[Xen-devel,RFC,v4,6/8] xen/iommu: smmu-v3: Add Xen specific code to enable the ported driver

Message ID 20171219031703.23420-7-sameer.goel@linaro.org
State New
Headers show
Series
  • SMMUv3 driver
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Commit Message

Sameer Goel Dec. 19, 2017, 3:17 a.m.
This driver follows an approach similar to smmu driver. The intent here
is to reuse as much Linux code as possible.
- Glue code has been introduced to bridge the API calls.
- Called Linux functions from the Xen IOMMU function calls.
- Xen modifications are preceded by /*Xen: comment */

Signed-off-by: Sameer Goel <sameer.goel@linaro.org>
---
 xen/arch/arm/p2m.c                    |   1 +
 xen/drivers/Kconfig                   |   2 +
 xen/drivers/passthrough/arm/Kconfig   |   8 +
 xen/drivers/passthrough/arm/Makefile  |   1 +
 xen/drivers/passthrough/arm/smmu-v3.c | 880 ++++++++++++++++++++++++++++++++--
 5 files changed, 861 insertions(+), 31 deletions(-)
 create mode 100644 xen/drivers/passthrough/arm/Kconfig

Comments

Manish Jaggi Jan. 3, 2018, 5:47 a.m. | #1
Hi Sameer,

Comments on this patch are only for nomenclature...

On 12/19/2017 08:47 AM, Sameer Goel wrote:
> This driver follows an approach similar to smmu driver. The intent here
> is to reuse as much Linux code as possible.
> - Glue code has been introduced to bridge the API calls.
> - Called Linux functions from the Xen IOMMU function calls.
> - Xen modifications are preceded by /*Xen: comment */
>
> Signed-off-by: Sameer Goel <sameer.goel@linaro.org>
> ---
>   xen/arch/arm/p2m.c                    |   1 +
>   xen/drivers/Kconfig                   |   2 +
>   xen/drivers/passthrough/arm/Kconfig   |   8 +
>   xen/drivers/passthrough/arm/Makefile  |   1 +
>   xen/drivers/passthrough/arm/smmu-v3.c | 880 ++++++++++++++++++++++++++++++++--
>   5 files changed, 861 insertions(+), 31 deletions(-)
>   create mode 100644 xen/drivers/passthrough/arm/Kconfig
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 22165ae376..6aa24cae48 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -1460,6 +1460,7 @@ err:
>   static void __init setup_virt_paging_one(void *data)
>   {
>       unsigned long val = (unsigned long)data;
> +    /* SMMUv3 S2 cfg vtcr reuses the following value */
>       WRITE_SYSREG32(val, VTCR_EL2);
>       isb();
>   }
> diff --git a/xen/drivers/Kconfig b/xen/drivers/Kconfig
> index bc3a54f0ea..612655386d 100644
> --- a/xen/drivers/Kconfig
> +++ b/xen/drivers/Kconfig
> @@ -12,4 +12,6 @@ source "drivers/pci/Kconfig"
>   
>   source "drivers/video/Kconfig"
>   
> +source "drivers/passthrough/arm/Kconfig"
> +
>   endmenu
> diff --git a/xen/drivers/passthrough/arm/Kconfig b/xen/drivers/passthrough/arm/Kconfig
> new file mode 100644
> index 0000000000..cda899f608
> --- /dev/null
> +++ b/xen/drivers/passthrough/arm/Kconfig
> @@ -0,0 +1,8 @@
> +
> +config ARM_SMMU_v3
> +	bool "ARM SMMUv3 Support"
> +	depends on ARM_64
> +	help
> +	 Support for implementations of the ARM System MMU architecture
> +	 version 3.
> +
> diff --git a/xen/drivers/passthrough/arm/Makefile b/xen/drivers/passthrough/arm/Makefile
> index f4cd26e15d..e14732b55c 100644
> --- a/xen/drivers/passthrough/arm/Makefile
> +++ b/xen/drivers/passthrough/arm/Makefile
> @@ -1,2 +1,3 @@
>   obj-y += iommu.o
>   obj-y += smmu.o
> +obj-$(CONFIG_ARM_SMMU_v3) += smmu-v3.o
> diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
> index e67ba6c40f..3488184ad4 100644
> --- a/xen/drivers/passthrough/arm/smmu-v3.c
> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
> @@ -18,28 +18,402 @@
>    * Author: Will Deacon <will.deacon@arm.com>
>    *
>    * This driver is powered by bad coffee and bombay mix.
> + *
> + *
> + * Based on Linux drivers/iommu/arm-smmu-v3.c
> + * => commit 7aa8619a66aea52b145e04cbab4f8d6a4e5f3f3b
> + *
> + * Xen modifications:
> + * Sameer Goel <sameer.goel@linaro.org>
> + * Copyright (C) 2017, The Linux Foundation, All rights reserved.
> + *
> + */
> +
> +#include <xen/acpi.h>
> +#include <xen/config.h>
> +#include <xen/delay.h>
> +#include <xen/errno.h>
> +#include <xen/err.h>
> +#include <xen/irq.h>
> +#include <xen/lib.h>
> +#include <xen/linux_compat.h>
> +#include <xen/list.h>
> +#include <xen/mm.h>
> +#include <xen/rbtree.h>
> +#include <xen/sched.h>
> +#include <xen/sizes.h>
> +#include <xen/vmap.h>
> +#include <acpi/acpi_iort.h>
> +#include <asm/atomic.h>
> +#include <asm/device.h>
> +#include <asm/io.h>
> +#include <asm/platform.h>
> +
> +
> +/* Xen: Helpers to get device MMIO and IRQs */
> +struct resource {
> +	u64 addr;
> +	u64 size;
> +	unsigned int type;
> +};
> +
> +#define resource_size(res) ((res)->size)
> +
> +#define platform_device device
> +
> +#define IORESOURCE_MEM 0
> +#define IORESOURCE_IRQ 1
> +
> +static struct resource *platform_get_resource(struct platform_device *pdev,
> +					      unsigned int type,
> +					      unsigned int num)
> +{
> +	/*
> +	 * The resource is only used between 2 calls of platform_get_resource.
> +	 * It's quite ugly but it's avoid to add too much code in the part
> +	 * imported from Linux
> +	 */
> +	static struct resource res;
> +	struct acpi_iort_node *iort_node;
> +	struct acpi_iort_smmu_v3 *node_smmu_data;
> +	int ret = 0;
> +
> +	res.type = type;
> +
> +	switch (type) {
> +	case IORESOURCE_MEM:
> +		if (pdev->type == DEV_ACPI) {
> +			ret = 1;
> +			iort_node = pdev->acpi_node;
> +			node_smmu_data =
> +				(struct acpi_iort_smmu_v3 *)iort_node->node_data;
> +
> +			if (node_smmu_data != NULL) {
> +				res.addr = node_smmu_data->base_address;
> +				res.size = SZ_128K;
> +				ret = 0;
> +			}
> +		} else {
> +			ret = dt_device_get_address(dev_to_dt(pdev), num,
> +						    &res.addr, &res.size);
> +		}
> +
> +		return ((ret) ? NULL : &res);
> +
> +	case IORESOURCE_IRQ:
> +		/* ACPI case not implemented as there is no use case for it */
> +		ret = platform_get_irq(dev_to_dt(pdev), num);
> +
> +		if (ret < 0)
> +			return NULL;
> +
> +		res.addr = ret;
> +		res.size = 1;
> +
> +		return &res;
> +
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +static int platform_get_irq_byname(struct platform_device *pdev, const char *name)
> +{
> +	const struct dt_property *dtprop;
> +	struct acpi_iort_node *iort_node;
> +	struct acpi_iort_smmu_v3 *node_smmu_data;
> +	int ret = 0;
> +
> +	if (pdev->type == DEV_ACPI) {
> +		iort_node = pdev->acpi_node;
> +		node_smmu_data = (struct acpi_iort_smmu_v3 *)iort_node->node_data;
> +
> +		if (node_smmu_data != NULL) {
> +			if (!strcmp(name, "eventq"))
> +				ret = node_smmu_data->event_gsiv;
> +			else if (!strcmp(name, "priq"))
> +				ret = node_smmu_data->pri_gsiv;
> +			else if (!strcmp(name, "cmdq-sync"))
> +				ret = node_smmu_data->sync_gsiv;
> +			else if (!strcmp(name, "gerror"))
> +				ret = node_smmu_data->gerr_gsiv;
> +			else
> +				ret = -EINVAL;
> +		}
> +	} else {
> +		dtprop = dt_find_property(dev_to_dt(pdev), "interrupt-names", NULL);
> +		if (!dtprop)
> +			return -EINVAL;
> +
> +		if (!dtprop->value)
> +			return -ENODATA;
> +	}
> +
> +	return ret;
> +}
> +
> +/*
> + * Xen: Helpers for DMA allocation. Just the function name is reused for
> + * porting code these allocation are not managed allocations
> + */
> +
> +void *dmam_alloc_coherent(struct device *dev, size_t size,
> +			   dma_addr_t *dma_handle, gfp_t gfp)
> +{
> +	void *vaddr;
> +	unsigned long alignment = size;
> +
> +	/*
> +	 * _xzalloc requires that the (align & (align -1)) = 0. Most of the
> +	 * allocations in SMMU code should send the right value for size. In
> +	 * case this is not true print a warning and align to the size of a
> +	 * (void *)
> +	 */
> +	if (size & (size - 1)) {
> +		dev_warn(dev, "Fixing alignment for the DMA buffer\n");
> +		alignment = sizeof(void *);
> +	}
> +
> +	vaddr = _xzalloc(size, alignment);
> +	if (!vaddr) {
> +		dev_err(dev, "DMA allocation failed\n");
> +		return NULL;
> +	}
> +
> +	*dma_handle = virt_to_maddr(vaddr);
> +
> +	return vaddr;
> +}
> +
> +
> +void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
> +			dma_addr_t dma_handle)
> +{
> +	xfree(vaddr);
> +}
> +
> +/* Xen: Stub out DMA domain related functions */
> +#define iommu_get_dma_cookie(dom) 0
> +#define iommu_put_dma_cookie(dom)
> +
> +/* Xen: Stub out module param related function */
> +#define module_param_named(a, b, c, d)
> +#define MODULE_PARM_DESC(a, b)
> +
> +#define dma_set_mask_and_coherent(d, b) 0
> +
> +#define of_dma_is_coherent(n) 0
> +
> +#define MODULE_DEVICE_TABLE(type, name)
> +#define of_device_id dt_device_match
> +
> +static void __iomem *devm_ioremap_resource(struct device *dev,
> +					   struct resource *res)
> +{
> +	void __iomem *ptr;
> +
> +	if (!res || res->type != IORESOURCE_MEM) {
> +		dev_err(dev, "Invalid resource\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	ptr = ioremap_nocache(res->addr, res->size);
> +	if (!ptr) {
> +		dev_err(dev,
> +			"ioremap failed (addr 0x%"PRIx64" size 0x%"PRIx64")\n",
> +			res->addr, res->size);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	return ptr;
> +}
> +
> +/* Xen: Compatibility define for iommu_domain_geometry.*/
> +struct iommu_domain_geometry {
> +	dma_addr_t aperture_start; /* First address that can be mapped    */
> +	dma_addr_t aperture_end;   /* Last address that can be mapped     */
> +	bool force_aperture;       /* DMA only allowed in mappable range? */
> +};
> +
> +
> +/* Xen: Type definitions for iommu_domain */
> +#define IOMMU_DOMAIN_UNMANAGED 0
> +#define IOMMU_DOMAIN_DMA 1
> +#define IOMMU_DOMAIN_IDENTITY 2
> +
> +/* Xen: Dummy iommu_domain */
> +struct iommu_domain {
> +	/* Runtime SMMU configuration for this iommu_domain */
> +	struct arm_smmu_domain		*priv;
Can we use a more meaningful name in place of priv.
> +	unsigned int type;
> +
> +	/* Dummy compatibility defines */
> +	unsigned long pgsize_bitmap;
> +	struct iommu_domain_geometry geometry;
> +
> +	atomic_t ref;
> +	/*
> +	 * Used to link iommu_domain contexts for a same domain.
> +	 * There is at least one per-SMMU to used by the domain.
> +	 */
> +	struct list_head		list;
> +};
> +
> +
> +/* Xen: Describes information required for a Xen domain */
> +struct arm_smmu_xen_domain {
> +	spinlock_t			lock;
> +	/* List of iommu domains associated to this domain */
> +	struct list_head		iommu_domains;
> +};
> +
> +/*
> + * Xen: Information about each device stored in dev->archdata.iommu
> + *
> + * The dev->archdata.iommu stores the iommu_domain (runtime configuration of
> + * the SMMU).
>    */
> +struct arm_smmu_xen_device {
> +	struct iommu_domain *domain;
domain name is confusing, if you read just the variable name it is not 
easy to understand that it is a struct domain pointer or few other 
structures which have _domain in their names.
Same comment for all usages of variables with just the name domain.
> +};
> +
> +/*
> + * Xen: io_pgtable compatibility defines.
> + * Most of these are to port in the S1 translation code as is.
> + */
> +struct io_pgtable_ops {
> +};
> +
> +struct iommu_gather_ops {
> +	void (*tlb_flush_all)(void *cookie);
> +	void (*tlb_add_flush)(unsigned long iova, size_t size, size_t granule,
> +			      bool leaf, void *cookie);
> +	void (*tlb_sync)(void *cookie);
> +};
> +
> +struct io_pgtable_cfg {
> +	/*
> +	 * IO_PGTABLE_QUIRK_ARM_NS: (ARM formats) Set NS and NSTABLE bits in
> +	 *	stage 1 PTEs, for hardware which insists on validating them
> +	 *	even in	non-secure state where they should normally be ignored.
> +	 *
> +	 * IO_PGTABLE_QUIRK_NO_PERMS: Ignore the IOMMU_READ, IOMMU_WRITE and
> +	 *	IOMMU_NOEXEC flags and map everything with full access, for
> +	 *	hardware which does not implement the permissions of a given
> +	 *	format, and/or requires some format-specific default value.
> +	 *
> +	 * IO_PGTABLE_QUIRK_TLBI_ON_MAP: If the format forbids caching invalid
> +	 *	(unmapped) entries but the hardware might do so anyway, perform
> +	 *	TLB maintenance when mapping as well as when unmapping.
> +	 *
> +	 * IO_PGTABLE_QUIRK_ARM_MTK_4GB: (ARM v7s format) Set bit 9 in all
> +	 *	PTEs, for Mediatek IOMMUs which treat it as a 33rd address bit
> +	 *	when the SoC is in "4GB mode" and they can only access the high
> +	 *	remap of DRAM (0x1_00000000 to 0x1_ffffffff).
> +	 *
> +	 * IO_PGTABLE_QUIRK_NO_DMA: Guarantees that the tables will only ever
> +	 *	be accessed by a fully cache-coherent IOMMU or CPU (e.g. for a
> +	 *	software-emulated IOMMU), such that pagetable updates need not
> +	 *	be treated as explicit DMA data.
> +	 */
> +	#define IO_PGTABLE_QUIRK_ARM_NS		BIT(0)
> +	#define IO_PGTABLE_QUIRK_NO_PERMS	BIT(1)
> +	#define IO_PGTABLE_QUIRK_TLBI_ON_MAP	BIT(2)
> +	#define IO_PGTABLE_QUIRK_ARM_MTK_4GB	BIT(3)
> +	#define IO_PGTABLE_QUIRK_NO_DMA		BIT(4)
> +	unsigned long			quirks;
> +	unsigned long			pgsize_bitmap;
> +	unsigned int			ias;
> +	unsigned int			oas;
> +	const struct iommu_gather_ops	*tlb;
> +	struct device			*iommu_dev;
> +
> +	/* Low-level data specific to the table format */
> +	union {
> +		struct {
> +			u64	ttbr[2];
> +			u64	tcr;
> +			u64	mair[2];
> +		} arm_lpae_s1_cfg;
> +
> +		struct {
> +			u64	vttbr;
> +			u64	vtcr;
> +		} arm_lpae_s2_cfg;
> +
> +		struct {
> +			u32	ttbr[2];
> +			u32	tcr;
> +			u32	nmrr;
> +			u32	prrr;
> +		} arm_v7s_cfg;
> +	};
> +};
> +
> +enum io_pgtable_fmt {
> +	ARM_32_LPAE_S1,
> +	ARM_32_LPAE_S2,
> +	ARM_64_LPAE_S1,
> +	ARM_64_LPAE_S2,
> +	ARM_V7S,
> +	IO_PGTABLE_NUM_FMTS,
> +};
> +
> +/*
> + * Xen: The pgtable_ops are used by the S1 translations, so return the dummy
> + * address.
> + */
> +#define alloc_io_pgtable_ops(f, c, o) ((struct io_pgtable_ops *)0xDEADBEEF)
> +#define free_io_pgtable_ops(o) (o = 0)
> +
> +/* Xen: Define wrapper for requesting IRQs */
> +#define IRQF_ONESHOT 0
> +
> +typedef void (*irq_handler_t)(int, void *, struct cpu_user_regs *);
> +
> +static inline int devm_request_irq(struct device *dev, unsigned int irq,
> +				   irq_handler_t handler, unsigned long irqflags,
> +				   const char *devname, void *dev_id)
> +{
> +	/*TODO: Check if we really need to set a type */
> +	irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
> +	return request_irq(irq, irqflags, handler, devname, dev_id);
> +
> +}
> +
> +int devm_request_threaded_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
> +			      irq_handler_t thread_fn, unsigned long irqflags,
> +			      const char *devname, void *dev_id)
> +{
> +	return devm_request_irq(dev, irq, thread_fn, irqflags, devname, dev_id);
> +}
Is it possible to change the name from threaded to something more 
meaningful as IIUC in xen we dont  have threaded irqs.
Though the code is coming from linux, but it has to be called/named in 
the place it is intended to be used
> .
>   
> -#include <linux/acpi.h>
> -#include <linux/acpi_iort.h>
> -#include <linux/delay.h>
> -#include <linux/dma-iommu.h>
> -#include <linux/err.h>
> -#include <linux/interrupt.h>
> -#include <linux/iommu.h>
> -#include <linux/iopoll.h>
> -#include <linux/module.h>
> -#include <linux/msi.h>
> -#include <linux/of.h>
> -#include <linux/of_address.h>
> -#include <linux/of_iommu.h>
> -#include <linux/of_platform.h>
> -#include <linux/pci.h>
> -#include <linux/platform_device.h>
> -
> -#include <linux/amba/bus.h>
> -
> -#include "io-pgtable.h"
> +/* Xen: The mutex is used only during initialization so the typecast is safe */
> +#define mutex spinlock_t
> +#define mutex_init spin_lock_init
> +#define mutex_lock spin_lock
> +#define mutex_unlock spin_unlock
> +
> +#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
> +({ \
> +	s_time_t deadline = NOW() + MICROSECS(timeout_us); \
> +	for (;;) { \
> +		(val) = op(addr); \
> +		if (cond) \
> +			break; \
> +		if (NOW() > deadline) { \
> +			(val) = op(addr); \
> +			break; \
> +		} \
> +	udelay(sleep_us); \
> +	} \
> +	(cond) ? 0 : -ETIMEDOUT; \
> +})
> +
> +#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
> +	readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
> +
> +#define VA_BITS 0 /* Only needed for S1 translations */
>   
>   /* MMIO registers */
>   #define ARM_SMMU_IDR0			0x0
> @@ -433,6 +807,7 @@ enum pri_resp {
>   	PRI_RESP_SUCC,
>   };
>   
> +#if 0 /* Xen: No MSI support in this iteration */
>   enum arm_smmu_msi_index {
>   	EVTQ_MSI_INDEX,
>   	GERROR_MSI_INDEX,
> @@ -457,6 +832,7 @@ static phys_addr_t arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
>   		ARM_SMMU_PRIQ_IRQ_CFG2,
>   	},
>   };
> +#endif
>   
IMHO can we avoid #if 0 from the code, unless we intend to use the code 
in future.
>   struct arm_smmu_cmdq_ent {
>   	/* Common fields */
> @@ -561,6 +937,8 @@ struct arm_smmu_s2_cfg {
>   	u16				vmid;
>   	u64				vttbr;
>   	u64				vtcr;
> +	/* Xen: Domain associated to this configuration */
> +	struct domain			*domain;
See now this domain and other domain variables would confuse reader.
I hope this example provides rationale to my argument.
>   };
>   
>   struct arm_smmu_strtab_ent {
> @@ -635,9 +1013,21 @@ struct arm_smmu_device {
>   	struct arm_smmu_strtab_cfg	strtab_cfg;
>   
>   	/* IOMMU core code handle */
> +#if 0 /*Xen: Generic iommu_device ref not needed here */
>   	struct iommu_device		iommu;
> +#endif
> +	/* Xen: Need to keep a list of SMMU devices */
> +	struct list_head                devices;
>   };
>   
> +/* Xen: Keep a list of devices associated with this driver */
> +static DEFINE_SPINLOCK(arm_smmu_devices_lock);
> +static LIST_HEAD(arm_smmu_devices);
> +/* Xen: Helper for finding a device using fwnode */
> +static
> +struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode);
> +
> +
>   /* SMMU private data for each master */
>   struct arm_smmu_master_data {
>   	struct arm_smmu_device		*smmu;
> @@ -654,7 +1044,7 @@ enum arm_smmu_domain_stage {
>   
>   struct arm_smmu_domain {
>   	struct arm_smmu_device		*smmu;
> -	struct mutex			init_mutex; /* Protects smmu pointer */
> +	mutex				init_mutex; /* Protects smmu pointer */
>   
>   	struct io_pgtable_ops		*pgtbl_ops;
>   
> @@ -1232,7 +1622,7 @@ static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
>   
>   	dev_info(smmu->dev, "unexpected PRI request received:\n");
>   	dev_info(smmu->dev,
> -		 "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova 0x%016llx\n",
> +		 "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova %#" PRIx64 "\n",
>   		 sid, ssid, grpid, last ? "L" : "",
>   		 evt[0] & PRIQ_0_PERM_PRIV ? "" : "un",
>   		 evt[0] & PRIQ_0_PERM_READ ? "R" : "",
> @@ -1346,6 +1736,8 @@ static irqreturn_t arm_smmu_combined_irq_handler(int irq, void *dev)
>   {
>   	arm_smmu_gerror_handler(irq, dev);
>   	arm_smmu_cmdq_sync_handler(irq, dev);
> +	/*Xen: No threaded irq. So call the required function from here */
> +	arm_smmu_combined_irq_thread(irq, dev);
>   	return IRQ_WAKE_THREAD;
>   }
>   
> @@ -1358,6 +1750,46 @@ static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu)
>   	arm_smmu_cmdq_issue_cmd(smmu, &cmd);
>   }
>   
> +/*
> + * Xen: Define the IRQ handlers for xen. The linux functions would be
> + * modified to use the functions defined in the following code.
> + */
> +static void arm_smmu_evtq_thread_xen(int irq, void *dev,
> +				       struct cpu_user_regs *regs)
> +{
> +	arm_smmu_evtq_thread(irq, dev);
> +}
> +
> +static void arm_smmu_priq_thread_xen(int irq, void *dev,
> +				       struct cpu_user_regs *regs)
> +{
> +	arm_smmu_priq_thread(irq, dev);
> +}
> +
Again can we avoid _therad from the nomenclature.
> +static void arm_smmu_cmdq_sync_handler_xen(int irq, void *dev,
> +				       struct cpu_user_regs *regs)
> +{
> +	arm_smmu_cmdq_sync_handler(irq, dev);
> +}
> +
> +static void arm_smmu_gerror_handler_xen(int irq, void *dev,
> +				       struct cpu_user_regs *regs)
> +{
> +	arm_smmu_gerror_handler(irq, dev);
> +}
> +
> +static void arm_smmu_combined_irq_handler_xen(int irq, void *dev,
> +				       struct cpu_user_regs *regs)
> +{
> +	arm_smmu_combined_irq_handler(irq, dev);
> +}
> +
> +#define arm_smmu_evtq_thread arm_smmu_evtq_thread_xen
> +#define arm_smmu_priq_thread arm_smmu_priq_thread_xen
> +#define arm_smmu_cmdq_sync_handler arm_smmu_cmdq_sync_handler_xen
> +#define arm_smmu_gerror_handler arm_smmu_gerror_handler_xen
> +#define arm_smmu_combined_irq_handler arm_smmu_combined_irq_handler_xen
> +
>   static void arm_smmu_tlb_sync(void *cookie)
>   {
>   	struct arm_smmu_domain *smmu_domain = cookie;
> @@ -1415,6 +1847,7 @@ static const struct iommu_gather_ops arm_smmu_gather_ops = {
>   	.tlb_sync	= arm_smmu_tlb_sync,
>   };
>   
> +#if 0 /*Xen: Unused functionality */
>   /* IOMMU API */
>   static bool arm_smmu_capable(enum iommu_cap cap)
>   {
> @@ -1427,6 +1860,7 @@ static bool arm_smmu_capable(enum iommu_cap cap)
>   		return false;
>   	}
>   }
> +#endif
>   
>   static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
>   {
> @@ -1546,9 +1980,15 @@ static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
>   	if (vmid < 0)
>   		return vmid;
>   
> -	cfg->vmid	= (u16)vmid;
> -	cfg->vttbr	= pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
> -	cfg->vtcr	= pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
> +	/* Xen: Get the ttbr and vtcr values
> +	 * vttbr: This is a shared value with the domain page table
> +	 * vtcr: The TCR settings are the same as CPU since the page
> +	 * tables are shared
> +	 */
> +
> +	cfg->vmid	= vmid;
> +	cfg->vttbr	= page_to_maddr(cfg->domain->arch.p2m.root);
> +	cfg->vtcr	= READ_SYSREG32(VTCR_EL2) & STRTAB_STE_2_VTCR_MASK;
>   	return 0;
>   }
>   
> @@ -1604,6 +2044,7 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain)
>   	if (smmu->features & ARM_SMMU_FEAT_COHERENCY)
>   		pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA;
>   
> +	/* Xen: pgtbl_ops gets an invalid address */
>   	pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
>   	if (!pgtbl_ops)
>   		return -ENOMEM;
> @@ -1721,6 +2162,7 @@ out_unlock:
>   	return ret;
>   }
>   
> +#if 0 /* Xen: Unused functionlity */
>   static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
>   			phys_addr_t paddr, size_t size, int prot)
>   {
> @@ -1772,6 +2214,7 @@ struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
>   	put_device(dev);
>   	return dev ? dev_get_drvdata(dev) : NULL;
>   }
> +#endif
>   
>   static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
>   {
> @@ -1783,7 +2226,9 @@ static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
>   	return sid < limit;
>   }
>   
> +#if 0
>   static struct iommu_ops arm_smmu_ops;
> +#endif
>   
>   static int arm_smmu_add_device(struct device *dev)
>   {
> @@ -1791,9 +2236,12 @@ static int arm_smmu_add_device(struct device *dev)
>   	struct arm_smmu_device *smmu;
>   	struct arm_smmu_master_data *master;
>   	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
> +#if 0 /*Xen: iommu_group is not needed */
>   	struct iommu_group *group;
> +#endif
>   
> -	if (!fwspec || fwspec->ops != &arm_smmu_ops)
> +	/* Xen: fwspec->ops are not needed */
> +	if (!fwspec)
>   		return -ENODEV;
>   	/*
>   	 * We _can_ actually withstand dodgy bus code re-calling add_device()
> @@ -1830,6 +2278,11 @@ static int arm_smmu_add_device(struct device *dev)
>   		}
>   	}
>   
> +/*
> + * Xen: Do not need an iommu group as the stream data is carried by the SMMU
> + * master device object
> + */
> +#if 0
>   	group = iommu_group_get_for_dev(dev);
>   	if (!IS_ERR(group)) {
>   		iommu_group_put(group);
> @@ -1837,8 +2290,16 @@ static int arm_smmu_add_device(struct device *dev)
>   	}
>   
>   	return PTR_ERR_OR_ZERO(group);
> +#endif
> +	return 0;
>   }
>   
> +/*
> + * Xen: We can potentially support this function and destroy a device. This
> + * will be relevant for PCI hotplug. So, will be implemented as needed after
> + * passthrough support is available.
> + */
> +#if 0
>   static void arm_smmu_remove_device(struct device *dev)
>   {
>   	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
> @@ -1974,6 +2435,7 @@ static struct iommu_ops arm_smmu_ops = {
>   	.put_resv_regions	= arm_smmu_put_resv_regions,
>   	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
>   };
> +#endif
>   
>   /* Probing and initialisation functions */
>   static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
> @@ -2182,6 +2644,7 @@ static int arm_smmu_update_gbpa(struct arm_smmu_device *smmu, u32 set, u32 clr)
>   					  1, ARM_SMMU_POLL_TIMEOUT_US);
>   }
>   
> +#if 0 /* Xen: There is no MSI support as yet */
>   static void arm_smmu_free_msis(void *data)
>   {
>   	struct device *dev = data;
> @@ -2247,12 +2710,15 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
>   	/* Add callback to free MSIs on teardown */
>   	devm_add_action(dev, arm_smmu_free_msis, dev);
>   }
> +#endif
>   
>   static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
>   {
>   	int irq, ret;
>   
> +#if 0 /*Xen: Cannot setup msis for now */
>   	arm_smmu_setup_msis(smmu);
> +#endif
>   
>   	/* Request interrupt lines */
>   	irq = smmu->evtq.q.irq;
> @@ -2316,9 +2782,13 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
>   		 * Cavium ThunderX2 implementation doesn't not support unique
>   		 * irq lines. Use single irq line for all the SMMUv3 interrupts.
>   		 */
> -		ret = devm_request_threaded_irq(smmu->dev, irq,
> +		/*
> +		 * Xen: Does not support threaded irqs, so serialise the setup.
> +		 * This is the same for pris and event interrupt lines on other
> +		 * systems
> +		 */
> +		ret = devm_request_irq(smmu->dev, irq,
>   					arm_smmu_combined_irq_handler,
> -					arm_smmu_combined_irq_thread,
>   					IRQF_ONESHOT,
>   					"arm-smmu-v3-combined-irq", smmu);
>   		if (ret < 0)
> @@ -2542,8 +3012,14 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
>   		smmu->features |= ARM_SMMU_FEAT_STALLS;
>   	}
>   
> +/*
> + * Xen: Block stage 1 translations. By doing this here we do not need to set the
> + * domain->stage explicitly.
> + */
> +#if 0
>   	if (reg & IDR0_S1P)
>   		smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
> +#endif
>   
>   	if (reg & IDR0_S2P)
>   		smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
> @@ -2616,10 +3092,12 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
>   	if (reg & IDR5_GRAN4K)
>   		smmu->pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
>   
> +#if 0 /* Xen: SMMU ops do not have a pgsize_bitmap member for Xen */
>   	if (arm_smmu_ops.pgsize_bitmap == -1UL)
>   		arm_smmu_ops.pgsize_bitmap = smmu->pgsize_bitmap;
>   	else
>   		arm_smmu_ops.pgsize_bitmap |= smmu->pgsize_bitmap;
> +#endif
>   
>   	/* Output address size */
>   	switch (reg & IDR5_OAS_MASK << IDR5_OAS_SHIFT) {
> @@ -2680,7 +3158,8 @@ static int arm_smmu_device_acpi_probe(struct platform_device *pdev,
>   	struct device *dev = smmu->dev;
>   	struct acpi_iort_node *node;
>   
> -	node = *(struct acpi_iort_node **)dev_get_platdata(dev);
> +	/* Xen: Modification to get iort_node */
> +	node = (struct acpi_iort_node *)dev->acpi_node;
>   
>   	/* Retrieve SMMUv3 specific data */
>   	iort_smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
> @@ -2703,7 +3182,7 @@ static inline int arm_smmu_device_acpi_probe(struct platform_device *pdev,
>   static int arm_smmu_device_dt_probe(struct platform_device *pdev,
>   				    struct arm_smmu_device *smmu)
>   {
> -	struct device *dev = &pdev->dev;
> +	struct device *dev = pdev;
>   	u32 cells;
>   	int ret = -EINVAL;
>   
> @@ -2716,6 +3195,7 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
>   
>   	parse_driver_options(smmu);
>   
> +	/* Xen: of_dma_is_coherent is a stub till dt support is introduced */
>   	if (of_dma_is_coherent(dev->of_node))
>   		smmu->features |= ARM_SMMU_FEAT_COHERENCY;
>   
> @@ -2734,9 +3214,11 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>   {
>   	int irq, ret;
>   	struct resource *res;
> +#if 0 /*Xen: Do not need to setup sysfs */
>   	resource_size_t ioaddr;
> +#endif
>   	struct arm_smmu_device *smmu;
> -	struct device *dev = &pdev->dev;
> +	struct device *dev = pdev;/* Xen: dev is ignored */
>   	bool bypass;
>   
>   	smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
> @@ -2763,7 +3245,9 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>   		dev_err(dev, "MMIO region too small (%pr)\n", res);
>   		return -EINVAL;
>   	}
> +#if 0 /*Xen: Do not need to setup sysfs */
>   	ioaddr = res->start;
> +#endif
>   
>   	smmu->base = devm_ioremap_resource(dev, res);
>   	if (IS_ERR(smmu->base))
> @@ -2802,13 +3286,18 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>   		return ret;
>   
>   	/* Record our private device structure */
> +	/* Xen: SMMU is not treated a a platform device*/
> +#if 0
>   	platform_set_drvdata(pdev, smmu);
> +#endif
>   
>   	/* Reset the device */
>   	ret = arm_smmu_device_reset(smmu, bypass);
>   	if (ret)
>   		return ret;
>   
> +/* Xen: Not creating an IOMMU device list for Xen */
> +#if 0
>   	/* And we're up. Go go go! */
>   	ret = iommu_device_sysfs_add(&smmu->iommu, dev, NULL,
>   				     "smmu3.%pa", &ioaddr);
> @@ -2844,9 +3333,20 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>   		if (ret)
>   			return ret;
>   	}
> +#endif
> +	/*
> +	 * Xen: Keep a list of all probed devices. This will be used to query
> +	 * the smmu devices based on the fwnode.
> +	 */
> +	INIT_LIST_HEAD(&smmu->devices);
> +	spin_lock(&arm_smmu_devices_lock);
> +	list_add(&smmu->devices, &arm_smmu_devices);
> +	spin_unlock(&arm_smmu_devices_lock);
>   	return 0;
>   }
>   
> +/* Xen: Unused function */
> +#if 0
>   static int arm_smmu_device_remove(struct platform_device *pdev)
>   {
>   	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
> @@ -2860,6 +3360,8 @@ static void arm_smmu_device_shutdown(struct platform_device *pdev)
>   {
>   	arm_smmu_device_remove(pdev);
>   }
> +#endif
> +
>   
>   static const struct of_device_id arm_smmu_of_match[] = {
>   	{ .compatible = "arm,smmu-v3", },
> @@ -2867,6 +3369,7 @@ static const struct of_device_id arm_smmu_of_match[] = {
>   };
>   MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
>   
> +#if 0
>   static struct platform_driver arm_smmu_driver = {
>   	.driver	= {
>   		.name		= "arm-smmu-v3",
> @@ -2883,3 +3386,318 @@ IOMMU_OF_DECLARE(arm_smmuv3, "arm,smmu-v3", NULL);
>   MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
>   MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
>   MODULE_LICENSE("GPL v2");
> +#endif
> +
> +/***** Start of Xen specific code *****/
> +
> +static int __must_check arm_smmu_iotlb_flush_all(struct domain *d)
> +{
> +	struct arm_smmu_xen_domain *smmu_domain = dom_iommu(d)->arch.priv;
> +	struct iommu_domain *cfg;
> +
> +	spin_lock(&smmu_domain->lock);
> +	list_for_each_entry(cfg, &smmu_domain->iommu_domains, list) {
> +		/*
> +		 * Only invalidate the context when SMMU is present.
> +		 * This is because the context initialization is delayed
> +		 * until a master has been added.
> +		 */
> +		if (unlikely(!ACCESS_ONCE(cfg->priv->smmu)))
> +			continue;
> +		arm_smmu_tlb_inv_context(cfg->priv);
> +	}
> +	spin_unlock(&smmu_domain->lock);
> +	return 0;
> +}
> +
> +static int __must_check arm_smmu_iotlb_flush(struct domain *d,
> +					     unsigned long gfn,
> +					     unsigned int page_count)
> +{
> +	return arm_smmu_iotlb_flush_all(d);
> +}
> +
> +static struct iommu_domain *arm_smmu_get_domain(struct domain *d,
> +						struct device *dev)
> +{
> +	struct iommu_domain *domain;
fix domain variable.
> +	struct arm_smmu_xen_domain *xen_domain;
> +	struct arm_smmu_device *smmu;
> +	struct arm_smmu_domain *smmu_domain;
> +
> +	xen_domain = dom_iommu(d)->arch.priv;
> +
> +	smmu = arm_smmu_get_by_fwnode(dev->iommu_fwspec->iommu_fwnode);
> +	if (!smmu)
> +		return NULL;
> +
> +	/*
> +	 * Loop through the &xen_domain->contexts to locate a context
> +	 * assigned to this SMMU
> +	 */
> +	list_for_each_entry(domain, &xen_domain->iommu_domains, list) {
> +		smmu_domain = to_smmu_domain(domain);
> +		if (smmu_domain->smmu == smmu)
> +			return domain;
> +	}
> +
> +	return NULL;
> +}
> +
> +static void arm_smmu_destroy_iommu_domain(struct iommu_domain *domain)
> +{
> +	list_del(&domain->list);
> +	arm_smmu_domain_free(domain);
> +}
> +
> +static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
> +			       struct device *dev, u32 flag)
> +{
> +	int ret = 0;
> +	struct iommu_domain *domain;
> +	struct arm_smmu_xen_domain *xen_domain;
> +	struct arm_smmu_domain *arm_smmu;
> +
> +	xen_domain = dom_iommu(d)->arch.priv;
> +
> +	if (!dev->archdata.iommu) {
> +		dev->archdata.iommu = xzalloc(struct arm_smmu_xen_device);
> +		if (!dev->archdata.iommu)
> +			return -ENOMEM;
> +	}
> +
> +	ret = arm_smmu_add_device(dev);
> +	if (ret)
> +		return ret;
> +
> +	spin_lock(&xen_domain->lock);
> +
> +	/*
> +	 * Check to see if an iommu_domain already exists for this xen domain
> +	 * under the same SMMU
> +	 */
> +	domain = arm_smmu_get_domain(d, dev);
> +	if (!domain) {
> +
> +		domain = arm_smmu_domain_alloc(IOMMU_DOMAIN_DMA);
> +		if (!domain) {
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +
> +		arm_smmu = to_smmu_domain(domain);
> +		arm_smmu->s2_cfg.domain = d;
> +
> +		/* Chain the new context to the domain */
> +		list_add(&domain->list, &xen_domain->iommu_domains);
> +
> +	}
> +
> +	ret = arm_smmu_attach_dev(domain, dev);
> +	if (ret) {
> +		if (domain->ref.counter == 0)
> +			arm_smmu_destroy_iommu_domain(domain);
> +	} else {
> +		atomic_inc(&domain->ref);
> +	}
> +
> +out:
> +	spin_unlock(&xen_domain->lock);
> +	return ret;
> +}
> +
> +static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
> +{
> +	struct iommu_domain *domain = arm_smmu_get_domain(d, dev);
> +	struct arm_smmu_xen_domain *xen_domain;
> +	struct arm_smmu_domain *arm_smmu = to_smmu_domain(domain);
> +
> +	xen_domain = dom_iommu(d)->arch.priv;
> +
> +	if (!arm_smmu || arm_smmu->s2_cfg.domain != d) {
> +		dev_err(dev, " not attached to domain %d\n", d->domain_id);
> +		return -ESRCH;
> +	}
> +
> +	spin_lock(&xen_domain->lock);
> +
> +	arm_smmu_detach_dev(dev);
> +	atomic_dec(&domain->ref);
> +
> +	if (domain->ref.counter == 0)
> +		arm_smmu_destroy_iommu_domain(domain);
> +
> +	spin_unlock(&xen_domain->lock);
> +
> +
> +
> +	return 0;
> +}
> +
> +static int arm_smmu_reassign_dev(struct domain *s, struct domain *t,
> +				 u8 devfn,  struct device *dev)
> +{
> +	int ret = 0;
> +
> +	/* Don't allow remapping on other domain than hwdom */
> +	if (t && t != hardware_domain)
> +		return -EPERM;
> +
> +	if (t == s)
> +		return 0;
> +
> +	ret = arm_smmu_deassign_dev(s, dev);
> +	if (ret)
> +		return ret;
> +
> +	if (t) {
> +		/* No flags are defined for ARM. */
> +		ret = arm_smmu_assign_dev(t, devfn, dev, 0);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int arm_smmu_iommu_domain_init(struct domain *d)
> +{
> +	struct arm_smmu_xen_domain *xen_domain;
> +
> +	xen_domain = xzalloc(struct arm_smmu_xen_domain);
> +	if (!xen_domain)
> +		return -ENOMEM;
> +
> +	spin_lock_init(&xen_domain->lock);
> +	INIT_LIST_HEAD(&xen_domain->iommu_domains);
> +
> +	dom_iommu(d)->arch.priv = xen_domain;
> +
> +	return 0;
> +}
> +
> +static void __hwdom_init arm_smmu_iommu_hwdom_init(struct domain *d)
> +{
> +}
> +
> +static void arm_smmu_iommu_domain_teardown(struct domain *d)
> +{
> +	struct arm_smmu_xen_domain *xen_domain = dom_iommu(d)->arch.priv;
> +
> +	ASSERT(list_empty(&xen_domain->iommu_domains));
> +	xfree(xen_domain);
> +}
> +
> +static int __must_check arm_smmu_map_page(struct domain *d, unsigned long gfn,
> +			unsigned long mfn, unsigned int flags)
> +{
> +	p2m_type_t t;
> +
> +	/*
> +	 * Grant mappings can be used for DMA requests. The dev_bus_addr
> +	 * returned by the hypercall is the MFN (not the IPA). For device
> +	 * protected by an IOMMU, Xen needs to add a 1:1 mapping in the domain
> +	 * p2m to allow DMA request to work.
> +	 * This is only valid when the domain is directed mapped. Hence this
> +	 * function should only be used by gnttab code with gfn == mfn.
> +	 */
> +	BUG_ON(!is_domain_direct_mapped(d));
> +	BUG_ON(mfn != gfn);
> +
> +	/* We only support readable and writable flags */
> +	if (!(flags & (IOMMUF_readable | IOMMUF_writable)))
> +		return -EINVAL;
> +
> +	t = (flags & IOMMUF_writable) ? p2m_iommu_map_rw : p2m_iommu_map_ro;
> +
> +	/*
> +	 * The function guest_physmap_add_entry replaces the current mapping
> +	 * if there is already one...
> +	 */
> +	return guest_physmap_add_entry(d, _gfn(gfn), _mfn(mfn), 0, t);
> +}
> +
> +static int __must_check arm_smmu_unmap_page(struct domain *d, unsigned long gfn)
> +{
> +	/*
> +	 * This function should only be used by gnttab code when the domain
> +	 * is direct mapped
> +	 */
> +	if (!is_domain_direct_mapped(d))
> +		return -EINVAL;
> +
> +	return guest_physmap_remove_page(d, _gfn(gfn), _mfn(gfn), 0);
> +}
> +
> +static const struct iommu_ops arm_smmu_iommu_ops = {
> +	.init = arm_smmu_iommu_domain_init,
> +	.hwdom_init = arm_smmu_iommu_hwdom_init,
> +	.teardown = arm_smmu_iommu_domain_teardown,
> +	.iotlb_flush = arm_smmu_iotlb_flush,
> +	.iotlb_flush_all = arm_smmu_iotlb_flush_all,
> +	.assign_device = arm_smmu_assign_dev,
> +	.reassign_device = arm_smmu_reassign_dev,
> +	.map_page = arm_smmu_map_page,
> +	.unmap_page = arm_smmu_unmap_page,
> +};
> +
> +static
> +struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
> +{
> +	struct arm_smmu_device *smmu = NULL;
> +
> +	spin_lock(&arm_smmu_devices_lock);
> +	list_for_each_entry(smmu, &arm_smmu_devices, devices) {
> +		if (smmu->dev->fwnode == fwnode)
> +			break;
> +	}
> +	spin_unlock(&arm_smmu_devices_lock);
> +
> +	return smmu;
> +}
> +
> +static __init int arm_smmu_dt_init(struct dt_device_node *dev,
> +				   const void *data)
> +{
> +	int rc;
> +
> +	/*
> +	 * Even if the device can't be initialized, we don't want to
> +	 * give the SMMU device to dom0.
> +	 */
> +	dt_device_set_used_by(dev, DOMID_XEN);
> +
> +	rc = arm_smmu_device_probe(dt_to_dev(dev));
> +	if (rc)
> +		return rc;
> +
> +	iommu_set_ops(&arm_smmu_iommu_ops);
> +
> +	return 0;
> +}
> +
> +DT_DEVICE_START(smmuv3, "ARM SMMU V3", DEVICE_IOMMU)
> +	.dt_match = arm_smmu_of_match,
> +	.init = arm_smmu_dt_init,
> +DT_DEVICE_END
> +
> +#ifdef CONFIG_ACPI
> +/* Set up the IOMMU */
> +static int __init arm_smmu_acpi_init(const void *data)
> +{
> +	int rc;
> +
> +	rc = arm_smmu_device_probe((struct device *)data);
> +	if (rc)
> +		return rc;
> +
> +	iommu_set_ops(&arm_smmu_iommu_ops);
> +	return 0;
> +}
> +
> +ACPI_DEVICE_START(asmmuv3, "ARM SMMU V3", DEVICE_IOMMU)
> +	.class_type = ACPI_IORT_NODE_SMMU_V3,
> +	.init = arm_smmu_acpi_init,
> +ACPI_DEVICE_END
> +
> +#endif
Julien Grall Jan. 15, 2018, 8:34 p.m. | #2
On 01/03/2018 05:47 AM, Manish Jaggi wrote:
> 
> Hi Sameer,

Hi Manish,

>> +
>> +/* Xen: Type definitions for iommu_domain */
>> +#define IOMMU_DOMAIN_UNMANAGED 0
>> +#define IOMMU_DOMAIN_DMA 1
>> +#define IOMMU_DOMAIN_IDENTITY 2
>> +
>> +/* Xen: Dummy iommu_domain */
>> +struct iommu_domain {
>> +    /* Runtime SMMU configuration for this iommu_domain */
>> +    struct arm_smmu_domain        *priv;
> Can we use a more meaningful name in place of priv.

I believe this was taken from the iommu_domain structure in SMMUv2 which 
was based on an ancient version of Linux. It looks like recent Linux 
will not use priv, so I am wondering why it is added here?

>> +    unsigned int type;
>> +
>> +    /* Dummy compatibility defines */
>> +    unsigned long pgsize_bitmap;
>> +    struct iommu_domain_geometry geometry;
>> +
>> +    atomic_t ref;
>> +    /*
>> +     * Used to link iommu_domain contexts for a same domain.
>> +     * There is at least one per-SMMU to used by the domain.
>> +     */
>> +    struct list_head        list;
>> +};
>> +
>> +
>> +/* Xen: Describes information required for a Xen domain */
>> +struct arm_smmu_xen_domain {
>> +    spinlock_t            lock;
>> +    /* List of iommu domains associated to this domain */
>> +    struct list_head        iommu_domains;
>> +};
>> +
>> +/*
>> + * Xen: Information about each device stored in dev->archdata.iommu
>> + *
>> + * The dev->archdata.iommu stores the iommu_domain (runtime 
>> configuration of
>> + * the SMMU).
>>    */
>> +struct arm_smmu_xen_device {
>> +    struct iommu_domain *domain;
> domain name is confusing, if you read just the variable name it is not 
> easy to understand that it is a struct domain pointer or few other 
> structures which have _domain in their names.
> Same comment for all usages of variables with just the name domain.

If this is used by Xen only code, then it should be alright. Which name 
do you suggest? iommu_domain?

[...]

>> +/*
>> + * Xen: The pgtable_ops are used by the S1 translations, so return 
>> the dummy
>> + * address.
>> + */
>> +#define alloc_io_pgtable_ops(f, c, o) ((struct io_pgtable_ops 
>> *)0xDEADBEEF)
>> +#define free_io_pgtable_ops(o) (o = 0)
>> +
>> +/* Xen: Define wrapper for requesting IRQs */
>> +#define IRQF_ONESHOT 0
>> +
>> +typedef void (*irq_handler_t)(int, void *, struct cpu_user_regs *);
>> +
>> +static inline int devm_request_irq(struct device *dev, unsigned int irq,
>> +                   irq_handler_t handler, unsigned long irqflags,
>> +                   const char *devname, void *dev_id)
>> +{
>> +    /*TODO: Check if we really need to set a type */
>> +    irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
>> +    return request_irq(irq, irqflags, handler, devname, dev_id);
>> +
>> +}
>> +
>> +int devm_request_threaded_irq(struct device *dev, unsigned int irq, 
>> irq_handler_t handler,
>> +                  irq_handler_t thread_fn, unsigned long irqflags,
>> +                  const char *devname, void *dev_id)
>> +{
>> +    return devm_request_irq(dev, irq, thread_fn, irqflags, devname, 
>> dev_id);
>> +}
> Is it possible to change the name from threaded to something more 
> meaningful as IIUC in xen we dont  have threaded irqs.
> Though the code is coming from linux, but it has to be called/named in 
> the place it is intended to be used

What do you mean? This is a wrapper for Linux. So we should keep the 
name as it is.

[...]

>> @@ -433,6 +807,7 @@ enum pri_resp {
>>       PRI_RESP_SUCC,
>>   };
>> +#if 0 /* Xen: No MSI support in this iteration */
>>   enum arm_smmu_msi_index {
>>       EVTQ_MSI_INDEX,
>>       GERROR_MSI_INDEX,
>> @@ -457,6 +832,7 @@ static phys_addr_t 
>> arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
>>           ARM_SMMU_PRIQ_IRQ_CFG2,
>>       },
>>   };
>> +#endif
> IMHO can we avoid #if 0 from the code, unless we intend to use the code 
> in future.

In the past, I made the mistake to remove all unecessary code from 
SMMUv2. Few months after, we decided to delete it and import directly 
from Linux with limited modifications. This was the best choice because 
it is easier to track difference.

We are in the same situation here. We want to stay as close as Linux. 
This means no renaming, no code removal, and very limited change in the 
code to accommodate Xen.

In that particular case, we likely going to want to support MSIs because 
an implementation may only support that.

Cheers,
Manish Jaggi Jan. 16, 2018, 12:37 p.m. | #3
Hi Julien,


On 01/16/2018 02:04 AM, Julien Grall wrote:
>
>
> On 01/03/2018 05:47 AM, Manish Jaggi wrote:
>>
>> Hi Sameer,
>
> Hi Manish,
>
>>> +
>>> +/* Xen: Type definitions for iommu_domain */
>>> +#define IOMMU_DOMAIN_UNMANAGED 0
>>> +#define IOMMU_DOMAIN_DMA 1
>>> +#define IOMMU_DOMAIN_IDENTITY 2
>>> +
>>> +/* Xen: Dummy iommu_domain */
>>> +struct iommu_domain {
>>> +    /* Runtime SMMU configuration for this iommu_domain */
>>> +    struct arm_smmu_domain        *priv;
>> Can we use a more meaningful name in place of priv.
>
> I believe this was taken from the iommu_domain structure in SMMUv2 
> which was based on an ancient version of Linux. It looks like recent 
> Linux will not use priv, so I am wondering why it is added here?
>
>>> +    unsigned int type;
>>> +
>>> +    /* Dummy compatibility defines */
>>> +    unsigned long pgsize_bitmap;
>>> +    struct iommu_domain_geometry geometry;
>>> +
>>> +    atomic_t ref;
>>> +    /*
>>> +     * Used to link iommu_domain contexts for a same domain.
>>> +     * There is at least one per-SMMU to used by the domain.
>>> +     */
>>> +    struct list_head        list;
>>> +};
>>> +
>>> +
>>> +/* Xen: Describes information required for a Xen domain */
>>> +struct arm_smmu_xen_domain {
>>> +    spinlock_t            lock;
>>> +    /* List of iommu domains associated to this domain */
>>> +    struct list_head        iommu_domains;
>>> +};
>>> +
>>> +/*
>>> + * Xen: Information about each device stored in dev->archdata.iommu
>>> + *
>>> + * The dev->archdata.iommu stores the iommu_domain (runtime 
>>> configuration of
>>> + * the SMMU).
>>>    */
>>> +struct arm_smmu_xen_device {
>>> +    struct iommu_domain *domain;
>> domain name is confusing, if you read just the variable name it is 
>> not easy to understand that it is a struct domain pointer or few 
>> other structures which have _domain in their names.
>> Same comment for all usages of variables with just the name domain.
>
> If this is used by Xen only code, then it should be alright. Which 
> name do you suggest? iommu_domain?
Looks ok.
>
> [...]
>
>>> +/*
>>> + * Xen: The pgtable_ops are used by the S1 translations, so return 
>>> the dummy
>>> + * address.
>>> + */
>>> +#define alloc_io_pgtable_ops(f, c, o) ((struct io_pgtable_ops 
>>> *)0xDEADBEEF)
>>> +#define free_io_pgtable_ops(o) (o = 0)
>>> +
>>> +/* Xen: Define wrapper for requesting IRQs */
>>> +#define IRQF_ONESHOT 0
>>> +
>>> +typedef void (*irq_handler_t)(int, void *, struct cpu_user_regs *);
>>> +
>>> +static inline int devm_request_irq(struct device *dev, unsigned int 
>>> irq,
>>> +                   irq_handler_t handler, unsigned long irqflags,
>>> +                   const char *devname, void *dev_id)
>>> +{
>>> +    /*TODO: Check if we really need to set a type */
>>> +    irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
>>> +    return request_irq(irq, irqflags, handler, devname, dev_id);
>>> +
>>> +}
>>> +
>>> +int devm_request_threaded_irq(struct device *dev, unsigned int irq, 
>>> irq_handler_t handler,
>>> +                  irq_handler_t thread_fn, unsigned long irqflags,
>>> +                  const char *devname, void *dev_id)
>>> +{
>>> +    return devm_request_irq(dev, irq, thread_fn, irqflags, devname, 
>>> dev_id);
>>> +}
>> Is it possible to change the name from threaded to something more 
>> meaningful as IIUC in xen we dont  have threaded irqs.
>> Though the code is coming from linux, but it has to be called/named 
>> in the place it is intended to be used
>
> What do you mean? This is a wrapper for Linux. So we should keep the 
> name as it is.
It creates confusion as xne doesnt use threads. So we should rename it.
There is no reason why we cannot rename a function used in linux.
>
> [...]
>
>>> @@ -433,6 +807,7 @@ enum pri_resp {
>>>       PRI_RESP_SUCC,
>>>   };
>>> +#if 0 /* Xen: No MSI support in this iteration */
>>>   enum arm_smmu_msi_index {
>>>       EVTQ_MSI_INDEX,
>>>       GERROR_MSI_INDEX,
>>> @@ -457,6 +832,7 @@ static phys_addr_t 
>>> arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
>>>           ARM_SMMU_PRIQ_IRQ_CFG2,
>>>       },
>>>   };
>>> +#endif
>> IMHO can we avoid #if 0 from the code, unless we intend to use the 
>> code in future.
>
> In the past, I made the mistake to remove all unecessary code from 
> SMMUv2. Few months after, we decided to delete it and import directly 
> from Linux with limited modifications. This was the best choice 
> because it is easier to track difference.
>
> We are in the same situation here. We want to stay as close as Linux. 
> This means no renaming, no code removal, and very limited change in 
> the code to accommodate Xen.
>
> In that particular case, we likely going to want to support MSIs 
> because an implementation may only support that.
ok for this case, but the code looks clumsy.
>
> Cheers,
Julien Grall Jan. 16, 2018, 1:13 p.m. | #4
Hi,

On 16/01/18 12:37, Manish Jaggi wrote:
> On 01/16/2018 02:04 AM, Julien Grall wrote:
>> On 01/03/2018 05:47 AM, Manish Jaggi wrote:
>>>> +int devm_request_threaded_irq(struct device *dev, unsigned int irq, 
>>>> irq_handler_t handler,
>>>> +                  irq_handler_t thread_fn, unsigned long irqflags,
>>>> +                  const char *devname, void *dev_id)
>>>> +{
>>>> +    return devm_request_irq(dev, irq, thread_fn, irqflags, devname, 
>>>> dev_id);
>>>> +}
>>> Is it possible to change the name from threaded to something more 
>>> meaningful as IIUC in xen we dont  have threaded irqs.
>>> Though the code is coming from linux, but it has to be called/named 
>>> in the place it is intended to be used
>>
>> What do you mean? This is a wrapper for Linux. So we should keep the 
>> name as it is.
> It creates confusion as xne doesnt use threads. So we should rename it.
> There is no reason why we cannot rename a function used in linux.

Read my previous e-mail until the end to understand the reason...

>>
>> [...]
>>
>>>> @@ -433,6 +807,7 @@ enum pri_resp {
>>>>       PRI_RESP_SUCC,
>>>>   };
>>>> +#if 0 /* Xen: No MSI support in this iteration */
>>>>   enum arm_smmu_msi_index {
>>>>       EVTQ_MSI_INDEX,
>>>>       GERROR_MSI_INDEX,
>>>> @@ -457,6 +832,7 @@ static phys_addr_t 
>>>> arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
>>>>           ARM_SMMU_PRIQ_IRQ_CFG2,
>>>>       },
>>>>   };
>>>> +#endif
>>> IMHO can we avoid #if 0 from the code, unless we intend to use the 
>>> code in future.
>>
>> In the past, I made the mistake to remove all unecessary code from 
>> SMMUv2. Few months after, we decided to delete it and import directly 
>> from Linux with limited modifications. This was the best choice 
>> because it is easier to track difference.
>>
>> We are in the same situation here. We want to stay as close as Linux. 
>> This means no renaming, no code removal, and very limited change in 
>> the code to accommodate Xen.

... particularly this paragraph.

Cheers,

Patch

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 22165ae376..6aa24cae48 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1460,6 +1460,7 @@  err:
 static void __init setup_virt_paging_one(void *data)
 {
     unsigned long val = (unsigned long)data;
+    /* SMMUv3 S2 cfg vtcr reuses the following value */
     WRITE_SYSREG32(val, VTCR_EL2);
     isb();
 }
diff --git a/xen/drivers/Kconfig b/xen/drivers/Kconfig
index bc3a54f0ea..612655386d 100644
--- a/xen/drivers/Kconfig
+++ b/xen/drivers/Kconfig
@@ -12,4 +12,6 @@  source "drivers/pci/Kconfig"
 
 source "drivers/video/Kconfig"
 
+source "drivers/passthrough/arm/Kconfig"
+
 endmenu
diff --git a/xen/drivers/passthrough/arm/Kconfig b/xen/drivers/passthrough/arm/Kconfig
new file mode 100644
index 0000000000..cda899f608
--- /dev/null
+++ b/xen/drivers/passthrough/arm/Kconfig
@@ -0,0 +1,8 @@ 
+
+config ARM_SMMU_v3
+	bool "ARM SMMUv3 Support"
+	depends on ARM_64
+	help
+	 Support for implementations of the ARM System MMU architecture
+	 version 3.
+
diff --git a/xen/drivers/passthrough/arm/Makefile b/xen/drivers/passthrough/arm/Makefile
index f4cd26e15d..e14732b55c 100644
--- a/xen/drivers/passthrough/arm/Makefile
+++ b/xen/drivers/passthrough/arm/Makefile
@@ -1,2 +1,3 @@ 
 obj-y += iommu.o
 obj-y += smmu.o
+obj-$(CONFIG_ARM_SMMU_v3) += smmu-v3.o
diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
index e67ba6c40f..3488184ad4 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -18,28 +18,402 @@ 
  * Author: Will Deacon <will.deacon@arm.com>
  *
  * This driver is powered by bad coffee and bombay mix.
+ *
+ *
+ * Based on Linux drivers/iommu/arm-smmu-v3.c
+ * => commit 7aa8619a66aea52b145e04cbab4f8d6a4e5f3f3b
+ *
+ * Xen modifications:
+ * Sameer Goel <sameer.goel@linaro.org>
+ * Copyright (C) 2017, The Linux Foundation, All rights reserved.
+ *
+ */
+
+#include <xen/acpi.h>
+#include <xen/config.h>
+#include <xen/delay.h>
+#include <xen/errno.h>
+#include <xen/err.h>
+#include <xen/irq.h>
+#include <xen/lib.h>
+#include <xen/linux_compat.h>
+#include <xen/list.h>
+#include <xen/mm.h>
+#include <xen/rbtree.h>
+#include <xen/sched.h>
+#include <xen/sizes.h>
+#include <xen/vmap.h>
+#include <acpi/acpi_iort.h>
+#include <asm/atomic.h>
+#include <asm/device.h>
+#include <asm/io.h>
+#include <asm/platform.h>
+
+
+/* Xen: Helpers to get device MMIO and IRQs */
+struct resource {
+	u64 addr;
+	u64 size;
+	unsigned int type;
+};
+
+#define resource_size(res) ((res)->size)
+
+#define platform_device device
+
+#define IORESOURCE_MEM 0
+#define IORESOURCE_IRQ 1
+
+static struct resource *platform_get_resource(struct platform_device *pdev,
+					      unsigned int type,
+					      unsigned int num)
+{
+	/*
+	 * The resource is only used between 2 calls of platform_get_resource.
+	 * It's quite ugly but it's avoid to add too much code in the part
+	 * imported from Linux
+	 */
+	static struct resource res;
+	struct acpi_iort_node *iort_node;
+	struct acpi_iort_smmu_v3 *node_smmu_data;
+	int ret = 0;
+
+	res.type = type;
+
+	switch (type) {
+	case IORESOURCE_MEM:
+		if (pdev->type == DEV_ACPI) {
+			ret = 1;
+			iort_node = pdev->acpi_node;
+			node_smmu_data =
+				(struct acpi_iort_smmu_v3 *)iort_node->node_data;
+
+			if (node_smmu_data != NULL) {
+				res.addr = node_smmu_data->base_address;
+				res.size = SZ_128K;
+				ret = 0;
+			}
+		} else {
+			ret = dt_device_get_address(dev_to_dt(pdev), num,
+						    &res.addr, &res.size);
+		}
+
+		return ((ret) ? NULL : &res);
+
+	case IORESOURCE_IRQ:
+		/* ACPI case not implemented as there is no use case for it */
+		ret = platform_get_irq(dev_to_dt(pdev), num);
+
+		if (ret < 0)
+			return NULL;
+
+		res.addr = ret;
+		res.size = 1;
+
+		return &res;
+
+	default:
+		return NULL;
+	}
+}
+
+static int platform_get_irq_byname(struct platform_device *pdev, const char *name)
+{
+	const struct dt_property *dtprop;
+	struct acpi_iort_node *iort_node;
+	struct acpi_iort_smmu_v3 *node_smmu_data;
+	int ret = 0;
+
+	if (pdev->type == DEV_ACPI) {
+		iort_node = pdev->acpi_node;
+		node_smmu_data = (struct acpi_iort_smmu_v3 *)iort_node->node_data;
+
+		if (node_smmu_data != NULL) {
+			if (!strcmp(name, "eventq"))
+				ret = node_smmu_data->event_gsiv;
+			else if (!strcmp(name, "priq"))
+				ret = node_smmu_data->pri_gsiv;
+			else if (!strcmp(name, "cmdq-sync"))
+				ret = node_smmu_data->sync_gsiv;
+			else if (!strcmp(name, "gerror"))
+				ret = node_smmu_data->gerr_gsiv;
+			else
+				ret = -EINVAL;
+		}
+	} else {
+		dtprop = dt_find_property(dev_to_dt(pdev), "interrupt-names", NULL);
+		if (!dtprop)
+			return -EINVAL;
+
+		if (!dtprop->value)
+			return -ENODATA;
+	}
+
+	return ret;
+}
+
+/*
+ * Xen: Helpers for DMA allocation. Just the function name is reused for
+ * porting code these allocation are not managed allocations
+ */
+
+void *dmam_alloc_coherent(struct device *dev, size_t size,
+			   dma_addr_t *dma_handle, gfp_t gfp)
+{
+	void *vaddr;
+	unsigned long alignment = size;
+
+	/*
+	 * _xzalloc requires that the (align & (align -1)) = 0. Most of the
+	 * allocations in SMMU code should send the right value for size. In
+	 * case this is not true print a warning and align to the size of a
+	 * (void *)
+	 */
+	if (size & (size - 1)) {
+		dev_warn(dev, "Fixing alignment for the DMA buffer\n");
+		alignment = sizeof(void *);
+	}
+
+	vaddr = _xzalloc(size, alignment);
+	if (!vaddr) {
+		dev_err(dev, "DMA allocation failed\n");
+		return NULL;
+	}
+
+	*dma_handle = virt_to_maddr(vaddr);
+
+	return vaddr;
+}
+
+
+void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
+			dma_addr_t dma_handle)
+{
+	xfree(vaddr);
+}
+
+/* Xen: Stub out DMA domain related functions */
+#define iommu_get_dma_cookie(dom) 0
+#define iommu_put_dma_cookie(dom)
+
+/* Xen: Stub out module param related function */
+#define module_param_named(a, b, c, d)
+#define MODULE_PARM_DESC(a, b)
+
+#define dma_set_mask_and_coherent(d, b) 0
+
+#define of_dma_is_coherent(n) 0
+
+#define MODULE_DEVICE_TABLE(type, name)
+#define of_device_id dt_device_match
+
+static void __iomem *devm_ioremap_resource(struct device *dev,
+					   struct resource *res)
+{
+	void __iomem *ptr;
+
+	if (!res || res->type != IORESOURCE_MEM) {
+		dev_err(dev, "Invalid resource\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	ptr = ioremap_nocache(res->addr, res->size);
+	if (!ptr) {
+		dev_err(dev,
+			"ioremap failed (addr 0x%"PRIx64" size 0x%"PRIx64")\n",
+			res->addr, res->size);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return ptr;
+}
+
+/* Xen: Compatibility define for iommu_domain_geometry.*/
+struct iommu_domain_geometry {
+	dma_addr_t aperture_start; /* First address that can be mapped    */
+	dma_addr_t aperture_end;   /* Last address that can be mapped     */
+	bool force_aperture;       /* DMA only allowed in mappable range? */
+};
+
+
+/* Xen: Type definitions for iommu_domain */
+#define IOMMU_DOMAIN_UNMANAGED 0
+#define IOMMU_DOMAIN_DMA 1
+#define IOMMU_DOMAIN_IDENTITY 2
+
+/* Xen: Dummy iommu_domain */
+struct iommu_domain {
+	/* Runtime SMMU configuration for this iommu_domain */
+	struct arm_smmu_domain		*priv;
+	unsigned int type;
+
+	/* Dummy compatibility defines */
+	unsigned long pgsize_bitmap;
+	struct iommu_domain_geometry geometry;
+
+	atomic_t ref;
+	/*
+	 * Used to link iommu_domain contexts for a same domain.
+	 * There is at least one per-SMMU to used by the domain.
+	 */
+	struct list_head		list;
+};
+
+
+/* Xen: Describes information required for a Xen domain */
+struct arm_smmu_xen_domain {
+	spinlock_t			lock;
+	/* List of iommu domains associated to this domain */
+	struct list_head		iommu_domains;
+};
+
+/*
+ * Xen: Information about each device stored in dev->archdata.iommu
+ *
+ * The dev->archdata.iommu stores the iommu_domain (runtime configuration of
+ * the SMMU).
  */
+struct arm_smmu_xen_device {
+	struct iommu_domain *domain;
+};
+
+/*
+ * Xen: io_pgtable compatibility defines.
+ * Most of these are to port in the S1 translation code as is.
+ */
+struct io_pgtable_ops {
+};
+
+struct iommu_gather_ops {
+	void (*tlb_flush_all)(void *cookie);
+	void (*tlb_add_flush)(unsigned long iova, size_t size, size_t granule,
+			      bool leaf, void *cookie);
+	void (*tlb_sync)(void *cookie);
+};
+
+struct io_pgtable_cfg {
+	/*
+	 * IO_PGTABLE_QUIRK_ARM_NS: (ARM formats) Set NS and NSTABLE bits in
+	 *	stage 1 PTEs, for hardware which insists on validating them
+	 *	even in	non-secure state where they should normally be ignored.
+	 *
+	 * IO_PGTABLE_QUIRK_NO_PERMS: Ignore the IOMMU_READ, IOMMU_WRITE and
+	 *	IOMMU_NOEXEC flags and map everything with full access, for
+	 *	hardware which does not implement the permissions of a given
+	 *	format, and/or requires some format-specific default value.
+	 *
+	 * IO_PGTABLE_QUIRK_TLBI_ON_MAP: If the format forbids caching invalid
+	 *	(unmapped) entries but the hardware might do so anyway, perform
+	 *	TLB maintenance when mapping as well as when unmapping.
+	 *
+	 * IO_PGTABLE_QUIRK_ARM_MTK_4GB: (ARM v7s format) Set bit 9 in all
+	 *	PTEs, for Mediatek IOMMUs which treat it as a 33rd address bit
+	 *	when the SoC is in "4GB mode" and they can only access the high
+	 *	remap of DRAM (0x1_00000000 to 0x1_ffffffff).
+	 *
+	 * IO_PGTABLE_QUIRK_NO_DMA: Guarantees that the tables will only ever
+	 *	be accessed by a fully cache-coherent IOMMU or CPU (e.g. for a
+	 *	software-emulated IOMMU), such that pagetable updates need not
+	 *	be treated as explicit DMA data.
+	 */
+	#define IO_PGTABLE_QUIRK_ARM_NS		BIT(0)
+	#define IO_PGTABLE_QUIRK_NO_PERMS	BIT(1)
+	#define IO_PGTABLE_QUIRK_TLBI_ON_MAP	BIT(2)
+	#define IO_PGTABLE_QUIRK_ARM_MTK_4GB	BIT(3)
+	#define IO_PGTABLE_QUIRK_NO_DMA		BIT(4)
+	unsigned long			quirks;
+	unsigned long			pgsize_bitmap;
+	unsigned int			ias;
+	unsigned int			oas;
+	const struct iommu_gather_ops	*tlb;
+	struct device			*iommu_dev;
+
+	/* Low-level data specific to the table format */
+	union {
+		struct {
+			u64	ttbr[2];
+			u64	tcr;
+			u64	mair[2];
+		} arm_lpae_s1_cfg;
+
+		struct {
+			u64	vttbr;
+			u64	vtcr;
+		} arm_lpae_s2_cfg;
+
+		struct {
+			u32	ttbr[2];
+			u32	tcr;
+			u32	nmrr;
+			u32	prrr;
+		} arm_v7s_cfg;
+	};
+};
+
+enum io_pgtable_fmt {
+	ARM_32_LPAE_S1,
+	ARM_32_LPAE_S2,
+	ARM_64_LPAE_S1,
+	ARM_64_LPAE_S2,
+	ARM_V7S,
+	IO_PGTABLE_NUM_FMTS,
+};
+
+/*
+ * Xen: The pgtable_ops are used by the S1 translations, so return the dummy
+ * address.
+ */
+#define alloc_io_pgtable_ops(f, c, o) ((struct io_pgtable_ops *)0xDEADBEEF)
+#define free_io_pgtable_ops(o) (o = 0)
+
+/* Xen: Define wrapper for requesting IRQs */
+#define IRQF_ONESHOT 0
+
+typedef void (*irq_handler_t)(int, void *, struct cpu_user_regs *);
+
+static inline int devm_request_irq(struct device *dev, unsigned int irq,
+				   irq_handler_t handler, unsigned long irqflags,
+				   const char *devname, void *dev_id)
+{
+	/*TODO: Check if we really need to set a type */
+	irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
+	return request_irq(irq, irqflags, handler, devname, dev_id);
+
+}
+
+int devm_request_threaded_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
+			      irq_handler_t thread_fn, unsigned long irqflags,
+			      const char *devname, void *dev_id)
+{
+	return devm_request_irq(dev, irq, thread_fn, irqflags, devname, dev_id);
+}
 
-#include <linux/acpi.h>
-#include <linux/acpi_iort.h>
-#include <linux/delay.h>
-#include <linux/dma-iommu.h>
-#include <linux/err.h>
-#include <linux/interrupt.h>
-#include <linux/iommu.h>
-#include <linux/iopoll.h>
-#include <linux/module.h>
-#include <linux/msi.h>
-#include <linux/of.h>
-#include <linux/of_address.h>
-#include <linux/of_iommu.h>
-#include <linux/of_platform.h>
-#include <linux/pci.h>
-#include <linux/platform_device.h>
-
-#include <linux/amba/bus.h>
-
-#include "io-pgtable.h"
+/* Xen: The mutex is used only during initialization so the typecast is safe */
+#define mutex spinlock_t
+#define mutex_init spin_lock_init
+#define mutex_lock spin_lock
+#define mutex_unlock spin_unlock
+
+#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
+({ \
+	s_time_t deadline = NOW() + MICROSECS(timeout_us); \
+	for (;;) { \
+		(val) = op(addr); \
+		if (cond) \
+			break; \
+		if (NOW() > deadline) { \
+			(val) = op(addr); \
+			break; \
+		} \
+	udelay(sleep_us); \
+	} \
+	(cond) ? 0 : -ETIMEDOUT; \
+})
+
+#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
+	readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
+
+#define VA_BITS 0 /* Only needed for S1 translations */
 
 /* MMIO registers */
 #define ARM_SMMU_IDR0			0x0
@@ -433,6 +807,7 @@  enum pri_resp {
 	PRI_RESP_SUCC,
 };
 
+#if 0 /* Xen: No MSI support in this iteration */
 enum arm_smmu_msi_index {
 	EVTQ_MSI_INDEX,
 	GERROR_MSI_INDEX,
@@ -457,6 +832,7 @@  static phys_addr_t arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
 		ARM_SMMU_PRIQ_IRQ_CFG2,
 	},
 };
+#endif
 
 struct arm_smmu_cmdq_ent {
 	/* Common fields */
@@ -561,6 +937,8 @@  struct arm_smmu_s2_cfg {
 	u16				vmid;
 	u64				vttbr;
 	u64				vtcr;
+	/* Xen: Domain associated to this configuration */
+	struct domain			*domain;
 };
 
 struct arm_smmu_strtab_ent {
@@ -635,9 +1013,21 @@  struct arm_smmu_device {
 	struct arm_smmu_strtab_cfg	strtab_cfg;
 
 	/* IOMMU core code handle */
+#if 0 /*Xen: Generic iommu_device ref not needed here */
 	struct iommu_device		iommu;
+#endif
+	/* Xen: Need to keep a list of SMMU devices */
+	struct list_head                devices;
 };
 
+/* Xen: Keep a list of devices associated with this driver */
+static DEFINE_SPINLOCK(arm_smmu_devices_lock);
+static LIST_HEAD(arm_smmu_devices);
+/* Xen: Helper for finding a device using fwnode */
+static
+struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode);
+
+
 /* SMMU private data for each master */
 struct arm_smmu_master_data {
 	struct arm_smmu_device		*smmu;
@@ -654,7 +1044,7 @@  enum arm_smmu_domain_stage {
 
 struct arm_smmu_domain {
 	struct arm_smmu_device		*smmu;
-	struct mutex			init_mutex; /* Protects smmu pointer */
+	mutex				init_mutex; /* Protects smmu pointer */
 
 	struct io_pgtable_ops		*pgtbl_ops;
 
@@ -1232,7 +1622,7 @@  static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
 
 	dev_info(smmu->dev, "unexpected PRI request received:\n");
 	dev_info(smmu->dev,
-		 "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova 0x%016llx\n",
+		 "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova %#" PRIx64 "\n",
 		 sid, ssid, grpid, last ? "L" : "",
 		 evt[0] & PRIQ_0_PERM_PRIV ? "" : "un",
 		 evt[0] & PRIQ_0_PERM_READ ? "R" : "",
@@ -1346,6 +1736,8 @@  static irqreturn_t arm_smmu_combined_irq_handler(int irq, void *dev)
 {
 	arm_smmu_gerror_handler(irq, dev);
 	arm_smmu_cmdq_sync_handler(irq, dev);
+	/*Xen: No threaded irq. So call the required function from here */
+	arm_smmu_combined_irq_thread(irq, dev);
 	return IRQ_WAKE_THREAD;
 }
 
@@ -1358,6 +1750,46 @@  static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu)
 	arm_smmu_cmdq_issue_cmd(smmu, &cmd);
 }
 
+/*
+ * Xen: Define the IRQ handlers for xen. The linux functions would be
+ * modified to use the functions defined in the following code. 
+ */
+static void arm_smmu_evtq_thread_xen(int irq, void *dev,
+				       struct cpu_user_regs *regs)
+{
+	arm_smmu_evtq_thread(irq, dev);
+}
+
+static void arm_smmu_priq_thread_xen(int irq, void *dev,
+				       struct cpu_user_regs *regs)
+{
+	arm_smmu_priq_thread(irq, dev);
+}
+
+static void arm_smmu_cmdq_sync_handler_xen(int irq, void *dev,
+				       struct cpu_user_regs *regs)
+{
+	arm_smmu_cmdq_sync_handler(irq, dev);
+}
+
+static void arm_smmu_gerror_handler_xen(int irq, void *dev,
+				       struct cpu_user_regs *regs)
+{
+	arm_smmu_gerror_handler(irq, dev);
+}
+
+static void arm_smmu_combined_irq_handler_xen(int irq, void *dev,
+				       struct cpu_user_regs *regs)
+{
+	arm_smmu_combined_irq_handler(irq, dev);
+}
+
+#define arm_smmu_evtq_thread arm_smmu_evtq_thread_xen
+#define arm_smmu_priq_thread arm_smmu_priq_thread_xen
+#define arm_smmu_cmdq_sync_handler arm_smmu_cmdq_sync_handler_xen
+#define arm_smmu_gerror_handler arm_smmu_gerror_handler_xen
+#define arm_smmu_combined_irq_handler arm_smmu_combined_irq_handler_xen
+
 static void arm_smmu_tlb_sync(void *cookie)
 {
 	struct arm_smmu_domain *smmu_domain = cookie;
@@ -1415,6 +1847,7 @@  static const struct iommu_gather_ops arm_smmu_gather_ops = {
 	.tlb_sync	= arm_smmu_tlb_sync,
 };
 
+#if 0 /*Xen: Unused functionality */
 /* IOMMU API */
 static bool arm_smmu_capable(enum iommu_cap cap)
 {
@@ -1427,6 +1860,7 @@  static bool arm_smmu_capable(enum iommu_cap cap)
 		return false;
 	}
 }
+#endif
 
 static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 {
@@ -1546,9 +1980,15 @@  static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
 	if (vmid < 0)
 		return vmid;
 
-	cfg->vmid	= (u16)vmid;
-	cfg->vttbr	= pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
-	cfg->vtcr	= pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
+	/* Xen: Get the ttbr and vtcr values
+	 * vttbr: This is a shared value with the domain page table
+	 * vtcr: The TCR settings are the same as CPU since the page
+	 * tables are shared
+	 */
+
+	cfg->vmid	= vmid;
+	cfg->vttbr	= page_to_maddr(cfg->domain->arch.p2m.root);
+	cfg->vtcr	= READ_SYSREG32(VTCR_EL2) & STRTAB_STE_2_VTCR_MASK;
 	return 0;
 }
 
@@ -1604,6 +2044,7 @@  static int arm_smmu_domain_finalise(struct iommu_domain *domain)
 	if (smmu->features & ARM_SMMU_FEAT_COHERENCY)
 		pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA;
 
+	/* Xen: pgtbl_ops gets an invalid address */
 	pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
 	if (!pgtbl_ops)
 		return -ENOMEM;
@@ -1721,6 +2162,7 @@  out_unlock:
 	return ret;
 }
 
+#if 0 /* Xen: Unused functionlity */
 static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
 			phys_addr_t paddr, size_t size, int prot)
 {
@@ -1772,6 +2214,7 @@  struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
 	put_device(dev);
 	return dev ? dev_get_drvdata(dev) : NULL;
 }
+#endif
 
 static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
 {
@@ -1783,7 +2226,9 @@  static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
 	return sid < limit;
 }
 
+#if 0
 static struct iommu_ops arm_smmu_ops;
+#endif
 
 static int arm_smmu_add_device(struct device *dev)
 {
@@ -1791,9 +2236,12 @@  static int arm_smmu_add_device(struct device *dev)
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_master_data *master;
 	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+#if 0 /*Xen: iommu_group is not needed */
 	struct iommu_group *group;
+#endif
 
-	if (!fwspec || fwspec->ops != &arm_smmu_ops)
+	/* Xen: fwspec->ops are not needed */
+	if (!fwspec)
 		return -ENODEV;
 	/*
 	 * We _can_ actually withstand dodgy bus code re-calling add_device()
@@ -1830,6 +2278,11 @@  static int arm_smmu_add_device(struct device *dev)
 		}
 	}
 
+/*
+ * Xen: Do not need an iommu group as the stream data is carried by the SMMU
+ * master device object
+ */
+#if 0
 	group = iommu_group_get_for_dev(dev);
 	if (!IS_ERR(group)) {
 		iommu_group_put(group);
@@ -1837,8 +2290,16 @@  static int arm_smmu_add_device(struct device *dev)
 	}
 
 	return PTR_ERR_OR_ZERO(group);
+#endif
+	return 0;
 }
 
+/*
+ * Xen: We can potentially support this function and destroy a device. This
+ * will be relevant for PCI hotplug. So, will be implemented as needed after
+ * passthrough support is available.
+ */
+#if 0
 static void arm_smmu_remove_device(struct device *dev)
 {
 	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
@@ -1974,6 +2435,7 @@  static struct iommu_ops arm_smmu_ops = {
 	.put_resv_regions	= arm_smmu_put_resv_regions,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
 };
+#endif
 
 /* Probing and initialisation functions */
 static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
@@ -2182,6 +2644,7 @@  static int arm_smmu_update_gbpa(struct arm_smmu_device *smmu, u32 set, u32 clr)
 					  1, ARM_SMMU_POLL_TIMEOUT_US);
 }
 
+#if 0 /* Xen: There is no MSI support as yet */
 static void arm_smmu_free_msis(void *data)
 {
 	struct device *dev = data;
@@ -2247,12 +2710,15 @@  static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
 	/* Add callback to free MSIs on teardown */
 	devm_add_action(dev, arm_smmu_free_msis, dev);
 }
+#endif
 
 static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
 {
 	int irq, ret;
 
+#if 0 /*Xen: Cannot setup msis for now */
 	arm_smmu_setup_msis(smmu);
+#endif
 
 	/* Request interrupt lines */
 	irq = smmu->evtq.q.irq;
@@ -2316,9 +2782,13 @@  static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
 		 * Cavium ThunderX2 implementation doesn't not support unique
 		 * irq lines. Use single irq line for all the SMMUv3 interrupts.
 		 */
-		ret = devm_request_threaded_irq(smmu->dev, irq,
+		/*
+		 * Xen: Does not support threaded irqs, so serialise the setup.
+		 * This is the same for pris and event interrupt lines on other
+		 * systems
+		 */
+		ret = devm_request_irq(smmu->dev, irq,
 					arm_smmu_combined_irq_handler,
-					arm_smmu_combined_irq_thread,
 					IRQF_ONESHOT,
 					"arm-smmu-v3-combined-irq", smmu);
 		if (ret < 0)
@@ -2542,8 +3012,14 @@  static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 		smmu->features |= ARM_SMMU_FEAT_STALLS;
 	}
 
+/*
+ * Xen: Block stage 1 translations. By doing this here we do not need to set the
+ * domain->stage explicitly.
+ */
+#if 0
 	if (reg & IDR0_S1P)
 		smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
+#endif
 
 	if (reg & IDR0_S2P)
 		smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
@@ -2616,10 +3092,12 @@  static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 	if (reg & IDR5_GRAN4K)
 		smmu->pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
 
+#if 0 /* Xen: SMMU ops do not have a pgsize_bitmap member for Xen */
 	if (arm_smmu_ops.pgsize_bitmap == -1UL)
 		arm_smmu_ops.pgsize_bitmap = smmu->pgsize_bitmap;
 	else
 		arm_smmu_ops.pgsize_bitmap |= smmu->pgsize_bitmap;
+#endif
 
 	/* Output address size */
 	switch (reg & IDR5_OAS_MASK << IDR5_OAS_SHIFT) {
@@ -2680,7 +3158,8 @@  static int arm_smmu_device_acpi_probe(struct platform_device *pdev,
 	struct device *dev = smmu->dev;
 	struct acpi_iort_node *node;
 
-	node = *(struct acpi_iort_node **)dev_get_platdata(dev);
+	/* Xen: Modification to get iort_node */
+	node = (struct acpi_iort_node *)dev->acpi_node;
 
 	/* Retrieve SMMUv3 specific data */
 	iort_smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
@@ -2703,7 +3182,7 @@  static inline int arm_smmu_device_acpi_probe(struct platform_device *pdev,
 static int arm_smmu_device_dt_probe(struct platform_device *pdev,
 				    struct arm_smmu_device *smmu)
 {
-	struct device *dev = &pdev->dev;
+	struct device *dev = pdev;
 	u32 cells;
 	int ret = -EINVAL;
 
@@ -2716,6 +3195,7 @@  static int arm_smmu_device_dt_probe(struct platform_device *pdev,
 
 	parse_driver_options(smmu);
 
+	/* Xen: of_dma_is_coherent is a stub till dt support is introduced */
 	if (of_dma_is_coherent(dev->of_node))
 		smmu->features |= ARM_SMMU_FEAT_COHERENCY;
 
@@ -2734,9 +3214,11 @@  static int arm_smmu_device_probe(struct platform_device *pdev)
 {
 	int irq, ret;
 	struct resource *res;
+#if 0 /*Xen: Do not need to setup sysfs */
 	resource_size_t ioaddr;
+#endif
 	struct arm_smmu_device *smmu;
-	struct device *dev = &pdev->dev;
+	struct device *dev = pdev;/* Xen: dev is ignored */
 	bool bypass;
 
 	smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
@@ -2763,7 +3245,9 @@  static int arm_smmu_device_probe(struct platform_device *pdev)
 		dev_err(dev, "MMIO region too small (%pr)\n", res);
 		return -EINVAL;
 	}
+#if 0 /*Xen: Do not need to setup sysfs */
 	ioaddr = res->start;
+#endif
 
 	smmu->base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(smmu->base))
@@ -2802,13 +3286,18 @@  static int arm_smmu_device_probe(struct platform_device *pdev)
 		return ret;
 
 	/* Record our private device structure */
+	/* Xen: SMMU is not treated a a platform device*/
+#if 0
 	platform_set_drvdata(pdev, smmu);
+#endif
 
 	/* Reset the device */
 	ret = arm_smmu_device_reset(smmu, bypass);
 	if (ret)
 		return ret;
 
+/* Xen: Not creating an IOMMU device list for Xen */
+#if 0
 	/* And we're up. Go go go! */
 	ret = iommu_device_sysfs_add(&smmu->iommu, dev, NULL,
 				     "smmu3.%pa", &ioaddr);
@@ -2844,9 +3333,20 @@  static int arm_smmu_device_probe(struct platform_device *pdev)
 		if (ret)
 			return ret;
 	}
+#endif
+	/*
+	 * Xen: Keep a list of all probed devices. This will be used to query
+	 * the smmu devices based on the fwnode.
+	 */
+	INIT_LIST_HEAD(&smmu->devices);
+	spin_lock(&arm_smmu_devices_lock);
+	list_add(&smmu->devices, &arm_smmu_devices);
+	spin_unlock(&arm_smmu_devices_lock);
 	return 0;
 }
 
+/* Xen: Unused function */
+#if 0
 static int arm_smmu_device_remove(struct platform_device *pdev)
 {
 	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
@@ -2860,6 +3360,8 @@  static void arm_smmu_device_shutdown(struct platform_device *pdev)
 {
 	arm_smmu_device_remove(pdev);
 }
+#endif
+
 
 static const struct of_device_id arm_smmu_of_match[] = {
 	{ .compatible = "arm,smmu-v3", },
@@ -2867,6 +3369,7 @@  static const struct of_device_id arm_smmu_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
 
+#if 0
 static struct platform_driver arm_smmu_driver = {
 	.driver	= {
 		.name		= "arm-smmu-v3",
@@ -2883,3 +3386,318 @@  IOMMU_OF_DECLARE(arm_smmuv3, "arm,smmu-v3", NULL);
 MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
 MODULE_LICENSE("GPL v2");
+#endif
+
+/***** Start of Xen specific code *****/
+
+static int __must_check arm_smmu_iotlb_flush_all(struct domain *d)
+{
+	struct arm_smmu_xen_domain *smmu_domain = dom_iommu(d)->arch.priv;
+	struct iommu_domain *cfg;
+
+	spin_lock(&smmu_domain->lock);
+	list_for_each_entry(cfg, &smmu_domain->iommu_domains, list) {
+		/*
+		 * Only invalidate the context when SMMU is present.
+		 * This is because the context initialization is delayed
+		 * until a master has been added.
+		 */
+		if (unlikely(!ACCESS_ONCE(cfg->priv->smmu)))
+			continue;
+		arm_smmu_tlb_inv_context(cfg->priv);
+	}
+	spin_unlock(&smmu_domain->lock);
+	return 0;
+}
+
+static int __must_check arm_smmu_iotlb_flush(struct domain *d,
+					     unsigned long gfn,
+					     unsigned int page_count)
+{
+	return arm_smmu_iotlb_flush_all(d);
+}
+
+static struct iommu_domain *arm_smmu_get_domain(struct domain *d,
+						struct device *dev)
+{
+	struct iommu_domain *domain;
+	struct arm_smmu_xen_domain *xen_domain;
+	struct arm_smmu_device *smmu;
+	struct arm_smmu_domain *smmu_domain;
+
+	xen_domain = dom_iommu(d)->arch.priv;
+
+	smmu = arm_smmu_get_by_fwnode(dev->iommu_fwspec->iommu_fwnode);
+	if (!smmu)
+		return NULL;
+
+	/*
+	 * Loop through the &xen_domain->contexts to locate a context
+	 * assigned to this SMMU
+	 */
+	list_for_each_entry(domain, &xen_domain->iommu_domains, list) {
+		smmu_domain = to_smmu_domain(domain);
+		if (smmu_domain->smmu == smmu)
+			return domain;
+	}
+
+	return NULL;
+}
+
+static void arm_smmu_destroy_iommu_domain(struct iommu_domain *domain)
+{
+	list_del(&domain->list);
+	arm_smmu_domain_free(domain);
+}
+
+static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
+			       struct device *dev, u32 flag)
+{
+	int ret = 0;
+	struct iommu_domain *domain;
+	struct arm_smmu_xen_domain *xen_domain;
+	struct arm_smmu_domain *arm_smmu;
+
+	xen_domain = dom_iommu(d)->arch.priv;
+
+	if (!dev->archdata.iommu) {
+		dev->archdata.iommu = xzalloc(struct arm_smmu_xen_device);
+		if (!dev->archdata.iommu)
+			return -ENOMEM;
+	}
+
+	ret = arm_smmu_add_device(dev);
+	if (ret)
+		return ret;
+
+	spin_lock(&xen_domain->lock);
+
+	/*
+	 * Check to see if an iommu_domain already exists for this xen domain
+	 * under the same SMMU
+	 */
+	domain = arm_smmu_get_domain(d, dev);
+	if (!domain) {
+
+		domain = arm_smmu_domain_alloc(IOMMU_DOMAIN_DMA);
+		if (!domain) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		arm_smmu = to_smmu_domain(domain);
+		arm_smmu->s2_cfg.domain = d;
+
+		/* Chain the new context to the domain */
+		list_add(&domain->list, &xen_domain->iommu_domains);
+
+	}
+
+	ret = arm_smmu_attach_dev(domain, dev);
+	if (ret) {
+		if (domain->ref.counter == 0)
+			arm_smmu_destroy_iommu_domain(domain);
+	} else {
+		atomic_inc(&domain->ref);
+	}
+
+out:
+	spin_unlock(&xen_domain->lock);
+	return ret;
+}
+
+static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
+{
+	struct iommu_domain *domain = arm_smmu_get_domain(d, dev);
+	struct arm_smmu_xen_domain *xen_domain;
+	struct arm_smmu_domain *arm_smmu = to_smmu_domain(domain);
+
+	xen_domain = dom_iommu(d)->arch.priv;
+
+	if (!arm_smmu || arm_smmu->s2_cfg.domain != d) {
+		dev_err(dev, " not attached to domain %d\n", d->domain_id);
+		return -ESRCH;
+	}
+
+	spin_lock(&xen_domain->lock);
+
+	arm_smmu_detach_dev(dev);
+	atomic_dec(&domain->ref);
+
+	if (domain->ref.counter == 0)
+		arm_smmu_destroy_iommu_domain(domain);
+
+	spin_unlock(&xen_domain->lock);
+
+
+
+	return 0;
+}
+
+static int arm_smmu_reassign_dev(struct domain *s, struct domain *t,
+				 u8 devfn,  struct device *dev)
+{
+	int ret = 0;
+
+	/* Don't allow remapping on other domain than hwdom */
+	if (t && t != hardware_domain)
+		return -EPERM;
+
+	if (t == s)
+		return 0;
+
+	ret = arm_smmu_deassign_dev(s, dev);
+	if (ret)
+		return ret;
+
+	if (t) {
+		/* No flags are defined for ARM. */
+		ret = arm_smmu_assign_dev(t, devfn, dev, 0);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int arm_smmu_iommu_domain_init(struct domain *d)
+{
+	struct arm_smmu_xen_domain *xen_domain;
+
+	xen_domain = xzalloc(struct arm_smmu_xen_domain);
+	if (!xen_domain)
+		return -ENOMEM;
+
+	spin_lock_init(&xen_domain->lock);
+	INIT_LIST_HEAD(&xen_domain->iommu_domains);
+
+	dom_iommu(d)->arch.priv = xen_domain;
+
+	return 0;
+}
+
+static void __hwdom_init arm_smmu_iommu_hwdom_init(struct domain *d)
+{
+}
+
+static void arm_smmu_iommu_domain_teardown(struct domain *d)
+{
+	struct arm_smmu_xen_domain *xen_domain = dom_iommu(d)->arch.priv;
+
+	ASSERT(list_empty(&xen_domain->iommu_domains));
+	xfree(xen_domain);
+}
+
+static int __must_check arm_smmu_map_page(struct domain *d, unsigned long gfn,
+			unsigned long mfn, unsigned int flags)
+{
+	p2m_type_t t;
+
+	/*
+	 * Grant mappings can be used for DMA requests. The dev_bus_addr
+	 * returned by the hypercall is the MFN (not the IPA). For device
+	 * protected by an IOMMU, Xen needs to add a 1:1 mapping in the domain
+	 * p2m to allow DMA request to work.
+	 * This is only valid when the domain is directed mapped. Hence this
+	 * function should only be used by gnttab code with gfn == mfn.
+	 */
+	BUG_ON(!is_domain_direct_mapped(d));
+	BUG_ON(mfn != gfn);
+
+	/* We only support readable and writable flags */
+	if (!(flags & (IOMMUF_readable | IOMMUF_writable)))
+		return -EINVAL;
+
+	t = (flags & IOMMUF_writable) ? p2m_iommu_map_rw : p2m_iommu_map_ro;
+
+	/*
+	 * The function guest_physmap_add_entry replaces the current mapping
+	 * if there is already one...
+	 */
+	return guest_physmap_add_entry(d, _gfn(gfn), _mfn(mfn), 0, t);
+}
+
+static int __must_check arm_smmu_unmap_page(struct domain *d, unsigned long gfn)
+{
+	/*
+	 * This function should only be used by gnttab code when the domain
+	 * is direct mapped
+	 */
+	if (!is_domain_direct_mapped(d))
+		return -EINVAL;
+
+	return guest_physmap_remove_page(d, _gfn(gfn), _mfn(gfn), 0);
+}
+
+static const struct iommu_ops arm_smmu_iommu_ops = {
+	.init = arm_smmu_iommu_domain_init,
+	.hwdom_init = arm_smmu_iommu_hwdom_init,
+	.teardown = arm_smmu_iommu_domain_teardown,
+	.iotlb_flush = arm_smmu_iotlb_flush,
+	.iotlb_flush_all = arm_smmu_iotlb_flush_all,
+	.assign_device = arm_smmu_assign_dev,
+	.reassign_device = arm_smmu_reassign_dev,
+	.map_page = arm_smmu_map_page,
+	.unmap_page = arm_smmu_unmap_page,
+};
+
+static
+struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
+{
+	struct arm_smmu_device *smmu = NULL;
+
+	spin_lock(&arm_smmu_devices_lock);
+	list_for_each_entry(smmu, &arm_smmu_devices, devices) {
+		if (smmu->dev->fwnode == fwnode)
+			break;
+	}
+	spin_unlock(&arm_smmu_devices_lock);
+
+	return smmu;
+}
+
+static __init int arm_smmu_dt_init(struct dt_device_node *dev,
+				   const void *data)
+{
+	int rc;
+
+	/*
+	 * Even if the device can't be initialized, we don't want to
+	 * give the SMMU device to dom0.
+	 */
+	dt_device_set_used_by(dev, DOMID_XEN);
+
+	rc = arm_smmu_device_probe(dt_to_dev(dev));
+	if (rc)
+		return rc;
+
+	iommu_set_ops(&arm_smmu_iommu_ops);
+
+	return 0;
+}
+
+DT_DEVICE_START(smmuv3, "ARM SMMU V3", DEVICE_IOMMU)
+	.dt_match = arm_smmu_of_match,
+	.init = arm_smmu_dt_init,
+DT_DEVICE_END
+
+#ifdef CONFIG_ACPI
+/* Set up the IOMMU */
+static int __init arm_smmu_acpi_init(const void *data)
+{
+	int rc;
+
+	rc = arm_smmu_device_probe((struct device *)data);
+	if (rc)
+		return rc;
+
+	iommu_set_ops(&arm_smmu_iommu_ops);
+	return 0;
+}
+
+ACPI_DEVICE_START(asmmuv3, "ARM SMMU V3", DEVICE_IOMMU)
+	.class_type = ACPI_IORT_NODE_SMMU_V3,
+	.init = arm_smmu_acpi_init,
+ACPI_DEVICE_END
+
+#endif