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Re: [Xen-devel] [PATCH v2 12/12] xen/iommu: smmu: Add Xen specific code to be able to use the driver



On Fri, 16 Jan 2015, Julien Grall wrote:
> The main goal is to modify as little the Linux code to be able to port
> easily new feature added in Linux repo for the driver.

Agreed.


> To achieve that we:
>     - Add helpers to Linux function not implemented on Xen

Good idea, I would take it further and move the helpers to a separate
file that smmu.c #includes. Or it could work the other way around: you
could move the original code to smmu-linux.c that get #included into
smmu.c


>     - Add callbacks used by Xen to do our own stuff and call Linux ones
>     - Only modify when required the code which comes from Linux. If so a
>     comment has been added with /* Xen: ... */ explaining why it's
>     necessary.

I wonder if it makes sense to keep your changes in patch format and
apply the patch at run time as part of the make system.

Of course you would need to be careful to keep the patched smmu.c
separate from the original, otherwise it would get very confusing when
people works on their changes.


> 
> The support for PCI has been commented because it's not yet supported by
> Xen ARM and therefore won't compile.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> 
> ---
>     Changes in v2:
>         - Add the ACCESS_ONCE definition in the drivers. The patch to
>         introduce the one in common code has been dropped.
>         - The include xen/device.h has been dropped in favor of
>         asm/device.h
> ---
>  xen/drivers/passthrough/arm/Makefile |   1 +
>  xen/drivers/passthrough/arm/smmu.c   | 678 
> +++++++++++++++++++++++++++++++----
>  2 files changed, 612 insertions(+), 67 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/arm/Makefile 
> b/xen/drivers/passthrough/arm/Makefile
> index 0484b79..f4cd26e 100644
> --- a/xen/drivers/passthrough/arm/Makefile
> +++ b/xen/drivers/passthrough/arm/Makefile
> @@ -1 +1,2 @@
>  obj-y += iommu.o
> +obj-y += smmu.o
> diff --git a/xen/drivers/passthrough/arm/smmu.c 
> b/xen/drivers/passthrough/arm/smmu.c
> index 8a6514f..373eee8 100644
> --- a/xen/drivers/passthrough/arm/smmu.c
> +++ b/xen/drivers/passthrough/arm/smmu.c
> @@ -18,6 +18,13 @@
>   *
>   * Author: Will Deacon <will.deacon@xxxxxxx>
>   *
> + * Based on Linux drivers/iommu/arm-smmu.c
> + *   => commit e6b5be2be4e30037eb551e0ed09dd97bd00d85d3
> + *
> + * Xen modification:
> + * Julien Grall <julien.grall@xxxxxxxxxx>
> + * Copyright (C) 2014 Linaro Limited.
> + *
>   * This driver currently supports:
>   *   - SMMUv1 and v2 implementations
>   *   - Stream-matching and stream-indexing
> @@ -28,26 +35,164 @@
>   *   - Context fault reporting
>   */
>  
> -#define pr_fmt(fmt) "arm-smmu: " fmt
>  
> -#include <linux/delay.h>
> -#include <linux/dma-mapping.h>
> -#include <linux/err.h>
> -#include <linux/interrupt.h>
> -#include <linux/io.h>
> -#include <linux/iommu.h>
> -#include <linux/mm.h>
> -#include <linux/module.h>
> -#include <linux/of.h>
> -#include <linux/pci.h>
> -#include <linux/platform_device.h>
> -#include <linux/slab.h>
> -#include <linux/spinlock.h>
> -#include <linux/bitops.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/list.h>
> +#include <xen/mm.h>
> +#include <xen/vmap.h>
> +#include <xen/rbtree.h>
> +#include <xen/sched.h>
> +#include <xen/sizes.h>
> +#include <asm/atomic.h>
> +#include <asm/device.h>
> +#include <asm/io.h>
> +#include <asm/platform.h>
> +
> +/* Xen: The below defines are redefined within the file. Undef it */
> +#undef SCTLR_AFE
> +#undef SCTLR_TRE
> +#undef SCTLR_M
> +#undef TTBCR_EAE
> +
> +/* 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 dt_device_node
> +
> +#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;
> +     int ret = 0;
> +
> +     res.type = type;
> +
> +     switch (type) {
> +     case IORESOURCE_MEM:
> +             ret = dt_device_get_address(pdev, num, &res.addr, &res.size);
> +
> +             return ((ret) ? NULL : &res);
> +
> +     case IORESOURCE_IRQ:
> +             ret = platform_get_irq(pdev, num);
> +             if (ret < 0)
> +                     return NULL;
> +
> +             res.addr = ret;
> +             res.size = 1;
> +
> +             return &res;
> +
> +     default:
> +             return NULL;
> +     }
> +}
> +
> +/* Alias to Xen IRQ functions */
> +#define request_irq(irq, func, flags, name, dev) request_irq(irq, flags, 
> func, name, dev)
> +#define free_irq release_irq
> +
> +/*
> + * Device logger functions
> + * TODO: Handle PCI
> + */
> +#define dev_print(dev, lvl, fmt, ...)                                        
>         \
> +      printk(lvl "smmu: %s: " fmt, dt_node_full_name(dev_to_dt(dev)), ## 
> __VA_ARGS__)
> +
> +#define dev_dbg(dev, fmt, ...) dev_print(dev, XENLOG_DEBUG, fmt, ## 
> __VA_ARGS__)
> +#define dev_notice(dev, fmt, ...) dev_print(dev, XENLOG_INFO, fmt, ## 
> __VA_ARGS__)
> +#define dev_warn(dev, fmt, ...) dev_print(dev, XENLOG_WARNING, fmt, ## 
> __VA_ARGS__)
> +#define dev_err(dev, fmt, ...) dev_print(dev, XENLOG_ERR, fmt, ## 
> __VA_ARGS__)
> +
> +#define dev_err_ratelimited(dev, fmt, ...)                                   
> \
> +      dev_print(dev, XENLOG_ERR, fmt, ## __VA_ARGS__)
>  
> -#include <linux/amba/bus.h>
> +#define dev_name(dev) dt_node_full_name(dev_to_dt(dev))
>  
> -#include <asm/pgalloc.h>
> +/* Alias to Xen allocation helpers */
> +#define kfree xfree
> +#define kmalloc(size, flags)         _xmalloc(size, sizeof(void *))
> +#define kzalloc(size, flags)         _xzalloc(size, sizeof(void *))
> +#define devm_kzalloc(dev, size, flags)       _xzalloc(size, sizeof(void *))
> +#define kmalloc_array(size, n, flags)        _xmalloc_array(size, 
> sizeof(void *), n)
> +
> +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 doesn't handle IOMMU fault */
> +#define report_iommu_fault(...)      1
> +
> +#define IOMMU_FAULT_READ     0
> +#define IOMMU_FAULT_WRITE    1
> +
> +/* Xen: misc */
> +#define PHYS_MASK_SHIFT              PADDR_BITS
> +
> +#ifdef CONFIG_ARM_64
> +# define CONFIG_64BIT
> +#endif
> +
> +#define VA_BITS              0       /* Only used for configuring stage-1 
> input size */
> +
> +/* The macro ACCESS_ONCE start to be replaced in Linux in favor of
> + * {READ, WRITE}_ONCE. Rather than introducing in the common code, keep a
> + * version here. We will have to drop it when the SMMU code in Linux will
> + * switch to {READ, WRITE}_ONCE.
> + */
> +#define __ACCESS_ONCE(x) ({ \
> +      __maybe_unused typeof(x) __var = 0; \
> +     (volatile typeof(x) *)&(x); })
> +#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
> +
> +/***** Start of SMMU definitions *****/
>  
>  /* Maximum number of stream IDs assigned to a single device */
>  #define MAX_MASTER_STREAMIDS         MAX_PHANDLE_ARGS
> @@ -330,10 +475,14 @@
>  
>  #define FSYNR0_WNR                   (1 << 4)
>  
> -static int force_stage;
> -module_param_named(force_stage, force_stage, int, S_IRUGO | S_IWUSR);
> -MODULE_PARM_DESC(force_stage,
> -     "Force SMMU mappings to be installed at a particular stage of 
> translation. A value of '1' or '2' forces the corresponding stage. All other 
> values are ignored (i.e. no stage is forced). Note that selecting a specific 
> stage will disable support for nested translation.");
> +/* Force SMMU mapping to be installed at a particular stage of translation.
> + * A value of '1' or '2' forces the corresponding state. All other values
> + * are ignored (i.e no stage is forced). Note that selecting a specific stage
> + * will disable support for nested translation.
> + *
> + * Xen is only supported stage-2 translation, so force the value to 2.
> + */
> +static const int force_stage = 2;
>  
>  enum arm_smmu_arch_version {
>       ARM_SMMU_V1 = 1,
> @@ -406,7 +555,9 @@ struct arm_smmu_cfg {
>       u8                              cbndx;
>       u8                              irptndx;
>       u32                             cbar;
> -     pgd_t                           *pgd;
> +
> +     /* Xen: Domain associated to this configuration */
> +     struct domain                   *domain;
>  };
>  #define INVALID_IRPTNDX                      0xff
>  
> @@ -426,6 +577,90 @@ struct arm_smmu_domain {
>       spinlock_t                      lock;
>  };
>  
> +/* Xen: Dummy iommu_domain */
> +struct iommu_domain
> +{
> +     struct arm_smmu_domain          *priv;
> +
> +     /* Used to link domain contexts for a same domain */
> +     struct list_head                list;
> +};
> +
> +/* Xen: Describes informations required for a Xen domain */
> +struct arm_smmu_xen_domain {
> +     spinlock_t                      lock;
> +     /* List of context (i.e iommu_domain) associated to this domain */
> +     struct list_head                contexts;
> +};
> +
> +/* Xen: Information about each device stored in dev->archdata.iommu */
> +struct arm_smmu_xen_device {
> +     struct iommu_domain *domain;
> +     struct iommu_group *group;
> +};
> +
> +#define dev_archdata(dev) ((struct arm_smmu_xen_device *)dev->archdata.iommu)
> +#define dev_iommu_domain(dev) (dev_archdata(dev)->domain)
> +#define dev_iommu_group(dev) (dev_archdata(dev)->group)
> +
> +/* Xen: Dummy iommu_group */
> +struct iommu_group
> +{
> +     struct arm_smmu_master_cfg *cfg;
> +
> +     atomic_t ref;
> +};
> +
> +static struct iommu_group *iommu_group_alloc(void)
> +{
> +     struct iommu_group *group = xzalloc(struct iommu_group);
> +
> +     if (!group)
> +             return ERR_PTR(-ENOMEM);
> +
> +     atomic_set(&group->ref, 1);
> +
> +     return group;
> +}
> +
> +static void iommu_group_put(struct iommu_group *group)
> +{
> +     if (atomic_dec_and_test(&group->ref))
> +             xfree(group);
> +}
> +
> +static void iommu_group_set_iommudata(struct iommu_group *group,
> +                                   struct arm_smmu_master_cfg *cfg,
> +                                   void (*releasefn)(void *))
> +{
> +     /* TODO: Store the releasefn for the PCI */
> +     ASSERT(releasefn == NULL);
> +
> +     group->cfg = cfg;
> +}
> +
> +static int iommu_group_add_device(struct iommu_group *group,
> +                               struct device *dev)
> +{
> +     dev_iommu_group(dev) = group;
> +
> +     atomic_inc(&group->ref);
> +
> +     return 0;
> +}
> +
> +static struct iommu_group *iommu_group_get(struct device *dev)
> +{
> +     struct iommu_group *group = dev_iommu_group(dev);
> +
> +     if (group)
> +             atomic_inc(&group->ref);
> +
> +     return group;
> +}
> +
> +#define iommu_group_get_iommudata(group) (group)->cfg
> +
>  static DEFINE_SPINLOCK(arm_smmu_devices_lock);
>  static LIST_HEAD(arm_smmu_devices);
>  
> @@ -455,6 +690,8 @@ static void parse_driver_options(struct arm_smmu_device 
> *smmu)
>  
>  static struct device_node *dev_get_dev_node(struct device *dev)
>  {
> +     /* Xen: TODO: Add support for PCI */
> +#if 0
>       if (dev_is_pci(dev)) {
>               struct pci_bus *bus = to_pci_dev(dev)->bus;
>  
> @@ -462,7 +699,7 @@ static struct device_node *dev_get_dev_node(struct device 
> *dev)
>                       bus = bus->parent;
>               return bus->bridge->parent->of_node;
>       }
> -
> +#endif
>       return dev->of_node;
>  }
>  
> @@ -556,6 +793,9 @@ static int register_smmu_master(struct arm_smmu_device 
> *smmu,
>       master->of_node                 = masterspec->np;
>       master->cfg.num_streamids       = masterspec->args_count;
>  
> +     /* Xen: Let Xen knows that the device is protected by an SMMU */
> +     dt_device_set_protected(masterspec->np);
> +
>       for (i = 0; i < master->cfg.num_streamids; ++i) {
>               u16 streamid = masterspec->args[i];
>  
> @@ -651,11 +891,12 @@ static void arm_smmu_tlb_inv_context(struct 
> arm_smmu_domain *smmu_domain)
>       arm_smmu_tlb_sync(smmu);
>  }
>  
> -static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
> +static void arm_smmu_context_fault(int irq, void *dev,
> +                                struct cpu_user_regs *regs)
>  {
> -     int flags, ret;
> +     int flags;
>       u32 fsr, far, fsynr, resume;
> -     unsigned long iova;
> +     paddr_t iova;
>       struct iommu_domain *domain = dev;
>       struct arm_smmu_domain *smmu_domain = domain->priv;
>       struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
> @@ -666,7 +907,7 @@ static irqreturn_t arm_smmu_context_fault(int irq, void 
> *dev)
>       fsr = readl_relaxed(cb_base + ARM_SMMU_CB_FSR);
>  
>       if (!(fsr & FSR_FAULT))
> -             return IRQ_NONE;
> +             return;
>  
>       if (fsr & FSR_IGN)
>               dev_err_ratelimited(smmu->dev,
> @@ -678,19 +919,16 @@ static irqreturn_t arm_smmu_context_fault(int irq, void 
> *dev)
>  
>       far = readl_relaxed(cb_base + ARM_SMMU_CB_FAR_LO);
>       iova = far;
> -#ifdef CONFIG_64BIT
> +     /* Xen: The fault address maybe higher than 32 bits on arm32 */
>       far = readl_relaxed(cb_base + ARM_SMMU_CB_FAR_HI);
> -     iova |= ((unsigned long)far << 32);
> -#endif
> +     iova |= ((paddr_t)far << 32);
>  
>       if (!report_iommu_fault(domain, smmu->dev, iova, flags)) {
> -             ret = IRQ_HANDLED;
>               resume = RESUME_RETRY;
>       } else {
>               dev_err_ratelimited(smmu->dev,
> -                 "Unhandled context fault: iova=0x%08lx, fsynr=0x%x, 
> cb=%d\n",
> +                 "Unhandled context fault: iova=0x%"PRIpaddr", fsynr=0x%x, 
> cb=%d\n",
>                   iova, fsynr, cfg->cbndx);
> -             ret = IRQ_NONE;
>               resume = RESUME_TERMINATE;
>       }
>  
> @@ -700,11 +938,10 @@ static irqreturn_t arm_smmu_context_fault(int irq, void 
> *dev)
>       /* Retry or terminate any stalled transactions */
>       if (fsr & FSR_SS)
>               writel_relaxed(resume, cb_base + ARM_SMMU_CB_RESUME);
> -
> -     return ret;
>  }
>  
> -static irqreturn_t arm_smmu_global_fault(int irq, void *dev)
> +static void arm_smmu_global_fault(int irq, void *dev,
> +                                  struct cpu_user_regs *regs)
>  {
>       u32 gfsr, gfsynr0, gfsynr1, gfsynr2;
>       struct arm_smmu_device *smmu = dev;
> @@ -716,7 +953,7 @@ static irqreturn_t arm_smmu_global_fault(int irq, void 
> *dev)
>       gfsynr2 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sGFSYNR2);
>  
>       if (!gfsr)
> -             return IRQ_NONE;
> +             return;
>  
>       dev_err_ratelimited(smmu->dev,
>               "Unexpected global fault, this could be serious\n");
> @@ -725,9 +962,10 @@ static irqreturn_t arm_smmu_global_fault(int irq, void 
> *dev)
>               gfsr, gfsynr0, gfsynr1, gfsynr2);
>  
>       writel(gfsr, gr0_base + ARM_SMMU_GR0_sGFSR);
> -     return IRQ_HANDLED;
>  }
>  
> +/* Xen: Page tables are shared with the processor */
> +#if 0
>  static void arm_smmu_flush_pgtable(struct arm_smmu_device *smmu, void *addr,
>                                  size_t size)
>  {
> @@ -749,6 +987,7 @@ static void arm_smmu_flush_pgtable(struct arm_smmu_device 
> *smmu, void *addr,
>                               DMA_TO_DEVICE);
>       }
>  }
> +#endif
>  
>  static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain)
>  {
> @@ -757,6 +996,7 @@ static void arm_smmu_init_context_bank(struct 
> arm_smmu_domain *smmu_domain)
>       struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
>       struct arm_smmu_device *smmu = smmu_domain->smmu;
>       void __iomem *cb_base, *gr0_base, *gr1_base;
> +     paddr_t p2maddr;
>  
>       gr0_base = ARM_SMMU_GR0(smmu);
>       gr1_base = ARM_SMMU_GR1(smmu);
> @@ -840,11 +1080,16 @@ static void arm_smmu_init_context_bank(struct 
> arm_smmu_domain *smmu_domain)
>       }
>  
>       /* TTBR0 */
> -     arm_smmu_flush_pgtable(smmu, cfg->pgd,
> -                            PTRS_PER_PGD * sizeof(pgd_t));
> -     reg = __pa(cfg->pgd);
> +     /* Xen: The page table is shared with the P2M code */
> +     ASSERT(smmu_domain->cfg.domain != NULL);
> +     p2maddr = page_to_maddr(smmu_domain->cfg.domain->arch.p2m.root);
> +
> +     dev_notice(smmu->dev, "d%u: p2maddr 0x%"PRIpaddr"\n",
> +                smmu_domain->cfg.domain->domain_id, p2maddr);
> +
> +     reg = (p2maddr & ((1ULL << 32) - 1));
>       writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBR0_LO);
> -     reg = (phys_addr_t)__pa(cfg->pgd) >> 32;
> +     reg = (p2maddr >> 32);
>       if (stage1)
>               reg |= ARM_SMMU_CB_ASID(cfg) << TTBRn_HI_ASID_SHIFT;
>       writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBR0_HI);
> @@ -886,9 +1131,21 @@ static void arm_smmu_init_context_bank(struct 
> arm_smmu_domain *smmu_domain)
>                       reg |= (64 - smmu->s1_input_size) << TTBCR_T0SZ_SHIFT;
>               }
>       } else {
> +#if CONFIG_ARM_32
> +             /* Xen: Midway is using 40-bit address space. Though it may
> +              * not work on other ARM32 platform with SMMU-v1.
> +              * TODO: A quirk may be necessary if we have to support
> +              * other ARM32 platform with SMMU-v1.
> +              */
> +             reg = 0x18 << TTBCR_T0SZ_SHIFT;
> +#else
>               reg = 0;
> +#endif
>       }
>  
> +     /* Xen: The attributes to walk the page table should be the same as
> +      * VTCR_EL2. Currently doesn't differ from Linux ones.
> +      */
>       reg |= TTBCR_EAE |
>             (TTBCR_SH_IS << TTBCR_SH0_SHIFT) |
>             (TTBCR_RGN_WBWA << TTBCR_ORGN0_SHIFT) |
> @@ -1031,7 +1288,6 @@ static void arm_smmu_destroy_domain_context(struct 
> iommu_domain *domain)
>  static int arm_smmu_domain_init(struct iommu_domain *domain)
>  {
>       struct arm_smmu_domain *smmu_domain;
> -     pgd_t *pgd;
>  
>       /*
>        * Allocate the domain and initialise some of its data structures.
> @@ -1042,20 +1298,12 @@ static int arm_smmu_domain_init(struct iommu_domain 
> *domain)
>       if (!smmu_domain)
>               return -ENOMEM;
>  
> -     pgd = kcalloc(PTRS_PER_PGD, sizeof(pgd_t), GFP_KERNEL);
> -     if (!pgd)
> -             goto out_free_domain;
> -     smmu_domain->cfg.pgd = pgd;
> -
>       spin_lock_init(&smmu_domain->lock);
>       domain->priv = smmu_domain;
>       return 0;
> -
> -out_free_domain:
> -     kfree(smmu_domain);
> -     return -ENOMEM;
>  }
>  
> +#if 0
>  static void arm_smmu_free_ptes(pmd_t *pmd)
>  {
>       pgtable_t table = pmd_pgtable(*pmd);
> @@ -1118,6 +1366,7 @@ static void arm_smmu_free_pgtables(struct 
> arm_smmu_domain *smmu_domain)
>  
>       kfree(pgd_base);
>  }
> +#endif
>  
>  /*
>   * For a given set N of 2**order different stream IDs (no duplicates
> @@ -1259,7 +1508,6 @@ static void arm_smmu_domain_destroy(struct iommu_domain 
> *domain)
>        * already been detached.
>        */
>       arm_smmu_destroy_domain_context(domain);
> -     arm_smmu_free_pgtables(smmu_domain);
>       kfree(smmu_domain);
>  }
>  
> @@ -1384,11 +1632,12 @@ static void arm_smmu_domain_remove_master(struct 
> arm_smmu_domain *smmu_domain,
>       /*
>        * We *must* clear the S2CR first, because freeing the SMR means
>        * that it can be re-allocated immediately.
> +      * Xen: Unlike Linux, any access to non-configured stream will fault.
>        */
>       for (i = 0; i < cfg->num_streamids; ++i) {
>               u32 idx = cfg->smrs ? cfg->smrs[i].idx : cfg->streamids[i];
>  
> -             writel_relaxed(S2CR_TYPE_BYPASS,
> +             writel_relaxed(S2CR_TYPE_FAULT,
>                              gr0_base + ARM_SMMU_GR0_S2CR(idx));
>       }
>  
> @@ -1408,7 +1657,7 @@ static int arm_smmu_attach_dev(struct iommu_domain 
> *domain, struct device *dev)
>               return -ENXIO;
>       }
>  
> -     if (dev->archdata.iommu) {
> +     if (dev_iommu_domain(dev)) {
>               dev_err(dev, "already attached to IOMMU domain\n");
>               return -EEXIST;
>       }
> @@ -1440,8 +1689,9 @@ static int arm_smmu_attach_dev(struct iommu_domain 
> *domain, struct device *dev)
>               return -ENODEV;
>  
>       ret = arm_smmu_domain_add_master(smmu_domain, cfg);
> +
>       if (!ret)
> -             dev->archdata.iommu = domain;
> +             dev_iommu_domain(dev) = domain;
>       return ret;
>  }
>  
> @@ -1454,10 +1704,14 @@ static void arm_smmu_detach_dev(struct iommu_domain 
> *domain, struct device *dev)
>       if (!cfg)
>               return;
>  
> -     dev->archdata.iommu = NULL;
> +     dev_iommu_domain(dev) = NULL;
>       arm_smmu_domain_remove_master(smmu_domain, cfg);
>  }
>  
> +/* Xen: the page table is shared with the processor, therefore helpers to
> + * implement separate is not necessary.
> + */
> +#if 0
>  static bool arm_smmu_pte_is_contiguous_range(unsigned long addr,
>                                            unsigned long end)
>  {
> @@ -1746,7 +2000,10 @@ static phys_addr_t arm_smmu_iova_to_phys(struct 
> iommu_domain *domain,
>  
>       return __pfn_to_phys(pte_pfn(pte)) | (iova & ~PAGE_MASK);
>  }
> +#endif
>  
> +/* Xen: Functions are not used at the moment */
> +#if 0
>  static bool arm_smmu_capable(enum iommu_cap cap)
>  {
>       switch (cap) {
> @@ -1775,6 +2032,7 @@ static void __arm_smmu_release_pci_iommudata(void *data)
>  {
>       kfree(data);
>  }
> +#endif
>  
>  static int arm_smmu_add_device(struct device *dev)
>  {
> @@ -1784,6 +2042,10 @@ static int arm_smmu_add_device(struct device *dev)
>       void (*releasefn)(void *) = NULL;
>       int ret;
>  
> +     /* Xen: Check if the device has already been added */
> +     if (dev_iommu_group(dev))
> +             return -EBUSY;
> +
>       smmu = find_smmu_for_device(dev);
>       if (!smmu)
>               return -ENODEV;
> @@ -1795,6 +2057,9 @@ static int arm_smmu_add_device(struct device *dev)
>       }
>  
>       if (dev_is_pci(dev)) {
> +             /* Xen: TODO: Add PCI support */
> +             BUG();
> +#if 0
>               struct pci_dev *pdev = to_pci_dev(dev);
>  
>               cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
> @@ -1811,6 +2076,7 @@ static int arm_smmu_add_device(struct device *dev)
>               pci_for_each_dma_alias(pdev, __arm_smmu_get_pci_sid,
>                                      &cfg->streamids[0]);
>               releasefn = __arm_smmu_release_pci_iommudata;
> +#endif
>       } else {
>               struct arm_smmu_master *master;
>  
> @@ -1831,6 +2097,8 @@ out_put_group:
>       return ret;
>  }
>  
> +/* Xen: We don't support remove device for now. Will be useful for PCI */
> +#if 0
>  static void arm_smmu_remove_device(struct device *dev)
>  {
>       iommu_group_remove_device(dev);
> @@ -1888,6 +2156,7 @@ static const struct iommu_ops arm_smmu_ops = {
>                                  ARM_SMMU_PTE_CONT_SIZE |
>                                  PAGE_SIZE),
>  };
> +#endif
>  
>  static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
>  {
> @@ -1903,7 +2172,11 @@ static void arm_smmu_device_reset(struct 
> arm_smmu_device *smmu)
>       /* Mark all SMRn as invalid and all S2CRn as bypass */
>       for (i = 0; i < smmu->num_mapping_groups; ++i) {
>               writel_relaxed(0, gr0_base + ARM_SMMU_GR0_SMR(i));
> -             writel_relaxed(S2CR_TYPE_BYPASS,
> +             /*
> +              * Xen: Unlike Linux, any access to a non-configure stream
> +              * will fault by default.
> +              */
> +             writel_relaxed(S2CR_TYPE_FAULT,
>                       gr0_base + ARM_SMMU_GR0_S2CR(i));
>       }
>  
> @@ -1929,6 +2202,8 @@ static void arm_smmu_device_reset(struct 
> arm_smmu_device *smmu)
>  
>       /* Enable client access, but bypass when no mapping is found */
>       reg &= ~(sCR0_CLIENTPD | sCR0_USFCFG);
> +     /* Xen: Unlike Linux, generate a fault when no mapping is found */
> +     reg |= sCR0_USFCFG;
>  
>       /* Disable forced broadcasting */
>       reg &= ~sCR0_FB;
> @@ -2039,7 +2314,7 @@ static int arm_smmu_device_cfg_probe(struct 
> arm_smmu_device *smmu)
>               smmu->smr_id_mask = sid;
>  
>               dev_notice(smmu->dev,
> -                        "\tstream matching with %u register groups, mask 
> 0x%x",
> +                        "\tstream matching with %u register groups, mask 
> 0x%x\n",
>                          smmu->num_mapping_groups, mask);
>       } else {
>               smmu->num_mapping_groups = (id >> ID0_NUMSIDB_SHIFT) &
> @@ -2074,12 +2349,30 @@ static int arm_smmu_device_cfg_probe(struct 
> arm_smmu_device *smmu)
>       size = arm_smmu_id_size_to_bits((id >> ID2_IAS_SHIFT) & ID2_IAS_MASK);
>       smmu->s1_output_size = min_t(unsigned long, PHYS_MASK_SHIFT, size);
>  
> +     /* Xen: Stage-2 input size is not restricted */
> +     smmu->s2_input_size = size;
> +#if 0
>       /* Stage-2 input size limited due to pgd allocation (PTRS_PER_PGD) */
>  #ifdef CONFIG_64BIT
>       smmu->s2_input_size = min_t(unsigned long, VA_BITS, size);
>  #else
>       smmu->s2_input_size = min(32UL, size);
>  #endif
> +#endif
> +
> +     /*
> +      * Xen: SMMU v1: Only 40 bits input address size is supported for
> +      * arm32. See arm_smmu_init_context_bank
> +      */
> +#ifdef CONFIG_ARM_32
> +     if ( smmu->version == ARM_SMMU_V1 && smmu->s2_input_size != 40 )
> +     {
> +             dev_err(smmu->dev,
> +                     "Stage-2 Input size %ld not supported for SMMUv1\n",
> +                     smmu->s2_input_size);
> +             return -ENODEV;;
> +     }
> +#endif
>  
>       /* The stage-2 output mask is also applied for bypass */
>       size = arm_smmu_id_size_to_bits((id >> ID2_OAS_SHIFT) & ID2_OAS_MASK);
> @@ -2124,8 +2417,11 @@ static const struct of_device_id arm_smmu_of_match[] = 
> {
>       { .compatible = "arm,mmu-500", .data = (void *)ARM_SMMU_V2 },
>       { },
>  };
> -MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
>  
> +/*
> + * Xen: We don't have refcount allocated memory so manually free memory when
> + * an error occured.
> + */
>  static int arm_smmu_device_dt_probe(struct platform_device *pdev)
>  {
>       const struct of_device_id *of_id;
> @@ -2149,14 +2445,17 @@ static int arm_smmu_device_dt_probe(struct 
> platform_device *pdev)
>  
>       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>       smmu->base = devm_ioremap_resource(dev, res);
> -     if (IS_ERR(smmu->base))
> -             return PTR_ERR(smmu->base);
> +     if (IS_ERR(smmu->base)) {
> +             err = PTR_ERR(smmu->base);
> +             goto out_free;
> +     }
>       smmu->size = resource_size(res);
>  
>       if (of_property_read_u32(dev->of_node, "#global-interrupts",
>                                &smmu->num_global_irqs)) {
>               dev_err(dev, "missing #global-interrupts property\n");
> -             return -ENODEV;
> +             err = -ENODEV;
> +             goto out_free;
>       }
>  
>       num_irqs = 0;
> @@ -2169,14 +2468,16 @@ static int arm_smmu_device_dt_probe(struct 
> platform_device *pdev)
>       if (!smmu->num_context_irqs) {
>               dev_err(dev, "found %d interrupts but expected at least %d\n",
>                       num_irqs, smmu->num_global_irqs + 1);
> -             return -ENODEV;
> +             err = -ENODEV;
> +             goto out_free;
>       }
>  
>       smmu->irqs = devm_kzalloc(dev, sizeof(*smmu->irqs) * num_irqs,
>                                 GFP_KERNEL);
>       if (!smmu->irqs) {
>               dev_err(dev, "failed to allocate %d irqs\n", num_irqs);
> -             return -ENOMEM;
> +             err = -ENOMEM;
> +             goto out_free;
>       }
>  
>       for (i = 0; i < num_irqs; ++i) {
> @@ -2184,7 +2485,8 @@ static int arm_smmu_device_dt_probe(struct 
> platform_device *pdev)
>  
>               if (irq < 0) {
>                       dev_err(dev, "failed to get irq index %d\n", i);
> -                     return -ENODEV;
> +                     err = -ENODEV;
> +                     goto out_free;
>               }
>               smmu->irqs[i] = irq;
>       }
> @@ -2259,12 +2561,20 @@ out_put_masters:
>       for (node = rb_first(&smmu->masters); node; node = rb_next(node)) {
>               struct arm_smmu_master *master
>                       = container_of(node, struct arm_smmu_master, node);
> -             of_node_put(master->of_node);
> +             kfree(master);
>       }
>  
> +out_free:
> +     kfree(smmu->irqs);
> +     if (!IS_ERR(smmu->base))
> +             iounmap(smmu->base);
> +     kfree(smmu);
> +
>       return err;
>  }
>  
> +/* Xen: We never remove SMMU */
> +#if 0
>  static int arm_smmu_device_remove(struct platform_device *pdev)
>  {
>       int i;
> @@ -2359,3 +2669,237 @@ module_exit(arm_smmu_exit);
>  MODULE_DESCRIPTION("IOMMU API for ARM architected SMMU implementations");
>  MODULE_AUTHOR("Will Deacon <will.deacon@xxxxxxx>");
>  MODULE_LICENSE("GPL v2");
> +#endif
> +
> +/* Xen specific function */
> +
> +static void arm_smmu_iotlb_flush_all(struct domain *d)
> +{
> +     struct arm_smmu_xen_domain *smmu_domain = 
> domain_hvm_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);
> +}
> +
> +static void arm_smmu_iotlb_flush(struct domain *d, unsigned long gfn,
> +                                 unsigned int page_count)
> +{
> +    /* ARM SMMU v1 doesn't have flush by VMA and VMID */
> +    arm_smmu_iotlb_flush_all(d);
> +}
> +
> +static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
> +                            struct device *dev)
> +{
> +     struct iommu_domain *domain;
> +     struct arm_smmu_xen_domain *xen_domain;
> +     int ret;
> +
> +     xen_domain = domain_hvm_iommu(d)->arch.priv;
> +
> +     if (!dev->archdata.iommu) {
> +             dev->archdata.iommu = xzalloc(struct arm_smmu_xen_device);
> +             if (!dev->archdata.iommu)
> +                     return -ENOMEM;
> +     }
> +
> +     if (!dev_iommu_group(dev)) {
> +             ret = arm_smmu_add_device(dev);
> +             if (ret)
> +                     return ret;
> +     }
> +
> +     /*
> +      * TODO: Share the context bank (i.e iommu_domain) when the device is
> +      * under the same SMMU as another device assigned to this domain.
> +      * Would it useful for PCI
> +      */
> +     domain = xzalloc(struct iommu_domain);
> +     if (!domain)
> +             return -ENOMEM;
> +
> +     ret = arm_smmu_domain_init(domain);
> +     if (ret)
> +             goto err_dom_init;
> +
> +     domain->priv->cfg.domain = d;
> +
> +     ret = arm_smmu_attach_dev(domain, dev);
> +     if (ret)
> +             goto err_attach_dev;
> +
> +     spin_lock(&xen_domain->lock);
> +     /* Chain the new context to the domain */
> +     list_add(&domain->list, &xen_domain->contexts);
> +     spin_unlock(&xen_domain->lock);
> +
> +     return 0;
> +
> +err_attach_dev:
> +     arm_smmu_domain_destroy(domain);
> +err_dom_init:
> +     xfree(domain);
> +
> +     return ret;
> +}
> +
> +static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
> +{
> +     struct iommu_domain *domain = dev_iommu_domain(dev);
> +     struct arm_smmu_xen_domain *xen_domain;
> +
> +     xen_domain = domain_hvm_iommu(d)->arch.priv;
> +
> +     if (!domain || domain->priv->cfg.domain != d) {
> +             dev_err(dev, " not attached to domain %d\n", d->domain_id);
> +             return -ESRCH;
> +     }
> +
> +     arm_smmu_detach_dev(domain, dev);
> +
> +     spin_lock(&xen_domain->lock);
> +     list_del(&domain->list);
> +     spin_unlock(&xen_domain->lock);
> +
> +     arm_smmu_domain_destroy(domain);
> +     xfree(domain);
> +
> +     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 != hardware_domain)
> +             return -EPERM;
> +
> +     if (t == s)
> +             return 0;
> +
> +     ret = arm_smmu_deassign_dev(s, dev);
> +     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->contexts);
> +
> +     domain_hvm_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 = domain_hvm_iommu(d)->arch.priv;
> +
> +     ASSERT(list_empty(&xen_domain->contexts));
> +     xfree(xen_domain);
> +}
> +
> +
> +static int 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, mfn, 0, t);
> +}
> +
> +static int 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;
> +
> +     guest_physmap_remove_page(d, gfn, gfn, 0);
> +
> +     return 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 __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_dt_probe(dev);
> +     if ( !rc )
> +             iommu_set_ops(&arm_smmu_iommu_ops);
> +
> +     return rc;
> +}
> +
> +DT_DEVICE_START(smmu, "ARM SMMU", DEVICE_IOMMU)
> +     .dt_match = arm_smmu_of_match,
> +     .init = arm_smmu_dt_init,
> +DT_DEVICE_END
> -- 
> 2.1.4
> 

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