Re: [v2 4/6] xen/iommu: smmu-v3: Add Xen specific code to enable the ported driver

[Sameer Goel <sameer.goel@linaro.org>]

On 05/23/2018 10:48 PM, Manish Jaggi wrote:
> Hi Sameer,
>
> General Comment, please use appropriate variable names for XXX_domain 
> structures in code which is xen specific.
I thought that we had discussed this before on one of the RFCs. At this 
point we are just using the format used for smmu-v2. I don't think that 
the variable names are inappropriate. Unless there is a very specific 
issue with the variable names, I think we should stick with the current 
version.

>
>
> On 05/24/2018 06:16 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 */
>> - xen/linux_compat: Add a Linux compat header
>>    For porting files directly from Linux it is useful to have a 
>> function mapping
>>    definitions from Linux to Xen. This file adds common API functions 
>> and
>>    other defines that are needed for porting arm SMMU drivers.
>>
>> 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 | 934 +++++++++++++++++++++++++-
>>   xen/include/xen/linux_compat.h        |  84 +++
>>   6 files changed, 1001 insertions(+), 29 deletions(-)
>>   create mode 100644 xen/drivers/passthrough/arm/Kconfig
>>   create mode 100644 xen/include/xen/linux_compat.h
>>
>> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
>> index d43c3aa896..38aa9f00c1 100644
>> --- a/xen/arch/arm/p2m.c
>> +++ b/xen/arch/arm/p2m.c
>> @@ -1454,6 +1454,7 @@ 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 db94393f47..59ca00f850 100644
>> --- a/xen/drivers/Kconfig
>> +++ b/xen/drivers/Kconfig
>> @@ -15,4 +15,6 @@ source "drivers/video/Kconfig"
>>   config HAS_VPCI
>>       bool
>>   +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..df81626785 100644
>> --- a/xen/drivers/passthrough/arm/smmu-v3.c
>> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
>> @@ -18,28 +18,414 @@
>>    * 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 <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"
>> +#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>
>> +
>> +/* Alias to Xen device tree helpers */
>> +#define device_node dt_device_node
>> +#define of_phandle_args dt_phandle_args
>> +#define of_device_id dt_device_match
>> +#define of_match_node dt_match_node
>> +#define of_property_read_u32(np, pname, out) 
>> (!dt_property_read_u32(np, pname, out))
>> +#define of_property_read_bool dt_property_read_bool
>> +#define of_parse_phandle_with_args dt_parse_phandle_with_args
>> +
>> +/* 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
>> + */
>> +
>> +static void *dmam_alloc_coherent(struct device *dev, size_t size,
>> +               dma_addr_t *dma_handle, gfp_t gfp)
> I believe the formatting needs to be checked.
>> +{
>> +    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;
>> +}
>> +
>> +
>> +static void dmam_free_coherent(struct device *dev, size_t size, void 
>> *vaddr,
>> +            dma_addr_t dma_handle)
> same
>> +{
>> +    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)
>> +
>> +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        contexts;
>> +};
>> +
>> +/*
>> + * 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;
>> +};
>> +
> As this is a xen specific code, can the variable names be used 
> appropriately.
> Repeating my comment  from earlier version.
> a domain is  usually a VM in Xen. So it is a bit confusing to use 
> domain for iommu_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 *)0x1)
>> +#define free_io_pgtable_ops(o)
>> +
>> +/* 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)
>> +{
>> +    /*
>> +     * SMMUv3 implementation can support wired interrupt outputs 
>> that are
>> +     * edge-triggered. Set the irq type as per the spec.
>> +     */
>> +    irq_set_type(irq, IRQ_TYPE_EDGE_BOTH);
>> +    return request_irq(irq, irqflags, handler, devname, dev_id);
>> +}
>> +
>> +/*
>> + * Xen does not have a concept of threaded irq, but we can use 
>> tasklets to
>> + * achieve the desired functionality as needed.
>> + */
>> +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);
>> +}
>> +
>> +/* Xen: The mutex is used only during initialization so the typecast 
>> is safe */
>> +#define mutex spinlock
>> +#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 +819,7 @@ 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 +844,7 @@ 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 +949,8 @@ 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 +1025,25 @@ 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
> Is it clean to put #if 0, can this line be deleted or used with a 
> proper macro
>> +    /* Xen: Need to keep a list of SMMU devices */
>> +    struct list_head                devices;
>> +    /* Xen: Tasklets for handling evts/faults and pci page request 
>> IRQs*/
>> +    struct tasklet            evtq_tasklet;
>> +    struct tasklet            priq_tasklet;
>> +    struct tasklet            combined_irq_tasklet;
>>   };
>>   +/* 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;
>> @@ -1232,7 +1638,7 @@ 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" : "",
>> @@ -1342,10 +1748,20 @@ static irqreturn_t 
>> arm_smmu_combined_irq_thread(int irq, void *dev)
>>       return IRQ_HANDLED;
>>   }
>>   +/* Xen: Forward define for combined_irq tasklet */
>> +static void arm_smmu_combined_irq_tasklet(unsigned long dev);
>> +
>>   static irqreturn_t arm_smmu_combined_irq_handler(int irq, void *dev)
>>   {
>> +    /* Xen: Need an smmu reference to schedule the tasklet */
>> +    struct arm_smmu_device *smmu = (struct arm_smmu_device *)dev;
>> +
>>       arm_smmu_gerror_handler(irq, dev);
>>       arm_smmu_cmdq_sync_handler(irq, dev);
>> +
>> +    /*Xen: No threaded irq. So, schedule the right tasklet*/
>> +    tasklet_schedule(&(smmu->combined_irq_tasklet));
>> +
>>       return IRQ_WAKE_THREAD;
>>   }
>>   @@ -1358,6 +1774,69 @@ static void __arm_smmu_tlb_sync(struct 
>> arm_smmu_device *smmu)
>>       arm_smmu_cmdq_issue_cmd(smmu, &cmd);
>>   }
>>   +/*
>> + * Xen: Define the IRQ handlers and tasklets for xen. The linux 
>> functions
>> + * would be modified to use the functions defined in the following 
>> code.
>> + */
>> +
>> +static void arm_smmu_evtq_tasklet(unsigned long dev)
>> +{
>> +    /* The IRQ number is not relevent for the evtq thread processing */
>> +    arm_smmu_evtq_thread(0, (void *)dev);
>> +}
>> +
>> +static void arm_smmu_priq_tasklet(unsigned long dev)
>> +{
>> +    /* The IRQ number is not relevent for the priq thread processing */
>> +    arm_smmu_priq_thread(0, (void *)dev);
>> +}
>> +
>> +static void arm_smmu_combined_irq_tasklet(unsigned long dev)
>> +{
>> +    /* The IRQ number is not relevent for the combined irq handler.*/
>> +    arm_smmu_combined_irq_thread(0, (void *)dev);
>> +}
>> +
>> +static void arm_smmu_evtq_thread_xen(int irq, void *dev,
>> +                       struct cpu_user_regs *regs)
>> +{
>> +    struct arm_smmu_device *smmu = (struct arm_smmu_device *)dev;
>> +
>> +    tasklet_schedule(&(smmu->evtq_tasklet));
>> +}
>> +
>> +static void arm_smmu_priq_thread_xen(int irq, void *dev,
>> +                       struct cpu_user_regs *regs)
>> +{
>> +    struct arm_smmu_device *smmu = (struct arm_smmu_device *)dev;
>> +
>> +    tasklet_schedule(&(smmu->priq_tasklet));
>> +}
>> +
>> +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 +1894,7 @@ 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 +1907,7 @@ static bool arm_smmu_capable(enum iommu_cap cap)
>>           return false;
>>       }
>>   }
>> +#endif
>>     static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
>>   {
>> @@ -1546,9 +2027,16 @@ 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 +2092,7 @@ 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 +2210,7 @@ out_unlock:
>>       return ret;
>>   }
>>   +#if 0 /* Xen: Unused functionality */
> same
>>   static int arm_smmu_map(struct iommu_domain *domain, unsigned long 
>> iova,
>>               phys_addr_t paddr, size_t size, int prot)
>>   {
>> @@ -1772,6 +2262,7 @@ 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 +2274,14 @@ static bool arm_smmu_sid_in_range(struct 
>> arm_smmu_device *smmu, u32 sid)
>>       return sid < limit;
>>   }
>>   +/* Xen: Unused */
>> +#if 0
>>   static struct iommu_ops arm_smmu_ops;
>> +#endif
>> +
>> +/* Xen: Redefine arm_smmu_ops to what fwspec should evaluate */
>> +static const struct iommu_ops arm_smmu_iommu_ops;
>> +#define arm_smmu_ops arm_smmu_iommu_ops
>>     static int arm_smmu_add_device(struct device *dev)
>>   {
>> @@ -1791,8 +2289,11 @@ 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
>>   +    /* Xen: fwspec->ops are not needed */
>>       if (!fwspec || fwspec->ops != &arm_smmu_ops)
>>           return -ENODEV;
>>       /*
>> @@ -1830,6 +2331,11 @@ 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 +2343,16 @@ 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 +2488,7 @@ 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 +2697,7 @@ 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 +2763,15 @@ 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 +2835,13 @@ 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)
>> @@ -2452,6 +2975,13 @@ static int arm_smmu_device_reset(struct 
>> arm_smmu_device *smmu, bool bypass)
>>           return ret;
>>       }
>>   +    /* Xen: Initialize tasklets */
>> +    tasklet_init(&smmu->evtq_tasklet, arm_smmu_evtq_tasklet,
>> +            (unsigned long)smmu);
>> +    tasklet_init(&smmu->priq_tasklet, arm_smmu_priq_tasklet,
>> +            (unsigned long)smmu);
>> +    tasklet_init(&smmu->combined_irq_tasklet, 
>> arm_smmu_combined_irq_tasklet,
>> +            (unsigned long)smmu);
>>         /* Enable the SMMU interface, or ensure bypass */
>>       if (!bypass || disable_bypass) {
>> @@ -2542,8 +3072,14 @@ 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 +3152,12 @@ 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 +3218,8 @@ 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 +3242,7 @@ 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 +3255,7 @@ 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 +3274,11 @@ 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 +3305,9 @@ 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 +3346,18 @@ 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 +3393,20 @@ 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 +3420,8 @@ 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 +3429,7 @@ 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 +3446,316 @@ 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->contexts, 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)
> This is returning iommu_domain and not a domain.
> Please change the name of function.
>> +{
>> +    struct iommu_domain *domain;
>> +    struct arm_smmu_xen_domain *xen_domain;
> A suggestion
> 1. as you have used in above function smmu_domain variable for 
> arm_smmu_xen_domain
> Can similar logic be used for iommu_domain.
>
> 2. When smmu_domain variable name is used in above function why 
> xen_domain is used in this function.
> It is quite confusing.
> logically xen_domain should mean a VM.
>> +    struct arm_smmu_device *smmu;
>> +    struct arm_smmu_domain *smmu_domain;
> smmu_domain was used for arm_smmu_xen_domain.
> consistency of variable names is necessary for code clarity
>> +
>> +    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->contexts, 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)
> same
>> +{
>> +    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;
> same
>> +    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->contexts);
>> +
>> +    }
>> +
>> +    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);
> same
>> +
>> +    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)
> Where is iommu_domain initialized?
> The function does not use a iommu_domain * variable
>> +{
>> +    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->contexts);
>> +
>> +    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->contexts));
>> +    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
>> diff --git a/xen/include/xen/linux_compat.h 
>> b/xen/include/xen/linux_compat.h
>> new file mode 100644
>> index 0000000000..8037be0a3e
>> --- /dev/null
>> +++ b/xen/include/xen/linux_compat.h
>> @@ -0,0 +1,84 @@
>> +/****************************************************************************** 
>>
>> + * include/xen/linux_compat.h
>> + *
>> + * Compatibility defines for porting code from Linux to Xen
>> + *
>> + * Copyright (c) 2017 Linaro Limited
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +#ifndef __XEN_LINUX_COMPAT_H__
>> +#define __XEN_LINUX_COMPAT_H__
>> +
>> +#include <asm/types.h>
>> +
>> +typedef paddr_t phys_addr_t;
>> +typedef paddr_t dma_addr_t;
>> +
>> +typedef unsigned int gfp_t;
>> +#define GFP_KERNEL 0
>> +#define __GFP_ZERO 0x01U
>> +
>> +/* Helpers for IRQ functions */
>> +#define free_irq release_irq
>> +
>> +enum irqreturn {
>> +    IRQ_NONE,
>> +    IRQ_HANDLED,
>> +    IRQ_WAKE_THREAD,
>> +};
>> +
>> +typedef enum irqreturn irqreturn_t;
>> +
>> +/* Device logger functions */
>> +#define dev_dbg(dev, fmt, ...) printk(XENLOG_DEBUG fmt, ## __VA_ARGS__)
>> +#define dev_notice(dev, fmt, ...) printk(XENLOG_INFO fmt, ## 
>> __VA_ARGS__)
>> +#define dev_warn(dev, fmt, ...) printk(XENLOG_WARNING fmt, ## 
>> __VA_ARGS__)
>> +#define dev_err(dev, fmt, ...) printk(XENLOG_ERR fmt, ## __VA_ARGS__)
>> +#define dev_info(dev, fmt, ...) printk(XENLOG_INFO fmt, ## __VA_ARGS__)
>> +
>> +#define dev_err_ratelimited(dev, fmt, ...)                  \
>> +     printk(XENLOG_ERR fmt, ## __VA_ARGS__)
>> +
>> +#define dev_name(dev) dt_node_full_name(dev_to_dt(dev))
>> +
>> +/* Alias to Xen allocation helpers */
>> +#define kfree xfree
>> +#define kmalloc(size, flags) ({\
>> +    void *__ret_alloc = NULL; \
>> +    if (flags & __GFP_ZERO) \
>> +        __ret_alloc = _xzalloc(size, sizeof(void *)); \
>> +    else \
>> +        __ret_alloc = _xmalloc(size, sizeof(void *)); \
>> +    __ret_alloc; \
>> +})
>> +#define kzalloc(size, flags)        _xzalloc(size, sizeof(void *))
>> +#define devm_kzalloc(dev, size, flags)  _xzalloc(size, sizeof(void *))
>> +#define kmalloc_array(size, n, flags) ({\
>> +    void *__ret_alloc = NULL; \
>> +    if (flags & __GFP_ZERO) \
>> +        __ret_alloc = _xzalloc_array(size, sizeof(void *), n); \
>> +    else \
>> +        __ret_alloc = _xmalloc_array(size, sizeof(void *), n); \
>> +    __ret_alloc; \
>> +})
>> +
>> +/* Alias to Xen time functions */
>> +#define ktime_t s_time_t
>> +#define ktime_get()             (NOW())
>> +#define ktime_add_us(t,i)       (t + MICROSECS(i))
>> +#define ktime_compare(t,i)      (t > (i))
>> +
>> +#endif /* __XEN_LINUX_COMPAT_H__ */
>


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