_dev_msg msg = { 0 };

> > +

> > +     if (last < start)

> > +             return -EINVAL;

> > +

> > +     msg.req.type = VDUSE_UPDATE_IOTLB;

> > +     msg.req.request_id = vduse_dev_get_request_id(dev);

> > +     msg.req.iova.start = start;

> > +     msg.req.iova.last = last;

> > +

> > +     return vduse_dev_msg_sync(dev, &msg);

> > +}

> > +

> > +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)

> > +{

> > +     struct file *file = iocb->ki_filp;

> > +     struct vduse_dev *dev = file->private_data;

> > +     struct vduse_dev_msg *msg;

> > +     int size = sizeof(struct vduse_dev_request);

> > +     ssize_t ret = 0;

> > +

> > +     if (iov_iter_count(to) < size)

> > +             return 0;

> > +

> > +     spin_lock(&dev->msg_lock);

> > +     while (1) {

> > +             msg = vduse_dequeue_msg(&dev->send_list);

> > +             if (msg)

> > +                     break;

> > +

> > +             ret = -EAGAIN;

> > +             if (file->f_flags & O_NONBLOCK)

> > +                     goto unlock;

> > +

> > +             spin_unlock(&dev->msg_lock);

> > +             ret = wait_event_interruptible_exclusive(dev->waitq,

> > +                                     !list_empty(&dev->send_list));

> > +             if (ret)

> > +                     return ret;

> > +

> > +             spin_lock(&dev->msg_lock);

> > +     }

> > +     spin_unlock(&dev->msg_lock);

> > +     ret = copy_to_iter(&msg->req, size, to);

> > +     spin_lock(&dev->msg_lock);

> > +     if (ret != size) {

> > +             ret = -EFAULT;

> > +             vduse_enqueue_msg(&dev->send_list, msg);

> > +             goto unlock;

> > +     }

> > +     vduse_enqueue_msg(&dev->recv_list, msg);

> > +     wake_up(&dev->waitq);

> > +unlock:

> > +     spin_unlock(&dev->msg_lock);

> > +

> > +     return ret;

> > +}

> > +

> > +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)

> > +{

> > +     struct file *file = iocb->ki_filp;

> > +     struct vduse_dev *dev = file->private_data;

> > +     struct vduse_dev_response resp;

> > +     struct vduse_dev_msg *msg;

> > +     size_t ret;

> > +

> > +     ret = copy_from_iter(&resp, sizeof(resp), from);

> > +     if (ret != sizeof(resp))

> > +             return -EINVAL;

> > +

> > +     spin_lock(&dev->msg_lock);

> > +     msg = vduse_find_msg(&dev->recv_list, resp.request_id);

> > +     if (!msg) {

> > +             ret = -EINVAL;

> > +             goto unlock;

> > +     }

> > +

> > +     memcpy(&msg->resp, &resp, sizeof(resp));

> > +     msg->completed = 1;

> > +     wake_up(&msg->waitq);

> > +unlock:

> > +     spin_unlock(&dev->msg_lock);

> > +

> > +     return ret;

> > +}

> > +

> > +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)

> > +{

> > +     struct vduse_dev *dev = file->private_data;

> > +     __poll_t mask = 0;

> > +

> > +     poll_wait(file, &dev->waitq, wait);

> > +

> > +     if (!list_empty(&dev->send_list))

> > +             mask |= EPOLLIN | EPOLLRDNORM;

> > +     if (!list_empty(&dev->recv_list))

> > +             mask |= EPOLLOUT;

> > +

> > +     return mask;

> > +}

> > +

> > +static void vduse_dev_reset(struct vduse_dev *dev)

> > +{

> > +     int i;

> > +

> > +     /* The coherent mappings are handled in vduse_dev_free_coherent() */

> > +     vduse_domain_reset_bounce_map(dev->domain);

> > +     vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);

> > +

> > +     spin_lock(&dev->irq_lock);

> > +     dev->config_cb.callback = NULL;

> > +     dev->config_cb.private = NULL;

> > +     spin_unlock(&dev->irq_lock);

> > +

> > +     for (i = 0; i < dev->vq_num; i++) {

> > +             struct vduse_virtqueue *vq = &dev->vqs[i];

> > +

> > +             spin_lock(&vq->irq_lock);

> > +             vq->ready = false;

> > +             vq->cb.callback = NULL;

> > +             vq->cb.private = NULL;

> > +             spin_unlock(&vq->irq_lock);

> > +     }

> > +}

> > +

> > +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,

> > +                             u64 desc_area, u64 driver_area,

> > +                             u64 device_area)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> > +

> > +     return vduse_dev_set_vq_addr(dev, vq, desc_area,

> > +                                     driver_area, device_area);

> > +}

> > +

> > +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> > +

> > +     spin_lock(&vq->kick_lock);

> > +     if (vq->ready && vq->kickfd)

> > +             eventfd_signal(vq->kickfd, 1);

> > +     spin_unlock(&vq->kick_lock);

> > +}

> > +

> > +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,

> > +                           struct vdpa_callback *cb)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> > +

> > +     spin_lock(&vq->irq_lock);

> > +     vq->cb.callback = cb->callback;

> > +     vq->cb.private = cb->private;

> > +     spin_unlock(&vq->irq_lock);

> > +}

> > +

> > +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> > +

> > +     vduse_dev_set_vq_num(dev, vq, num);

> > +}

> > +

> > +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,

> > +                                     u16 idx, bool ready)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> > +

> > +     vduse_dev_set_vq_ready(dev, vq, ready);

> > +     vq->ready = ready;

> > +}

> > +

> > +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> > +

> > +     vq->ready = vduse_dev_get_vq_ready(dev, vq);

> > +

> > +     return vq->ready;

> > +}

> > +

> > +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,

> > +                             const struct vdpa_vq_state *state)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> > +

> > +     return vduse_dev_set_vq_state(dev, vq, state);

> > +}

> > +

> > +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,

> > +                             struct vdpa_vq_state *state)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> > +

> > +     return vduse_dev_get_vq_state(dev, vq, state);

> > +}

> > +

> > +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     return dev->vq_align;

> > +}

> > +

> > +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     return vduse_dev_get_features(dev);

> > +}

> > +

> > +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))

> > +             return -EINVAL;

> > +

> > +     return vduse_dev_set_features(dev, features);

> > +}

> > +

> > +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,

> > +                               struct vdpa_callback *cb)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     spin_lock(&dev->irq_lock);

> > +     dev->config_cb.callback = cb->callback;

> > +     dev->config_cb.private = cb->private;

> > +     spin_unlock(&dev->irq_lock);

> > +}

> > +

> > +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     return dev->vq_size_max;

> > +}

> > +

> > +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     return dev->device_id;

> > +}

> > +

> > +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     return dev->vendor_id;

> > +}

> > +

> > +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     return vduse_dev_get_status(dev);

> > +}

> > +

> > +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     vduse_dev_set_status(dev, status);

> > +

> > +     if (status == 0)

> > +             vduse_dev_reset(dev);

> > +}

> > +

> > +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,

> > +                          void *buf, unsigned int len)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     vduse_dev_get_config(dev, offset, buf, len);

> > +}

> > +

> > +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,

> > +                     const void *buf, unsigned int len)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     vduse_dev_set_config(dev, offset, buf, len);

> > +}

> > +

> > +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,

> > +                             struct vhost_iotlb *iotlb)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +     int ret;

> > +

> > +     ret = vduse_domain_set_map(dev->domain, iotlb);

> > +     vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);

> > +

> > +     return ret;

> > +}

> > +

> > +static void vduse_vdpa_free(struct vdpa_device *vdpa)

> > +{

> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> > +

> > +     WARN_ON(!list_empty(&dev->send_list));

> > +     WARN_ON(!list_empty(&dev->recv_list));

> > +     dev->vdev = NULL;

> > +}

> > +

> > +static const struct vdpa_config_ops vduse_vdpa_config_ops = {

> > +     .set_vq_address         = vduse_vdpa_set_vq_address,

> > +     .kick_vq                = vduse_vdpa_kick_vq,

> > +     .set_vq_cb              = vduse_vdpa_set_vq_cb,

> > +     .set_vq_num             = vduse_vdpa_set_vq_num,

> > +     .set_vq_ready           = vduse_vdpa_set_vq_ready,

> > +     .get_vq_ready           = vduse_vdpa_get_vq_ready,

> > +     .set_vq_state           = vduse_vdpa_set_vq_state,

> > +     .get_vq_state           = vduse_vdpa_get_vq_state,

> > +     .get_vq_align           = vduse_vdpa_get_vq_align,

> > +     .get_features           = vduse_vdpa_get_features,

> > +     .set_features           = vduse_vdpa_set_features,

> > +     .set_config_cb          = vduse_vdpa_set_config_cb,

> > +     .get_vq_num_max         = vduse_vdpa_get_vq_num_max,

> > +     .get_device_id          = vduse_vdpa_get_device_id,

> > +     .get_vendor_id          = vduse_vdpa_get_vendor_id,

> > +     .get_status             = vduse_vdpa_get_status,

> > +     .set_status             = vduse_vdpa_set_status,

> > +     .get_config             = vduse_vdpa_get_config,

> > +     .set_config             = vduse_vdpa_set_config,

> > +     .set_map                = vduse_vdpa_set_map,

> > +     .free                   = vduse_vdpa_free,

> > +};

> > +

> > +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,

> > +                                  unsigned long offset, size_t size,

> > +                                  enum dma_data_direction dir,

> > +                                  unsigned long attrs)

> > +{

> > +     struct vduse_dev *vdev = dev_to_vduse(dev);

> > +     struct vduse_iova_domain *domain = vdev->domain;

> > +

> > +     return vduse_domain_map_page(domain, page, offset, size, dir, attrs);

> > +}

> > +

> > +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,

> > +                             size_t size, enum dma_data_direction dir,

> > +                             unsigned long attrs)

> > +{

> > +     struct vduse_dev *vdev = dev_to_vduse(dev);

> > +     struct vduse_iova_domain *domain = vdev->domain;

> > +

> > +     return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);

> > +}

> > +

> > +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,

> > +                                     dma_addr_t *dma_addr, gfp_t flag,

> > +                                     unsigned long attrs)

> > +{

> > +     struct vduse_dev *vdev = dev_to_vduse(dev);

> > +     struct vduse_iova_domain *domain = vdev->domain;

> > +     unsigned long iova;

> > +     void *addr;

> > +

> > +     *dma_addr = DMA_MAPPING_ERROR;

> > +     addr = vduse_domain_alloc_coherent(domain, size,

> > +                             (dma_addr_t *)&iova, flag, attrs);

> > +     if (!addr)

> > +             return NULL;

> > +

> > +     *dma_addr = (dma_addr_t)iova;

> > +     vduse_dev_update_iotlb(vdev, iova, iova + size - 1);

> > +

> > +     return addr;

> > +}

> > +

> > +static void vduse_dev_free_coherent(struct device *dev, size_t size,

> > +                                     void *vaddr, dma_addr_t dma_addr,

> > +                                     unsigned long attrs)

> > +{

> > +     struct vduse_dev *vdev = dev_to_vduse(dev);

> > +     struct vduse_iova_domain *domain = vdev->domain;

> > +     unsigned long start = (unsigned long)dma_addr;

> > +     unsigned long last = start + size - 1;

> > +

> > +     vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);

> > +     vduse_dev_update_iotlb(vdev, start, last);

> > +}

> > +

> > +static const struct dma_map_ops vduse_dev_dma_ops = {

> > +     .map_page = vduse_dev_map_page,

> > +     .unmap_page = vduse_dev_unmap_page,

> > +     .alloc = vduse_dev_alloc_coherent,

> > +     .free = vduse_dev_free_coherent,

> > +};

> > +

> > +static unsigned int perm_to_file_flags(u8 perm)

> > +{

> > +     unsigned int flags = 0;

> > +

> > +     switch (perm) {

> > +     case VDUSE_ACCESS_WO:

> > +             flags |= O_WRONLY;

> > +             break;

> > +     case VDUSE_ACCESS_RO:

> > +             flags |= O_RDONLY;

> > +             break;

> > +     case VDUSE_ACCESS_RW:

> > +             flags |= O_RDWR;

> > +             break;

> > +     default:

> > +             WARN(1, "invalidate vhost IOTLB permission\n");

> > +             break;

> > +     }

> > +

> > +     return flags;

> > +}

> > +

> > +static int vduse_kickfd_setup(struct vduse_dev *dev,

> > +                     struct vduse_vq_eventfd *eventfd)

> > +{

> > +     struct eventfd_ctx *ctx = NULL;

> > +     struct vduse_virtqueue *vq;

> > +

> > +     if (eventfd->index >= dev->vq_num)

> > +             return -EINVAL;

> > +

> > +     vq = &dev->vqs[eventfd->index];

> > +     if (eventfd->fd > 0) {

> > +             ctx = eventfd_ctx_fdget(eventfd->fd);

> > +             if (IS_ERR(ctx))

> > +                     return PTR_ERR(ctx);

> > +     } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)

> > +             return 0;

>

>

> Do we allow the userspace to switch kickfd here? If yes, we need to deal

> with that.

>


Do you mean the case that eventfd->fd > 0? I think we have dealt with it.

>

> > +

> > +     spin_lock(&vq->kick_lock);

> > +     if (vq->kickfd)

> > +             eventfd_ctx_put(vq->kickfd);

> > +     vq->kickfd = ctx;

> > +     spin_unlock(&vq->kick_lock);

> > +

> > +     return 0;

> > +}

> > +

> > +static void vduse_vq_irq_inject(struct work_struct *work)

> > +{

> > +     struct vduse_virtqueue *vq = container_of(work,

> > +                                     struct vduse_virtqueue, inject);

> > +

> > +     spin_lock_irq(&vq->irq_lock);

> > +     if (vq->ready && vq->cb.callback)

> > +             vq->cb.callback(vq->cb.private);

> > +     spin_unlock_irq(&vq->irq_lock);

> > +}

> > +

> > +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,

> > +                         unsigned long arg)

> > +{

> > +     struct vduse_dev *dev = file->private_data;

> > +     void __user *argp = (void __user *)arg;

> > +     int ret;

> > +

> > +     switch (cmd) {

> > +     case VDUSE_IOTLB_GET_FD: {

> > +             struct vduse_iotlb_entry entry;

> > +             struct vhost_iotlb_map *map;

> > +             struct vdpa_map_file *map_file;

> > +             struct vduse_iova_domain *domain = dev->domain;

> > +             struct file *f = NULL;

> > +

> > +             ret = -EFAULT;

> > +             if (copy_from_user(&entry, argp, sizeof(entry)))

> > +                     break;

> > +

> > +             ret = -EINVAL;

> > +             if (entry.start > entry.last)

> > +                     break;

> > +

> > +             spin_lock(&domain->iotlb_lock);

> > +             map = vhost_iotlb_itree_first(domain->iotlb,

> > +                                           entry.start, entry.last);

> > +             if (map) {

> > +                     map_file = (struct vdpa_map_file *)map->opaque;

> > +                     f = get_file(map_file->file);

> > +                     entry.offset = map_file->offset;

> > +                     entry.start = map->start;

> > +                     entry.last = map->last;

> > +                     entry.perm = map->perm;

> > +             }

> > +             spin_unlock(&domain->iotlb_lock);

> > +             ret = -EINVAL;

> > +             if (!f)

> > +                     break;

> > +

> > +             ret = -EFAULT;

> > +             if (copy_to_user(argp, &entry, sizeof(entry))) {

> > +                     fput(f);

> > +                     break;

> > +             }

> > +             ret = receive_fd(f, perm_to_file_flags(entry.perm));

> > +             fput(f);

>

>

> Any reason to drop the refcnt here?

>


We will do get_file() in receive_fd() too.

>

> > +             break;

> > +     }

> > +     case VDUSE_VQ_SETUP_KICKFD: {

> > +             struct vduse_vq_eventfd eventfd;

> > +

> > +             ret = -EFAULT;

> > +             if (copy_from_user(&eventfd, argp, sizeof(eventfd)))

> > +                     break;

> > +

> > +             ret = vduse_kickfd_setup(dev, &eventfd);

> > +             break;

> > +     }

> > +     case VDUSE_INJECT_VQ_IRQ:

> > +             ret = -EINVAL;

> > +             if (arg >= dev->vq_num)

> > +                     break;

> > +

> > +             ret = 0;

> > +             queue_work(vduse_irq_wq, &dev->vqs[arg].inject);

> > +             break;

> > +     case VDUSE_INJECT_CONFIG_IRQ:

> > +             ret = -EINVAL;

> > +             spin_lock_irq(&dev->irq_lock);

> > +             if (dev->config_cb.callback) {

> > +                     dev->config_cb.callback(dev->config_cb.private);

> > +                     ret = 0;

> > +             }

> > +             spin_unlock_irq(&dev->irq_lock);

>

>

> For consistency, is it better to use vduse_irq_wq here?

>


Looks good to me.

>

> > +             break;

> > +     default:

> > +             ret = -ENOIOCTLCMD;

> > +             break;

> > +     }

> > +

> > +     return ret;

> > +}

> > +

> > +static int vduse_dev_release(struct inode *inode, struct file *file)

> > +{

> > +     struct vduse_dev *dev = file->private_data;

> > +     struct vduse_dev_msg *msg;

> > +     int i;

> > +

> > +     for (i = 0; i < dev->vq_num; i++) {

> > +             struct vduse_virtqueue *vq = &dev->vqs[i];

> > +

> > +             spin_lock(&vq->kick_lock);

> > +             if (vq->kickfd)

> > +                     eventfd_ctx_put(vq->kickfd);

> > +             vq->kickfd = NULL;

> > +             spin_unlock(&vq->kick_lock);

> > +     }

> > +

> > +     spin_lock(&dev->msg_lock);

> > +     /*  Make sure the inflight messages can processed */

>

>

> This might be better:

>

> /*  Make sure the inflight messages can processed after reconncection */

>


OK.

> > +     while ((msg = vduse_dequeue_msg(&dev->recv_list)))

> > +             vduse_enqueue_msg(&dev->send_list, msg);

> > +     spin_unlock(&dev->msg_lock);

> > +

> > +     dev->connected = false;

> > +

> > +     return 0;

> > +}

> > +

> > +static int vduse_dev_open(struct inode *inode, struct file *file)

> > +{

> > +     struct vduse_dev *dev = container_of(inode->i_cdev,

> > +                                     struct vduse_dev, cdev);

> > +     int ret = -EBUSY;

> > +

> > +     mutex_lock(&dev->lock);

> > +     if (dev->connected)

> > +             goto unlock;

> > +

> > +     ret = 0;

> > +     dev->connected = true;

> > +     file->private_data = dev;

> > +unlock:

> > +     mutex_unlock(&dev->lock);

> > +

> > +     return ret;

> > +}

> > +

> > +static const struct file_operations vduse_dev_fops = {

> > +     .owner          = THIS_MODULE,

> > +     .open           = vduse_dev_open,

> > +     .release        = vduse_dev_release,

> > +     .read_iter      = vduse_dev_read_iter,

> > +     .write_iter     = vduse_dev_write_iter,

> > +     .poll           = vduse_dev_poll,

> > +     .unlocked_ioctl = vduse_dev_ioctl,

> > +     .compat_ioctl   = compat_ptr_ioctl,

> > +     .llseek         = noop_llseek,

> > +};

> > +

> > +static struct vduse_dev *vduse_dev_create(void)

> > +{

> > +     struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);

> > +

> > +     if (!dev)

> > +             return NULL;

> > +

> > +     mutex_init(&dev->lock);

> > +     spin_lock_init(&dev->msg_lock);

> > +     INIT_LIST_HEAD(&dev->send_list);

> > +     INIT_LIST_HEAD(&dev->recv_list);

> > +     atomic64_set(&dev->msg_unique, 0);

> > +     spin_lock_init(&dev->irq_lock);

> > +

> > +     init_waitqueue_head(&dev->waitq);

> > +

> > +     return dev;

> > +}

> > +

> > +static void vduse_dev_destroy(struct vduse_dev *dev)

> > +{

> > +     kfree(dev);

> > +}

> > +

> > +static struct vduse_dev *vduse_find_dev(const char *name)

> > +{

> > +     struct vduse_dev *tmp, *dev = NULL;

> > +

> > +     list_for_each_entry(tmp, &vduse_devs, list) {

> > +             if (!strcmp(dev_name(&tmp->dev), name)) {

> > +                     dev = tmp;

> > +                     break;

> > +             }

> > +     }

> > +     return dev;

> > +}

> > +

> > +static int vduse_destroy_dev(char *name)

> > +{

> > +     struct vduse_dev *dev = vduse_find_dev(name);

> > +

> > +     if (!dev)

> > +             return -EINVAL;

> > +

> > +     mutex_lock(&dev->lock);

> > +     if (dev->vdev || dev->connected) {

> > +             mutex_unlock(&dev->lock);

> > +             return -EBUSY;

> > +     }

> > +     dev->connected = true;

> > +     mutex_unlock(&dev->lock);

> > +

> > +     list_del(&dev->list);

> > +     cdev_device_del(&dev->cdev, &dev->dev);

> > +     put_device(&dev->dev);

> > +     module_put(THIS_MODULE);

> > +

> > +     return 0;

> > +}

> > +

> > +static void vduse_release_dev(struct device *device)

> > +{

> > +     struct vduse_dev *dev =

> > +             container_of(device, struct vduse_dev, dev);

> > +

> > +     ida_simple_remove(&vduse_ida, dev->minor);

> > +     kfree(dev->vqs);

> > +     vduse_domain_destroy(dev->domain);

> > +     vduse_dev_destroy(dev);

> > +}

> > +

> > +static int vduse_create_dev(struct vduse_dev_config *config,

> > +                         unsigned long api_version)

> > +{

> > +     int i, ret = -ENOMEM;

> > +     struct vduse_dev *dev;

> > +

> > +     if (config->bounce_size > max_bounce_size)

> > +             return -EINVAL;

> > +

> > +     if (config->bounce_size > max_iova_size)

> > +             return -EINVAL;

> > +

> > +     if (vduse_find_dev(config->name))

> > +             return -EEXIST;

> > +

> > +     dev = vduse_dev_create();

> > +     if (!dev)

> > +             return -ENOMEM;

> > +

> > +     dev->api_version = api_version;

> > +     dev->device_id = config->device_id;

> > +     dev->vendor_id = config->vendor_id;

> > +     dev->domain = vduse_domain_create(max_iova_size - 1,

> > +                                     config->bounce_size);

> > +     if (!dev->domain)

> > +             goto err_domain;

> > +

> > +     dev->vq_align = config->vq_align;

> > +     dev->vq_size_max = config->vq_size_max;

> > +     dev->vq_num = config->vq_num;

> > +     dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);

> > +     if (!dev->vqs)

> > +             goto err_vqs;

> > +

> > +     for (i = 0; i < dev->vq_num; i++) {

> > +             dev->vqs[i].index = i;

> > +             INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);

> > +             spin_lock_init(&dev->vqs[i].kick_lock);

> > +             spin_lock_init(&dev->vqs[i].irq_lock);

> > +     }

> > +

> > +     ret = ida_simple_get(&vduse_ida, 0, VDUSE_DEV_MAX, GFP_KERNEL);

> > +     if (ret < 0)

> > +             goto err_ida;

> > +

> > +     dev->minor = ret;

> > +     device_initialize(&dev->dev);

> > +     dev->dev.release = vduse_release_dev;

> > +     dev->dev.class = vduse_class;

> > +     dev->dev.devt = MKDEV(MAJOR(vduse_major), dev->minor);

> > +     ret = dev_set_name(&dev->dev, "%s", config->name);

> > +     if (ret) {

> > +             put_device(&dev->dev);

> > +             return ret;

> > +     }

> > +     cdev_init(&dev->cdev, &vduse_dev_fops);

> > +     dev->cdev.owner = THIS_MODULE;

> > +

> > +     ret = cdev_device_add(&dev->cdev, &dev->dev);

> > +     if (ret) {

> > +             put_device(&dev->dev);

> > +             return ret;

>

>

> Let's introduce an error label for this.

>


But put_device() would be duplicated with the below error handling.

>

> > +     }

> > +     list_add(&dev->list, &vduse_devs);

> > +     __module_get(THIS_MODULE);

> > +

> > +     return 0;

> > +err_ida:

> > +     kfree(dev->vqs);

> > +err_vqs:

> > +     vduse_domain_destroy(dev->domain);

> > +err_domain:

> > +     vduse_dev_destroy(dev);

> > +     return ret;

> > +}

> > +

> > +static long vduse_ioctl(struct file *file, unsigned int cmd,

> > +                     unsigned long arg)

> > +{

> > +     int ret;

> > +     void __user *argp = (void __user *)arg;

> > +     struct vduse_control *control = file->private_data;

> > +

> > +     mutex_lock(&vduse_lock);

> > +     switch (cmd) {

> > +     case VDUSE_GET_API_VERSION:

> > +             ret = control->api_version;

> > +             break;

> > +     case VDUSE_SET_API_VERSION:

> > +             ret = -EINVAL;

> > +             if (arg > VDUSE_API_VERSION)

> > +                     break;

> > +

> > +             ret = 0;

> > +             control->api_version = arg;

> > +             break;

> > +     case VDUSE_CREATE_DEV: {

> > +             struct vduse_dev_config config;

> > +

> > +             ret = -EFAULT;

> > +             if (copy_from_user(&config, argp, sizeof(config)))

> > +                     break;

> > +

> > +             ret = vduse_create_dev(&config, control->api_version);

> > +             break;

> > +     }

> > +     case VDUSE_DESTROY_DEV: {

> > +             char name[VDUSE_NAME_MAX];

> > +

> > +             ret = -EFAULT;

> > +             if (copy_from_user(name, argp, VDUSE_NAME_MAX))

> > +                     break;

> > +

> > +             ret = vduse_destroy_dev(name);

> > +             break;

> > +     }

> > +     default:

> > +             ret = -EINVAL;

> > +             break;

> > +     }

> > +     mutex_unlock(&vduse_lock);

> > +

> > +     return ret;

> > +}

> > +

> > +static int vduse_release(struct inode *inode, struct file *file)

> > +{

> > +     struct vduse_control *control = file->private_data;

> > +

> > +     kfree(control);

> > +     return 0;

> > +}

> > +

> > +static int vduse_open(struct inode *inode, struct file *file)

> > +{

> > +     struct vduse_control *control;

> > +

> > +     control = kmalloc(sizeof(struct vduse_control), GFP_KERNEL);

> > +     if (!control)

> > +             return -ENOMEM;

> > +

> > +     control->api_version = VDUSE_API_VERSION;

> > +     file->private_data = control;

> > +

> > +     return 0;

> > +}

> > +

> > +static const struct file_operations vduse_fops = {

> > +     .owner          = THIS_MODULE,

> > +     .open           = vduse_open,

> > +     .release        = vduse_release,

> > +     .unlocked_ioctl = vduse_ioctl,

> > +     .compat_ioctl   = compat_ptr_ioctl,

> > +     .llseek         = noop_llseek,

> > +};

> > +

> > +static char *vduse_devnode(struct device *dev, umode_t *mode)

> > +{

> > +     return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));

> > +}

> > +

> > +static struct miscdevice vduse_misc = {

> > +     .fops = &vduse_fops,

> > +     .minor = MISC_DYNAMIC_MINOR,

> > +     .name = "vduse",

> > +     .nodename = "vduse/control",

> > +};

> > +

> > +static void vduse_mgmtdev_release(struct device *dev)

> > +{

> > +}

> > +

> > +static struct device vduse_mgmtdev = {

> > +     .init_name = "vduse",

> > +     .release = vduse_mgmtdev_release,

> > +};

> > +

> > +static struct vdpa_mgmt_dev mgmt_dev;

> > +

> > +static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)

> > +{

> > +     struct vduse_vdpa *vdev;

> > +     int ret;

> > +

> > +     if (dev->vdev)

> > +             return -EEXIST;

> > +

> > +     vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, &dev->dev,

> > +                              &vduse_vdpa_config_ops, name, true);

> > +     if (!vdev)

> > +             return -ENOMEM;

> > +

> > +     dev->vdev = vdev;

> > +     vdev->dev = dev;

> > +     vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;

> > +     ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));

> > +     if (ret) {

> > +             put_device(&vdev->vdpa.dev);

> > +             return ret;

> > +     }

> > +     set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);

> > +     vdev->vdpa.dma_dev = &vdev->vdpa.dev;

> > +     vdev->vdpa.mdev = &mgmt_dev;

> > +

> > +     return 0;

> > +}

> > +

> > +static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)

> > +{

> > +     struct vduse_dev *dev;

> > +     int ret = -EINVAL;

> > +

> > +     mutex_lock(&vduse_lock);

> > +     dev = vduse_find_dev(name);

> > +     if (!dev) {

> > +             mutex_unlock(&vduse_lock);

> > +             return -EINVAL;

> > +     }

> > +     ret = vduse_dev_init_vdpa(dev, name);

> > +     mutex_unlock(&vduse_lock);

> > +     if (ret)

> > +             return ret;

> > +

> > +     ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);

> > +     if (ret) {

> > +             put_device(&dev->vdev->vdpa.dev);

> > +             return ret;

> > +     }

> > +

> > +     return 0;

> > +}

> > +

> > +static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)

> > +{

> > +     _vdpa_unregister_device(dev);

> > +}

> > +

> > +static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {

> > +     .dev_add = vdpa_dev_add,

> > +     .dev_del = vdpa_dev_del,

> > +};

> > +

> > +static struct virtio_device_id id_table[] = {

> > +     { VIRTIO_DEV_ANY_ID, VIRTIO_DEV_ANY_ID },

> > +     { 0 },

> > +};

> > +

> > +static struct vdpa_mgmt_dev mgmt_dev = {

> > +     .device = &vduse_mgmtdev,

> > +     .id_table = id_table,

> > +     .ops = &vdpa_dev_mgmtdev_ops,

> > +};

> > +

> > +static int vduse_mgmtdev_init(void)

> > +{

> > +     int ret;

> > +

> > +     ret = device_register(&vduse_mgmtdev);

> > +     if (ret)

> > +             return ret;

> > +

> > +     ret = vdpa_mgmtdev_register(&mgmt_dev);

> > +     if (ret)

> > +             goto err;

> > +

> > +     return 0;

> > +err:

> > +     device_unregister(&vduse_mgmtdev);

> > +     return ret;

> > +}

> > +

> > +static void vduse_mgmtdev_exit(void)

> > +{

> > +     vdpa_mgmtdev_unregister(&mgmt_dev);

> > +     device_unregister(&vduse_mgmtdev);

> > +}

> > +

> > +static int vduse_init(void)

> > +{

> > +     int ret;

> > +

> > +     if (max_bounce_size >= max_iova_size)

> > +             return -EINVAL;

> > +

> > +     ret = misc_register(&vduse_misc);

> > +     if (ret)

> > +             return ret;

> > +

> > +     vduse_class = class_create(THIS_MODULE, "vduse");

> > +     if (IS_ERR(vduse_class)) {

> > +             ret = PTR_ERR(vduse_class);

> > +             goto err_class;

> > +     }

> > +     vduse_class->devnode = vduse_devnode;

> > +

> > +     ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");

> > +     if (ret)

> > +             goto err_chardev;

> > +

> > +     vduse_irq_wq = alloc_workqueue("vduse-irq",

> > +                             WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);

> > +     if (!vduse_irq_wq)

> > +             goto err_wq;

> > +

> > +     ret = vduse_domain_init();

> > +     if (ret)

> > +             goto err_domain;

> > +

> > +     ret = vduse_mgmtdev_init();

> > +     if (ret)

> > +             goto err_mgmtdev;

> > +

> > +     return 0;

> > +err_mgmtdev:

> > +     vduse_domain_exit();

> > +err_domain:

> > +     destroy_workqueue(vduse_irq_wq);

> > +err_wq:

> > +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);

> > +err_chardev:

> > +     class_destroy(vduse_class);

> > +err_class:

> > +     misc_deregister(&vduse_misc);

> > +     return ret;

> > +}

> > +module_init(vduse_init);

> > +

> > +static void vduse_exit(void)

> > +{

> > +     misc_deregister(&vduse_misc);

> > +     class_destroy(vduse_class);

> > +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);

> > +     destroy_workqueue(vduse_irq_wq);

> > +     vduse_domain_exit();

> > +     vduse_mgmtdev_exit();

> > +}

> > +module_exit(vduse_exit);

> > +

> > +MODULE_VERSION(DRV_VERSION);

> > +MODULE_LICENSE(DRV_LICENSE);

> > +MODULE_AUTHOR(DRV_AUTHOR);

> > +MODULE_DESCRIPTION(DRV_DESC);

> > diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h

> > new file mode 100644

> > index 000000000000..66a6e5212226

> > --- /dev/null

> > +++ b/include/uapi/linux/vduse.h

> > @@ -0,0 +1,175 @@

> > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */

> > +#ifndef _UAPI_VDUSE_H_

> > +#define _UAPI_VDUSE_H_

> > +

> > +#include <linux/types.h>

> > +

> > +#define VDUSE_API_VERSION    0

> > +

> > +#define VDUSE_CONFIG_DATA_LEN        256

> > +#define VDUSE_NAME_MAX       256

> > +

> > +/* the control messages definition for read/write */

> > +

> > +enum vduse_req_type {

> > +     /* Set the vring address of virtqueue. */

> > +     VDUSE_SET_VQ_NUM,

> > +     /* Set the vring address of virtqueue. */

> > +     VDUSE_SET_VQ_ADDR,

> > +     /* Set ready status of virtqueue */

> > +     VDUSE_SET_VQ_READY,

> > +     /* Get ready status of virtqueue */

> > +     VDUSE_GET_VQ_READY,

> > +     /* Set the state for virtqueue */

> > +     VDUSE_SET_VQ_STATE,

> > +     /* Get the state for virtqueue */

> > +     VDUSE_GET_VQ_STATE,

> > +     /* Set virtio features supported by the driver */

> > +     VDUSE_SET_FEATURES,

> > +     /* Get virtio features supported by the device */

> > +     VDUSE_GET_FEATURES,

> > +     /* Set the device status */

> > +     VDUSE_SET_STATUS,

> > +     /* Get the device status */

> > +     VDUSE_GET_STATUS,

> > +     /* Write to device specific configuration space */

> > +     VDUSE_SET_CONFIG,

> > +     /* Read from device specific configuration space */

> > +     VDUSE_GET_CONFIG,

> > +     /* Notify userspace to update the memory mapping in device IOTLB */

> > +     VDUSE_UPDATE_IOTLB,

> > +};

> > +

> > +struct vduse_vq_num {

> > +     __u32 index; /* virtqueue index */

>

>

> I think it's better to have a consistent style of the doc/comment. If

> yes, let's move those comment above the field.

>


Fine.

>

> > +     __u32 num; /* the size of virtqueue */

> > +};

> > +

> > +struct vduse_vq_addr {

> > +     __u32 index; /* virtqueue index */

> > +     __u64 desc_addr; /* address of desc area */

> > +     __u64 driver_addr; /* address of driver area */

> > +     __u64 device_addr; /* address of device area */

> > +};

> > +

> > +struct vduse_vq_ready {

> > +     __u32 index; /* virtqueue index */

> > +     __u8 ready; /* ready status of virtqueue */

> > +};

> > +

> > +struct vduse_vq_state {

> > +     __u32 index; /* virtqueue index */

> > +     __u16 avail_idx; /* virtqueue state (last_avail_idx) */

>

>

> Let's use __u64 here to be consistent with get_vq_state(). The idea is

> to support packed virtqueue.

>


OK. But looks like sizeof(struct vdpa_vq_state) is still equal to 2.
Do you mean we will extend it in the future?

>

> > +};

> > +

> > +struct vduse_dev_config_data {

> > +     __u32 offset; /* offset from the beginning of config space */

> > +     __u32 len; /* the length to read/write */

> > +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

>

>

> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

> not change it in the future.

>

> So this might suffcient for future features or all type of virtio devices.

>


Do you mean 256 is no enough here?

>

> > +};

> > +

> > +struct vduse_iova_range {

> > +     __u64 start; /* start of the IOVA range */

> > +     __u64 last; /* end of the IOVA range */

> > +};

> > +

> > +struct vduse_features {

> > +     __u64 features; /* virtio features */

> > +};

> > +

> > +struct vduse_status {

> > +     __u8 status; /* device status */

> > +};

> > +

> > +struct vduse_dev_request {

> > +     __u32 type; /* request type */

> > +     __u32 request_id; /* request id */

> > +     __u32 reserved[2]; /* for future use */

> > +     union {

> > +             struct vduse_vq_num vq_num; /* virtqueue num */

> > +             struct vduse_vq_addr vq_addr; /* virtqueue address */

> > +             struct vduse_vq_ready vq_ready; /* virtqueue ready status */

> > +             struct vduse_vq_state vq_state; /* virtqueue state */

> > +             struct vduse_dev_config_data config; /* virtio device config space */

> > +             struct vduse_iova_range iova; /* iova range for updating */

> > +             struct vduse_features f; /* virtio features */

> > +             struct vduse_status s; /* device status */

> > +             __u32 padding[16]; /* padding */

> > +     };

> > +};

> > +

> > +struct vduse_dev_response {

> > +     __u32 request_id; /* corresponding request id */

> > +#define VDUSE_REQUEST_OK     0x00

> > +#define VDUSE_REQUEST_FAILED 0x01

> > +     __u32 result; /* the result of request */

> > +     __u32 reserved[2]; /* for future use */

> > +     union {

> > +             struct vduse_vq_ready vq_ready; /* virtqueue ready status */

> > +             struct vduse_vq_state vq_state; /* virtqueue state */

> > +             struct vduse_dev_config_data config; /* virtio device config space */

> > +             struct vduse_features f; /* virtio features */

> > +             struct vduse_status s; /* device status */

> > +             __u32 padding[16]; /* padding */

>

>

> So it looks to me this padding doesn't work since vduse_dev_config_data

> is larger than it.

>


Oh, my bad. Will fix it.

>

> > +     };

> > +};

> > +

> > +/* ioctls */

> > +

> > +struct vduse_dev_config {

> > +     char name[VDUSE_NAME_MAX]; /* vduse device name */

> > +     __u32 vendor_id; /* virtio vendor id */

> > +     __u32 device_id; /* virtio device id */

> > +     __u64 bounce_size; /* bounce buffer size for iommu */

> > +     __u16 vq_num; /* the number of virtqueues */

> > +     __u16 vq_size_max; /* the max size of virtqueue */

> > +     __u32 vq_align; /* the allocation alignment of virtqueue's metadata */

> > +     __u32 reserved[8]; /* for future use */

>

>

> Is there a hole before reserved?

>


But I don't find the hole in below layout:

| 256 | 4 | 4 | 8 | 2 | 2 | 4 | 32 |

>

> > +};

> > +

> > +struct vduse_iotlb_entry {

> > +     __u64 offset; /* the mmap offset on fd */

> > +     __u64 start; /* start of the IOVA range */

> > +     __u64 last; /* last of the IOVA range */

> > +#define VDUSE_ACCESS_RO 0x1

> > +#define VDUSE_ACCESS_WO 0x2

> > +#define VDUSE_ACCESS_RW 0x3

> > +     __u8 perm; /* access permission of this range */

> > +};

> > +

> > +struct vduse_vq_eventfd {

> > +     __u32 index; /* virtqueue index */

> > +#define VDUSE_EVENTFD_DEASSIGN -1

> > +     int fd; /* eventfd, -1 means de-assigning the eventfd */

> > +};

> > +

> > +#define VDUSE_BASE   0x81

> > +

> > +/* Get the version of VDUSE API. This is used for future extension */

> > +#define VDUSE_GET_API_VERSION        _IO(VDUSE_BASE, 0x00)

> > +

> > +/* Set the version of VDUSE API. */

> > +#define VDUSE_SET_API_VERSION        _IO(VDUSE_BASE, 0x01)

> > +

> > +/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */

> > +#define VDUSE_CREATE_DEV     _IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)

> > +

> > +/* Destroy a vduse device. Make sure there are no references to the char device */

> > +#define VDUSE_DESTROY_DEV    _IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])

> > +

> > +/*

> > + * Get a file descriptor for the first overlapped iova region,

> > + * -EINVAL means the iova region doesn't exist.

> > + */

> > +#define VDUSE_IOTLB_GET_FD   _IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)

> > +

> > +/* Setup an eventfd to receive kick for virtqueue */

> > +#define VDUSE_VQ_SETUP_KICKFD        _IOW(VDUSE_BASE, 0x05, struct vduse_vq_eventfd)

> > +

> > +/* Inject an interrupt for specific virtqueue */

> > +#define VDUSE_INJECT_VQ_IRQ  _IO(VDUSE_BASE, 0x06)

>

>

> Missing parameter?

>


We use the argp to store the virtqueue index here. Is it OK?

Thanks,
Yongji
Jason Wang April 9, 2021, 5:36 a.m. UTC | #5
在 2021/4/8 下午5:36, Yongji Xie 写道:
> On Thu, Apr 8, 2021 at 2:57 PM Jason Wang <jasowang@redhat.com> wrote:

>>

>> 在 2021/3/31 下午4:05, Xie Yongji 写道:

>>> This VDUSE driver enables implementing vDPA devices in userspace.

>>> Both control path and data path of vDPA devices will be able to

>>> be handled in userspace.

>>>

>>> In the control path, the VDUSE driver will make use of message

>>> mechnism to forward the config operation from vdpa bus driver

>>> to userspace. Userspace can use read()/write() to receive/reply

>>> those control messages.

>>>

>>> In the data path, VDUSE_IOTLB_GET_FD ioctl will be used to get

>>> the file descriptors referring to vDPA device's iova regions. Then

>>> userspace can use mmap() to access those iova regions. Besides,

>>> userspace can use ioctl() to inject interrupt and use the eventfd

>>> mechanism to receive virtqueue kicks.

>>>

>>> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>

>>> ---

>>>    Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +

>>>    drivers/vdpa/Kconfig                               |   10 +

>>>    drivers/vdpa/Makefile                              |    1 +

>>>    drivers/vdpa/vdpa_user/Makefile                    |    5 +

>>>    drivers/vdpa/vdpa_user/vduse_dev.c                 | 1362 ++++++++++++++++++++

>>>    include/uapi/linux/vduse.h                         |  175 +++

>>>    6 files changed, 1554 insertions(+)

>>>    create mode 100644 drivers/vdpa/vdpa_user/Makefile

>>>    create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c

>>>    create mode 100644 include/uapi/linux/vduse.h

>>>

>>> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst

>>> index a4c75a28c839..71722e6f8f23 100644

>>> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst

>>> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst

>>> @@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments

>>>    'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!

>>>    '|'   00-7F  linux/media.h

>>>    0x80  00-1F  linux/fb.h

>>> +0x81  00-1F  linux/vduse.h

>>>    0x89  00-06  arch/x86/include/asm/sockios.h

>>>    0x89  0B-DF  linux/sockios.h

>>>    0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range

>>> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig

>>> index a245809c99d0..77a1da522c21 100644

>>> --- a/drivers/vdpa/Kconfig

>>> +++ b/drivers/vdpa/Kconfig

>>> @@ -25,6 +25,16 @@ config VDPA_SIM_NET

>>>        help

>>>          vDPA networking device simulator which loops TX traffic back to RX.

>>>

>>> +config VDPA_USER

>>> +     tristate "VDUSE (vDPA Device in Userspace) support"

>>> +     depends on EVENTFD && MMU && HAS_DMA

>>> +     select DMA_OPS

>>> +     select VHOST_IOTLB

>>> +     select IOMMU_IOVA

>>> +     help

>>> +       With VDUSE it is possible to emulate a vDPA Device

>>> +       in a userspace program.

>>> +

>>>    config IFCVF

>>>        tristate "Intel IFC VF vDPA driver"

>>>        depends on PCI_MSI

>>> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile

>>> index 67fe7f3d6943..f02ebed33f19 100644

>>> --- a/drivers/vdpa/Makefile

>>> +++ b/drivers/vdpa/Makefile

>>> @@ -1,6 +1,7 @@

>>>    # SPDX-License-Identifier: GPL-2.0

>>>    obj-$(CONFIG_VDPA) += vdpa.o

>>>    obj-$(CONFIG_VDPA_SIM) += vdpa_sim/

>>> +obj-$(CONFIG_VDPA_USER) += vdpa_user/

>>>    obj-$(CONFIG_IFCVF)    += ifcvf/

>>>    obj-$(CONFIG_MLX5_VDPA) += mlx5/

>>>    obj-$(CONFIG_VP_VDPA)    += virtio_pci/

>>> diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile

>>> new file mode 100644

>>> index 000000000000..260e0b26af99

>>> --- /dev/null

>>> +++ b/drivers/vdpa/vdpa_user/Makefile

>>> @@ -0,0 +1,5 @@

>>> +# SPDX-License-Identifier: GPL-2.0

>>> +

>>> +vduse-y := vduse_dev.o iova_domain.o

>>> +

>>> +obj-$(CONFIG_VDPA_USER) += vduse.o

>>> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c

>>> new file mode 100644

>>> index 000000000000..51ca73464d0d

>>> --- /dev/null

>>> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c

>>> @@ -0,0 +1,1362 @@

>>> +// SPDX-License-Identifier: GPL-2.0-only

>>> +/*

>>> + * VDUSE: vDPA Device in Userspace

>>> + *

>>> + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.

>>> + *

>>> + * Author: Xie Yongji <xieyongji@bytedance.com>

>>> + *

>>> + */

>>> +

>>> +#include <linux/init.h>

>>> +#include <linux/module.h>

>>> +#include <linux/miscdevice.h>

>>> +#include <linux/cdev.h>

>>> +#include <linux/device.h>

>>> +#include <linux/eventfd.h>

>>> +#include <linux/slab.h>

>>> +#include <linux/wait.h>

>>> +#include <linux/dma-map-ops.h>

>>> +#include <linux/poll.h>

>>> +#include <linux/file.h>

>>> +#include <linux/uio.h>

>>> +#include <linux/vdpa.h>

>>> +#include <uapi/linux/vduse.h>

>>> +#include <uapi/linux/vdpa.h>

>>> +#include <uapi/linux/virtio_config.h>

>>> +#include <linux/mod_devicetable.h>

>>> +

>>> +#include "iova_domain.h"

>>> +

>>> +#define DRV_VERSION  "1.0"

>>> +#define DRV_AUTHOR   "Yongji Xie <xieyongji@bytedance.com>"

>>> +#define DRV_DESC     "vDPA Device in Userspace"

>>> +#define DRV_LICENSE  "GPL v2"

>>> +

>>> +#define VDUSE_DEV_MAX (1U << MINORBITS)

>>> +

>>> +struct vduse_virtqueue {

>>> +     u16 index;

>>> +     bool ready;

>>> +     spinlock_t kick_lock;

>>> +     spinlock_t irq_lock;

>>> +     struct eventfd_ctx *kickfd;

>>> +     struct vdpa_callback cb;

>>> +     struct work_struct inject;

>>> +};

>>> +

>>> +struct vduse_dev;

>>> +

>>> +struct vduse_vdpa {

>>> +     struct vdpa_device vdpa;

>>> +     struct vduse_dev *dev;

>>> +};

>>> +

>>> +struct vduse_dev {

>>> +     struct vduse_vdpa *vdev;

>>> +     struct device dev;

>>> +     struct cdev cdev;

>>> +     struct vduse_virtqueue *vqs;

>>> +     struct vduse_iova_domain *domain;

>>> +     struct mutex lock;

>>> +     spinlock_t msg_lock;

>>> +     atomic64_t msg_unique;

>>> +     wait_queue_head_t waitq;

>>> +     struct list_head send_list;

>>> +     struct list_head recv_list;

>>> +     struct list_head list;

>>> +     struct vdpa_callback config_cb;

>>> +     spinlock_t irq_lock;

>>> +     unsigned long api_version;

>>> +     bool connected;

>>> +     int minor;

>>> +     u16 vq_size_max;

>>> +     u16 vq_num;

>>> +     u32 vq_align;

>>> +     u32 device_id;

>>> +     u32 vendor_id;

>>> +};

>>> +

>>> +struct vduse_dev_msg {

>>> +     struct vduse_dev_request req;

>>> +     struct vduse_dev_response resp;

>>> +     struct list_head list;

>>> +     wait_queue_head_t waitq;

>>> +     bool completed;

>>> +};

>>> +

>>> +struct vduse_control {

>>> +     unsigned long api_version;

>>> +};

>>> +

>>> +static unsigned long max_bounce_size = (64 * 1024 * 1024);

>>> +module_param(max_bounce_size, ulong, 0444);

>>> +MODULE_PARM_DESC(max_bounce_size, "Maximum bounce buffer size. (default: 64M)");

>>> +

>>> +static unsigned long max_iova_size = (128 * 1024 * 1024);

>>> +module_param(max_iova_size, ulong, 0444);

>>> +MODULE_PARM_DESC(max_iova_size, "Maximum iova space size (default: 128M)");

>>> +

>>> +static DEFINE_MUTEX(vduse_lock);

>>> +static LIST_HEAD(vduse_devs);

>>> +static DEFINE_IDA(vduse_ida);

>>> +

>>> +static dev_t vduse_major;

>>> +static struct class *vduse_class;

>>> +static struct workqueue_struct *vduse_irq_wq;

>>> +

>>> +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)

>>> +{

>>> +     struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);

>>> +

>>> +     return vdev->dev;

>>> +}

>>> +

>>> +static inline struct vduse_dev *dev_to_vduse(struct device *dev)

>>> +{

>>> +     struct vdpa_device *vdpa = dev_to_vdpa(dev);

>>> +

>>> +     return vdpa_to_vduse(vdpa);

>>> +}

>>> +

>>> +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,

>>> +                                         uint32_t request_id)

>>> +{

>>> +     struct vduse_dev_msg *tmp, *msg = NULL;

>>> +

>>> +     list_for_each_entry(tmp, head, list) {

>>> +             if (tmp->req.request_id == request_id) {

>>> +                     msg = tmp;

>>> +                     list_del(&tmp->list);

>>> +                     break;

>>> +             }

>>> +     }

>>> +

>>> +     return msg;

>>> +}

>>> +

>>> +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)

>>> +{

>>> +     struct vduse_dev_msg *msg = NULL;

>>> +

>>> +     if (!list_empty(head)) {

>>> +             msg = list_first_entry(head, struct vduse_dev_msg, list);

>>> +             list_del(&msg->list);

>>> +     }

>>> +

>>> +     return msg;

>>> +}

>>> +

>>> +static void vduse_enqueue_msg(struct list_head *head,

>>> +                           struct vduse_dev_msg *msg)

>>> +{

>>> +     list_add_tail(&msg->list, head);

>>> +}

>>> +

>>> +static int vduse_dev_msg_sync(struct vduse_dev *dev,

>>> +                           struct vduse_dev_msg *msg)

>>> +{

>>> +     init_waitqueue_head(&msg->waitq);

>>> +     spin_lock(&dev->msg_lock);

>>> +     vduse_enqueue_msg(&dev->send_list, msg);

>>> +     wake_up(&dev->waitq);

>>> +     spin_unlock(&dev->msg_lock);

>>> +     wait_event_interruptible(msg->waitq, msg->completed);

>>> +     spin_lock(&dev->msg_lock);

>>> +     if (!msg->completed)

>>> +             list_del(&msg->list);

>>> +     spin_unlock(&dev->msg_lock);

>>> +

>>> +     return (msg->resp.result == VDUSE_REQUEST_OK) ? 0 : -1;

>>> +}

>>> +

>>> +static u32 vduse_dev_get_request_id(struct vduse_dev *dev)

>>> +{

>>> +     return atomic64_fetch_inc(&dev->msg_unique);

>>> +}

>>> +

>>> +static u64 vduse_dev_get_features(struct vduse_dev *dev)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_GET_FEATURES;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +

>>> +     return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.f.features;

>>> +}

>>> +

>>> +static int vduse_dev_set_features(struct vduse_dev *dev, u64 features)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_SET_FEATURES;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.f.features = features;

>>> +

>>> +     return vduse_dev_msg_sync(dev, &msg);

>>> +}

>>> +

>>> +static u8 vduse_dev_get_status(struct vduse_dev *dev)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_GET_STATUS;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +

>>> +     return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.s.status;

>>> +}

>>> +

>>> +static void vduse_dev_set_status(struct vduse_dev *dev, u8 status)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_SET_STATUS;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.s.status = status;

>>> +

>>> +     vduse_dev_msg_sync(dev, &msg);

>>> +}

>>> +

>>> +static void vduse_dev_get_config(struct vduse_dev *dev, unsigned int offset,

>>> +                              void *buf, unsigned int len)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +     unsigned int sz;

>>> +

>>> +     while (len) {

>>> +             sz = min_t(unsigned int, len, sizeof(msg.req.config.data));

>>> +             msg.req.type = VDUSE_GET_CONFIG;

>>> +             msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +             msg.req.config.offset = offset;

>>> +             msg.req.config.len = sz;

>>> +             vduse_dev_msg_sync(dev, &msg);

>>> +             memcpy(buf, msg.resp.config.data, sz);

>>> +             buf += sz;

>>> +             offset += sz;

>>> +             len -= sz;

>>> +     }

>>> +}

>>> +

>>> +static void vduse_dev_set_config(struct vduse_dev *dev, unsigned int offset,

>>> +                              const void *buf, unsigned int len)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +     unsigned int sz;

>>> +

>>> +     while (len) {

>>> +             sz = min_t(unsigned int, len, sizeof(msg.req.config.data));

>>> +             msg.req.type = VDUSE_SET_CONFIG;

>>> +             msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +             msg.req.config.offset = offset;

>>> +             msg.req.config.len = sz;

>>> +             memcpy(msg.req.config.data, buf, sz);

>>> +             vduse_dev_msg_sync(dev, &msg);

>>> +             buf += sz;

>>> +             offset += sz;

>>> +             len -= sz;

>>> +     }

>>> +}

>>> +

>>> +static void vduse_dev_set_vq_num(struct vduse_dev *dev,

>>> +                              struct vduse_virtqueue *vq, u32 num)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_SET_VQ_NUM;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.vq_num.index = vq->index;

>>> +     msg.req.vq_num.num = num;

>>> +

>>> +     vduse_dev_msg_sync(dev, &msg);

>>> +}

>>> +

>>> +static int vduse_dev_set_vq_addr(struct vduse_dev *dev,

>>> +                              struct vduse_virtqueue *vq, u64 desc_addr,

>>> +                              u64 driver_addr, u64 device_addr)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_SET_VQ_ADDR;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.vq_addr.index = vq->index;

>>> +     msg.req.vq_addr.desc_addr = desc_addr;

>>> +     msg.req.vq_addr.driver_addr = driver_addr;

>>> +     msg.req.vq_addr.device_addr = device_addr;

>>> +

>>> +     return vduse_dev_msg_sync(dev, &msg);

>>> +}

>>> +

>>> +static void vduse_dev_set_vq_ready(struct vduse_dev *dev,

>>> +                             struct vduse_virtqueue *vq, bool ready)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_SET_VQ_READY;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.vq_ready.index = vq->index;

>>> +     msg.req.vq_ready.ready = ready;

>>> +

>>> +     vduse_dev_msg_sync(dev, &msg);

>>> +}

>>> +

>>> +static bool vduse_dev_get_vq_ready(struct vduse_dev *dev,

>>> +                                struct vduse_virtqueue *vq)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_GET_VQ_READY;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.vq_ready.index = vq->index;

>>> +

>>> +     return vduse_dev_msg_sync(dev, &msg) ? false : msg.resp.vq_ready.ready;

>>> +}

>>> +

>>> +static int vduse_dev_get_vq_state(struct vduse_dev *dev,

>>> +                             struct vduse_virtqueue *vq,

>>> +                             struct vdpa_vq_state *state)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +     int ret;

>>> +

>>> +     msg.req.type = VDUSE_GET_VQ_STATE;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.vq_state.index = vq->index;

>>> +

>>> +     ret = vduse_dev_msg_sync(dev, &msg);

>>> +     if (!ret)

>>> +             state->avail_index = msg.resp.vq_state.avail_idx;

>>> +

>>> +     return ret;

>>> +}

>>> +

>>> +static int vduse_dev_set_vq_state(struct vduse_dev *dev,

>>> +                             struct vduse_virtqueue *vq,

>>> +                             const struct vdpa_vq_state *state)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     msg.req.type = VDUSE_SET_VQ_STATE;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.vq_state.index = vq->index;

>>> +     msg.req.vq_state.avail_idx = state->avail_index;

>>> +

>>> +     return vduse_dev_msg_sync(dev, &msg);

>>> +}

>>> +

>>> +static int vduse_dev_update_iotlb(struct vduse_dev *dev,

>>> +                             u64 start, u64 last)

>>> +{

>>> +     struct vduse_dev_msg msg = { 0 };

>>> +

>>> +     if (last < start)

>>> +             return -EINVAL;

>>> +

>>> +     msg.req.type = VDUSE_UPDATE_IOTLB;

>>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

>>> +     msg.req.iova.start = start;

>>> +     msg.req.iova.last = last;

>>> +

>>> +     return vduse_dev_msg_sync(dev, &msg);

>>> +}

>>> +

>>> +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)

>>> +{

>>> +     struct file *file = iocb->ki_filp;

>>> +     struct vduse_dev *dev = file->private_data;

>>> +     struct vduse_dev_msg *msg;

>>> +     int size = sizeof(struct vduse_dev_request);

>>> +     ssize_t ret = 0;

>>> +

>>> +     if (iov_iter_count(to) < size)

>>> +             return 0;

>>> +

>>> +     spin_lock(&dev->msg_lock);

>>> +     while (1) {

>>> +             msg = vduse_dequeue_msg(&dev->send_list);

>>> +             if (msg)

>>> +                     break;

>>> +

>>> +             ret = -EAGAIN;

>>> +             if (file->f_flags & O_NONBLOCK)

>>> +                     goto unlock;

>>> +

>>> +             spin_unlock(&dev->msg_lock);

>>> +             ret = wait_event_interruptible_exclusive(dev->waitq,

>>> +                                     !list_empty(&dev->send_list));

>>> +             if (ret)

>>> +                     return ret;

>>> +

>>> +             spin_lock(&dev->msg_lock);

>>> +     }

>>> +     spin_unlock(&dev->msg_lock);

>>> +     ret = copy_to_iter(&msg->req, size, to);

>>> +     spin_lock(&dev->msg_lock);

>>> +     if (ret != size) {

>>> +             ret = -EFAULT;

>>> +             vduse_enqueue_msg(&dev->send_list, msg);

>>> +             goto unlock;

>>> +     }

>>> +     vduse_enqueue_msg(&dev->recv_list, msg);

>>> +     wake_up(&dev->waitq);

>>> +unlock:

>>> +     spin_unlock(&dev->msg_lock);

>>> +

>>> +     return ret;

>>> +}

>>> +

>>> +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)

>>> +{

>>> +     struct file *file = iocb->ki_filp;

>>> +     struct vduse_dev *dev = file->private_data;

>>> +     struct vduse_dev_response resp;

>>> +     struct vduse_dev_msg *msg;

>>> +     size_t ret;

>>> +

>>> +     ret = copy_from_iter(&resp, sizeof(resp), from);

>>> +     if (ret != sizeof(resp))

>>> +             return -EINVAL;

>>> +

>>> +     spin_lock(&dev->msg_lock);

>>> +     msg = vduse_find_msg(&dev->recv_list, resp.request_id);

>>> +     if (!msg) {

>>> +             ret = -EINVAL;

>>> +             goto unlock;

>>> +     }

>>> +

>>> +     memcpy(&msg->resp, &resp, sizeof(resp));

>>> +     msg->completed = 1;

>>> +     wake_up(&msg->waitq);

>>> +unlock:

>>> +     spin_unlock(&dev->msg_lock);

>>> +

>>> +     return ret;

>>> +}

>>> +

>>> +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)

>>> +{

>>> +     struct vduse_dev *dev = file->private_data;

>>> +     __poll_t mask = 0;

>>> +

>>> +     poll_wait(file, &dev->waitq, wait);

>>> +

>>> +     if (!list_empty(&dev->send_list))

>>> +             mask |= EPOLLIN | EPOLLRDNORM;

>>> +     if (!list_empty(&dev->recv_list))

>>> +             mask |= EPOLLOUT;

>>> +

>>> +     return mask;

>>> +}

>>> +

>>> +static void vduse_dev_reset(struct vduse_dev *dev)

>>> +{

>>> +     int i;

>>> +

>>> +     /* The coherent mappings are handled in vduse_dev_free_coherent() */

>>> +     vduse_domain_reset_bounce_map(dev->domain);

>>> +     vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);

>>> +

>>> +     spin_lock(&dev->irq_lock);

>>> +     dev->config_cb.callback = NULL;

>>> +     dev->config_cb.private = NULL;

>>> +     spin_unlock(&dev->irq_lock);

>>> +

>>> +     for (i = 0; i < dev->vq_num; i++) {

>>> +             struct vduse_virtqueue *vq = &dev->vqs[i];

>>> +

>>> +             spin_lock(&vq->irq_lock);

>>> +             vq->ready = false;

>>> +             vq->cb.callback = NULL;

>>> +             vq->cb.private = NULL;

>>> +             spin_unlock(&vq->irq_lock);

>>> +     }

>>> +}

>>> +

>>> +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,

>>> +                             u64 desc_area, u64 driver_area,

>>> +                             u64 device_area)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

>>> +

>>> +     return vduse_dev_set_vq_addr(dev, vq, desc_area,

>>> +                                     driver_area, device_area);

>>> +}

>>> +

>>> +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

>>> +

>>> +     spin_lock(&vq->kick_lock);

>>> +     if (vq->ready && vq->kickfd)

>>> +             eventfd_signal(vq->kickfd, 1);

>>> +     spin_unlock(&vq->kick_lock);

>>> +}

>>> +

>>> +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,

>>> +                           struct vdpa_callback *cb)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

>>> +

>>> +     spin_lock(&vq->irq_lock);

>>> +     vq->cb.callback = cb->callback;

>>> +     vq->cb.private = cb->private;

>>> +     spin_unlock(&vq->irq_lock);

>>> +}

>>> +

>>> +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

>>> +

>>> +     vduse_dev_set_vq_num(dev, vq, num);

>>> +}

>>> +

>>> +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,

>>> +                                     u16 idx, bool ready)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

>>> +

>>> +     vduse_dev_set_vq_ready(dev, vq, ready);

>>> +     vq->ready = ready;

>>> +}

>>> +

>>> +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

>>> +

>>> +     vq->ready = vduse_dev_get_vq_ready(dev, vq);

>>> +

>>> +     return vq->ready;

>>> +}

>>> +

>>> +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,

>>> +                             const struct vdpa_vq_state *state)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

>>> +

>>> +     return vduse_dev_set_vq_state(dev, vq, state);

>>> +}

>>> +

>>> +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,

>>> +                             struct vdpa_vq_state *state)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

>>> +

>>> +     return vduse_dev_get_vq_state(dev, vq, state);

>>> +}

>>> +

>>> +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     return dev->vq_align;

>>> +}

>>> +

>>> +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     return vduse_dev_get_features(dev);

>>> +}

>>> +

>>> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))

>>> +             return -EINVAL;

>>> +

>>> +     return vduse_dev_set_features(dev, features);

>>> +}

>>> +

>>> +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,

>>> +                               struct vdpa_callback *cb)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     spin_lock(&dev->irq_lock);

>>> +     dev->config_cb.callback = cb->callback;

>>> +     dev->config_cb.private = cb->private;

>>> +     spin_unlock(&dev->irq_lock);

>>> +}

>>> +

>>> +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     return dev->vq_size_max;

>>> +}

>>> +

>>> +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     return dev->device_id;

>>> +}

>>> +

>>> +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     return dev->vendor_id;

>>> +}

>>> +

>>> +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     return vduse_dev_get_status(dev);

>>> +}

>>> +

>>> +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     vduse_dev_set_status(dev, status);

>>> +

>>> +     if (status == 0)

>>> +             vduse_dev_reset(dev);

>>> +}

>>> +

>>> +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,

>>> +                          void *buf, unsigned int len)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     vduse_dev_get_config(dev, offset, buf, len);

>>> +}

>>> +

>>> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,

>>> +                     const void *buf, unsigned int len)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     vduse_dev_set_config(dev, offset, buf, len);

>>> +}

>>> +

>>> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,

>>> +                             struct vhost_iotlb *iotlb)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +     int ret;

>>> +

>>> +     ret = vduse_domain_set_map(dev->domain, iotlb);

>>> +     vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);

>>> +

>>> +     return ret;

>>> +}

>>> +

>>> +static void vduse_vdpa_free(struct vdpa_device *vdpa)

>>> +{

>>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

>>> +

>>> +     WARN_ON(!list_empty(&dev->send_list));

>>> +     WARN_ON(!list_empty(&dev->recv_list));

>>> +     dev->vdev = NULL;

>>> +}

>>> +

>>> +static const struct vdpa_config_ops vduse_vdpa_config_ops = {

>>> +     .set_vq_address         = vduse_vdpa_set_vq_address,

>>> +     .kick_vq                = vduse_vdpa_kick_vq,

>>> +     .set_vq_cb              = vduse_vdpa_set_vq_cb,

>>> +     .set_vq_num             = vduse_vdpa_set_vq_num,

>>> +     .set_vq_ready           = vduse_vdpa_set_vq_ready,

>>> +     .get_vq_ready           = vduse_vdpa_get_vq_ready,

>>> +     .set_vq_state           = vduse_vdpa_set_vq_state,

>>> +     .get_vq_state           = vduse_vdpa_get_vq_state,

>>> +     .get_vq_align           = vduse_vdpa_get_vq_align,

>>> +     .get_features           = vduse_vdpa_get_features,

>>> +     .set_features           = vduse_vdpa_set_features,

>>> +     .set_config_cb          = vduse_vdpa_set_config_cb,

>>> +     .get_vq_num_max         = vduse_vdpa_get_vq_num_max,

>>> +     .get_device_id          = vduse_vdpa_get_device_id,

>>> +     .get_vendor_id          = vduse_vdpa_get_vendor_id,

>>> +     .get_status             = vduse_vdpa_get_status,

>>> +     .set_status             = vduse_vdpa_set_status,

>>> +     .get_config             = vduse_vdpa_get_config,

>>> +     .set_config             = vduse_vdpa_set_config,

>>> +     .set_map                = vduse_vdpa_set_map,

>>> +     .free                   = vduse_vdpa_free,

>>> +};

>>> +

>>> +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,

>>> +                                  unsigned long offset, size_t size,

>>> +                                  enum dma_data_direction dir,

>>> +                                  unsigned long attrs)

>>> +{

>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);

>>> +     struct vduse_iova_domain *domain = vdev->domain;

>>> +

>>> +     return vduse_domain_map_page(domain, page, offset, size, dir, attrs);

>>> +}

>>> +

>>> +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,

>>> +                             size_t size, enum dma_data_direction dir,

>>> +                             unsigned long attrs)

>>> +{

>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);

>>> +     struct vduse_iova_domain *domain = vdev->domain;

>>> +

>>> +     return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);

>>> +}

>>> +

>>> +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,

>>> +                                     dma_addr_t *dma_addr, gfp_t flag,

>>> +                                     unsigned long attrs)

>>> +{

>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);

>>> +     struct vduse_iova_domain *domain = vdev->domain;

>>> +     unsigned long iova;

>>> +     void *addr;

>>> +

>>> +     *dma_addr = DMA_MAPPING_ERROR;

>>> +     addr = vduse_domain_alloc_coherent(domain, size,

>>> +                             (dma_addr_t *)&iova, flag, attrs);

>>> +     if (!addr)

>>> +             return NULL;

>>> +

>>> +     *dma_addr = (dma_addr_t)iova;

>>> +     vduse_dev_update_iotlb(vdev, iova, iova + size - 1);

>>> +

>>> +     return addr;

>>> +}

>>> +

>>> +static void vduse_dev_free_coherent(struct device *dev, size_t size,

>>> +                                     void *vaddr, dma_addr_t dma_addr,

>>> +                                     unsigned long attrs)

>>> +{

>>> +     struct vduse_dev *vdev = dev_to_vduse(dev);

>>> +     struct vduse_iova_domain *domain = vdev->domain;

>>> +     unsigned long start = (unsigned long)dma_addr;

>>> +     unsigned long last = start + size - 1;

>>> +

>>> +     vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);

>>> +     vduse_dev_update_iotlb(vdev, start, last);

>>> +}

>>> +

>>> +static const struct dma_map_ops vduse_dev_dma_ops = {

>>> +     .map_page = vduse_dev_map_page,

>>> +     .unmap_page = vduse_dev_unmap_page,

>>> +     .alloc = vduse_dev_alloc_coherent,

>>> +     .free = vduse_dev_free_coherent,

>>> +};

>>> +

>>> +static unsigned int perm_to_file_flags(u8 perm)

>>> +{

>>> +     unsigned int flags = 0;

>>> +

>>> +     switch (perm) {

>>> +     case VDUSE_ACCESS_WO:

>>> +             flags |= O_WRONLY;

>>> +             break;

>>> +     case VDUSE_ACCESS_RO:

>>> +             flags |= O_RDONLY;

>>> +             break;

>>> +     case VDUSE_ACCESS_RW:

>>> +             flags |= O_RDWR;

>>> +             break;

>>> +     default:

>>> +             WARN(1, "invalidate vhost IOTLB permission\n");

>>> +             break;

>>> +     }

>>> +

>>> +     return flags;

>>> +}

>>> +

>>> +static int vduse_kickfd_setup(struct vduse_dev *dev,

>>> +                     struct vduse_vq_eventfd *eventfd)

>>> +{

>>> +     struct eventfd_ctx *ctx = NULL;

>>> +     struct vduse_virtqueue *vq;

>>> +

>>> +     if (eventfd->index >= dev->vq_num)

>>> +             return -EINVAL;

>>> +

>>> +     vq = &dev->vqs[eventfd->index];

>>> +     if (eventfd->fd > 0) {

>>> +             ctx = eventfd_ctx_fdget(eventfd->fd);

>>> +             if (IS_ERR(ctx))

>>> +                     return PTR_ERR(ctx);

>>> +     } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)

>>> +             return 0;

>>

>> Do we allow the userspace to switch kickfd here? If yes, we need to deal

>> with that.

>>

> Do you mean the case that eventfd->fd > 0? I think we have dealt with it.



Ok, but the above code still looks suspicious. E.g what happens if 
eventfd->fd is 0?


>

>>> +

>>> +     spin_lock(&vq->kick_lock);

>>> +     if (vq->kickfd)

>>> +             eventfd_ctx_put(vq->kickfd);

>>> +     vq->kickfd = ctx;

>>> +     spin_unlock(&vq->kick_lock);

>>> +

>>> +     return 0;

>>> +}

>>> +

>>> +static void vduse_vq_irq_inject(struct work_struct *work)

>>> +{

>>> +     struct vduse_virtqueue *vq = container_of(work,

>>> +                                     struct vduse_virtqueue, inject);

>>> +

>>> +     spin_lock_irq(&vq->irq_lock);

>>> +     if (vq->ready && vq->cb.callback)

>>> +             vq->cb.callback(vq->cb.private);

>>> +     spin_unlock_irq(&vq->irq_lock);

>>> +}

>>> +

>>> +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,

>>> +                         unsigned long arg)

>>> +{

>>> +     struct vduse_dev *dev = file->private_data;

>>> +     void __user *argp = (void __user *)arg;

>>> +     int ret;

>>> +

>>> +     switch (cmd) {

>>> +     case VDUSE_IOTLB_GET_FD: {

>>> +             struct vduse_iotlb_entry entry;

>>> +             struct vhost_iotlb_map *map;

>>> +             struct vdpa_map_file *map_file;

>>> +             struct vduse_iova_domain *domain = dev->domain;

>>> +             struct file *f = NULL;

>>> +

>>> +             ret = -EFAULT;

>>> +             if (copy_from_user(&entry, argp, sizeof(entry)))

>>> +                     break;

>>> +

>>> +             ret = -EINVAL;

>>> +             if (entry.start > entry.last)

>>> +                     break;

>>> +

>>> +             spin_lock(&domain->iotlb_lock);

>>> +             map = vhost_iotlb_itree_first(domain->iotlb,

>>> +                                           entry.start, entry.last);

>>> +             if (map) {

>>> +                     map_file = (struct vdpa_map_file *)map->opaque;

>>> +                     f = get_file(map_file->file);

>>> +                     entry.offset = map_file->offset;

>>> +                     entry.start = map->start;

>>> +                     entry.last = map->last;

>>> +                     entry.perm = map->perm;

>>> +             }

>>> +             spin_unlock(&domain->iotlb_lock);

>>> +             ret = -EINVAL;

>>> +             if (!f)

>>> +                     break;

>>> +

>>> +             ret = -EFAULT;

>>> +             if (copy_to_user(argp, &entry, sizeof(entry))) {

>>> +                     fput(f);

>>> +                     break;

>>> +             }

>>> +             ret = receive_fd(f, perm_to_file_flags(entry.perm));

>>> +             fput(f);

>>

>> Any reason to drop the refcnt here?

>>

> We will do get_file() in receive_fd() too.



I see.


>

>>> +             break;

>>> +     }

>>> +     case VDUSE_VQ_SETUP_KICKFD: {

>>> +             struct vduse_vq_eventfd eventfd;

>>> +

>>> +             ret = -EFAULT;

>>> +             if (copy_from_user(&eventfd, argp, sizeof(eventfd)))

>>> +                     break;

>>> +

>>> +             ret = vduse_kickfd_setup(dev, &eventfd);

>>> +             break;

>>> +     }

>>> +     case VDUSE_INJECT_VQ_IRQ:

>>> +             ret = -EINVAL;

>>> +             if (arg >= dev->vq_num)

>>> +                     break;

>>> +

>>> +             ret = 0;

>>> +             queue_work(vduse_irq_wq, &dev->vqs[arg].inject);

>>> +             break;

>>> +     case VDUSE_INJECT_CONFIG_IRQ:

>>> +             ret = -EINVAL;

>>> +             spin_lock_irq(&dev->irq_lock);

>>> +             if (dev->config_cb.callback) {

>>> +                     dev->config_cb.callback(dev->config_cb.private);

>>> +                     ret = 0;

>>> +             }

>>> +             spin_unlock_irq(&dev->irq_lock);

>>

>> For consistency, is it better to use vduse_irq_wq here?

>>

> Looks good to me.

>

>>> +             break;

>>> +     default:

>>> +             ret = -ENOIOCTLCMD;

>>> +             break;

>>> +     }

>>> +

>>> +     return ret;

>>> +}

>>> +

>>> +static int vduse_dev_release(struct inode *inode, struct file *file)

>>> +{

>>> +     struct vduse_dev *dev = file->private_data;

>>> +     struct vduse_dev_msg *msg;

>>> +     int i;

>>> +

>>> +     for (i = 0; i < dev->vq_num; i++) {

>>> +             struct vduse_virtqueue *vq = &dev->vqs[i];

>>> +

>>> +             spin_lock(&vq->kick_lock);

>>> +             if (vq->kickfd)

>>> +                     eventfd_ctx_put(vq->kickfd);

>>> +             vq->kickfd = NULL;

>>> +             spin_unlock(&vq->kick_lock);

>>> +     }

>>> +

>>> +     spin_lock(&dev->msg_lock);

>>> +     /*  Make sure the inflight messages can processed */

>>

>> This might be better:

>>

>> /*  Make sure the inflight messages can processed after reconncection */

>>

> OK.

>

>>> +     while ((msg = vduse_dequeue_msg(&dev->recv_list)))

>>> +             vduse_enqueue_msg(&dev->send_list, msg);

>>> +     spin_unlock(&dev->msg_lock);

>>> +

>>> +     dev->connected = false;

>>> +

>>> +     return 0;

>>> +}

>>> +

>>> +static int vduse_dev_open(struct inode *inode, struct file *file)

>>> +{

>>> +     struct vduse_dev *dev = container_of(inode->i_cdev,

>>> +                                     struct vduse_dev, cdev);

>>> +     int ret = -EBUSY;

>>> +

>>> +     mutex_lock(&dev->lock);

>>> +     if (dev->connected)

>>> +             goto unlock;

>>> +

>>> +     ret = 0;

>>> +     dev->connected = true;

>>> +     file->private_data = dev;

>>> +unlock:

>>> +     mutex_unlock(&dev->lock);

>>> +

>>> +     return ret;

>>> +}

>>> +

>>> +static const struct file_operations vduse_dev_fops = {

>>> +     .owner          = THIS_MODULE,

>>> +     .open           = vduse_dev_open,

>>> +     .release        = vduse_dev_release,

>>> +     .read_iter      = vduse_dev_read_iter,

>>> +     .write_iter     = vduse_dev_write_iter,

>>> +     .poll           = vduse_dev_poll,

>>> +     .unlocked_ioctl = vduse_dev_ioctl,

>>> +     .compat_ioctl   = compat_ptr_ioctl,

>>> +     .llseek         = noop_llseek,

>>> +};

>>> +

>>> +static struct vduse_dev *vduse_dev_create(void)

>>> +{

>>> +     struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);

>>> +

>>> +     if (!dev)

>>> +             return NULL;

>>> +

>>> +     mutex_init(&dev->lock);

>>> +     spin_lock_init(&dev->msg_lock);

>>> +     INIT_LIST_HEAD(&dev->send_list);

>>> +     INIT_LIST_HEAD(&dev->recv_list);

>>> +     atomic64_set(&dev->msg_unique, 0);

>>> +     spin_lock_init(&dev->irq_lock);

>>> +

>>> +     init_waitqueue_head(&dev->waitq);

>>> +

>>> +     return dev;

>>> +}

>>> +

>>> +static void vduse_dev_destroy(struct vduse_dev *dev)

>>> +{

>>> +     kfree(dev);

>>> +}

>>> +

>>> +static struct vduse_dev *vduse_find_dev(const char *name)

>>> +{

>>> +     struct vduse_dev *tmp, *dev = NULL;

>>> +

>>> +     list_for_each_entry(tmp, &vduse_devs, list) {

>>> +             if (!strcmp(dev_name(&tmp->dev), name)) {

>>> +                     dev = tmp;

>>> +                     break;

>>> +             }

>>> +     }

>>> +     return dev;

>>> +}

>>> +

>>> +static int vduse_destroy_dev(char *name)

>>> +{

>>> +     struct vduse_dev *dev = vduse_find_dev(name);

>>> +

>>> +     if (!dev)

>>> +             return -EINVAL;

>>> +

>>> +     mutex_lock(&dev->lock);

>>> +     if (dev->vdev || dev->connected) {

>>> +             mutex_unlock(&dev->lock);

>>> +             return -EBUSY;

>>> +     }

>>> +     dev->connected = true;

>>> +     mutex_unlock(&dev->lock);

>>> +

>>> +     list_del(&dev->list);

>>> +     cdev_device_del(&dev->cdev, &dev->dev);

>>> +     put_device(&dev->dev);

>>> +     module_put(THIS_MODULE);

>>> +

>>> +     return 0;

>>> +}

>>> +

>>> +static void vduse_release_dev(struct device *device)

>>> +{

>>> +     struct vduse_dev *dev =

>>> +             container_of(device, struct vduse_dev, dev);

>>> +

>>> +     ida_simple_remove(&vduse_ida, dev->minor);

>>> +     kfree(dev->vqs);

>>> +     vduse_domain_destroy(dev->domain);

>>> +     vduse_dev_destroy(dev);

>>> +}

>>> +

>>> +static int vduse_create_dev(struct vduse_dev_config *config,

>>> +                         unsigned long api_version)

>>> +{

>>> +     int i, ret = -ENOMEM;

>>> +     struct vduse_dev *dev;

>>> +

>>> +     if (config->bounce_size > max_bounce_size)

>>> +             return -EINVAL;

>>> +

>>> +     if (config->bounce_size > max_iova_size)

>>> +             return -EINVAL;

>>> +

>>> +     if (vduse_find_dev(config->name))

>>> +             return -EEXIST;

>>> +

>>> +     dev = vduse_dev_create();

>>> +     if (!dev)

>>> +             return -ENOMEM;

>>> +

>>> +     dev->api_version = api_version;

>>> +     dev->device_id = config->device_id;

>>> +     dev->vendor_id = config->vendor_id;

>>> +     dev->domain = vduse_domain_create(max_iova_size - 1,

>>> +                                     config->bounce_size);

>>> +     if (!dev->domain)

>>> +             goto err_domain;

>>> +

>>> +     dev->vq_align = config->vq_align;

>>> +     dev->vq_size_max = config->vq_size_max;

>>> +     dev->vq_num = config->vq_num;

>>> +     dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);

>>> +     if (!dev->vqs)

>>> +             goto err_vqs;

>>> +

>>> +     for (i = 0; i < dev->vq_num; i++) {

>>> +             dev->vqs[i].index = i;

>>> +             INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);

>>> +             spin_lock_init(&dev->vqs[i].kick_lock);

>>> +             spin_lock_init(&dev->vqs[i].irq_lock);

>>> +     }

>>> +

>>> +     ret = ida_simple_get(&vduse_ida, 0, VDUSE_DEV_MAX, GFP_KERNEL);

>>> +     if (ret < 0)

>>> +             goto err_ida;

>>> +

>>> +     dev->minor = ret;

>>> +     device_initialize(&dev->dev);

>>> +     dev->dev.release = vduse_release_dev;

>>> +     dev->dev.class = vduse_class;

>>> +     dev->dev.devt = MKDEV(MAJOR(vduse_major), dev->minor);

>>> +     ret = dev_set_name(&dev->dev, "%s", config->name);

>>> +     if (ret) {

>>> +             put_device(&dev->dev);

>>> +             return ret;

>>> +     }

>>> +     cdev_init(&dev->cdev, &vduse_dev_fops);

>>> +     dev->cdev.owner = THIS_MODULE;

>>> +

>>> +     ret = cdev_device_add(&dev->cdev, &dev->dev);

>>> +     if (ret) {

>>> +             put_device(&dev->dev);

>>> +             return ret;

>>

>> Let's introduce an error label for this.

>>

> But put_device() would be duplicated with the below error handling.



I think it's as simple as put the error label after the return.


>

>>> +     }

>>> +     list_add(&dev->list, &vduse_devs);

>>> +     __module_get(THIS_MODULE);

>>> +

>>> +     return 0;

>>> +err_ida:

>>> +     kfree(dev->vqs);

>>> +err_vqs:

>>> +     vduse_domain_destroy(dev->domain);

>>> +err_domain:

>>> +     vduse_dev_destroy(dev);

>>> +     return ret;

>>> +}

>>> +

>>> +static long vduse_ioctl(struct file *file, unsigned int cmd,

>>> +                     unsigned long arg)

>>> +{

>>> +     int ret;

>>> +     void __user *argp = (void __user *)arg;

>>> +     struct vduse_control *control = file->private_data;

>>> +

>>> +     mutex_lock(&vduse_lock);

>>> +     switch (cmd) {

>>> +     case VDUSE_GET_API_VERSION:

>>> +             ret = control->api_version;

>>> +             break;

>>> +     case VDUSE_SET_API_VERSION:

>>> +             ret = -EINVAL;

>>> +             if (arg > VDUSE_API_VERSION)

>>> +                     break;

>>> +

>>> +             ret = 0;

>>> +             control->api_version = arg;

>>> +             break;

>>> +     case VDUSE_CREATE_DEV: {

>>> +             struct vduse_dev_config config;

>>> +

>>> +             ret = -EFAULT;

>>> +             if (copy_from_user(&config, argp, sizeof(config)))

>>> +                     break;

>>> +

>>> +             ret = vduse_create_dev(&config, control->api_version);

>>> +             break;

>>> +     }

>>> +     case VDUSE_DESTROY_DEV: {

>>> +             char name[VDUSE_NAME_MAX];

>>> +

>>> +             ret = -EFAULT;

>>> +             if (copy_from_user(name, argp, VDUSE_NAME_MAX))

>>> +                     break;

>>> +

>>> +             ret = vduse_destroy_dev(name);

>>> +             break;

>>> +     }

>>> +     default:

>>> +             ret = -EINVAL;

>>> +             break;

>>> +     }

>>> +     mutex_unlock(&vduse_lock);

>>> +

>>> +     return ret;

>>> +}

>>> +

>>> +static int vduse_release(struct inode *inode, struct file *file)

>>> +{

>>> +     struct vduse_control *control = file->private_data;

>>> +

>>> +     kfree(control);

>>> +     return 0;

>>> +}

>>> +

>>> +static int vduse_open(struct inode *inode, struct file *file)

>>> +{

>>> +     struct vduse_control *control;

>>> +

>>> +     control = kmalloc(sizeof(struct vduse_control), GFP_KERNEL);

>>> +     if (!control)

>>> +             return -ENOMEM;

>>> +

>>> +     control->api_version = VDUSE_API_VERSION;

>>> +     file->private_data = control;

>>> +

>>> +     return 0;

>>> +}

>>> +

>>> +static const struct file_operations vduse_fops = {

>>> +     .owner          = THIS_MODULE,

>>> +     .open           = vduse_open,

>>> +     .release        = vduse_release,

>>> +     .unlocked_ioctl = vduse_ioctl,

>>> +     .compat_ioctl   = compat_ptr_ioctl,

>>> +     .llseek         = noop_llseek,

>>> +};

>>> +

>>> +static char *vduse_devnode(struct device *dev, umode_t *mode)

>>> +{

>>> +     return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));

>>> +}

>>> +

>>> +static struct miscdevice vduse_misc = {

>>> +     .fops = &vduse_fops,

>>> +     .minor = MISC_DYNAMIC_MINOR,

>>> +     .name = "vduse",

>>> +     .nodename = "vduse/control",

>>> +};

>>> +

>>> +static void vduse_mgmtdev_release(struct device *dev)

>>> +{

>>> +}

>>> +

>>> +static struct device vduse_mgmtdev = {

>>> +     .init_name = "vduse",

>>> +     .release = vduse_mgmtdev_release,

>>> +};

>>> +

>>> +static struct vdpa_mgmt_dev mgmt_dev;

>>> +

>>> +static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)

>>> +{

>>> +     struct vduse_vdpa *vdev;

>>> +     int ret;

>>> +

>>> +     if (dev->vdev)

>>> +             return -EEXIST;

>>> +

>>> +     vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, &dev->dev,

>>> +                              &vduse_vdpa_config_ops, name, true);

>>> +     if (!vdev)

>>> +             return -ENOMEM;

>>> +

>>> +     dev->vdev = vdev;

>>> +     vdev->dev = dev;

>>> +     vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;

>>> +     ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));

>>> +     if (ret) {

>>> +             put_device(&vdev->vdpa.dev);

>>> +             return ret;

>>> +     }

>>> +     set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);

>>> +     vdev->vdpa.dma_dev = &vdev->vdpa.dev;

>>> +     vdev->vdpa.mdev = &mgmt_dev;

>>> +

>>> +     return 0;

>>> +}

>>> +

>>> +static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)

>>> +{

>>> +     struct vduse_dev *dev;

>>> +     int ret = -EINVAL;

>>> +

>>> +     mutex_lock(&vduse_lock);

>>> +     dev = vduse_find_dev(name);

>>> +     if (!dev) {

>>> +             mutex_unlock(&vduse_lock);

>>> +             return -EINVAL;

>>> +     }

>>> +     ret = vduse_dev_init_vdpa(dev, name);

>>> +     mutex_unlock(&vduse_lock);

>>> +     if (ret)

>>> +             return ret;

>>> +

>>> +     ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);

>>> +     if (ret) {

>>> +             put_device(&dev->vdev->vdpa.dev);

>>> +             return ret;

>>> +     }

>>> +

>>> +     return 0;

>>> +}

>>> +

>>> +static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)

>>> +{

>>> +     _vdpa_unregister_device(dev);

>>> +}

>>> +

>>> +static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {

>>> +     .dev_add = vdpa_dev_add,

>>> +     .dev_del = vdpa_dev_del,

>>> +};

>>> +

>>> +static struct virtio_device_id id_table[] = {

>>> +     { VIRTIO_DEV_ANY_ID, VIRTIO_DEV_ANY_ID },

>>> +     { 0 },

>>> +};

>>> +

>>> +static struct vdpa_mgmt_dev mgmt_dev = {

>>> +     .device = &vduse_mgmtdev,

>>> +     .id_table = id_table,

>>> +     .ops = &vdpa_dev_mgmtdev_ops,

>>> +};

>>> +

>>> +static int vduse_mgmtdev_init(void)

>>> +{

>>> +     int ret;

>>> +

>>> +     ret = device_register(&vduse_mgmtdev);

>>> +     if (ret)

>>> +             return ret;

>>> +

>>> +     ret = vdpa_mgmtdev_register(&mgmt_dev);

>>> +     if (ret)

>>> +             goto err;

>>> +

>>> +     return 0;

>>> +err:

>>> +     device_unregister(&vduse_mgmtdev);

>>> +     return ret;

>>> +}

>>> +

>>> +static void vduse_mgmtdev_exit(void)

>>> +{

>>> +     vdpa_mgmtdev_unregister(&mgmt_dev);

>>> +     device_unregister(&vduse_mgmtdev);

>>> +}

>>> +

>>> +static int vduse_init(void)

>>> +{

>>> +     int ret;

>>> +

>>> +     if (max_bounce_size >= max_iova_size)

>>> +             return -EINVAL;

>>> +

>>> +     ret = misc_register(&vduse_misc);

>>> +     if (ret)

>>> +             return ret;

>>> +

>>> +     vduse_class = class_create(THIS_MODULE, "vduse");

>>> +     if (IS_ERR(vduse_class)) {

>>> +             ret = PTR_ERR(vduse_class);

>>> +             goto err_class;

>>> +     }

>>> +     vduse_class->devnode = vduse_devnode;

>>> +

>>> +     ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");

>>> +     if (ret)

>>> +             goto err_chardev;

>>> +

>>> +     vduse_irq_wq = alloc_workqueue("vduse-irq",

>>> +                             WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);

>>> +     if (!vduse_irq_wq)

>>> +             goto err_wq;

>>> +

>>> +     ret = vduse_domain_init();

>>> +     if (ret)

>>> +             goto err_domain;

>>> +

>>> +     ret = vduse_mgmtdev_init();

>>> +     if (ret)

>>> +             goto err_mgmtdev;

>>> +

>>> +     return 0;

>>> +err_mgmtdev:

>>> +     vduse_domain_exit();

>>> +err_domain:

>>> +     destroy_workqueue(vduse_irq_wq);

>>> +err_wq:

>>> +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);

>>> +err_chardev:

>>> +     class_destroy(vduse_class);

>>> +err_class:

>>> +     misc_deregister(&vduse_misc);

>>> +     return ret;

>>> +}

>>> +module_init(vduse_init);

>>> +

>>> +static void vduse_exit(void)

>>> +{

>>> +     misc_deregister(&vduse_misc);

>>> +     class_destroy(vduse_class);

>>> +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);

>>> +     destroy_workqueue(vduse_irq_wq);

>>> +     vduse_domain_exit();

>>> +     vduse_mgmtdev_exit();

>>> +}

>>> +module_exit(vduse_exit);

>>> +

>>> +MODULE_VERSION(DRV_VERSION);

>>> +MODULE_LICENSE(DRV_LICENSE);

>>> +MODULE_AUTHOR(DRV_AUTHOR);

>>> +MODULE_DESCRIPTION(DRV_DESC);

>>> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h

>>> new file mode 100644

>>> index 000000000000..66a6e5212226

>>> --- /dev/null

>>> +++ b/include/uapi/linux/vduse.h

>>> @@ -0,0 +1,175 @@

>>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */

>>> +#ifndef _UAPI_VDUSE_H_

>>> +#define _UAPI_VDUSE_H_

>>> +

>>> +#include <linux/types.h>

>>> +

>>> +#define VDUSE_API_VERSION    0

>>> +

>>> +#define VDUSE_CONFIG_DATA_LEN        256

>>> +#define VDUSE_NAME_MAX       256

>>> +

>>> +/* the control messages definition for read/write */

>>> +

>>> +enum vduse_req_type {

>>> +     /* Set the vring address of virtqueue. */

>>> +     VDUSE_SET_VQ_NUM,

>>> +     /* Set the vring address of virtqueue. */

>>> +     VDUSE_SET_VQ_ADDR,

>>> +     /* Set ready status of virtqueue */

>>> +     VDUSE_SET_VQ_READY,

>>> +     /* Get ready status of virtqueue */

>>> +     VDUSE_GET_VQ_READY,

>>> +     /* Set the state for virtqueue */

>>> +     VDUSE_SET_VQ_STATE,

>>> +     /* Get the state for virtqueue */

>>> +     VDUSE_GET_VQ_STATE,

>>> +     /* Set virtio features supported by the driver */

>>> +     VDUSE_SET_FEATURES,

>>> +     /* Get virtio features supported by the device */

>>> +     VDUSE_GET_FEATURES,

>>> +     /* Set the device status */

>>> +     VDUSE_SET_STATUS,

>>> +     /* Get the device status */

>>> +     VDUSE_GET_STATUS,

>>> +     /* Write to device specific configuration space */

>>> +     VDUSE_SET_CONFIG,

>>> +     /* Read from device specific configuration space */

>>> +     VDUSE_GET_CONFIG,

>>> +     /* Notify userspace to update the memory mapping in device IOTLB */

>>> +     VDUSE_UPDATE_IOTLB,

>>> +};

>>> +

>>> +struct vduse_vq_num {

>>> +     __u32 index; /* virtqueue index */

>>

>> I think it's better to have a consistent style of the doc/comment. If

>> yes, let's move those comment above the field.

>>

> Fine.

>

>>> +     __u32 num; /* the size of virtqueue */

>>> +};

>>> +

>>> +struct vduse_vq_addr {

>>> +     __u32 index; /* virtqueue index */

>>> +     __u64 desc_addr; /* address of desc area */

>>> +     __u64 driver_addr; /* address of driver area */

>>> +     __u64 device_addr; /* address of device area */

>>> +};

>>> +

>>> +struct vduse_vq_ready {

>>> +     __u32 index; /* virtqueue index */

>>> +     __u8 ready; /* ready status of virtqueue */

>>> +};

>>> +

>>> +struct vduse_vq_state {

>>> +     __u32 index; /* virtqueue index */

>>> +     __u16 avail_idx; /* virtqueue state (last_avail_idx) */

>>

>> Let's use __u64 here to be consistent with get_vq_state().



__u32 actually:

struct vhost_vring_state {
         unsigned int index;
         unsigned int num;
};


>>   The idea is

>> to support packed virtqueue.

>>

> OK. But looks like sizeof(struct vdpa_vq_state) is still equal to 2.



It's a bug that needs to be fixed.


> Do you mean we will extend it in the future?



u32 should be fine, and it's not for future. For packed virtqueue we 
need something like:

le32 {
     last_avai_idx : 15;
     last_avail_wrap_counter : 1;
     used_idx : 15;
     used_wrap_counter : 1;
}

As has been done in 
https://lore.kernel.org/lkml/20190717105255.63488-3-jasowang@redhat.com/T/


>

>>> +};

>>> +

>>> +struct vduse_dev_config_data {

>>> +     __u32 offset; /* offset from the beginning of config space */

>>> +     __u32 len; /* the length to read/write */

>>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

>>

>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

>> not change it in the future.

>>

>> So this might suffcient for future features or all type of virtio devices.

>>

> Do you mean 256 is no enough here?



Yes.


>

>>> +};

>>> +

>>> +struct vduse_iova_range {

>>> +     __u64 start; /* start of the IOVA range */

>>> +     __u64 last; /* end of the IOVA range */

>>> +};

>>> +

>>> +struct vduse_features {

>>> +     __u64 features; /* virtio features */

>>> +};

>>> +

>>> +struct vduse_status {

>>> +     __u8 status; /* device status */

>>> +};

>>> +

>>> +struct vduse_dev_request {

>>> +     __u32 type; /* request type */

>>> +     __u32 request_id; /* request id */

>>> +     __u32 reserved[2]; /* for future use */

>>> +     union {

>>> +             struct vduse_vq_num vq_num; /* virtqueue num */

>>> +             struct vduse_vq_addr vq_addr; /* virtqueue address */

>>> +             struct vduse_vq_ready vq_ready; /* virtqueue ready status */

>>> +             struct vduse_vq_state vq_state; /* virtqueue state */

>>> +             struct vduse_dev_config_data config; /* virtio device config space */

>>> +             struct vduse_iova_range iova; /* iova range for updating */

>>> +             struct vduse_features f; /* virtio features */

>>> +             struct vduse_status s; /* device status */

>>> +             __u32 padding[16]; /* padding */

>>> +     };

>>> +};

>>> +

>>> +struct vduse_dev_response {

>>> +     __u32 request_id; /* corresponding request id */

>>> +#define VDUSE_REQUEST_OK     0x00

>>> +#define VDUSE_REQUEST_FAILED 0x01

>>> +     __u32 result; /* the result of request */

>>> +     __u32 reserved[2]; /* for future use */

>>> +     union {

>>> +             struct vduse_vq_ready vq_ready; /* virtqueue ready status */

>>> +             struct vduse_vq_state vq_state; /* virtqueue state */

>>> +             struct vduse_dev_config_data config; /* virtio device config space */

>>> +             struct vduse_features f; /* virtio features */

>>> +             struct vduse_status s; /* device status */

>>> +             __u32 padding[16]; /* padding */

>>

>> So it looks to me this padding doesn't work since vduse_dev_config_data

>> is larger than it.

>>

> Oh, my bad. Will fix it.

>

>>> +     };

>>> +};

>>> +

>>> +/* ioctls */

>>> +

>>> +struct vduse_dev_config {

>>> +     char name[VDUSE_NAME_MAX]; /* vduse device name */

>>> +     __u32 vendor_id; /* virtio vendor id */

>>> +     __u32 device_id; /* virtio device id */

>>> +     __u64 bounce_size; /* bounce buffer size for iommu */

>>> +     __u16 vq_num; /* the number of virtqueues */

>>> +     __u16 vq_size_max; /* the max size of virtqueue */

>>> +     __u32 vq_align; /* the allocation alignment of virtqueue's metadata */

>>> +     __u32 reserved[8]; /* for future use */

>>

>> Is there a hole before reserved?

>>

> But I don't find the hole in below layout:

>

> | 256 | 4 | 4 | 8 | 2 | 2 | 4 | 32 |

>


Looks correct, better to check with pahole to double confirm.


>>> +};

>>> +

>>> +struct vduse_iotlb_entry {

>>> +     __u64 offset; /* the mmap offset on fd */

>>> +     __u64 start; /* start of the IOVA range */

>>> +     __u64 last; /* last of the IOVA range */

>>> +#define VDUSE_ACCESS_RO 0x1

>>> +#define VDUSE_ACCESS_WO 0x2

>>> +#define VDUSE_ACCESS_RW 0x3

>>> +     __u8 perm; /* access permission of this range */

>>> +};

>>> +

>>> +struct vduse_vq_eventfd {

>>> +     __u32 index; /* virtqueue index */

>>> +#define VDUSE_EVENTFD_DEASSIGN -1

>>> +     int fd; /* eventfd, -1 means de-assigning the eventfd */

>>> +};

>>> +

>>> +#define VDUSE_BASE   0x81

>>> +

>>> +/* Get the version of VDUSE API. This is used for future extension */

>>> +#define VDUSE_GET_API_VERSION        _IO(VDUSE_BASE, 0x00)

>>> +

>>> +/* Set the version of VDUSE API. */

>>> +#define VDUSE_SET_API_VERSION        _IO(VDUSE_BASE, 0x01)

>>> +

>>> +/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */

>>> +#define VDUSE_CREATE_DEV     _IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)

>>> +

>>> +/* Destroy a vduse device. Make sure there are no references to the char device */

>>> +#define VDUSE_DESTROY_DEV    _IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])

>>> +

>>> +/*

>>> + * Get a file descriptor for the first overlapped iova region,

>>> + * -EINVAL means the iova region doesn't exist.

>>> + */

>>> +#define VDUSE_IOTLB_GET_FD   _IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)

>>> +

>>> +/* Setup an eventfd to receive kick for virtqueue */

>>> +#define VDUSE_VQ_SETUP_KICKFD        _IOW(VDUSE_BASE, 0x05, struct vduse_vq_eventfd)

>>> +

>>> +/* Inject an interrupt for specific virtqueue */

>>> +#define VDUSE_INJECT_VQ_IRQ  _IO(VDUSE_BASE, 0x06)

>>

>> Missing parameter?

>>

> We use the argp to store the virtqueue index here. Is it OK?



So I meant it should be something like:

#define VDUSE_INJECT_VQ_IRQ  _IOW(VDUSE_BASE, 0x06, unsigned int)

?

Thanks


>

> Thanks,

> Yongji

>
Yongji Xie April 9, 2021, 8:02 a.m. UTC | #6
On Fri, Apr 9, 2021 at 1:36 PM Jason Wang <jasowang@redhat.com> wrote:
>

>

> 在 2021/4/8 下午5:36, Yongji Xie 写道:

> > On Thu, Apr 8, 2021 at 2:57 PM Jason Wang <jasowang@redhat.com> wrote:

> >>

> >> 在 2021/3/31 下午4:05, Xie Yongji 写道:

> >>> This VDUSE driver enables implementing vDPA devices in userspace.

> >>> Both control path and data path of vDPA devices will be able to

> >>> be handled in userspace.

> >>>

> >>> In the control path, the VDUSE driver will make use of message

> >>> mechnism to forward the config operation from vdpa bus driver

> >>> to userspace. Userspace can use read()/write() to receive/reply

> >>> those control messages.

> >>>

> >>> In the data path, VDUSE_IOTLB_GET_FD ioctl will be used to get

> >>> the file descriptors referring to vDPA device's iova regions. Then

> >>> userspace can use mmap() to access those iova regions. Besides,

> >>> userspace can use ioctl() to inject interrupt and use the eventfd

> >>> mechanism to receive virtqueue kicks.

> >>>

> >>> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>

> >>> ---

> >>>    Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +

> >>>    drivers/vdpa/Kconfig                               |   10 +

> >>>    drivers/vdpa/Makefile                              |    1 +

> >>>    drivers/vdpa/vdpa_user/Makefile                    |    5 +

> >>>    drivers/vdpa/vdpa_user/vduse_dev.c                 | 1362 ++++++++++++++++++++

> >>>    include/uapi/linux/vduse.h                         |  175 +++

> >>>    6 files changed, 1554 insertions(+)

> >>>    create mode 100644 drivers/vdpa/vdpa_user/Makefile

> >>>    create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c

> >>>    create mode 100644 include/uapi/linux/vduse.h

> >>>

> >>> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst

> >>> index a4c75a28c839..71722e6f8f23 100644

> >>> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst

> >>> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst

> >>> @@ -300,6 +300,7 @@ Code  Seq#    Include File                                           Comments

> >>>    'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!

> >>>    '|'   00-7F  linux/media.h

> >>>    0x80  00-1F  linux/fb.h

> >>> +0x81  00-1F  linux/vduse.h

> >>>    0x89  00-06  arch/x86/include/asm/sockios.h

> >>>    0x89  0B-DF  linux/sockios.h

> >>>    0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range

> >>> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig

> >>> index a245809c99d0..77a1da522c21 100644

> >>> --- a/drivers/vdpa/Kconfig

> >>> +++ b/drivers/vdpa/Kconfig

> >>> @@ -25,6 +25,16 @@ config VDPA_SIM_NET

> >>>        help

> >>>          vDPA networking device simulator which loops TX traffic back to RX.

> >>>

> >>> +config VDPA_USER

> >>> +     tristate "VDUSE (vDPA Device in Userspace) support"

> >>> +     depends on EVENTFD && MMU && HAS_DMA

> >>> +     select DMA_OPS

> >>> +     select VHOST_IOTLB

> >>> +     select IOMMU_IOVA

> >>> +     help

> >>> +       With VDUSE it is possible to emulate a vDPA Device

> >>> +       in a userspace program.

> >>> +

> >>>    config IFCVF

> >>>        tristate "Intel IFC VF vDPA driver"

> >>>        depends on PCI_MSI

> >>> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile

> >>> index 67fe7f3d6943..f02ebed33f19 100644

> >>> --- a/drivers/vdpa/Makefile

> >>> +++ b/drivers/vdpa/Makefile

> >>> @@ -1,6 +1,7 @@

> >>>    # SPDX-License-Identifier: GPL-2.0

> >>>    obj-$(CONFIG_VDPA) += vdpa.o

> >>>    obj-$(CONFIG_VDPA_SIM) += vdpa_sim/

> >>> +obj-$(CONFIG_VDPA_USER) += vdpa_user/

> >>>    obj-$(CONFIG_IFCVF)    += ifcvf/

> >>>    obj-$(CONFIG_MLX5_VDPA) += mlx5/

> >>>    obj-$(CONFIG_VP_VDPA)    += virtio_pci/

> >>> diff --git a/drivers/vdpa/vdpa_user/Makefile b/drivers/vdpa/vdpa_user/Makefile

> >>> new file mode 100644

> >>> index 000000000000..260e0b26af99

> >>> --- /dev/null

> >>> +++ b/drivers/vdpa/vdpa_user/Makefile

> >>> @@ -0,0 +1,5 @@

> >>> +# SPDX-License-Identifier: GPL-2.0

> >>> +

> >>> +vduse-y := vduse_dev.o iova_domain.o

> >>> +

> >>> +obj-$(CONFIG_VDPA_USER) += vduse.o

> >>> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c

> >>> new file mode 100644

> >>> index 000000000000..51ca73464d0d

> >>> --- /dev/null

> >>> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c

> >>> @@ -0,0 +1,1362 @@

> >>> +// SPDX-License-Identifier: GPL-2.0-only

> >>> +/*

> >>> + * VDUSE: vDPA Device in Userspace

> >>> + *

> >>> + * Copyright (C) 2020-2021 Bytedance Inc. and/or its affiliates. All rights reserved.

> >>> + *

> >>> + * Author: Xie Yongji <xieyongji@bytedance.com>

> >>> + *

> >>> + */

> >>> +

> >>> +#include <linux/init.h>

> >>> +#include <linux/module.h>

> >>> +#include <linux/miscdevice.h>

> >>> +#include <linux/cdev.h>

> >>> +#include <linux/device.h>

> >>> +#include <linux/eventfd.h>

> >>> +#include <linux/slab.h>

> >>> +#include <linux/wait.h>

> >>> +#include <linux/dma-map-ops.h>

> >>> +#include <linux/poll.h>

> >>> +#include <linux/file.h>

> >>> +#include <linux/uio.h>

> >>> +#include <linux/vdpa.h>

> >>> +#include <uapi/linux/vduse.h>

> >>> +#include <uapi/linux/vdpa.h>

> >>> +#include <uapi/linux/virtio_config.h>

> >>> +#include <linux/mod_devicetable.h>

> >>> +

> >>> +#include "iova_domain.h"

> >>> +

> >>> +#define DRV_VERSION  "1.0"

> >>> +#define DRV_AUTHOR   "Yongji Xie <xieyongji@bytedance.com>"

> >>> +#define DRV_DESC     "vDPA Device in Userspace"

> >>> +#define DRV_LICENSE  "GPL v2"

> >>> +

> >>> +#define VDUSE_DEV_MAX (1U << MINORBITS)

> >>> +

> >>> +struct vduse_virtqueue {

> >>> +     u16 index;

> >>> +     bool ready;

> >>> +     spinlock_t kick_lock;

> >>> +     spinlock_t irq_lock;

> >>> +     struct eventfd_ctx *kickfd;

> >>> +     struct vdpa_callback cb;

> >>> +     struct work_struct inject;

> >>> +};

> >>> +

> >>> +struct vduse_dev;

> >>> +

> >>> +struct vduse_vdpa {

> >>> +     struct vdpa_device vdpa;

> >>> +     struct vduse_dev *dev;

> >>> +};

> >>> +

> >>> +struct vduse_dev {

> >>> +     struct vduse_vdpa *vdev;

> >>> +     struct device dev;

> >>> +     struct cdev cdev;

> >>> +     struct vduse_virtqueue *vqs;

> >>> +     struct vduse_iova_domain *domain;

> >>> +     struct mutex lock;

> >>> +     spinlock_t msg_lock;

> >>> +     atomic64_t msg_unique;

> >>> +     wait_queue_head_t waitq;

> >>> +     struct list_head send_list;

> >>> +     struct list_head recv_list;

> >>> +     struct list_head list;

> >>> +     struct vdpa_callback config_cb;

> >>> +     spinlock_t irq_lock;

> >>> +     unsigned long api_version;

> >>> +     bool connected;

> >>> +     int minor;

> >>> +     u16 vq_size_max;

> >>> +     u16 vq_num;

> >>> +     u32 vq_align;

> >>> +     u32 device_id;

> >>> +     u32 vendor_id;

> >>> +};

> >>> +

> >>> +struct vduse_dev_msg {

> >>> +     struct vduse_dev_request req;

> >>> +     struct vduse_dev_response resp;

> >>> +     struct list_head list;

> >>> +     wait_queue_head_t waitq;

> >>> +     bool completed;

> >>> +};

> >>> +

> >>> +struct vduse_control {

> >>> +     unsigned long api_version;

> >>> +};

> >>> +

> >>> +static unsigned long max_bounce_size = (64 * 1024 * 1024);

> >>> +module_param(max_bounce_size, ulong, 0444);

> >>> +MODULE_PARM_DESC(max_bounce_size, "Maximum bounce buffer size. (default: 64M)");

> >>> +

> >>> +static unsigned long max_iova_size = (128 * 1024 * 1024);

> >>> +module_param(max_iova_size, ulong, 0444);

> >>> +MODULE_PARM_DESC(max_iova_size, "Maximum iova space size (default: 128M)");

> >>> +

> >>> +static DEFINE_MUTEX(vduse_lock);

> >>> +static LIST_HEAD(vduse_devs);

> >>> +static DEFINE_IDA(vduse_ida);

> >>> +

> >>> +static dev_t vduse_major;

> >>> +static struct class *vduse_class;

> >>> +static struct workqueue_struct *vduse_irq_wq;

> >>> +

> >>> +static inline struct vduse_dev *vdpa_to_vduse(struct vdpa_device *vdpa)

> >>> +{

> >>> +     struct vduse_vdpa *vdev = container_of(vdpa, struct vduse_vdpa, vdpa);

> >>> +

> >>> +     return vdev->dev;

> >>> +}

> >>> +

> >>> +static inline struct vduse_dev *dev_to_vduse(struct device *dev)

> >>> +{

> >>> +     struct vdpa_device *vdpa = dev_to_vdpa(dev);

> >>> +

> >>> +     return vdpa_to_vduse(vdpa);

> >>> +}

> >>> +

> >>> +static struct vduse_dev_msg *vduse_find_msg(struct list_head *head,

> >>> +                                         uint32_t request_id)

> >>> +{

> >>> +     struct vduse_dev_msg *tmp, *msg = NULL;

> >>> +

> >>> +     list_for_each_entry(tmp, head, list) {

> >>> +             if (tmp->req.request_id == request_id) {

> >>> +                     msg = tmp;

> >>> +                     list_del(&tmp->list);

> >>> +                     break;

> >>> +             }

> >>> +     }

> >>> +

> >>> +     return msg;

> >>> +}

> >>> +

> >>> +static struct vduse_dev_msg *vduse_dequeue_msg(struct list_head *head)

> >>> +{

> >>> +     struct vduse_dev_msg *msg = NULL;

> >>> +

> >>> +     if (!list_empty(head)) {

> >>> +             msg = list_first_entry(head, struct vduse_dev_msg, list);

> >>> +             list_del(&msg->list);

> >>> +     }

> >>> +

> >>> +     return msg;

> >>> +}

> >>> +

> >>> +static void vduse_enqueue_msg(struct list_head *head,

> >>> +                           struct vduse_dev_msg *msg)

> >>> +{

> >>> +     list_add_tail(&msg->list, head);

> >>> +}

> >>> +

> >>> +static int vduse_dev_msg_sync(struct vduse_dev *dev,

> >>> +                           struct vduse_dev_msg *msg)

> >>> +{

> >>> +     init_waitqueue_head(&msg->waitq);

> >>> +     spin_lock(&dev->msg_lock);

> >>> +     vduse_enqueue_msg(&dev->send_list, msg);

> >>> +     wake_up(&dev->waitq);

> >>> +     spin_unlock(&dev->msg_lock);

> >>> +     wait_event_interruptible(msg->waitq, msg->completed);

> >>> +     spin_lock(&dev->msg_lock);

> >>> +     if (!msg->completed)

> >>> +             list_del(&msg->list);

> >>> +     spin_unlock(&dev->msg_lock);

> >>> +

> >>> +     return (msg->resp.result == VDUSE_REQUEST_OK) ? 0 : -1;

> >>> +}

> >>> +

> >>> +static u32 vduse_dev_get_request_id(struct vduse_dev *dev)

> >>> +{

> >>> +     return atomic64_fetch_inc(&dev->msg_unique);

> >>> +}

> >>> +

> >>> +static u64 vduse_dev_get_features(struct vduse_dev *dev)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_GET_FEATURES;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +

> >>> +     return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.f.features;

> >>> +}

> >>> +

> >>> +static int vduse_dev_set_features(struct vduse_dev *dev, u64 features)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_SET_FEATURES;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.f.features = features;

> >>> +

> >>> +     return vduse_dev_msg_sync(dev, &msg);

> >>> +}

> >>> +

> >>> +static u8 vduse_dev_get_status(struct vduse_dev *dev)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_GET_STATUS;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +

> >>> +     return vduse_dev_msg_sync(dev, &msg) ? 0 : msg.resp.s.status;

> >>> +}

> >>> +

> >>> +static void vduse_dev_set_status(struct vduse_dev *dev, u8 status)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_SET_STATUS;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.s.status = status;

> >>> +

> >>> +     vduse_dev_msg_sync(dev, &msg);

> >>> +}

> >>> +

> >>> +static void vduse_dev_get_config(struct vduse_dev *dev, unsigned int offset,

> >>> +                              void *buf, unsigned int len)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +     unsigned int sz;

> >>> +

> >>> +     while (len) {

> >>> +             sz = min_t(unsigned int, len, sizeof(msg.req.config.data));

> >>> +             msg.req.type = VDUSE_GET_CONFIG;

> >>> +             msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +             msg.req.config.offset = offset;

> >>> +             msg.req.config.len = sz;

> >>> +             vduse_dev_msg_sync(dev, &msg);

> >>> +             memcpy(buf, msg.resp.config.data, sz);

> >>> +             buf += sz;

> >>> +             offset += sz;

> >>> +             len -= sz;

> >>> +     }

> >>> +}

> >>> +

> >>> +static void vduse_dev_set_config(struct vduse_dev *dev, unsigned int offset,

> >>> +                              const void *buf, unsigned int len)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +     unsigned int sz;

> >>> +

> >>> +     while (len) {

> >>> +             sz = min_t(unsigned int, len, sizeof(msg.req.config.data));

> >>> +             msg.req.type = VDUSE_SET_CONFIG;

> >>> +             msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +             msg.req.config.offset = offset;

> >>> +             msg.req.config.len = sz;

> >>> +             memcpy(msg.req.config.data, buf, sz);

> >>> +             vduse_dev_msg_sync(dev, &msg);

> >>> +             buf += sz;

> >>> +             offset += sz;

> >>> +             len -= sz;

> >>> +     }

> >>> +}

> >>> +

> >>> +static void vduse_dev_set_vq_num(struct vduse_dev *dev,

> >>> +                              struct vduse_virtqueue *vq, u32 num)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_SET_VQ_NUM;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.vq_num.index = vq->index;

> >>> +     msg.req.vq_num.num = num;

> >>> +

> >>> +     vduse_dev_msg_sync(dev, &msg);

> >>> +}

> >>> +

> >>> +static int vduse_dev_set_vq_addr(struct vduse_dev *dev,

> >>> +                              struct vduse_virtqueue *vq, u64 desc_addr,

> >>> +                              u64 driver_addr, u64 device_addr)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_SET_VQ_ADDR;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.vq_addr.index = vq->index;

> >>> +     msg.req.vq_addr.desc_addr = desc_addr;

> >>> +     msg.req.vq_addr.driver_addr = driver_addr;

> >>> +     msg.req.vq_addr.device_addr = device_addr;

> >>> +

> >>> +     return vduse_dev_msg_sync(dev, &msg);

> >>> +}

> >>> +

> >>> +static void vduse_dev_set_vq_ready(struct vduse_dev *dev,

> >>> +                             struct vduse_virtqueue *vq, bool ready)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_SET_VQ_READY;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.vq_ready.index = vq->index;

> >>> +     msg.req.vq_ready.ready = ready;

> >>> +

> >>> +     vduse_dev_msg_sync(dev, &msg);

> >>> +}

> >>> +

> >>> +static bool vduse_dev_get_vq_ready(struct vduse_dev *dev,

> >>> +                                struct vduse_virtqueue *vq)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_GET_VQ_READY;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.vq_ready.index = vq->index;

> >>> +

> >>> +     return vduse_dev_msg_sync(dev, &msg) ? false : msg.resp.vq_ready.ready;

> >>> +}

> >>> +

> >>> +static int vduse_dev_get_vq_state(struct vduse_dev *dev,

> >>> +                             struct vduse_virtqueue *vq,

> >>> +                             struct vdpa_vq_state *state)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +     int ret;

> >>> +

> >>> +     msg.req.type = VDUSE_GET_VQ_STATE;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.vq_state.index = vq->index;

> >>> +

> >>> +     ret = vduse_dev_msg_sync(dev, &msg);

> >>> +     if (!ret)

> >>> +             state->avail_index = msg.resp.vq_state.avail_idx;

> >>> +

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static int vduse_dev_set_vq_state(struct vduse_dev *dev,

> >>> +                             struct vduse_virtqueue *vq,

> >>> +                             const struct vdpa_vq_state *state)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     msg.req.type = VDUSE_SET_VQ_STATE;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.vq_state.index = vq->index;

> >>> +     msg.req.vq_state.avail_idx = state->avail_index;

> >>> +

> >>> +     return vduse_dev_msg_sync(dev, &msg);

> >>> +}

> >>> +

> >>> +static int vduse_dev_update_iotlb(struct vduse_dev *dev,

> >>> +                             u64 start, u64 last)

> >>> +{

> >>> +     struct vduse_dev_msg msg = { 0 };

> >>> +

> >>> +     if (last < start)

> >>> +             return -EINVAL;

> >>> +

> >>> +     msg.req.type = VDUSE_UPDATE_IOTLB;

> >>> +     msg.req.request_id = vduse_dev_get_request_id(dev);

> >>> +     msg.req.iova.start = start;

> >>> +     msg.req.iova.last = last;

> >>> +

> >>> +     return vduse_dev_msg_sync(dev, &msg);

> >>> +}

> >>> +

> >>> +static ssize_t vduse_dev_read_iter(struct kiocb *iocb, struct iov_iter *to)

> >>> +{

> >>> +     struct file *file = iocb->ki_filp;

> >>> +     struct vduse_dev *dev = file->private_data;

> >>> +     struct vduse_dev_msg *msg;

> >>> +     int size = sizeof(struct vduse_dev_request);

> >>> +     ssize_t ret = 0;

> >>> +

> >>> +     if (iov_iter_count(to) < size)

> >>> +             return 0;

> >>> +

> >>> +     spin_lock(&dev->msg_lock);

> >>> +     while (1) {

> >>> +             msg = vduse_dequeue_msg(&dev->send_list);

> >>> +             if (msg)

> >>> +                     break;

> >>> +

> >>> +             ret = -EAGAIN;

> >>> +             if (file->f_flags & O_NONBLOCK)

> >>> +                     goto unlock;

> >>> +

> >>> +             spin_unlock(&dev->msg_lock);

> >>> +             ret = wait_event_interruptible_exclusive(dev->waitq,

> >>> +                                     !list_empty(&dev->send_list));

> >>> +             if (ret)

> >>> +                     return ret;

> >>> +

> >>> +             spin_lock(&dev->msg_lock);

> >>> +     }

> >>> +     spin_unlock(&dev->msg_lock);

> >>> +     ret = copy_to_iter(&msg->req, size, to);

> >>> +     spin_lock(&dev->msg_lock);

> >>> +     if (ret != size) {

> >>> +             ret = -EFAULT;

> >>> +             vduse_enqueue_msg(&dev->send_list, msg);

> >>> +             goto unlock;

> >>> +     }

> >>> +     vduse_enqueue_msg(&dev->recv_list, msg);

> >>> +     wake_up(&dev->waitq);

> >>> +unlock:

> >>> +     spin_unlock(&dev->msg_lock);

> >>> +

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static ssize_t vduse_dev_write_iter(struct kiocb *iocb, struct iov_iter *from)

> >>> +{

> >>> +     struct file *file = iocb->ki_filp;

> >>> +     struct vduse_dev *dev = file->private_data;

> >>> +     struct vduse_dev_response resp;

> >>> +     struct vduse_dev_msg *msg;

> >>> +     size_t ret;

> >>> +

> >>> +     ret = copy_from_iter(&resp, sizeof(resp), from);

> >>> +     if (ret != sizeof(resp))

> >>> +             return -EINVAL;

> >>> +

> >>> +     spin_lock(&dev->msg_lock);

> >>> +     msg = vduse_find_msg(&dev->recv_list, resp.request_id);

> >>> +     if (!msg) {

> >>> +             ret = -EINVAL;

> >>> +             goto unlock;

> >>> +     }

> >>> +

> >>> +     memcpy(&msg->resp, &resp, sizeof(resp));

> >>> +     msg->completed = 1;

> >>> +     wake_up(&msg->waitq);

> >>> +unlock:

> >>> +     spin_unlock(&dev->msg_lock);

> >>> +

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)

> >>> +{

> >>> +     struct vduse_dev *dev = file->private_data;

> >>> +     __poll_t mask = 0;

> >>> +

> >>> +     poll_wait(file, &dev->waitq, wait);

> >>> +

> >>> +     if (!list_empty(&dev->send_list))

> >>> +             mask |= EPOLLIN | EPOLLRDNORM;

> >>> +     if (!list_empty(&dev->recv_list))

> >>> +             mask |= EPOLLOUT;

> >>> +

> >>> +     return mask;

> >>> +}

> >>> +

> >>> +static void vduse_dev_reset(struct vduse_dev *dev)

> >>> +{

> >>> +     int i;

> >>> +

> >>> +     /* The coherent mappings are handled in vduse_dev_free_coherent() */

> >>> +     vduse_domain_reset_bounce_map(dev->domain);

> >>> +     vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);

> >>> +

> >>> +     spin_lock(&dev->irq_lock);

> >>> +     dev->config_cb.callback = NULL;

> >>> +     dev->config_cb.private = NULL;

> >>> +     spin_unlock(&dev->irq_lock);

> >>> +

> >>> +     for (i = 0; i < dev->vq_num; i++) {

> >>> +             struct vduse_virtqueue *vq = &dev->vqs[i];

> >>> +

> >>> +             spin_lock(&vq->irq_lock);

> >>> +             vq->ready = false;

> >>> +             vq->cb.callback = NULL;

> >>> +             vq->cb.private = NULL;

> >>> +             spin_unlock(&vq->irq_lock);

> >>> +     }

> >>> +}

> >>> +

> >>> +static int vduse_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 idx,

> >>> +                             u64 desc_area, u64 driver_area,

> >>> +                             u64 device_area)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> >>> +

> >>> +     return vduse_dev_set_vq_addr(dev, vq, desc_area,

> >>> +                                     driver_area, device_area);

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_kick_vq(struct vdpa_device *vdpa, u16 idx)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> >>> +

> >>> +     spin_lock(&vq->kick_lock);

> >>> +     if (vq->ready && vq->kickfd)

> >>> +             eventfd_signal(vq->kickfd, 1);

> >>> +     spin_unlock(&vq->kick_lock);

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,

> >>> +                           struct vdpa_callback *cb)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> >>> +

> >>> +     spin_lock(&vq->irq_lock);

> >>> +     vq->cb.callback = cb->callback;

> >>> +     vq->cb.private = cb->private;

> >>> +     spin_unlock(&vq->irq_lock);

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> >>> +

> >>> +     vduse_dev_set_vq_num(dev, vq, num);

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa,

> >>> +                                     u16 idx, bool ready)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> >>> +

> >>> +     vduse_dev_set_vq_ready(dev, vq, ready);

> >>> +     vq->ready = ready;

> >>> +}

> >>> +

> >>> +static bool vduse_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 idx)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> >>> +

> >>> +     vq->ready = vduse_dev_get_vq_ready(dev, vq);

> >>> +

> >>> +     return vq->ready;

> >>> +}

> >>> +

> >>> +static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,

> >>> +                             const struct vdpa_vq_state *state)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> >>> +

> >>> +     return vduse_dev_set_vq_state(dev, vq, state);

> >>> +}

> >>> +

> >>> +static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,

> >>> +                             struct vdpa_vq_state *state)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     struct vduse_virtqueue *vq = &dev->vqs[idx];

> >>> +

> >>> +     return vduse_dev_get_vq_state(dev, vq, state);

> >>> +}

> >>> +

> >>> +static u32 vduse_vdpa_get_vq_align(struct vdpa_device *vdpa)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     return dev->vq_align;

> >>> +}

> >>> +

> >>> +static u64 vduse_vdpa_get_features(struct vdpa_device *vdpa)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     return vduse_dev_get_features(dev);

> >>> +}

> >>> +

> >>> +static int vduse_vdpa_set_features(struct vdpa_device *vdpa, u64 features)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))

> >>> +             return -EINVAL;

> >>> +

> >>> +     return vduse_dev_set_features(dev, features);

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_set_config_cb(struct vdpa_device *vdpa,

> >>> +                               struct vdpa_callback *cb)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     spin_lock(&dev->irq_lock);

> >>> +     dev->config_cb.callback = cb->callback;

> >>> +     dev->config_cb.private = cb->private;

> >>> +     spin_unlock(&dev->irq_lock);

> >>> +}

> >>> +

> >>> +static u16 vduse_vdpa_get_vq_num_max(struct vdpa_device *vdpa)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     return dev->vq_size_max;

> >>> +}

> >>> +

> >>> +static u32 vduse_vdpa_get_device_id(struct vdpa_device *vdpa)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     return dev->device_id;

> >>> +}

> >>> +

> >>> +static u32 vduse_vdpa_get_vendor_id(struct vdpa_device *vdpa)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     return dev->vendor_id;

> >>> +}

> >>> +

> >>> +static u8 vduse_vdpa_get_status(struct vdpa_device *vdpa)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     return vduse_dev_get_status(dev);

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_set_status(struct vdpa_device *vdpa, u8 status)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     vduse_dev_set_status(dev, status);

> >>> +

> >>> +     if (status == 0)

> >>> +             vduse_dev_reset(dev);

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,

> >>> +                          void *buf, unsigned int len)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     vduse_dev_get_config(dev, offset, buf, len);

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_set_config(struct vdpa_device *vdpa, unsigned int offset,

> >>> +                     const void *buf, unsigned int len)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     vduse_dev_set_config(dev, offset, buf, len);

> >>> +}

> >>> +

> >>> +static int vduse_vdpa_set_map(struct vdpa_device *vdpa,

> >>> +                             struct vhost_iotlb *iotlb)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +     int ret;

> >>> +

> >>> +     ret = vduse_domain_set_map(dev->domain, iotlb);

> >>> +     vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);

> >>> +

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static void vduse_vdpa_free(struct vdpa_device *vdpa)

> >>> +{

> >>> +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);

> >>> +

> >>> +     WARN_ON(!list_empty(&dev->send_list));

> >>> +     WARN_ON(!list_empty(&dev->recv_list));

> >>> +     dev->vdev = NULL;

> >>> +}

> >>> +

> >>> +static const struct vdpa_config_ops vduse_vdpa_config_ops = {

> >>> +     .set_vq_address         = vduse_vdpa_set_vq_address,

> >>> +     .kick_vq                = vduse_vdpa_kick_vq,

> >>> +     .set_vq_cb              = vduse_vdpa_set_vq_cb,

> >>> +     .set_vq_num             = vduse_vdpa_set_vq_num,

> >>> +     .set_vq_ready           = vduse_vdpa_set_vq_ready,

> >>> +     .get_vq_ready           = vduse_vdpa_get_vq_ready,

> >>> +     .set_vq_state           = vduse_vdpa_set_vq_state,

> >>> +     .get_vq_state           = vduse_vdpa_get_vq_state,

> >>> +     .get_vq_align           = vduse_vdpa_get_vq_align,

> >>> +     .get_features           = vduse_vdpa_get_features,

> >>> +     .set_features           = vduse_vdpa_set_features,

> >>> +     .set_config_cb          = vduse_vdpa_set_config_cb,

> >>> +     .get_vq_num_max         = vduse_vdpa_get_vq_num_max,

> >>> +     .get_device_id          = vduse_vdpa_get_device_id,

> >>> +     .get_vendor_id          = vduse_vdpa_get_vendor_id,

> >>> +     .get_status             = vduse_vdpa_get_status,

> >>> +     .set_status             = vduse_vdpa_set_status,

> >>> +     .get_config             = vduse_vdpa_get_config,

> >>> +     .set_config             = vduse_vdpa_set_config,

> >>> +     .set_map                = vduse_vdpa_set_map,

> >>> +     .free                   = vduse_vdpa_free,

> >>> +};

> >>> +

> >>> +static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,

> >>> +                                  unsigned long offset, size_t size,

> >>> +                                  enum dma_data_direction dir,

> >>> +                                  unsigned long attrs)

> >>> +{

> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);

> >>> +     struct vduse_iova_domain *domain = vdev->domain;

> >>> +

> >>> +     return vduse_domain_map_page(domain, page, offset, size, dir, attrs);

> >>> +}

> >>> +

> >>> +static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,

> >>> +                             size_t size, enum dma_data_direction dir,

> >>> +                             unsigned long attrs)

> >>> +{

> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);

> >>> +     struct vduse_iova_domain *domain = vdev->domain;

> >>> +

> >>> +     return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);

> >>> +}

> >>> +

> >>> +static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,

> >>> +                                     dma_addr_t *dma_addr, gfp_t flag,

> >>> +                                     unsigned long attrs)

> >>> +{

> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);

> >>> +     struct vduse_iova_domain *domain = vdev->domain;

> >>> +     unsigned long iova;

> >>> +     void *addr;

> >>> +

> >>> +     *dma_addr = DMA_MAPPING_ERROR;

> >>> +     addr = vduse_domain_alloc_coherent(domain, size,

> >>> +                             (dma_addr_t *)&iova, flag, attrs);

> >>> +     if (!addr)

> >>> +             return NULL;

> >>> +

> >>> +     *dma_addr = (dma_addr_t)iova;

> >>> +     vduse_dev_update_iotlb(vdev, iova, iova + size - 1);

> >>> +

> >>> +     return addr;

> >>> +}

> >>> +

> >>> +static void vduse_dev_free_coherent(struct device *dev, size_t size,

> >>> +                                     void *vaddr, dma_addr_t dma_addr,

> >>> +                                     unsigned long attrs)

> >>> +{

> >>> +     struct vduse_dev *vdev = dev_to_vduse(dev);

> >>> +     struct vduse_iova_domain *domain = vdev->domain;

> >>> +     unsigned long start = (unsigned long)dma_addr;

> >>> +     unsigned long last = start + size - 1;

> >>> +

> >>> +     vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);

> >>> +     vduse_dev_update_iotlb(vdev, start, last);

> >>> +}

> >>> +

> >>> +static const struct dma_map_ops vduse_dev_dma_ops = {

> >>> +     .map_page = vduse_dev_map_page,

> >>> +     .unmap_page = vduse_dev_unmap_page,

> >>> +     .alloc = vduse_dev_alloc_coherent,

> >>> +     .free = vduse_dev_free_coherent,

> >>> +};

> >>> +

> >>> +static unsigned int perm_to_file_flags(u8 perm)

> >>> +{

> >>> +     unsigned int flags = 0;

> >>> +

> >>> +     switch (perm) {

> >>> +     case VDUSE_ACCESS_WO:

> >>> +             flags |= O_WRONLY;

> >>> +             break;

> >>> +     case VDUSE_ACCESS_RO:

> >>> +             flags |= O_RDONLY;

> >>> +             break;

> >>> +     case VDUSE_ACCESS_RW:

> >>> +             flags |= O_RDWR;

> >>> +             break;

> >>> +     default:

> >>> +             WARN(1, "invalidate vhost IOTLB permission\n");

> >>> +             break;

> >>> +     }

> >>> +

> >>> +     return flags;

> >>> +}

> >>> +

> >>> +static int vduse_kickfd_setup(struct vduse_dev *dev,

> >>> +                     struct vduse_vq_eventfd *eventfd)

> >>> +{

> >>> +     struct eventfd_ctx *ctx = NULL;

> >>> +     struct vduse_virtqueue *vq;

> >>> +

> >>> +     if (eventfd->index >= dev->vq_num)

> >>> +             return -EINVAL;

> >>> +

> >>> +     vq = &dev->vqs[eventfd->index];

> >>> +     if (eventfd->fd > 0) {

> >>> +             ctx = eventfd_ctx_fdget(eventfd->fd);

> >>> +             if (IS_ERR(ctx))

> >>> +                     return PTR_ERR(ctx);

> >>> +     } else if (eventfd->fd != VDUSE_EVENTFD_DEASSIGN)

> >>> +             return 0;

> >>

> >> Do we allow the userspace to switch kickfd here? If yes, we need to deal

> >> with that.

> >>

> > Do you mean the case that eventfd->fd > 0? I think we have dealt with it.

>

>

> Ok, but the above code still looks suspicious. E.g what happens if

> eventfd->fd is 0?

>


Oh, yes. I think we need eventfd->fd >= 0 here.

>

> >

> >>> +

> >>> +     spin_lock(&vq->kick_lock);

> >>> +     if (vq->kickfd)

> >>> +             eventfd_ctx_put(vq->kickfd);

> >>> +     vq->kickfd = ctx;

> >>> +     spin_unlock(&vq->kick_lock);

> >>> +

> >>> +     return 0;

> >>> +}

> >>> +

> >>> +static void vduse_vq_irq_inject(struct work_struct *work)

> >>> +{

> >>> +     struct vduse_virtqueue *vq = container_of(work,

> >>> +                                     struct vduse_virtqueue, inject);

> >>> +

> >>> +     spin_lock_irq(&vq->irq_lock);

> >>> +     if (vq->ready && vq->cb.callback)

> >>> +             vq->cb.callback(vq->cb.private);

> >>> +     spin_unlock_irq(&vq->irq_lock);

> >>> +}

> >>> +

> >>> +static long vduse_dev_ioctl(struct file *file, unsigned int cmd,

> >>> +                         unsigned long arg)

> >>> +{

> >>> +     struct vduse_dev *dev = file->private_data;

> >>> +     void __user *argp = (void __user *)arg;

> >>> +     int ret;

> >>> +

> >>> +     switch (cmd) {

> >>> +     case VDUSE_IOTLB_GET_FD: {

> >>> +             struct vduse_iotlb_entry entry;

> >>> +             struct vhost_iotlb_map *map;

> >>> +             struct vdpa_map_file *map_file;

> >>> +             struct vduse_iova_domain *domain = dev->domain;

> >>> +             struct file *f = NULL;

> >>> +

> >>> +             ret = -EFAULT;

> >>> +             if (copy_from_user(&entry, argp, sizeof(entry)))

> >>> +                     break;

> >>> +

> >>> +             ret = -EINVAL;

> >>> +             if (entry.start > entry.last)

> >>> +                     break;

> >>> +

> >>> +             spin_lock(&domain->iotlb_lock);

> >>> +             map = vhost_iotlb_itree_first(domain->iotlb,

> >>> +                                           entry.start, entry.last);

> >>> +             if (map) {

> >>> +                     map_file = (struct vdpa_map_file *)map->opaque;

> >>> +                     f = get_file(map_file->file);

> >>> +                     entry.offset = map_file->offset;

> >>> +                     entry.start = map->start;

> >>> +                     entry.last = map->last;

> >>> +                     entry.perm = map->perm;

> >>> +             }

> >>> +             spin_unlock(&domain->iotlb_lock);

> >>> +             ret = -EINVAL;

> >>> +             if (!f)

> >>> +                     break;

> >>> +

> >>> +             ret = -EFAULT;

> >>> +             if (copy_to_user(argp, &entry, sizeof(entry))) {

> >>> +                     fput(f);

> >>> +                     break;

> >>> +             }

> >>> +             ret = receive_fd(f, perm_to_file_flags(entry.perm));

> >>> +             fput(f);

> >>

> >> Any reason to drop the refcnt here?

> >>

> > We will do get_file() in receive_fd() too.

>

>

> I see.

>

>

> >

> >>> +             break;

> >>> +     }

> >>> +     case VDUSE_VQ_SETUP_KICKFD: {

> >>> +             struct vduse_vq_eventfd eventfd;

> >>> +

> >>> +             ret = -EFAULT;

> >>> +             if (copy_from_user(&eventfd, argp, sizeof(eventfd)))

> >>> +                     break;

> >>> +

> >>> +             ret = vduse_kickfd_setup(dev, &eventfd);

> >>> +             break;

> >>> +     }

> >>> +     case VDUSE_INJECT_VQ_IRQ:

> >>> +             ret = -EINVAL;

> >>> +             if (arg >= dev->vq_num)

> >>> +                     break;

> >>> +

> >>> +             ret = 0;

> >>> +             queue_work(vduse_irq_wq, &dev->vqs[arg].inject);

> >>> +             break;

> >>> +     case VDUSE_INJECT_CONFIG_IRQ:

> >>> +             ret = -EINVAL;

> >>> +             spin_lock_irq(&dev->irq_lock);

> >>> +             if (dev->config_cb.callback) {

> >>> +                     dev->config_cb.callback(dev->config_cb.private);

> >>> +                     ret = 0;

> >>> +             }

> >>> +             spin_unlock_irq(&dev->irq_lock);

> >>

> >> For consistency, is it better to use vduse_irq_wq here?

> >>

> > Looks good to me.

> >

> >>> +             break;

> >>> +     default:

> >>> +             ret = -ENOIOCTLCMD;

> >>> +             break;

> >>> +     }

> >>> +

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static int vduse_dev_release(struct inode *inode, struct file *file)

> >>> +{

> >>> +     struct vduse_dev *dev = file->private_data;

> >>> +     struct vduse_dev_msg *msg;

> >>> +     int i;

> >>> +

> >>> +     for (i = 0; i < dev->vq_num; i++) {

> >>> +             struct vduse_virtqueue *vq = &dev->vqs[i];

> >>> +

> >>> +             spin_lock(&vq->kick_lock);

> >>> +             if (vq->kickfd)

> >>> +                     eventfd_ctx_put(vq->kickfd);

> >>> +             vq->kickfd = NULL;

> >>> +             spin_unlock(&vq->kick_lock);

> >>> +     }

> >>> +

> >>> +     spin_lock(&dev->msg_lock);

> >>> +     /*  Make sure the inflight messages can processed */

> >>

> >> This might be better:

> >>

> >> /*  Make sure the inflight messages can processed after reconncection */

> >>

> > OK.

> >

> >>> +     while ((msg = vduse_dequeue_msg(&dev->recv_list)))

> >>> +             vduse_enqueue_msg(&dev->send_list, msg);

> >>> +     spin_unlock(&dev->msg_lock);

> >>> +

> >>> +     dev->connected = false;

> >>> +

> >>> +     return 0;

> >>> +}

> >>> +

> >>> +static int vduse_dev_open(struct inode *inode, struct file *file)

> >>> +{

> >>> +     struct vduse_dev *dev = container_of(inode->i_cdev,

> >>> +                                     struct vduse_dev, cdev);

> >>> +     int ret = -EBUSY;

> >>> +

> >>> +     mutex_lock(&dev->lock);

> >>> +     if (dev->connected)

> >>> +             goto unlock;

> >>> +

> >>> +     ret = 0;

> >>> +     dev->connected = true;

> >>> +     file->private_data = dev;

> >>> +unlock:

> >>> +     mutex_unlock(&dev->lock);

> >>> +

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static const struct file_operations vduse_dev_fops = {

> >>> +     .owner          = THIS_MODULE,

> >>> +     .open           = vduse_dev_open,

> >>> +     .release        = vduse_dev_release,

> >>> +     .read_iter      = vduse_dev_read_iter,

> >>> +     .write_iter     = vduse_dev_write_iter,

> >>> +     .poll           = vduse_dev_poll,

> >>> +     .unlocked_ioctl = vduse_dev_ioctl,

> >>> +     .compat_ioctl   = compat_ptr_ioctl,

> >>> +     .llseek         = noop_llseek,

> >>> +};

> >>> +

> >>> +static struct vduse_dev *vduse_dev_create(void)

> >>> +{

> >>> +     struct vduse_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);

> >>> +

> >>> +     if (!dev)

> >>> +             return NULL;

> >>> +

> >>> +     mutex_init(&dev->lock);

> >>> +     spin_lock_init(&dev->msg_lock);

> >>> +     INIT_LIST_HEAD(&dev->send_list);

> >>> +     INIT_LIST_HEAD(&dev->recv_list);

> >>> +     atomic64_set(&dev->msg_unique, 0);

> >>> +     spin_lock_init(&dev->irq_lock);

> >>> +

> >>> +     init_waitqueue_head(&dev->waitq);

> >>> +

> >>> +     return dev;

> >>> +}

> >>> +

> >>> +static void vduse_dev_destroy(struct vduse_dev *dev)

> >>> +{

> >>> +     kfree(dev);

> >>> +}

> >>> +

> >>> +static struct vduse_dev *vduse_find_dev(const char *name)

> >>> +{

> >>> +     struct vduse_dev *tmp, *dev = NULL;

> >>> +

> >>> +     list_for_each_entry(tmp, &vduse_devs, list) {

> >>> +             if (!strcmp(dev_name(&tmp->dev), name)) {

> >>> +                     dev = tmp;

> >>> +                     break;

> >>> +             }

> >>> +     }

> >>> +     return dev;

> >>> +}

> >>> +

> >>> +static int vduse_destroy_dev(char *name)

> >>> +{

> >>> +     struct vduse_dev *dev = vduse_find_dev(name);

> >>> +

> >>> +     if (!dev)

> >>> +             return -EINVAL;

> >>> +

> >>> +     mutex_lock(&dev->lock);

> >>> +     if (dev->vdev || dev->connected) {

> >>> +             mutex_unlock(&dev->lock);

> >>> +             return -EBUSY;

> >>> +     }

> >>> +     dev->connected = true;

> >>> +     mutex_unlock(&dev->lock);

> >>> +

> >>> +     list_del(&dev->list);

> >>> +     cdev_device_del(&dev->cdev, &dev->dev);

> >>> +     put_device(&dev->dev);

> >>> +     module_put(THIS_MODULE);

> >>> +

> >>> +     return 0;

> >>> +}

> >>> +

> >>> +static void vduse_release_dev(struct device *device)

> >>> +{

> >>> +     struct vduse_dev *dev =

> >>> +             container_of(device, struct vduse_dev, dev);

> >>> +

> >>> +     ida_simple_remove(&vduse_ida, dev->minor);

> >>> +     kfree(dev->vqs);

> >>> +     vduse_domain_destroy(dev->domain);

> >>> +     vduse_dev_destroy(dev);

> >>> +}

> >>> +

> >>> +static int vduse_create_dev(struct vduse_dev_config *config,

> >>> +                         unsigned long api_version)

> >>> +{

> >>> +     int i, ret = -ENOMEM;

> >>> +     struct vduse_dev *dev;

> >>> +

> >>> +     if (config->bounce_size > max_bounce_size)

> >>> +             return -EINVAL;

> >>> +

> >>> +     if (config->bounce_size > max_iova_size)

> >>> +             return -EINVAL;

> >>> +

> >>> +     if (vduse_find_dev(config->name))

> >>> +             return -EEXIST;

> >>> +

> >>> +     dev = vduse_dev_create();

> >>> +     if (!dev)

> >>> +             return -ENOMEM;

> >>> +

> >>> +     dev->api_version = api_version;

> >>> +     dev->device_id = config->device_id;

> >>> +     dev->vendor_id = config->vendor_id;

> >>> +     dev->domain = vduse_domain_create(max_iova_size - 1,

> >>> +                                     config->bounce_size);

> >>> +     if (!dev->domain)

> >>> +             goto err_domain;

> >>> +

> >>> +     dev->vq_align = config->vq_align;

> >>> +     dev->vq_size_max = config->vq_size_max;

> >>> +     dev->vq_num = config->vq_num;

> >>> +     dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);

> >>> +     if (!dev->vqs)

> >>> +             goto err_vqs;

> >>> +

> >>> +     for (i = 0; i < dev->vq_num; i++) {

> >>> +             dev->vqs[i].index = i;

> >>> +             INIT_WORK(&dev->vqs[i].inject, vduse_vq_irq_inject);

> >>> +             spin_lock_init(&dev->vqs[i].kick_lock);

> >>> +             spin_lock_init(&dev->vqs[i].irq_lock);

> >>> +     }

> >>> +

> >>> +     ret = ida_simple_get(&vduse_ida, 0, VDUSE_DEV_MAX, GFP_KERNEL);

> >>> +     if (ret < 0)

> >>> +             goto err_ida;

> >>> +

> >>> +     dev->minor = ret;

> >>> +     device_initialize(&dev->dev);

> >>> +     dev->dev.release = vduse_release_dev;

> >>> +     dev->dev.class = vduse_class;

> >>> +     dev->dev.devt = MKDEV(MAJOR(vduse_major), dev->minor);

> >>> +     ret = dev_set_name(&dev->dev, "%s", config->name);

> >>> +     if (ret) {

> >>> +             put_device(&dev->dev);

> >>> +             return ret;

> >>> +     }

> >>> +     cdev_init(&dev->cdev, &vduse_dev_fops);

> >>> +     dev->cdev.owner = THIS_MODULE;

> >>> +

> >>> +     ret = cdev_device_add(&dev->cdev, &dev->dev);

> >>> +     if (ret) {

> >>> +             put_device(&dev->dev);

> >>> +             return ret;

> >>

> >> Let's introduce an error label for this.

> >>

> > But put_device() would be duplicated with the below error handling.

>

>

> I think it's as simple as put the error label after the return.

>


OK.

>

> >

> >>> +     }

> >>> +     list_add(&dev->list, &vduse_devs);

> >>> +     __module_get(THIS_MODULE);

> >>> +

> >>> +     return 0;

> >>> +err_ida:

> >>> +     kfree(dev->vqs);

> >>> +err_vqs:

> >>> +     vduse_domain_destroy(dev->domain);

> >>> +err_domain:

> >>> +     vduse_dev_destroy(dev);

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static long vduse_ioctl(struct file *file, unsigned int cmd,

> >>> +                     unsigned long arg)

> >>> +{

> >>> +     int ret;

> >>> +     void __user *argp = (void __user *)arg;

> >>> +     struct vduse_control *control = file->private_data;

> >>> +

> >>> +     mutex_lock(&vduse_lock);

> >>> +     switch (cmd) {

> >>> +     case VDUSE_GET_API_VERSION:

> >>> +             ret = control->api_version;

> >>> +             break;

> >>> +     case VDUSE_SET_API_VERSION:

> >>> +             ret = -EINVAL;

> >>> +             if (arg > VDUSE_API_VERSION)

> >>> +                     break;

> >>> +

> >>> +             ret = 0;

> >>> +             control->api_version = arg;

> >>> +             break;

> >>> +     case VDUSE_CREATE_DEV: {

> >>> +             struct vduse_dev_config config;

> >>> +

> >>> +             ret = -EFAULT;

> >>> +             if (copy_from_user(&config, argp, sizeof(config)))

> >>> +                     break;

> >>> +

> >>> +             ret = vduse_create_dev(&config, control->api_version);

> >>> +             break;

> >>> +     }

> >>> +     case VDUSE_DESTROY_DEV: {

> >>> +             char name[VDUSE_NAME_MAX];

> >>> +

> >>> +             ret = -EFAULT;

> >>> +             if (copy_from_user(name, argp, VDUSE_NAME_MAX))

> >>> +                     break;

> >>> +

> >>> +             ret = vduse_destroy_dev(name);

> >>> +             break;

> >>> +     }

> >>> +     default:

> >>> +             ret = -EINVAL;

> >>> +             break;

> >>> +     }

> >>> +     mutex_unlock(&vduse_lock);

> >>> +

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static int vduse_release(struct inode *inode, struct file *file)

> >>> +{

> >>> +     struct vduse_control *control = file->private_data;

> >>> +

> >>> +     kfree(control);

> >>> +     return 0;

> >>> +}

> >>> +

> >>> +static int vduse_open(struct inode *inode, struct file *file)

> >>> +{

> >>> +     struct vduse_control *control;

> >>> +

> >>> +     control = kmalloc(sizeof(struct vduse_control), GFP_KERNEL);

> >>> +     if (!control)

> >>> +             return -ENOMEM;

> >>> +

> >>> +     control->api_version = VDUSE_API_VERSION;

> >>> +     file->private_data = control;

> >>> +

> >>> +     return 0;

> >>> +}

> >>> +

> >>> +static const struct file_operations vduse_fops = {

> >>> +     .owner          = THIS_MODULE,

> >>> +     .open           = vduse_open,

> >>> +     .release        = vduse_release,

> >>> +     .unlocked_ioctl = vduse_ioctl,

> >>> +     .compat_ioctl   = compat_ptr_ioctl,

> >>> +     .llseek         = noop_llseek,

> >>> +};

> >>> +

> >>> +static char *vduse_devnode(struct device *dev, umode_t *mode)

> >>> +{

> >>> +     return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));

> >>> +}

> >>> +

> >>> +static struct miscdevice vduse_misc = {

> >>> +     .fops = &vduse_fops,

> >>> +     .minor = MISC_DYNAMIC_MINOR,

> >>> +     .name = "vduse",

> >>> +     .nodename = "vduse/control",

> >>> +};

> >>> +

> >>> +static void vduse_mgmtdev_release(struct device *dev)

> >>> +{

> >>> +}

> >>> +

> >>> +static struct device vduse_mgmtdev = {

> >>> +     .init_name = "vduse",

> >>> +     .release = vduse_mgmtdev_release,

> >>> +};

> >>> +

> >>> +static struct vdpa_mgmt_dev mgmt_dev;

> >>> +

> >>> +static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)

> >>> +{

> >>> +     struct vduse_vdpa *vdev;

> >>> +     int ret;

> >>> +

> >>> +     if (dev->vdev)

> >>> +             return -EEXIST;

> >>> +

> >>> +     vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, &dev->dev,

> >>> +                              &vduse_vdpa_config_ops, name, true);

> >>> +     if (!vdev)

> >>> +             return -ENOMEM;

> >>> +

> >>> +     dev->vdev = vdev;

> >>> +     vdev->dev = dev;

> >>> +     vdev->vdpa.dev.dma_mask = &vdev->vdpa.dev.coherent_dma_mask;

> >>> +     ret = dma_set_mask_and_coherent(&vdev->vdpa.dev, DMA_BIT_MASK(64));

> >>> +     if (ret) {

> >>> +             put_device(&vdev->vdpa.dev);

> >>> +             return ret;

> >>> +     }

> >>> +     set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);

> >>> +     vdev->vdpa.dma_dev = &vdev->vdpa.dev;

> >>> +     vdev->vdpa.mdev = &mgmt_dev;

> >>> +

> >>> +     return 0;

> >>> +}

> >>> +

> >>> +static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)

> >>> +{

> >>> +     struct vduse_dev *dev;

> >>> +     int ret = -EINVAL;

> >>> +

> >>> +     mutex_lock(&vduse_lock);

> >>> +     dev = vduse_find_dev(name);

> >>> +     if (!dev) {

> >>> +             mutex_unlock(&vduse_lock);

> >>> +             return -EINVAL;

> >>> +     }

> >>> +     ret = vduse_dev_init_vdpa(dev, name);

> >>> +     mutex_unlock(&vduse_lock);

> >>> +     if (ret)

> >>> +             return ret;

> >>> +

> >>> +     ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);

> >>> +     if (ret) {

> >>> +             put_device(&dev->vdev->vdpa.dev);

> >>> +             return ret;

> >>> +     }

> >>> +

> >>> +     return 0;

> >>> +}

> >>> +

> >>> +static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)

> >>> +{

> >>> +     _vdpa_unregister_device(dev);

> >>> +}

> >>> +

> >>> +static const struct vdpa_mgmtdev_ops vdpa_dev_mgmtdev_ops = {

> >>> +     .dev_add = vdpa_dev_add,

> >>> +     .dev_del = vdpa_dev_del,

> >>> +};

> >>> +

> >>> +static struct virtio_device_id id_table[] = {

> >>> +     { VIRTIO_DEV_ANY_ID, VIRTIO_DEV_ANY_ID },

> >>> +     { 0 },

> >>> +};

> >>> +

> >>> +static struct vdpa_mgmt_dev mgmt_dev = {

> >>> +     .device = &vduse_mgmtdev,

> >>> +     .id_table = id_table,

> >>> +     .ops = &vdpa_dev_mgmtdev_ops,

> >>> +};

> >>> +

> >>> +static int vduse_mgmtdev_init(void)

> >>> +{

> >>> +     int ret;

> >>> +

> >>> +     ret = device_register(&vduse_mgmtdev);

> >>> +     if (ret)

> >>> +             return ret;

> >>> +

> >>> +     ret = vdpa_mgmtdev_register(&mgmt_dev);

> >>> +     if (ret)

> >>> +             goto err;

> >>> +

> >>> +     return 0;

> >>> +err:

> >>> +     device_unregister(&vduse_mgmtdev);

> >>> +     return ret;

> >>> +}

> >>> +

> >>> +static void vduse_mgmtdev_exit(void)

> >>> +{

> >>> +     vdpa_mgmtdev_unregister(&mgmt_dev);

> >>> +     device_unregister(&vduse_mgmtdev);

> >>> +}

> >>> +

> >>> +static int vduse_init(void)

> >>> +{

> >>> +     int ret;

> >>> +

> >>> +     if (max_bounce_size >= max_iova_size)

> >>> +             return -EINVAL;

> >>> +

> >>> +     ret = misc_register(&vduse_misc);

> >>> +     if (ret)

> >>> +             return ret;

> >>> +

> >>> +     vduse_class = class_create(THIS_MODULE, "vduse");

> >>> +     if (IS_ERR(vduse_class)) {

> >>> +             ret = PTR_ERR(vduse_class);

> >>> +             goto err_class;

> >>> +     }

> >>> +     vduse_class->devnode = vduse_devnode;

> >>> +

> >>> +     ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse");

> >>> +     if (ret)

> >>> +             goto err_chardev;

> >>> +

> >>> +     vduse_irq_wq = alloc_workqueue("vduse-irq",

> >>> +                             WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);

> >>> +     if (!vduse_irq_wq)

> >>> +             goto err_wq;

> >>> +

> >>> +     ret = vduse_domain_init();

> >>> +     if (ret)

> >>> +             goto err_domain;

> >>> +

> >>> +     ret = vduse_mgmtdev_init();

> >>> +     if (ret)

> >>> +             goto err_mgmtdev;

> >>> +

> >>> +     return 0;

> >>> +err_mgmtdev:

> >>> +     vduse_domain_exit();

> >>> +err_domain:

> >>> +     destroy_workqueue(vduse_irq_wq);

> >>> +err_wq:

> >>> +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);

> >>> +err_chardev:

> >>> +     class_destroy(vduse_class);

> >>> +err_class:

> >>> +     misc_deregister(&vduse_misc);

> >>> +     return ret;

> >>> +}

> >>> +module_init(vduse_init);

> >>> +

> >>> +static void vduse_exit(void)

> >>> +{

> >>> +     misc_deregister(&vduse_misc);

> >>> +     class_destroy(vduse_class);

> >>> +     unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);

> >>> +     destroy_workqueue(vduse_irq_wq);

> >>> +     vduse_domain_exit();

> >>> +     vduse_mgmtdev_exit();

> >>> +}

> >>> +module_exit(vduse_exit);

> >>> +

> >>> +MODULE_VERSION(DRV_VERSION);

> >>> +MODULE_LICENSE(DRV_LICENSE);

> >>> +MODULE_AUTHOR(DRV_AUTHOR);

> >>> +MODULE_DESCRIPTION(DRV_DESC);

> >>> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h

> >>> new file mode 100644

> >>> index 000000000000..66a6e5212226

> >>> --- /dev/null

> >>> +++ b/include/uapi/linux/vduse.h

> >>> @@ -0,0 +1,175 @@

> >>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */

> >>> +#ifndef _UAPI_VDUSE_H_

> >>> +#define _UAPI_VDUSE_H_

> >>> +

> >>> +#include <linux/types.h>

> >>> +

> >>> +#define VDUSE_API_VERSION    0

> >>> +

> >>> +#define VDUSE_CONFIG_DATA_LEN        256

> >>> +#define VDUSE_NAME_MAX       256

> >>> +

> >>> +/* the control messages definition for read/write */

> >>> +

> >>> +enum vduse_req_type {

> >>> +     /* Set the vring address of virtqueue. */

> >>> +     VDUSE_SET_VQ_NUM,

> >>> +     /* Set the vring address of virtqueue. */

> >>> +     VDUSE_SET_VQ_ADDR,

> >>> +     /* Set ready status of virtqueue */

> >>> +     VDUSE_SET_VQ_READY,

> >>> +     /* Get ready status of virtqueue */

> >>> +     VDUSE_GET_VQ_READY,

> >>> +     /* Set the state for virtqueue */

> >>> +     VDUSE_SET_VQ_STATE,

> >>> +     /* Get the state for virtqueue */

> >>> +     VDUSE_GET_VQ_STATE,

> >>> +     /* Set virtio features supported by the driver */

> >>> +     VDUSE_SET_FEATURES,

> >>> +     /* Get virtio features supported by the device */

> >>> +     VDUSE_GET_FEATURES,

> >>> +     /* Set the device status */

> >>> +     VDUSE_SET_STATUS,

> >>> +     /* Get the device status */

> >>> +     VDUSE_GET_STATUS,

> >>> +     /* Write to device specific configuration space */

> >>> +     VDUSE_SET_CONFIG,

> >>> +     /* Read from device specific configuration space */

> >>> +     VDUSE_GET_CONFIG,

> >>> +     /* Notify userspace to update the memory mapping in device IOTLB */

> >>> +     VDUSE_UPDATE_IOTLB,

> >>> +};

> >>> +

> >>> +struct vduse_vq_num {

> >>> +     __u32 index; /* virtqueue index */

> >>

> >> I think it's better to have a consistent style of the doc/comment. If

> >> yes, let's move those comment above the field.

> >>

> > Fine.

> >

> >>> +     __u32 num; /* the size of virtqueue */

> >>> +};

> >>> +

> >>> +struct vduse_vq_addr {

> >>> +     __u32 index; /* virtqueue index */

> >>> +     __u64 desc_addr; /* address of desc area */

> >>> +     __u64 driver_addr; /* address of driver area */

> >>> +     __u64 device_addr; /* address of device area */

> >>> +};

> >>> +

> >>> +struct vduse_vq_ready {

> >>> +     __u32 index; /* virtqueue index */

> >>> +     __u8 ready; /* ready status of virtqueue */

> >>> +};

> >>> +

> >>> +struct vduse_vq_state {

> >>> +     __u32 index; /* virtqueue index */

> >>> +     __u16 avail_idx; /* virtqueue state (last_avail_idx) */

> >>

> >> Let's use __u64 here to be consistent with get_vq_state().

>

>

> __u32 actually:

>

> struct vhost_vring_state {

>          unsigned int index;

>          unsigned int num;

> };

>


OK.

>

> >>   The idea is

> >> to support packed virtqueue.

> >>

> > OK. But looks like sizeof(struct vdpa_vq_state) is still equal to 2.

>

>

> It's a bug that needs to be fixed.

>

>

> > Do you mean we will extend it in the future?

>

>

> u32 should be fine, and it's not for future. For packed virtqueue we

> need something like:

>

> le32 {

>      last_avai_idx : 15;

>      last_avail_wrap_counter : 1;

>      used_idx : 15;

>      used_wrap_counter : 1;

> }

>

> As has been done in

> https://lore.kernel.org/lkml/20190717105255.63488-3-jasowang@redhat.com/T/

>


I see.

>

> >

> >>> +};

> >>> +

> >>> +struct vduse_dev_config_data {

> >>> +     __u32 offset; /* offset from the beginning of config space */

> >>> +     __u32 len; /* the length to read/write */

> >>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

> >>

> >> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

> >> not change it in the future.

> >>

> >> So this might suffcient for future features or all type of virtio devices.

> >>

> > Do you mean 256 is no enough here?

>

>

> Yes.

>


But this request will be submitted multiple times if config lengh is
larger than 256. So do you think whether we need to extent the size to
512 or larger?

>

> >

> >>> +};

> >>> +

> >>> +struct vduse_iova_range {

> >>> +     __u64 start; /* start of the IOVA range */

> >>> +     __u64 last; /* end of the IOVA range */

> >>> +};

> >>> +

> >>> +struct vduse_features {

> >>> +     __u64 features; /* virtio features */

> >>> +};

> >>> +

> >>> +struct vduse_status {

> >>> +     __u8 status; /* device status */

> >>> +};

> >>> +

> >>> +struct vduse_dev_request {

> >>> +     __u32 type; /* request type */

> >>> +     __u32 request_id; /* request id */

> >>> +     __u32 reserved[2]; /* for future use */

> >>> +     union {

> >>> +             struct vduse_vq_num vq_num; /* virtqueue num */

> >>> +             struct vduse_vq_addr vq_addr; /* virtqueue address */

> >>> +             struct vduse_vq_ready vq_ready; /* virtqueue ready status */

> >>> +             struct vduse_vq_state vq_state; /* virtqueue state */

> >>> +             struct vduse_dev_config_data config; /* virtio device config space */

> >>> +             struct vduse_iova_range iova; /* iova range for updating */

> >>> +             struct vduse_features f; /* virtio features */

> >>> +             struct vduse_status s; /* device status */

> >>> +             __u32 padding[16]; /* padding */

> >>> +     };

> >>> +};

> >>> +

> >>> +struct vduse_dev_response {

> >>> +     __u32 request_id; /* corresponding request id */

> >>> +#define VDUSE_REQUEST_OK     0x00

> >>> +#define VDUSE_REQUEST_FAILED 0x01

> >>> +     __u32 result; /* the result of request */

> >>> +     __u32 reserved[2]; /* for future use */

> >>> +     union {

> >>> +             struct vduse_vq_ready vq_ready; /* virtqueue ready status */

> >>> +             struct vduse_vq_state vq_state; /* virtqueue state */

> >>> +             struct vduse_dev_config_data config; /* virtio device config space */

> >>> +             struct vduse_features f; /* virtio features */

> >>> +             struct vduse_status s; /* device status */

> >>> +             __u32 padding[16]; /* padding */

> >>

> >> So it looks to me this padding doesn't work since vduse_dev_config_data

> >> is larger than it.

> >>

> > Oh, my bad. Will fix it.

> >

> >>> +     };

> >>> +};

> >>> +

> >>> +/* ioctls */

> >>> +

> >>> +struct vduse_dev_config {

> >>> +     char name[VDUSE_NAME_MAX]; /* vduse device name */

> >>> +     __u32 vendor_id; /* virtio vendor id */

> >>> +     __u32 device_id; /* virtio device id */

> >>> +     __u64 bounce_size; /* bounce buffer size for iommu */

> >>> +     __u16 vq_num; /* the number of virtqueues */

> >>> +     __u16 vq_size_max; /* the max size of virtqueue */

> >>> +     __u32 vq_align; /* the allocation alignment of virtqueue's metadata */

> >>> +     __u32 reserved[8]; /* for future use */

> >>

> >> Is there a hole before reserved?

> >>

> > But I don't find the hole in below layout:

> >

> > | 256 | 4 | 4 | 8 | 2 | 2 | 4 | 32 |

> >

>

> Looks correct, better to check with pahole to double confirm.

>


OK. Sure.

>

> >>> +};

> >>> +

> >>> +struct vduse_iotlb_entry {

> >>> +     __u64 offset; /* the mmap offset on fd */

> >>> +     __u64 start; /* start of the IOVA range */

> >>> +     __u64 last; /* last of the IOVA range */

> >>> +#define VDUSE_ACCESS_RO 0x1

> >>> +#define VDUSE_ACCESS_WO 0x2

> >>> +#define VDUSE_ACCESS_RW 0x3

> >>> +     __u8 perm; /* access permission of this range */

> >>> +};

> >>> +

> >>> +struct vduse_vq_eventfd {

> >>> +     __u32 index; /* virtqueue index */

> >>> +#define VDUSE_EVENTFD_DEASSIGN -1

> >>> +     int fd; /* eventfd, -1 means de-assigning the eventfd */

> >>> +};

> >>> +

> >>> +#define VDUSE_BASE   0x81

> >>> +

> >>> +/* Get the version of VDUSE API. This is used for future extension */

> >>> +#define VDUSE_GET_API_VERSION        _IO(VDUSE_BASE, 0x00)

> >>> +

> >>> +/* Set the version of VDUSE API. */

> >>> +#define VDUSE_SET_API_VERSION        _IO(VDUSE_BASE, 0x01)

> >>> +

> >>> +/* Create a vduse device which is represented by a char device (/dev/vduse/<name>) */

> >>> +#define VDUSE_CREATE_DEV     _IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)

> >>> +

> >>> +/* Destroy a vduse device. Make sure there are no references to the char device */

> >>> +#define VDUSE_DESTROY_DEV    _IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])

> >>> +

> >>> +/*

> >>> + * Get a file descriptor for the first overlapped iova region,

> >>> + * -EINVAL means the iova region doesn't exist.

> >>> + */

> >>> +#define VDUSE_IOTLB_GET_FD   _IOWR(VDUSE_BASE, 0x04, struct vduse_iotlb_entry)

> >>> +

> >>> +/* Setup an eventfd to receive kick for virtqueue */

> >>> +#define VDUSE_VQ_SETUP_KICKFD        _IOW(VDUSE_BASE, 0x05, struct vduse_vq_eventfd)

> >>> +

> >>> +/* Inject an interrupt for specific virtqueue */

> >>> +#define VDUSE_INJECT_VQ_IRQ  _IO(VDUSE_BASE, 0x06)

> >>

> >> Missing parameter?

> >>

> > We use the argp to store the virtqueue index here. Is it OK?

>

>

> So I meant it should be something like:

>

> #define VDUSE_INJECT_VQ_IRQ  _IOW(VDUSE_BASE, 0x06, unsigned int)

>


It's OK to me.

Thanks,
Yongji
Jason Wang April 12, 2021, 7:16 a.m. UTC | #7
在 2021/4/9 下午4:02, Yongji Xie 写道:
>>>>> +};

>>>>> +

>>>>> +struct vduse_dev_config_data {

>>>>> +     __u32 offset; /* offset from the beginning of config space */

>>>>> +     __u32 len; /* the length to read/write */

>>>>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

>>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

>>>> not change it in the future.

>>>>

>>>> So this might suffcient for future features or all type of virtio devices.

>>>>

>>> Do you mean 256 is no enough here?

>> Yes.

>>

> But this request will be submitted multiple times if config lengh is

> larger than 256. So do you think whether we need to extent the size to

> 512 or larger?



So I think you'd better either:

1) document the limitation (256) in somewhere, (better both uapi and doc)

or

2) make it variable

Thanks


>
Yongji Xie April 12, 2021, 8:02 a.m. UTC | #8
On Mon, Apr 12, 2021 at 3:16 PM Jason Wang <jasowang@redhat.com> wrote:
>

>

> 在 2021/4/9 下午4:02, Yongji Xie 写道:

> >>>>> +};

> >>>>> +

> >>>>> +struct vduse_dev_config_data {

> >>>>> +     __u32 offset; /* offset from the beginning of config space */

> >>>>> +     __u32 len; /* the length to read/write */

> >>>>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

> >>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

> >>>> not change it in the future.

> >>>>

> >>>> So this might suffcient for future features or all type of virtio devices.

> >>>>

> >>> Do you mean 256 is no enough here?

> >> Yes.

> >>

> > But this request will be submitted multiple times if config lengh is

> > larger than 256. So do you think whether we need to extent the size to

> > 512 or larger?

>

>

> So I think you'd better either:

>

> 1) document the limitation (256) in somewhere, (better both uapi and doc)

>


But the VDUSE_CONFIG_DATA_LEN doesn't mean the limitation of
configuration space. It only means the maximum size of one data
transfer for configuration space. Do you mean document this?

Thanks,
Yongji
Jason Wang April 12, 2021, 9:37 a.m. UTC | #9
在 2021/4/12 下午4:02, Yongji Xie 写道:
> On Mon, Apr 12, 2021 at 3:16 PM Jason Wang <jasowang@redhat.com> wrote:

>>

>> 在 2021/4/9 下午4:02, Yongji Xie 写道:

>>>>>>> +};

>>>>>>> +

>>>>>>> +struct vduse_dev_config_data {

>>>>>>> +     __u32 offset; /* offset from the beginning of config space */

>>>>>>> +     __u32 len; /* the length to read/write */

>>>>>>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

>>>>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

>>>>>> not change it in the future.

>>>>>>

>>>>>> So this might suffcient for future features or all type of virtio devices.

>>>>>>

>>>>> Do you mean 256 is no enough here?

>>>> Yes.

>>>>

>>> But this request will be submitted multiple times if config lengh is

>>> larger than 256. So do you think whether we need to extent the size to

>>> 512 or larger?

>>

>> So I think you'd better either:

>>

>> 1) document the limitation (256) in somewhere, (better both uapi and doc)

>>

> But the VDUSE_CONFIG_DATA_LEN doesn't mean the limitation of

> configuration space. It only means the maximum size of one data

> transfer for configuration space. Do you mean document this?



Yes, and another thing is that since you're using 
data[VDUSE_CONFIG_DATA_LEN] in the uapi, it implies the length is always 
256 which seems not good and not what the code is wrote.

Thanks


>

> Thanks,

> Yongji

>
Yongji Xie April 12, 2021, 9:59 a.m. UTC | #10
On Mon, Apr 12, 2021 at 5:37 PM Jason Wang <jasowang@redhat.com> wrote:
>

>

> 在 2021/4/12 下午4:02, Yongji Xie 写道:

> > On Mon, Apr 12, 2021 at 3:16 PM Jason Wang <jasowang@redhat.com> wrote:

> >>

> >> 在 2021/4/9 下午4:02, Yongji Xie 写道:

> >>>>>>> +};

> >>>>>>> +

> >>>>>>> +struct vduse_dev_config_data {

> >>>>>>> +     __u32 offset; /* offset from the beginning of config space */

> >>>>>>> +     __u32 len; /* the length to read/write */

> >>>>>>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

> >>>>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

> >>>>>> not change it in the future.

> >>>>>>

> >>>>>> So this might suffcient for future features or all type of virtio devices.

> >>>>>>

> >>>>> Do you mean 256 is no enough here?

> >>>> Yes.

> >>>>

> >>> But this request will be submitted multiple times if config lengh is

> >>> larger than 256. So do you think whether we need to extent the size to

> >>> 512 or larger?

> >>

> >> So I think you'd better either:

> >>

> >> 1) document the limitation (256) in somewhere, (better both uapi and doc)

> >>

> > But the VDUSE_CONFIG_DATA_LEN doesn't mean the limitation of

> > configuration space. It only means the maximum size of one data

> > transfer for configuration space. Do you mean document this?

>

>

> Yes, and another thing is that since you're using

> data[VDUSE_CONFIG_DATA_LEN] in the uapi, it implies the length is always

> 256 which seems not good and not what the code is wrote.

>


How about renaming VDUSE_CONFIG_DATA_LEN to VDUSE_MAX_TRANSFER_LEN?

Thanks,
Yongji
Jason Wang April 13, 2021, 3:35 a.m. UTC | #11
在 2021/4/12 下午5:59, Yongji Xie 写道:
> On Mon, Apr 12, 2021 at 5:37 PM Jason Wang <jasowang@redhat.com> wrote:

>>

>> 在 2021/4/12 下午4:02, Yongji Xie 写道:

>>> On Mon, Apr 12, 2021 at 3:16 PM Jason Wang <jasowang@redhat.com> wrote:

>>>> 在 2021/4/9 下午4:02, Yongji Xie 写道:

>>>>>>>>> +};

>>>>>>>>> +

>>>>>>>>> +struct vduse_dev_config_data {

>>>>>>>>> +     __u32 offset; /* offset from the beginning of config space */

>>>>>>>>> +     __u32 len; /* the length to read/write */

>>>>>>>>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

>>>>>>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

>>>>>>>> not change it in the future.

>>>>>>>>

>>>>>>>> So this might suffcient for future features or all type of virtio devices.

>>>>>>>>

>>>>>>> Do you mean 256 is no enough here?

>>>>>> Yes.

>>>>>>

>>>>> But this request will be submitted multiple times if config lengh is

>>>>> larger than 256. So do you think whether we need to extent the size to

>>>>> 512 or larger?

>>>> So I think you'd better either:

>>>>

>>>> 1) document the limitation (256) in somewhere, (better both uapi and doc)

>>>>

>>> But the VDUSE_CONFIG_DATA_LEN doesn't mean the limitation of

>>> configuration space. It only means the maximum size of one data

>>> transfer for configuration space. Do you mean document this?

>>

>> Yes, and another thing is that since you're using

>> data[VDUSE_CONFIG_DATA_LEN] in the uapi, it implies the length is always

>> 256 which seems not good and not what the code is wrote.

>>

> How about renaming VDUSE_CONFIG_DATA_LEN to VDUSE_MAX_TRANSFER_LEN?

>

> Thanks,

> Yongji



So a question is the reason to have a limitation of this in the uAPI? 
Note that in vhost-vdpa we don't have such:

struct vhost_vdpa_config {
         __u32 off;
         __u32 len;
         __u8 buf[0];
};

Thanks


>
Yongji Xie April 13, 2021, 4:28 a.m. UTC | #12
On Tue, Apr 13, 2021 at 11:35 AM Jason Wang <jasowang@redhat.com> wrote:
>

>

> 在 2021/4/12 下午5:59, Yongji Xie 写道:

> > On Mon, Apr 12, 2021 at 5:37 PM Jason Wang <jasowang@redhat.com> wrote:

> >>

> >> 在 2021/4/12 下午4:02, Yongji Xie 写道:

> >>> On Mon, Apr 12, 2021 at 3:16 PM Jason Wang <jasowang@redhat.com> wrote:

> >>>> 在 2021/4/9 下午4:02, Yongji Xie 写道:

> >>>>>>>>> +};

> >>>>>>>>> +

> >>>>>>>>> +struct vduse_dev_config_data {

> >>>>>>>>> +     __u32 offset; /* offset from the beginning of config space */

> >>>>>>>>> +     __u32 len; /* the length to read/write */

> >>>>>>>>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

> >>>>>>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

> >>>>>>>> not change it in the future.

> >>>>>>>>

> >>>>>>>> So this might suffcient for future features or all type of virtio devices.

> >>>>>>>>

> >>>>>>> Do you mean 256 is no enough here?

> >>>>>> Yes.

> >>>>>>

> >>>>> But this request will be submitted multiple times if config lengh is

> >>>>> larger than 256. So do you think whether we need to extent the size to

> >>>>> 512 or larger?

> >>>> So I think you'd better either:

> >>>>

> >>>> 1) document the limitation (256) in somewhere, (better both uapi and doc)

> >>>>

> >>> But the VDUSE_CONFIG_DATA_LEN doesn't mean the limitation of

> >>> configuration space. It only means the maximum size of one data

> >>> transfer for configuration space. Do you mean document this?

> >>

> >> Yes, and another thing is that since you're using

> >> data[VDUSE_CONFIG_DATA_LEN] in the uapi, it implies the length is always

> >> 256 which seems not good and not what the code is wrote.

> >>

> > How about renaming VDUSE_CONFIG_DATA_LEN to VDUSE_MAX_TRANSFER_LEN?

> >

> > Thanks,

> > Yongji

>

>

> So a question is the reason to have a limitation of this in the uAPI?

> Note that in vhost-vdpa we don't have such:

>

> struct vhost_vdpa_config {

>          __u32 off;

>          __u32 len;

>          __u8 buf[0];

> };

>


If so, we need to call read()/write() multiple times each time
receiving/sending one request or response in userspace and kernel. For
example,

1. read and check request/response type
2. read and check config length if type is VDUSE_SET_CONFIG or VDUSE_GET_CONFIG
3. read the payload

Not sure if it's worth it.

Thanks,
Yongji
Michael S. Tsirkin April 14, 2021, 7:34 a.m. UTC | #13
On Wed, Mar 31, 2021 at 04:05:09PM +0800, Xie Yongji wrote:
> This series introduces a framework, which can be used to implement

> vDPA Devices in a userspace program. The work consist of two parts:

> control path forwarding and data path offloading.

> 

> In the control path, the VDUSE driver will make use of message

> mechnism to forward the config operation from vdpa bus driver

> to userspace. Userspace can use read()/write() to receive/reply

> those control messages.

> 

> In the data path, the core is mapping dma buffer into VDUSE

> daemon's address space, which can be implemented in different ways

> depending on the vdpa bus to which the vDPA device is attached.

> 

> In virtio-vdpa case, we implements a MMU-based on-chip IOMMU driver with

> bounce-buffering mechanism to achieve that. And in vhost-vdpa case, the dma

> buffer is reside in a userspace memory region which can be shared to the

> VDUSE userspace processs via transferring the shmfd.

> 

> The details and our user case is shown below:

> 

> ------------------------    -------------------------   ----------------------------------------------

> |            Container |    |              QEMU(VM) |   |                               VDUSE daemon |

> |       ---------      |    |  -------------------  |   | ------------------------- ---------------- |

> |       |dev/vdx|      |    |  |/dev/vhost-vdpa-x|  |   | | vDPA device emulation | | block driver | |

> ------------+-----------     -----------+------------   -------------+----------------------+---------

>             |                           |                            |                      |

>             |                           |                            |                      |

> ------------+---------------------------+----------------------------+----------------------+---------

> |    | block device |           |  vhost device |            | vduse driver |          | TCP/IP |    |

> |    -------+--------           --------+--------            -------+--------          -----+----    |

> |           |                           |                           |                       |        |

> | ----------+----------       ----------+-----------         -------+-------                |        |

> | | virtio-blk driver |       |  vhost-vdpa driver |         | vdpa device |                |        |

> | ----------+----------       ----------+-----------         -------+-------                |        |

> |           |      virtio bus           |                           |                       |        |

> |   --------+----+-----------           |                           |                       |        |

> |                |                      |                           |                       |        |

> |      ----------+----------            |                           |                       |        |

> |      | virtio-blk device |            |                           |                       |        |

> |      ----------+----------            |                           |                       |        |

> |                |                      |                           |                       |        |

> |     -----------+-----------           |                           |                       |        |

> |     |  virtio-vdpa driver |           |                           |                       |        |

> |     -----------+-----------           |                           |                       |        |

> |                |                      |                           |    vdpa bus           |        |

> |     -----------+----------------------+---------------------------+------------           |        |

> |                                                                                        ---+---     |

> -----------------------------------------------------------------------------------------| NIC |------

>                                                                                          ---+---

>                                                                                             |

>                                                                                    ---------+---------

>                                                                                    | Remote Storages |

>                                                                                    -------------------


This all looks quite similar to vhost-user-block except that one
does not need any kernel support at all.

So I am still scratching my head about its advantages over
vhost-user-block.


> We make use of it to implement a block device connecting to

> our distributed storage, which can be used both in containers and

> VMs. Thus, we can have an unified technology stack in this two cases.


Maybe the container part is the answer. How does that stack look?

> To test it with null-blk:

> 

>   $ qemu-storage-daemon \

>       --chardev socket,id=charmonitor,path=/tmp/qmp.sock,server,nowait \

>       --monitor chardev=charmonitor \

>       --blockdev driver=host_device,cache.direct=on,aio=native,filename=/dev/nullb0,node-name=disk0 \

>       --export type=vduse-blk,id=test,node-name=disk0,writable=on,name=vduse-null,num-queues=16,queue-size=128

> 

> The qemu-storage-daemon can be found at https://github.com/bytedance/qemu/tree/vduse

> 

> Future work:

>   - Improve performance

>   - Userspace library (find a way to reuse device emulation code in qemu/rust-vmm)

> 

> V5 to V6:

> - Export receive_fd() instead of __receive_fd()

> - Factor out the unmapping logic of pa and va separatedly

> - Remove the logic of bounce page allocation in page fault handler

> - Use PAGE_SIZE as IOVA allocation granule

> - Add EPOLLOUT support

> - Enable setting API version in userspace

> - Fix some bugs

> 

> V4 to V5:

> - Remove the patch for irq binding

> - Use a single IOTLB for all types of mapping

> - Factor out vhost_vdpa_pa_map()

> - Add some sample codes in document

> - Use receice_fd_user() to pass file descriptor

> - Fix some bugs

> 

> V3 to V4:

> - Rebase to vhost.git

> - Split some patches

> - Add some documents

> - Use ioctl to inject interrupt rather than eventfd

> - Enable config interrupt support

> - Support binding irq to the specified cpu

> - Add two module parameter to limit bounce/iova size

> - Create char device rather than anon inode per vduse

> - Reuse vhost IOTLB for iova domain

> - Rework the message mechnism in control path

> 

> V2 to V3:

> - Rework the MMU-based IOMMU driver

> - Use the iova domain as iova allocator instead of genpool

> - Support transferring vma->vm_file in vhost-vdpa

> - Add SVA support in vhost-vdpa

> - Remove the patches on bounce pages reclaim

> 

> V1 to V2:

> - Add vhost-vdpa support

> - Add some documents

> - Based on the vdpa management tool

> - Introduce a workqueue for irq injection

> - Replace interval tree with array map to store the iova_map

> 

> Xie Yongji (10):

>   file: Export receive_fd() to modules

>   eventfd: Increase the recursion depth of eventfd_signal()

>   vhost-vdpa: protect concurrent access to vhost device iotlb

>   vhost-iotlb: Add an opaque pointer for vhost IOTLB

>   vdpa: Add an opaque pointer for vdpa_config_ops.dma_map()

>   vdpa: factor out vhost_vdpa_pa_map() and vhost_vdpa_pa_unmap()

>   vdpa: Support transferring virtual addressing during DMA mapping

>   vduse: Implement an MMU-based IOMMU driver

>   vduse: Introduce VDUSE - vDPA Device in Userspace

>   Documentation: Add documentation for VDUSE

> 

>  Documentation/userspace-api/index.rst              |    1 +

>  Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +

>  Documentation/userspace-api/vduse.rst              |  212 +++

>  drivers/vdpa/Kconfig                               |   10 +

>  drivers/vdpa/Makefile                              |    1 +

>  drivers/vdpa/ifcvf/ifcvf_main.c                    |    2 +-

>  drivers/vdpa/mlx5/net/mlx5_vnet.c                  |    2 +-

>  drivers/vdpa/vdpa.c                                |    9 +-

>  drivers/vdpa/vdpa_sim/vdpa_sim.c                   |    8 +-

>  drivers/vdpa/vdpa_user/Makefile                    |    5 +

>  drivers/vdpa/vdpa_user/iova_domain.c               |  521 ++++++++

>  drivers/vdpa/vdpa_user/iova_domain.h               |   70 +

>  drivers/vdpa/vdpa_user/vduse_dev.c                 | 1362 ++++++++++++++++++++

>  drivers/vdpa/virtio_pci/vp_vdpa.c                  |    2 +-

>  drivers/vhost/iotlb.c                              |   20 +-

>  drivers/vhost/vdpa.c                               |  154 ++-

>  fs/eventfd.c                                       |    2 +-

>  fs/file.c                                          |    6 +

>  include/linux/eventfd.h                            |    5 +-

>  include/linux/file.h                               |    7 +-

>  include/linux/vdpa.h                               |   21 +-

>  include/linux/vhost_iotlb.h                        |    3 +

>  include/uapi/linux/vduse.h                         |  175 +++

>  23 files changed, 2548 insertions(+), 51 deletions(-)

>  create mode 100644 Documentation/userspace-api/vduse.rst

>  create mode 100644 drivers/vdpa/vdpa_user/Makefile

>  create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c

>  create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h

>  create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c

>  create mode 100644 include/uapi/linux/vduse.h

> 

> -- 

> 2.11.0
Jason Wang April 14, 2021, 7:49 a.m. UTC | #14
在 2021/4/14 下午3:34, Michael S. Tsirkin 写道:
> On Wed, Mar 31, 2021 at 04:05:09PM +0800, Xie Yongji wrote:

>> This series introduces a framework, which can be used to implement

>> vDPA Devices in a userspace program. The work consist of two parts:

>> control path forwarding and data path offloading.

>>

>> In the control path, the VDUSE driver will make use of message

>> mechnism to forward the config operation from vdpa bus driver

>> to userspace. Userspace can use read()/write() to receive/reply

>> those control messages.

>>

>> In the data path, the core is mapping dma buffer into VDUSE

>> daemon's address space, which can be implemented in different ways

>> depending on the vdpa bus to which the vDPA device is attached.

>>

>> In virtio-vdpa case, we implements a MMU-based on-chip IOMMU driver with

>> bounce-buffering mechanism to achieve that. And in vhost-vdpa case, the dma

>> buffer is reside in a userspace memory region which can be shared to the

>> VDUSE userspace processs via transferring the shmfd.

>>

>> The details and our user case is shown below:

>>

>> ------------------------    -------------------------   ----------------------------------------------

>> |            Container |    |              QEMU(VM) |   |                               VDUSE daemon |

>> |       ---------      |    |  -------------------  |   | ------------------------- ---------------- |

>> |       |dev/vdx|      |    |  |/dev/vhost-vdpa-x|  |   | | vDPA device emulation | | block driver | |

>> ------------+-----------     -----------+------------   -------------+----------------------+---------

>>              |                           |                            |                      |

>>              |                           |                            |                      |

>> ------------+---------------------------+----------------------------+----------------------+---------

>> |    | block device |           |  vhost device |            | vduse driver |          | TCP/IP |    |

>> |    -------+--------           --------+--------            -------+--------          -----+----    |

>> |           |                           |                           |                       |        |

>> | ----------+----------       ----------+-----------         -------+-------                |        |

>> | | virtio-blk driver |       |  vhost-vdpa driver |         | vdpa device |                |        |

>> | ----------+----------       ----------+-----------         -------+-------                |        |

>> |           |      virtio bus           |                           |                       |        |

>> |   --------+----+-----------           |                           |                       |        |

>> |                |                      |                           |                       |        |

>> |      ----------+----------            |                           |                       |        |

>> |      | virtio-blk device |            |                           |                       |        |

>> |      ----------+----------            |                           |                       |        |

>> |                |                      |                           |                       |        |

>> |     -----------+-----------           |                           |                       |        |

>> |     |  virtio-vdpa driver |           |                           |                       |        |

>> |     -----------+-----------           |                           |                       |        |

>> |                |                      |                           |    vdpa bus           |        |

>> |     -----------+----------------------+---------------------------+------------           |        |

>> |                                                                                        ---+---     |

>> -----------------------------------------------------------------------------------------| NIC |------

>>                                                                                           ---+---

>>                                                                                              |

>>                                                                                     ---------+---------

>>                                                                                     | Remote Storages |

>>                                                                                     -------------------

> This all looks quite similar to vhost-user-block except that one

> does not need any kernel support at all.

>

> So I am still scratching my head about its advantages over

> vhost-user-block.

>

>

>> We make use of it to implement a block device connecting to

>> our distributed storage, which can be used both in containers and

>> VMs. Thus, we can have an unified technology stack in this two cases.

> Maybe the container part is the answer. How does that stack look?



Yong Ji may add more and I think this has been demonstrated in the above 
figure: the userspace vDPA device can provide a kenrel virito-blk device 
via virtio_vdpa driver.

Thanks


>

>> To test it with null-blk:

>>

>>    $ qemu-storage-daemon \

>>        --chardev socket,id=charmonitor,path=/tmp/qmp.sock,server,nowait \

>>        --monitor chardev=charmonitor \

>>        --blockdev driver=host_device,cache.direct=on,aio=native,filename=/dev/nullb0,node-name=disk0 \

>>        --export type=vduse-blk,id=test,node-name=disk0,writable=on,name=vduse-null,num-queues=16,queue-size=128

>>

>> The qemu-storage-daemon can be found at https://github.com/bytedance/qemu/tree/vduse

>>

>> Future work:

>>    - Improve performance

>>    - Userspace library (find a way to reuse device emulation code in qemu/rust-vmm)

>>

>> V5 to V6:

>> - Export receive_fd() instead of __receive_fd()

>> - Factor out the unmapping logic of pa and va separatedly

>> - Remove the logic of bounce page allocation in page fault handler

>> - Use PAGE_SIZE as IOVA allocation granule

>> - Add EPOLLOUT support

>> - Enable setting API version in userspace

>> - Fix some bugs

>>

>> V4 to V5:

>> - Remove the patch for irq binding

>> - Use a single IOTLB for all types of mapping

>> - Factor out vhost_vdpa_pa_map()

>> - Add some sample codes in document

>> - Use receice_fd_user() to pass file descriptor

>> - Fix some bugs

>>

>> V3 to V4:

>> - Rebase to vhost.git

>> - Split some patches

>> - Add some documents

>> - Use ioctl to inject interrupt rather than eventfd

>> - Enable config interrupt support

>> - Support binding irq to the specified cpu

>> - Add two module parameter to limit bounce/iova size

>> - Create char device rather than anon inode per vduse

>> - Reuse vhost IOTLB for iova domain

>> - Rework the message mechnism in control path

>>

>> V2 to V3:

>> - Rework the MMU-based IOMMU driver

>> - Use the iova domain as iova allocator instead of genpool

>> - Support transferring vma->vm_file in vhost-vdpa

>> - Add SVA support in vhost-vdpa

>> - Remove the patches on bounce pages reclaim

>>

>> V1 to V2:

>> - Add vhost-vdpa support

>> - Add some documents

>> - Based on the vdpa management tool

>> - Introduce a workqueue for irq injection

>> - Replace interval tree with array map to store the iova_map

>>

>> Xie Yongji (10):

>>    file: Export receive_fd() to modules

>>    eventfd: Increase the recursion depth of eventfd_signal()

>>    vhost-vdpa: protect concurrent access to vhost device iotlb

>>    vhost-iotlb: Add an opaque pointer for vhost IOTLB

>>    vdpa: Add an opaque pointer for vdpa_config_ops.dma_map()

>>    vdpa: factor out vhost_vdpa_pa_map() and vhost_vdpa_pa_unmap()

>>    vdpa: Support transferring virtual addressing during DMA mapping

>>    vduse: Implement an MMU-based IOMMU driver

>>    vduse: Introduce VDUSE - vDPA Device in Userspace

>>    Documentation: Add documentation for VDUSE

>>

>>   Documentation/userspace-api/index.rst              |    1 +

>>   Documentation/userspace-api/ioctl/ioctl-number.rst |    1 +

>>   Documentation/userspace-api/vduse.rst              |  212 +++

>>   drivers/vdpa/Kconfig                               |   10 +

>>   drivers/vdpa/Makefile                              |    1 +

>>   drivers/vdpa/ifcvf/ifcvf_main.c                    |    2 +-

>>   drivers/vdpa/mlx5/net/mlx5_vnet.c                  |    2 +-

>>   drivers/vdpa/vdpa.c                                |    9 +-

>>   drivers/vdpa/vdpa_sim/vdpa_sim.c                   |    8 +-

>>   drivers/vdpa/vdpa_user/Makefile                    |    5 +

>>   drivers/vdpa/vdpa_user/iova_domain.c               |  521 ++++++++

>>   drivers/vdpa/vdpa_user/iova_domain.h               |   70 +

>>   drivers/vdpa/vdpa_user/vduse_dev.c                 | 1362 ++++++++++++++++++++

>>   drivers/vdpa/virtio_pci/vp_vdpa.c                  |    2 +-

>>   drivers/vhost/iotlb.c                              |   20 +-

>>   drivers/vhost/vdpa.c                               |  154 ++-

>>   fs/eventfd.c                                       |    2 +-

>>   fs/file.c                                          |    6 +

>>   include/linux/eventfd.h                            |    5 +-

>>   include/linux/file.h                               |    7 +-

>>   include/linux/vdpa.h                               |   21 +-

>>   include/linux/vhost_iotlb.h                        |    3 +

>>   include/uapi/linux/vduse.h                         |  175 +++

>>   23 files changed, 2548 insertions(+), 51 deletions(-)

>>   create mode 100644 Documentation/userspace-api/vduse.rst

>>   create mode 100644 drivers/vdpa/vdpa_user/Makefile

>>   create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c

>>   create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h

>>   create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c

>>   create mode 100644 include/uapi/linux/vduse.h

>>

>> -- 

>> 2.11.0
Yongji Xie April 14, 2021, 7:54 a.m. UTC | #15
On Wed, Apr 14, 2021 at 3:35 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>

> On Wed, Mar 31, 2021 at 04:05:09PM +0800, Xie Yongji wrote:

> > This series introduces a framework, which can be used to implement

> > vDPA Devices in a userspace program. The work consist of two parts:

> > control path forwarding and data path offloading.

> >

> > In the control path, the VDUSE driver will make use of message

> > mechnism to forward the config operation from vdpa bus driver

> > to userspace. Userspace can use read()/write() to receive/reply

> > those control messages.

> >

> > In the data path, the core is mapping dma buffer into VDUSE

> > daemon's address space, which can be implemented in different ways

> > depending on the vdpa bus to which the vDPA device is attached.

> >

> > In virtio-vdpa case, we implements a MMU-based on-chip IOMMU driver with

> > bounce-buffering mechanism to achieve that. And in vhost-vdpa case, the dma

> > buffer is reside in a userspace memory region which can be shared to the

> > VDUSE userspace processs via transferring the shmfd.

> >

> > The details and our user case is shown below:

> >

> > ------------------------    -------------------------   ----------------------------------------------

> > |            Container |    |              QEMU(VM) |   |                               VDUSE daemon |

> > |       ---------      |    |  -------------------  |   | ------------------------- ---------------- |

> > |       |dev/vdx|      |    |  |/dev/vhost-vdpa-x|  |   | | vDPA device emulation | | block driver | |

> > ------------+-----------     -----------+------------   -------------+----------------------+---------

> >             |                           |                            |                      |

> >             |                           |                            |                      |

> > ------------+---------------------------+----------------------------+----------------------+---------

> > |    | block device |           |  vhost device |            | vduse driver |          | TCP/IP |    |

> > |    -------+--------           --------+--------            -------+--------          -----+----    |

> > |           |                           |                           |                       |        |

> > | ----------+----------       ----------+-----------         -------+-------                |        |

> > | | virtio-blk driver |       |  vhost-vdpa driver |         | vdpa device |                |        |

> > | ----------+----------       ----------+-----------         -------+-------                |        |

> > |           |      virtio bus           |                           |                       |        |

> > |   --------+----+-----------           |                           |                       |        |

> > |                |                      |                           |                       |        |

> > |      ----------+----------            |                           |                       |        |

> > |      | virtio-blk device |            |                           |                       |        |

> > |      ----------+----------            |                           |                       |        |

> > |                |                      |                           |                       |        |

> > |     -----------+-----------           |                           |                       |        |

> > |     |  virtio-vdpa driver |           |                           |                       |        |

> > |     -----------+-----------           |                           |                       |        |

> > |                |                      |                           |    vdpa bus           |        |

> > |     -----------+----------------------+---------------------------+------------           |        |

> > |                                                                                        ---+---     |

> > -----------------------------------------------------------------------------------------| NIC |------

> >                                                                                          ---+---

> >                                                                                             |

> >                                                                                    ---------+---------

> >                                                                                    | Remote Storages |

> >                                                                                    -------------------

>

> This all looks quite similar to vhost-user-block except that one

> does not need any kernel support at all.

>

> So I am still scratching my head about its advantages over

> vhost-user-block.

>


It plays the same role as vhost-user-block in VM user cases.

>

> > We make use of it to implement a block device connecting to

> > our distributed storage, which can be used both in containers and

> > VMs. Thus, we can have an unified technology stack in this two cases.

>

> Maybe the container part is the answer. How does that stack look?

>


Yes, it enables containers to reuse virtio software stack. We can have
one daemon that provides service to both containers and virtual
machines.

Thanks,
Yongji
Jason Wang April 14, 2021, 8:18 a.m. UTC | #16
在 2021/4/13 下午12:28, Yongji Xie 写道:
> On Tue, Apr 13, 2021 at 11:35 AM Jason Wang <jasowang@redhat.com> wrote:

>>

>> 在 2021/4/12 下午5:59, Yongji Xie 写道:

>>> On Mon, Apr 12, 2021 at 5:37 PM Jason Wang <jasowang@redhat.com> wrote:

>>>> 在 2021/4/12 下午4:02, Yongji Xie 写道:

>>>>> On Mon, Apr 12, 2021 at 3:16 PM Jason Wang <jasowang@redhat.com> wrote:

>>>>>> 在 2021/4/9 下午4:02, Yongji Xie 写道:

>>>>>>>>>>> +};

>>>>>>>>>>> +

>>>>>>>>>>> +struct vduse_dev_config_data {

>>>>>>>>>>> +     __u32 offset; /* offset from the beginning of config space */

>>>>>>>>>>> +     __u32 len; /* the length to read/write */

>>>>>>>>>>> +     __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */

>>>>>>>>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can

>>>>>>>>>> not change it in the future.

>>>>>>>>>>

>>>>>>>>>> So this might suffcient for future features or all type of virtio devices.

>>>>>>>>>>

>>>>>>>>> Do you mean 256 is no enough here?

>>>>>>>> Yes.

>>>>>>>>

>>>>>>> But this request will be submitted multiple times if config lengh is

>>>>>>> larger than 256. So do you think whether we need to extent the size to

>>>>>>> 512 or larger?

>>>>>> So I think you'd better either:

>>>>>>

>>>>>> 1) document the limitation (256) in somewhere, (better both uapi and doc)

>>>>>>

>>>>> But the VDUSE_CONFIG_DATA_LEN doesn't mean the limitation of

>>>>> configuration space. It only means the maximum size of one data

>>>>> transfer for configuration space. Do you mean document this?

>>>> Yes, and another thing is that since you're using

>>>> data[VDUSE_CONFIG_DATA_LEN] in the uapi, it implies the length is always

>>>> 256 which seems not good and not what the code is wrote.

>>>>

>>> How about renaming VDUSE_CONFIG_DATA_LEN to VDUSE_MAX_TRANSFER_LEN?

>>>

>>> Thanks,

>>> Yongji

>>

>> So a question is the reason to have a limitation of this in the uAPI?

>> Note that in vhost-vdpa we don't have such:

>>

>> struct vhost_vdpa_config {

>>           __u32 off;

>>           __u32 len;

>>           __u8 buf[0];

>> };

>>

> If so, we need to call read()/write() multiple times each time

> receiving/sending one request or response in userspace and kernel. For

> example,

>

> 1. read and check request/response type

> 2. read and check config length if type is VDUSE_SET_CONFIG or VDUSE_GET_CONFIG

> 3. read the payload

>

> Not sure if it's worth it.

>

> Thanks,

> Yongji



Right, I see.

So I'm fine with current approach.

Thanks



>
Jason Wang April 16, 2021, 3:24 a.m. UTC | #17
在 2021/3/31 下午4:05, Xie Yongji 写道:
> +	}

> +	case VDUSE_INJECT_VQ_IRQ:

> +		ret = -EINVAL;

> +		if (arg >= dev->vq_num)

> +			break;

> +

> +		ret = 0;

> +		queue_work(vduse_irq_wq, &dev->vqs[arg].inject);

> +		break;



One additional note:

Please use array_index_nospec() for all vqs[idx] access where idx is 
under the control of userspace to avoid potential spectre exploitation.

Thanks
Yongji Xie April 16, 2021, 8:43 a.m. UTC | #18
On Fri, Apr 16, 2021 at 11:24 AM Jason Wang <jasowang@redhat.com> wrote:
>

>

> 在 2021/3/31 下午4:05, Xie Yongji 写道:

> > +     }

> > +     case VDUSE_INJECT_VQ_IRQ:

> > +             ret = -EINVAL;

> > +             if (arg >= dev->vq_num)

> > +                     break;

> > +

> > +             ret = 0;

> > +             queue_work(vduse_irq_wq, &dev->vqs[arg].inject);

> > +             break;

>

>

> One additional note:

>

> Please use array_index_nospec() for all vqs[idx] access where idx is

> under the control of userspace to avoid potential spectre exploitation.

>


OK, I see.

Thanks,
Yongji