[v9,5/5] KVM: arm/arm64: add irqfd support

Message ID 1425464076-20558-6-git-send-email-eric.auger@linaro.org
State New
Headers show

Commit Message

Auger Eric March 4, 2015, 10:14 a.m.
This patch enables irqfd on arm/arm64.

Both irqfd and resamplefd are supported. Injection is implemented
in vgic.c without routing.

This patch enables CONFIG_HAVE_KVM_EVENTFD and CONFIG_HAVE_KVM_IRQFD.

KVM_CAP_IRQFD is now advertised. KVM_CAP_IRQFD_RESAMPLE capability
automatically is advertised as soon as CONFIG_HAVE_KVM_IRQFD is set.

Irqfd injection is restricted to SPI. The rationale behind not
supporting PPI irqfd injection is that any device using a PPI would
be a private-to-the-CPU device (timer for instance), so its state
would have to be context-switched along with the VCPU and would
require in-kernel wiring anyhow. It is not a relevant use case for
irqfds.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

---
v8 -> v9:
- replace kvm_debug by trace_kvm_set_irq and add
  BUG_ON(!vgic_initialized(kvm));

v7 -> v8:
- remove kvm_irq_has_notifier call
- part of dist locking changes now are part of previous patch file
- remove gic_initialized() check in kvm_set_irq
- remove Christoffer's Reviewed-by after this change

v5 -> v6:
- KVM_CAP_IRQFD support depends on vgic_present
- add Christoffer's Reviewed-by

v4 -> v5:
- squash [PATCH v4 3/3] KVM: arm64: add irqfd support into this patch
- some rewording in Documentation/virtual/kvm/api.txt and in vgic
  vgic_process_maintenance unlock comment.
- move explanation of why not supporting PPI into commit message
- in case of injection before gic readiness, -ENODEV is returned. It is
  up to the user space to avoid this situation.

v3 -> v4:
- reword commit message
- explain why we unlock the distributor before calling kvm_notify_acked_irq
- rename is_assigned_irq into has_notifier
- change EOI and injection kvm_debug format string
- remove error local variable in kvm_set_irq
- Move HAVE_KVM_IRQCHIP unset in a separate patch
- handle case were the irqfd injection is attempted before the vgic is ready.
  in such a case the notifier, if any, is called immediatly
- use nr_irqs to test spi is within correct range

v2 -> v3:
- removal of irq.h from eventfd.c put in a separate patch to increase
  visibility
- properly expose KVM_CAP_IRQFD capability in arm.c
- remove CONFIG_HAVE_KVM_IRQCHIP meaningfull only if irq_comm.c is used

v1 -> v2:
- rebase on 3.17rc1
- move of the dist unlock in process_maintenance
- remove of dist lock in __kvm_vgic_sync_hwstate
- rewording of the commit message (add resamplefd reference)
- remove irq.h

Conflicts:
	arch/arm64/kvm/Kconfig
---
 Documentation/virtual/kvm/api.txt |  6 ++++-
 arch/arm/include/uapi/asm/kvm.h   |  3 +++
 arch/arm/kvm/Kconfig              |  2 ++
 arch/arm/kvm/Makefile             |  2 +-
 arch/arm/kvm/arm.c                |  5 ++++
 arch/arm64/include/uapi/asm/kvm.h |  3 +++
 arch/arm64/kvm/Kconfig            |  2 ++
 arch/arm64/kvm/Makefile           |  2 +-
 virt/kvm/arm/vgic.c               | 48 +++++++++++++++++++++++++++++++++++++++
 9 files changed, 70 insertions(+), 3 deletions(-)

Comments

Auger Eric March 5, 2015, 2:04 p.m. | #1
Hi Marc,
On 03/05/2015 11:53 AM, Marc Zyngier wrote:
> On 04/03/15 10:14, Eric Auger wrote:
>> This patch enables irqfd on arm/arm64.
>>
>> Both irqfd and resamplefd are supported. Injection is implemented
>> in vgic.c without routing.
>>
>> This patch enables CONFIG_HAVE_KVM_EVENTFD and CONFIG_HAVE_KVM_IRQFD.
>>
>> KVM_CAP_IRQFD is now advertised. KVM_CAP_IRQFD_RESAMPLE capability
>> automatically is advertised as soon as CONFIG_HAVE_KVM_IRQFD is set.
>>
>> Irqfd injection is restricted to SPI. The rationale behind not
>> supporting PPI irqfd injection is that any device using a PPI would
>> be a private-to-the-CPU device (timer for instance), so its state
>> would have to be context-switched along with the VCPU and would
>> require in-kernel wiring anyhow. It is not a relevant use case for
>> irqfds.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
>>
>> ---
>> v8 -> v9:
>> - replace kvm_debug by trace_kvm_set_irq and add
>>   BUG_ON(!vgic_initialized(kvm));
>>
>> v7 -> v8:
>> - remove kvm_irq_has_notifier call
>> - part of dist locking changes now are part of previous patch file
>> - remove gic_initialized() check in kvm_set_irq
>> - remove Christoffer's Reviewed-by after this change
>>
>> v5 -> v6:
>> - KVM_CAP_IRQFD support depends on vgic_present
>> - add Christoffer's Reviewed-by
>>
>> v4 -> v5:
>> - squash [PATCH v4 3/3] KVM: arm64: add irqfd support into this patch
>> - some rewording in Documentation/virtual/kvm/api.txt and in vgic
>>   vgic_process_maintenance unlock comment.
>> - move explanation of why not supporting PPI into commit message
>> - in case of injection before gic readiness, -ENODEV is returned. It is
>>   up to the user space to avoid this situation.
>>
>> v3 -> v4:
>> - reword commit message
>> - explain why we unlock the distributor before calling kvm_notify_acked_irq
>> - rename is_assigned_irq into has_notifier
>> - change EOI and injection kvm_debug format string
>> - remove error local variable in kvm_set_irq
>> - Move HAVE_KVM_IRQCHIP unset in a separate patch
>> - handle case were the irqfd injection is attempted before the vgic is ready.
>>   in such a case the notifier, if any, is called immediatly
>> - use nr_irqs to test spi is within correct range
>>
>> v2 -> v3:
>> - removal of irq.h from eventfd.c put in a separate patch to increase
>>   visibility
>> - properly expose KVM_CAP_IRQFD capability in arm.c
>> - remove CONFIG_HAVE_KVM_IRQCHIP meaningfull only if irq_comm.c is used
>>
>> v1 -> v2:
>> - rebase on 3.17rc1
>> - move of the dist unlock in process_maintenance
>> - remove of dist lock in __kvm_vgic_sync_hwstate
>> - rewording of the commit message (add resamplefd reference)
>> - remove irq.h
>>
>> Conflicts:
>> 	arch/arm64/kvm/Kconfig
>> ---
>>  Documentation/virtual/kvm/api.txt |  6 ++++-
>>  arch/arm/include/uapi/asm/kvm.h   |  3 +++
>>  arch/arm/kvm/Kconfig              |  2 ++
>>  arch/arm/kvm/Makefile             |  2 +-
>>  arch/arm/kvm/arm.c                |  5 ++++
>>  arch/arm64/include/uapi/asm/kvm.h |  3 +++
>>  arch/arm64/kvm/Kconfig            |  2 ++
>>  arch/arm64/kvm/Makefile           |  2 +-
>>  virt/kvm/arm/vgic.c               | 48 +++++++++++++++++++++++++++++++++++++++
>>  9 files changed, 70 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
>> index b112efc..b265d8e 100644
>> --- a/Documentation/virtual/kvm/api.txt
>> +++ b/Documentation/virtual/kvm/api.txt
>> @@ -2234,7 +2234,7 @@ into the hash PTE second double word).
>>  4.75 KVM_IRQFD
>>  
>>  Capability: KVM_CAP_IRQFD
>> -Architectures: x86 s390
>> +Architectures: x86 s390 arm arm64
>>  Type: vm ioctl
>>  Parameters: struct kvm_irqfd (in)
>>  Returns: 0 on success, -1 on error
>> @@ -2260,6 +2260,10 @@ Note that closing the resamplefd is not sufficient to disable the
>>  irqfd.  The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment
>>  and need not be specified with KVM_IRQFD_FLAG_DEASSIGN.
>>  
>> +On ARM/ARM64, the gsi field in the kvm_irqfd struct specifies the Shared
>> +Peripheral Interrupt (SPI) index, such that the GIC interrupt ID is
>> +given by gsi + 32.
>> +
>>  4.76 KVM_PPC_ALLOCATE_HTAB
>>  
>>  Capability: KVM_CAP_PPC_ALLOC_HTAB
>> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
>> index 0db25bc..2499867 100644
>> --- a/arch/arm/include/uapi/asm/kvm.h
>> +++ b/arch/arm/include/uapi/asm/kvm.h
>> @@ -198,6 +198,9 @@ struct kvm_arch_memory_slot {
>>  /* Highest supported SPI, from VGIC_NR_IRQS */
>>  #define KVM_ARM_IRQ_GIC_MAX		127
>>  
>> +/* One single KVM irqchip, ie. the VGIC */
>> +#define KVM_NR_IRQCHIPS          1
>> +
>>  /* PSCI interface */
>>  #define KVM_PSCI_FN_BASE		0x95c1ba5e
>>  #define KVM_PSCI_FN(n)			(KVM_PSCI_FN_BASE + (n))
>> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
>> index aae5242..d735a3e 100644
>> --- a/arch/arm/kvm/Kconfig
>> +++ b/arch/arm/kvm/Kconfig
>> @@ -27,6 +27,7 @@ config KVM
>>  	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
>>  	select SRCU
>>  	depends on ARM_VIRT_EXT && ARM_LPAE
>> +	select HAVE_KVM_EVENTFD
>>  	---help---
>>  	  Support hosting virtualized guest machines. You will also
>>  	  need to select one or more of the processor modules below.
>> @@ -58,6 +59,7 @@ config KVM_ARM_MAX_VCPUS
>>  config KVM_ARM_VGIC
>>  	bool "KVM support for Virtual GIC"
>>  	depends on KVM_ARM_HOST && OF
>> +	select HAVE_KVM_IRQFD
>>  	default y
>>  	---help---
>>  	  Adds support for a hardware assisted, in-kernel GIC emulation.
>> diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
>> index 443b8be..539c1a5 100644
>> --- a/arch/arm/kvm/Makefile
>> +++ b/arch/arm/kvm/Makefile
>> @@ -15,7 +15,7 @@ AFLAGS_init.o := -Wa,-march=armv7-a$(plus_virt)
>>  AFLAGS_interrupts.o := -Wa,-march=armv7-a$(plus_virt)
>>  
>>  KVM := ../../../virt/kvm
>> -kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o
>> +kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o
>>  
>>  obj-y += kvm-arm.o init.o interrupts.o
>>  obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>> index 5300d5a..4313776 100644
>> --- a/arch/arm/kvm/arm.c
>> +++ b/arch/arm/kvm/arm.c
>> @@ -175,6 +175,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>>  	case KVM_CAP_IRQCHIP:
>>  		r = vgic_present;
>>  		break;
>> +#ifdef CONFIG_HAVE_KVM_IRQFD
>> +	case KVM_CAP_IRQFD:
>> +		r = vgic_present;
>> +		break;
>> +#endif
> 
> Nitpick: we have "select HAVE_KVM_IRQFD", so we can lose the #ifdef-ery.
right. Also I think the vgic_present can be removed since
CONFIG_HAVE_KVM_IRQFD always is set when CONFIG_KVM_ARM_VGIC is set.
So overall this indeed can simply be replaced by Paolo's patch.
> 
>>  	case KVM_CAP_DEVICE_CTRL:
>>  	case KVM_CAP_USER_MEMORY:
>>  	case KVM_CAP_SYNC_MMU:
>> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
>> index 3ef77a4..c154c0b 100644
>> --- a/arch/arm64/include/uapi/asm/kvm.h
>> +++ b/arch/arm64/include/uapi/asm/kvm.h
>> @@ -191,6 +191,9 @@ struct kvm_arch_memory_slot {
>>  /* Highest supported SPI, from VGIC_NR_IRQS */
>>  #define KVM_ARM_IRQ_GIC_MAX		127
>>  
>> +/* One single KVM irqchip, ie. the VGIC */
>> +#define KVM_NR_IRQCHIPS          1
>> +
>>  /* PSCI interface */
>>  #define KVM_PSCI_FN_BASE		0x95c1ba5e
>>  #define KVM_PSCI_FN(n)			(KVM_PSCI_FN_BASE + (n))
>> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
>> index 039d8cf..143c9fd 100644
>> --- a/arch/arm64/kvm/Kconfig
>> +++ b/arch/arm64/kvm/Kconfig
>> @@ -29,6 +29,7 @@ config KVM
>>  	select KVM_ARM_TIMER
>>  	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
>>  	select SRCU
>> +	select HAVE_KVM_EVENTFD
>>  	---help---
>>  	  Support hosting virtualized guest machines.
>>  
>> @@ -53,6 +54,7 @@ config KVM_ARM_MAX_VCPUS
>>  config KVM_ARM_VGIC
>>  	bool
>>  	depends on KVM_ARM_HOST && OF
>> +	select HAVE_KVM_IRQFD
> 
> Hmmm. There is way too many selects here. Can't we just select it with
> CONFIG_KVM_ARM_VGIC, and be done with it?

I did that way since CONFIG_KVM_ARM_VGIC is not selected in the config
KVM section on 32b. Currently the IRQFD select location is same for arm
and arm64.

do you prefer I select HAVE_KVM_IRQFD in the config KVM section, ie. at
the same place we select CONFIG_KVM_ARM_VGIC?


> 
>>  	---help---
>>  	  Adds support for a hardware assisted, in-kernel GIC emulation.
>>  
>> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
>> index 4e6e09e..0dffb5f 100644
>> --- a/arch/arm64/kvm/Makefile
>> +++ b/arch/arm64/kvm/Makefile
>> @@ -11,7 +11,7 @@ ARM=../../../arch/arm/kvm
>>  
>>  obj-$(CONFIG_KVM_ARM_HOST) += kvm.o
>>  
>> -kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o
>> +kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o
>>  kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/arm.o $(ARM)/mmu.o $(ARM)/mmio.o
>>  kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o
>>  
>> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
>> index 4e9b6d3..2dfb299 100644
>> --- a/virt/kvm/arm/vgic.c
>> +++ b/virt/kvm/arm/vgic.c
>> @@ -31,6 +31,7 @@
>>  #include <asm/kvm_emulate.h>
>>  #include <asm/kvm_arm.h>
>>  #include <asm/kvm_mmu.h>
>> +#include <trace/events/kvm.h>
>>  
>>  /*
>>   * How the whole thing works (courtesy of Christoffer Dall):
>> @@ -1083,6 +1084,7 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
>>  	u32 status = vgic_get_interrupt_status(vcpu);
>>  	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
>>  	bool level_pending = false;
>> +	struct kvm *kvm = vcpu->kvm;
>>  
>>  	kvm_debug("STATUS = %08x\n", status);
>>  
>> @@ -1118,6 +1120,17 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
>>  			 */
>>  			vgic_dist_irq_clear_soft_pend(vcpu, vlr.irq);
>>  
>> +			/*
>> +			 * kvm_notify_acked_irq calls kvm_set_irq()
>> +			 * to reset the IRQ level. Need to release the
>> +			 * lock for kvm_set_irq to grab it.
>> +			 */
>> +			spin_unlock(&dist->lock);
>> +
>> +			kvm_notify_acked_irq(kvm, 0,
>> +					     vlr.irq - VGIC_NR_PRIVATE_IRQS);
>> +			spin_lock(&dist->lock);
>> +
> 
> I tried hard to break that one, and failed. It must be correct! ;-)
Knock on wood!

Do I need to post a v10 based on Paolo's patch?

Thanks

Eric
> 
>>  			/* Any additional pending interrupt? */
>>  			if (vgic_dist_irq_get_level(vcpu, vlr.irq)) {
>>  				vgic_cpu_irq_set(vcpu, vlr.irq);
>> @@ -1911,3 +1924,38 @@ out_free_irq:
>>  	free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
>>  	return ret;
>>  }
>> +
>> +int kvm_irq_map_gsi(struct kvm *kvm,
>> +		    struct kvm_kernel_irq_routing_entry *entries,
>> +		    int gsi)
>> +{
>> +	return gsi;
>> +}
>> +
>> +int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
>> +{
>> +	return pin;
>> +}
>> +
>> +int kvm_set_irq(struct kvm *kvm, int irq_source_id,
>> +		u32 irq, int level, bool line_status)
>> +{
>> +	unsigned int spi = irq + VGIC_NR_PRIVATE_IRQS;
>> +
>> +	trace_kvm_set_irq(irq, level, irq_source_id);
>> +
>> +	BUG_ON(!vgic_initialized(kvm));
>> +
>> +	if (spi > kvm->arch.vgic.nr_irqs)
>> +		return -EINVAL;
>> +	return kvm_vgic_inject_irq(kvm, 0, spi, level);
>> +
>> +}
>> +
>> +/* MSI not implemented yet */
>> +int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
>> +		struct kvm *kvm, int irq_source_id,
>> +		int level, bool line_status)
>> +{
>> +	return 0;
>> +}
>>
> 
> Despite from the nits mentionned before, this looks good, and I think we
> should merge it in 4.1 (or whatever this is called).
> 
> So for the whole series:
> 
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> 
> 	M.
>
Auger Eric March 5, 2015, 2:26 p.m. | #2
On 03/05/2015 03:20 PM, Marc Zyngier wrote:
> On 05/03/15 14:04, Eric Auger wrote:
>> Hi Marc,
>> On 03/05/2015 11:53 AM, Marc Zyngier wrote:
>>> On 04/03/15 10:14, Eric Auger wrote:
>>>> This patch enables irqfd on arm/arm64.
>>>>
>>>> Both irqfd and resamplefd are supported. Injection is implemented
>>>> in vgic.c without routing.
>>>>
>>>> This patch enables CONFIG_HAVE_KVM_EVENTFD and CONFIG_HAVE_KVM_IRQFD.
>>>>
>>>> KVM_CAP_IRQFD is now advertised. KVM_CAP_IRQFD_RESAMPLE capability
>>>> automatically is advertised as soon as CONFIG_HAVE_KVM_IRQFD is set.
>>>>
>>>> Irqfd injection is restricted to SPI. The rationale behind not
>>>> supporting PPI irqfd injection is that any device using a PPI would
>>>> be a private-to-the-CPU device (timer for instance), so its state
>>>> would have to be context-switched along with the VCPU and would
>>>> require in-kernel wiring anyhow. It is not a relevant use case for
>>>> irqfds.
>>>>
>>>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>>> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
>>>>
>>>> ---
>>>> v8 -> v9:
>>>> - replace kvm_debug by trace_kvm_set_irq and add
>>>>   BUG_ON(!vgic_initialized(kvm));
>>>>
>>>> v7 -> v8:
>>>> - remove kvm_irq_has_notifier call
>>>> - part of dist locking changes now are part of previous patch file
>>>> - remove gic_initialized() check in kvm_set_irq
>>>> - remove Christoffer's Reviewed-by after this change
>>>>
>>>> v5 -> v6:
>>>> - KVM_CAP_IRQFD support depends on vgic_present
>>>> - add Christoffer's Reviewed-by
>>>>
>>>> v4 -> v5:
>>>> - squash [PATCH v4 3/3] KVM: arm64: add irqfd support into this patch
>>>> - some rewording in Documentation/virtual/kvm/api.txt and in vgic
>>>>   vgic_process_maintenance unlock comment.
>>>> - move explanation of why not supporting PPI into commit message
>>>> - in case of injection before gic readiness, -ENODEV is returned. It is
>>>>   up to the user space to avoid this situation.
>>>>
>>>> v3 -> v4:
>>>> - reword commit message
>>>> - explain why we unlock the distributor before calling kvm_notify_acked_irq
>>>> - rename is_assigned_irq into has_notifier
>>>> - change EOI and injection kvm_debug format string
>>>> - remove error local variable in kvm_set_irq
>>>> - Move HAVE_KVM_IRQCHIP unset in a separate patch
>>>> - handle case were the irqfd injection is attempted before the vgic is ready.
>>>>   in such a case the notifier, if any, is called immediatly
>>>> - use nr_irqs to test spi is within correct range
>>>>
>>>> v2 -> v3:
>>>> - removal of irq.h from eventfd.c put in a separate patch to increase
>>>>   visibility
>>>> - properly expose KVM_CAP_IRQFD capability in arm.c
>>>> - remove CONFIG_HAVE_KVM_IRQCHIP meaningfull only if irq_comm.c is used
>>>>
>>>> v1 -> v2:
>>>> - rebase on 3.17rc1
>>>> - move of the dist unlock in process_maintenance
>>>> - remove of dist lock in __kvm_vgic_sync_hwstate
>>>> - rewording of the commit message (add resamplefd reference)
>>>> - remove irq.h
>>>>
>>>> Conflicts:
>>>>      arch/arm64/kvm/Kconfig
>>>> ---
>>>>  Documentation/virtual/kvm/api.txt |  6 ++++-
>>>>  arch/arm/include/uapi/asm/kvm.h   |  3 +++
>>>>  arch/arm/kvm/Kconfig              |  2 ++
>>>>  arch/arm/kvm/Makefile             |  2 +-
>>>>  arch/arm/kvm/arm.c                |  5 ++++
>>>>  arch/arm64/include/uapi/asm/kvm.h |  3 +++
>>>>  arch/arm64/kvm/Kconfig            |  2 ++
>>>>  arch/arm64/kvm/Makefile           |  2 +-
>>>>  virt/kvm/arm/vgic.c               | 48 +++++++++++++++++++++++++++++++++++++++
>>>>  9 files changed, 70 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
>>>> index b112efc..b265d8e 100644
>>>> --- a/Documentation/virtual/kvm/api.txt
>>>> +++ b/Documentation/virtual/kvm/api.txt
>>>> @@ -2234,7 +2234,7 @@ into the hash PTE second double word).
>>>>  4.75 KVM_IRQFD
>>>>
>>>>  Capability: KVM_CAP_IRQFD
>>>> -Architectures: x86 s390
>>>> +Architectures: x86 s390 arm arm64
>>>>  Type: vm ioctl
>>>>  Parameters: struct kvm_irqfd (in)
>>>>  Returns: 0 on success, -1 on error
>>>> @@ -2260,6 +2260,10 @@ Note that closing the resamplefd is not sufficient to disable the
>>>>  irqfd.  The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment
>>>>  and need not be specified with KVM_IRQFD_FLAG_DEASSIGN.
>>>>
>>>> +On ARM/ARM64, the gsi field in the kvm_irqfd struct specifies the Shared
>>>> +Peripheral Interrupt (SPI) index, such that the GIC interrupt ID is
>>>> +given by gsi + 32.
>>>> +
>>>>  4.76 KVM_PPC_ALLOCATE_HTAB
>>>>
>>>>  Capability: KVM_CAP_PPC_ALLOC_HTAB
>>>> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
>>>> index 0db25bc..2499867 100644
>>>> --- a/arch/arm/include/uapi/asm/kvm.h
>>>> +++ b/arch/arm/include/uapi/asm/kvm.h
>>>> @@ -198,6 +198,9 @@ struct kvm_arch_memory_slot {
>>>>  /* Highest supported SPI, from VGIC_NR_IRQS */
>>>>  #define KVM_ARM_IRQ_GIC_MAX         127
>>>>
>>>> +/* One single KVM irqchip, ie. the VGIC */
>>>> +#define KVM_NR_IRQCHIPS          1
>>>> +
>>>>  /* PSCI interface */
>>>>  #define KVM_PSCI_FN_BASE            0x95c1ba5e
>>>>  #define KVM_PSCI_FN(n)                      (KVM_PSCI_FN_BASE + (n))
>>>> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
>>>> index aae5242..d735a3e 100644
>>>> --- a/arch/arm/kvm/Kconfig
>>>> +++ b/arch/arm/kvm/Kconfig
>>>> @@ -27,6 +27,7 @@ config KVM
>>>>      select KVM_GENERIC_DIRTYLOG_READ_PROTECT
>>>>      select SRCU
>>>>      depends on ARM_VIRT_EXT && ARM_LPAE
>>>> +    select HAVE_KVM_EVENTFD
>>>>      ---help---
>>>>        Support hosting virtualized guest machines. You will also
>>>>        need to select one or more of the processor modules below.
>>>> @@ -58,6 +59,7 @@ config KVM_ARM_MAX_VCPUS
>>>>  config KVM_ARM_VGIC
>>>>      bool "KVM support for Virtual GIC"
>>>>      depends on KVM_ARM_HOST && OF
>>>> +    select HAVE_KVM_IRQFD
>>>>      default y
>>>>      ---help---
>>>>        Adds support for a hardware assisted, in-kernel GIC emulation.
>>>> diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
>>>> index 443b8be..539c1a5 100644
>>>> --- a/arch/arm/kvm/Makefile
>>>> +++ b/arch/arm/kvm/Makefile
>>>> @@ -15,7 +15,7 @@ AFLAGS_init.o := -Wa,-march=armv7-a$(plus_virt)
>>>>  AFLAGS_interrupts.o := -Wa,-march=armv7-a$(plus_virt)
>>>>
>>>>  KVM := ../../../virt/kvm
>>>> -kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o
>>>> +kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o
>>>>
>>>>  obj-y += kvm-arm.o init.o interrupts.o
>>>>  obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
>>>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>>>> index 5300d5a..4313776 100644
>>>> --- a/arch/arm/kvm/arm.c
>>>> +++ b/arch/arm/kvm/arm.c
>>>> @@ -175,6 +175,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>>>>      case KVM_CAP_IRQCHIP:
>>>>              r = vgic_present;
>>>>              break;
>>>> +#ifdef CONFIG_HAVE_KVM_IRQFD
>>>> +    case KVM_CAP_IRQFD:
>>>> +            r = vgic_present;
>>>> +            break;
>>>> +#endif
>>>
>>> Nitpick: we have "select HAVE_KVM_IRQFD", so we can lose the #ifdef-ery.
>> right. Also I think the vgic_present can be removed since
>> CONFIG_HAVE_KVM_IRQFD always is set when CONFIG_KVM_ARM_VGIC is set.
>> So overall this indeed can simply be replaced by Paolo's patch.
>>>
>>>>      case KVM_CAP_DEVICE_CTRL:
>>>>      case KVM_CAP_USER_MEMORY:
>>>>      case KVM_CAP_SYNC_MMU:
>>>> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
>>>> index 3ef77a4..c154c0b 100644
>>>> --- a/arch/arm64/include/uapi/asm/kvm.h
>>>> +++ b/arch/arm64/include/uapi/asm/kvm.h
>>>> @@ -191,6 +191,9 @@ struct kvm_arch_memory_slot {
>>>>  /* Highest supported SPI, from VGIC_NR_IRQS */
>>>>  #define KVM_ARM_IRQ_GIC_MAX         127
>>>>
>>>> +/* One single KVM irqchip, ie. the VGIC */
>>>> +#define KVM_NR_IRQCHIPS          1
>>>> +
>>>>  /* PSCI interface */
>>>>  #define KVM_PSCI_FN_BASE            0x95c1ba5e
>>>>  #define KVM_PSCI_FN(n)                      (KVM_PSCI_FN_BASE + (n))
>>>> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
>>>> index 039d8cf..143c9fd 100644
>>>> --- a/arch/arm64/kvm/Kconfig
>>>> +++ b/arch/arm64/kvm/Kconfig
>>>> @@ -29,6 +29,7 @@ config KVM
>>>>      select KVM_ARM_TIMER
>>>>      select KVM_GENERIC_DIRTYLOG_READ_PROTECT
>>>>      select SRCU
>>>> +    select HAVE_KVM_EVENTFD
>>>>      ---help---
>>>>        Support hosting virtualized guest machines.
>>>>
>>>> @@ -53,6 +54,7 @@ config KVM_ARM_MAX_VCPUS
>>>>  config KVM_ARM_VGIC
>>>>      bool
>>>>      depends on KVM_ARM_HOST && OF
>>>> +    select HAVE_KVM_IRQFD
>>>
>>> Hmmm. There is way too many selects here. Can't we just select it with
>>> CONFIG_KVM_ARM_VGIC, and be done with it?
>>
>> I did that way since CONFIG_KVM_ARM_VGIC is not selected in the config
>> KVM section on 32b. Currently the IRQFD select location is same for arm
>> and arm64.
>>
>> do you prefer I select HAVE_KVM_IRQFD in the config KVM section, ie. at
>> the same place we select CONFIG_KVM_ARM_VGIC?
> 
> We cannot have irqfd without vgic, can we? Or am I misunderstanding the
> dependency chain entirely?

No we can't have irqfd without vgic.
> 
> [...]
> 
>> Do I need to post a v10 based on Paolo's patch?
> 
> I don't think so, we can probably fixup things when we merge things.
> Let's sort the above first, and we should be good.

OK

Thanks
Eric
> 
> Thanks,
> 
> 	M.
>
Christoffer Dall March 11, 2015, 2:24 p.m. | #3
On Thu, Mar 05, 2015 at 12:27:42PM +0100, Paolo Bonzini wrote:
> 
> 
> On 05/03/2015 11:53, Marc Zyngier wrote:
> > > +#ifdef CONFIG_HAVE_KVM_IRQFD
> > > +	case KVM_CAP_IRQFD:
> > > +		r = vgic_present;
> > > +		break;
> > > +#endif
> > 
> > Nitpick: we have "select HAVE_KVM_IRQFD", so we can lose the #ifdef-ery.
> 
> Alternatively, I've just posted a patch to move the KVM_CAP_IRQFD case
> to common code.
> 
> vgic_present probably should be replaced by
> IS_ENABLED(CONFIG_KVM_ARM_VGIC).  I've sent a patch for this.
> 
I have applied all of this together with my kill-the-vgic-config-option
patch here:

git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git queue

Take a look please.

Thanks,
-Christoffer
Auger Eric March 11, 2015, 4:54 p.m. | #4
On 03/11/2015 03:24 PM, Christoffer Dall wrote:
> On Thu, Mar 05, 2015 at 12:27:42PM +0100, Paolo Bonzini wrote:
>>
>>
>> On 05/03/2015 11:53, Marc Zyngier wrote:
>>>> +#ifdef CONFIG_HAVE_KVM_IRQFD
>>>> +	case KVM_CAP_IRQFD:
>>>> +		r = vgic_present;
>>>> +		break;
>>>> +#endif
>>>
>>> Nitpick: we have "select HAVE_KVM_IRQFD", so we can lose the #ifdef-ery.
>>
>> Alternatively, I've just posted a patch to move the KVM_CAP_IRQFD case
>> to common code.
>>
>> vgic_present probably should be replaced by
>> IS_ENABLED(CONFIG_KVM_ARM_VGIC).  I've sent a patch for this.
>>
> I have applied all of this together with my kill-the-vgic-config-option
> patch here:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git queue
> 
> Take a look please.

Hi Christoffer,

This looks good to me. Thanks for the integration.

- Eric
> 
> Thanks,
> -Christoffer
>

Patch

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index b112efc..b265d8e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2234,7 +2234,7 @@  into the hash PTE second double word).
 4.75 KVM_IRQFD
 
 Capability: KVM_CAP_IRQFD
-Architectures: x86 s390
+Architectures: x86 s390 arm arm64
 Type: vm ioctl
 Parameters: struct kvm_irqfd (in)
 Returns: 0 on success, -1 on error
@@ -2260,6 +2260,10 @@  Note that closing the resamplefd is not sufficient to disable the
 irqfd.  The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment
 and need not be specified with KVM_IRQFD_FLAG_DEASSIGN.
 
+On ARM/ARM64, the gsi field in the kvm_irqfd struct specifies the Shared
+Peripheral Interrupt (SPI) index, such that the GIC interrupt ID is
+given by gsi + 32.
+
 4.76 KVM_PPC_ALLOCATE_HTAB
 
 Capability: KVM_CAP_PPC_ALLOC_HTAB
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index 0db25bc..2499867 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -198,6 +198,9 @@  struct kvm_arch_memory_slot {
 /* Highest supported SPI, from VGIC_NR_IRQS */
 #define KVM_ARM_IRQ_GIC_MAX		127
 
+/* One single KVM irqchip, ie. the VGIC */
+#define KVM_NR_IRQCHIPS          1
+
 /* PSCI interface */
 #define KVM_PSCI_FN_BASE		0x95c1ba5e
 #define KVM_PSCI_FN(n)			(KVM_PSCI_FN_BASE + (n))
diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index aae5242..d735a3e 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -27,6 +27,7 @@  config KVM
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select SRCU
 	depends on ARM_VIRT_EXT && ARM_LPAE
+	select HAVE_KVM_EVENTFD
 	---help---
 	  Support hosting virtualized guest machines. You will also
 	  need to select one or more of the processor modules below.
@@ -58,6 +59,7 @@  config KVM_ARM_MAX_VCPUS
 config KVM_ARM_VGIC
 	bool "KVM support for Virtual GIC"
 	depends on KVM_ARM_HOST && OF
+	select HAVE_KVM_IRQFD
 	default y
 	---help---
 	  Adds support for a hardware assisted, in-kernel GIC emulation.
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index 443b8be..539c1a5 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -15,7 +15,7 @@  AFLAGS_init.o := -Wa,-march=armv7-a$(plus_virt)
 AFLAGS_interrupts.o := -Wa,-march=armv7-a$(plus_virt)
 
 KVM := ../../../virt/kvm
-kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o
+kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o
 
 obj-y += kvm-arm.o init.o interrupts.o
 obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 5300d5a..4313776 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -175,6 +175,11 @@  int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_IRQCHIP:
 		r = vgic_present;
 		break;
+#ifdef CONFIG_HAVE_KVM_IRQFD
+	case KVM_CAP_IRQFD:
+		r = vgic_present;
+		break;
+#endif
 	case KVM_CAP_DEVICE_CTRL:
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_SYNC_MMU:
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 3ef77a4..c154c0b 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -191,6 +191,9 @@  struct kvm_arch_memory_slot {
 /* Highest supported SPI, from VGIC_NR_IRQS */
 #define KVM_ARM_IRQ_GIC_MAX		127
 
+/* One single KVM irqchip, ie. the VGIC */
+#define KVM_NR_IRQCHIPS          1
+
 /* PSCI interface */
 #define KVM_PSCI_FN_BASE		0x95c1ba5e
 #define KVM_PSCI_FN(n)			(KVM_PSCI_FN_BASE + (n))
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 039d8cf..143c9fd 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -29,6 +29,7 @@  config KVM
 	select KVM_ARM_TIMER
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select SRCU
+	select HAVE_KVM_EVENTFD
 	---help---
 	  Support hosting virtualized guest machines.
 
@@ -53,6 +54,7 @@  config KVM_ARM_MAX_VCPUS
 config KVM_ARM_VGIC
 	bool
 	depends on KVM_ARM_HOST && OF
+	select HAVE_KVM_IRQFD
 	---help---
 	  Adds support for a hardware assisted, in-kernel GIC emulation.
 
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 4e6e09e..0dffb5f 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -11,7 +11,7 @@  ARM=../../../arch/arm/kvm
 
 obj-$(CONFIG_KVM_ARM_HOST) += kvm.o
 
-kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o
+kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/arm.o $(ARM)/mmu.o $(ARM)/mmio.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o
 
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 4e9b6d3..2dfb299 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -31,6 +31,7 @@ 
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_mmu.h>
+#include <trace/events/kvm.h>
 
 /*
  * How the whole thing works (courtesy of Christoffer Dall):
@@ -1083,6 +1084,7 @@  static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
 	u32 status = vgic_get_interrupt_status(vcpu);
 	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
 	bool level_pending = false;
+	struct kvm *kvm = vcpu->kvm;
 
 	kvm_debug("STATUS = %08x\n", status);
 
@@ -1118,6 +1120,17 @@  static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
 			 */
 			vgic_dist_irq_clear_soft_pend(vcpu, vlr.irq);
 
+			/*
+			 * kvm_notify_acked_irq calls kvm_set_irq()
+			 * to reset the IRQ level. Need to release the
+			 * lock for kvm_set_irq to grab it.
+			 */
+			spin_unlock(&dist->lock);
+
+			kvm_notify_acked_irq(kvm, 0,
+					     vlr.irq - VGIC_NR_PRIVATE_IRQS);
+			spin_lock(&dist->lock);
+
 			/* Any additional pending interrupt? */
 			if (vgic_dist_irq_get_level(vcpu, vlr.irq)) {
 				vgic_cpu_irq_set(vcpu, vlr.irq);
@@ -1911,3 +1924,38 @@  out_free_irq:
 	free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
 	return ret;
 }
+
+int kvm_irq_map_gsi(struct kvm *kvm,
+		    struct kvm_kernel_irq_routing_entry *entries,
+		    int gsi)
+{
+	return gsi;
+}
+
+int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
+{
+	return pin;
+}
+
+int kvm_set_irq(struct kvm *kvm, int irq_source_id,
+		u32 irq, int level, bool line_status)
+{
+	unsigned int spi = irq + VGIC_NR_PRIVATE_IRQS;
+
+	trace_kvm_set_irq(irq, level, irq_source_id);
+
+	BUG_ON(!vgic_initialized(kvm));
+
+	if (spi > kvm->arch.vgic.nr_irqs)
+		return -EINVAL;
+	return kvm_vgic_inject_irq(kvm, 0, spi, level);
+
+}
+
+/* MSI not implemented yet */
+int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
+		struct kvm *kvm, int irq_source_id,
+		int level, bool line_status)
+{
+	return 0;
+}