Re: [PATCH v4 7/7] iommu/riscv: Paging domain support

[Zong Li]

On Sat, May 4, 2024 at 12:13 AM Tomasz Jeznach <tjeznach@xxxxxxxxxxxx> wrote:
>
> Introduce first-stage address translation support.
>
> Page table configured by the IOMMU driver will use the highest mode
> implemented by the hardware, unless not known at the domain allocation
> time falling back to the CPU’s MMU page mode.
>
> This change introduces IOTINVAL.VMA command, required to invalidate
> any cached IOATC entries after mapping is updated and/or removed from
> the paging domain.  Invalidations for the non-leaf page entries use
> IOTINVAL for all addresses assigned to the protection domain for
> hardware not supporting more granular non-leaf page table cache
> invalidations.
>
> Signed-off-by: Tomasz Jeznach <tjeznach@xxxxxxxxxxxx>
> ---
>  drivers/iommu/riscv/iommu.c | 587 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 585 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
> index 4349ac8a3990..ec701fde520f 100644
> --- a/drivers/iommu/riscv/iommu.c
> +++ b/drivers/iommu/riscv/iommu.c
> @@ -41,6 +41,10 @@
>  #define dev_to_iommu(dev) \
>         iommu_get_iommu_dev(dev, struct riscv_iommu_device, iommu)
>
> +/* IOMMU PSCID allocation namespace. */
> +static DEFINE_IDA(riscv_iommu_pscids);
> +#define RISCV_IOMMU_MAX_PSCID          (BIT(20) - 1)
> +
>  /* Device resource-managed allocations */
>  struct riscv_iommu_devres {
>         void *addr;
> @@ -766,6 +770,143 @@ static int riscv_iommu_iodir_set_mode(struct riscv_iommu_device *iommu,
>         return 0;
>  }
>
> +/* This struct contains protection domain specific IOMMU driver data. */
> +struct riscv_iommu_domain {
> +       struct iommu_domain domain;
> +       struct list_head bonds;
> +       spinlock_t lock;                /* protect bonds list updates. */
> +       int pscid;
> +       int numa_node;
> +       int amo_enabled:1;
> +       unsigned int pgd_mode;
> +       unsigned long *pgd_root;
> +};
> +
> +#define iommu_domain_to_riscv(iommu_domain) \
> +       container_of(iommu_domain, struct riscv_iommu_domain, domain)
> +
> +/* Private IOMMU data for managed devices, dev_iommu_priv_* */
> +struct riscv_iommu_info {
> +       struct riscv_iommu_domain *domain;
> +};
> +
> +/* Linkage between an iommu_domain and attached devices. */
> +struct riscv_iommu_bond {
> +       struct list_head list;
> +       struct rcu_head rcu;
> +       struct device *dev;
> +};
> +
> +static int riscv_iommu_bond_link(struct riscv_iommu_domain *domain,
> +                                struct device *dev)
> +{
> +       struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> +       struct riscv_iommu_bond *bond;
> +       struct list_head *bonds;
> +
> +       bond = kzalloc(sizeof(*bond), GFP_KERNEL);
> +       if (!bond)
> +               return -ENOMEM;
> +       bond->dev = dev;
> +
> +       /*
> +        * Linked device pointer and iommu data remain stable in bond struct
> +        * as long the device is attached to the managed IOMMU at _probe_device(),
> +        * up to completion of _release_device() call. Release of the bond will be
> +        * synchronized at the device release, to guarantee no stale pointer is
> +        * used inside rcu protected sections.
> +        *
> +        * List of devices attached to the domain is arranged based on
> +        * managed IOMMU device.
> +        */
> +
> +       spin_lock(&domain->lock);
> +       list_for_each_rcu(bonds, &domain->bonds)
> +               if (dev_to_iommu(list_entry(bonds, struct riscv_iommu_bond, list)->dev) == iommu)
> +                       break;
> +       list_add_rcu(&bond->list, bonds);
> +       spin_unlock(&domain->lock);
> +
> +       return 0;
> +}
> +
> +static void riscv_iommu_bond_unlink(struct riscv_iommu_domain *domain,
> +                                   struct device *dev)
> +{
> +       struct riscv_iommu_bond *bond, *found = NULL;
> +
> +       if (!domain)
> +               return;
> +
> +       spin_lock(&domain->lock);
> +       list_for_each_entry_rcu(bond, &domain->bonds, list) {
> +               if (bond->dev == dev) {
> +                       list_del_rcu(&bond->list);
> +                       found = bond;
> +               }
> +       }
> +       spin_unlock(&domain->lock);
> +       kfree_rcu(found, rcu);
> +}
> +
> +/*
> + * Send IOTLB.INVAL for whole address space for ranges larger than 2MB.
> + * This limit will be replaced with range invalidations, if supported by
> + * the hardware, when RISC-V IOMMU architecture specification update for
> + * range invalidations update will be available.
> + */
> +#define RISCV_IOMMU_IOTLB_INVAL_LIMIT  (2 << 20)
> +
> +static void riscv_iommu_iotlb_inval(struct riscv_iommu_domain *domain,
> +                                   unsigned long start, unsigned long end)
> +{
> +       struct riscv_iommu_bond *bond;
> +       struct riscv_iommu_device *iommu, *prev;
> +       struct riscv_iommu_command cmd;
> +       unsigned long len = end - start + 1;
> +       unsigned long iova;
> +
> +       rcu_read_lock();
> +
> +       prev = NULL;
> +       list_for_each_entry_rcu(bond, &domain->bonds, list) {
> +               iommu = dev_to_iommu(bond->dev);
> +
> +               /*
> +                * IOTLB invalidation request can be safely omitted if already sent
> +                * to the IOMMU for the same PSCID, and with domain->bonds list
> +                * arranged based on the device's IOMMU, it's sufficient to check
> +                * last device the invalidation was sent to.
> +                */
> +               if (iommu == prev)
> +                       continue;
> +
> +               riscv_iommu_cmd_inval_vma(&cmd);
> +               riscv_iommu_cmd_inval_set_pscid(&cmd, domain->pscid);
> +               if (len && len >= RISCV_IOMMU_IOTLB_INVAL_LIMIT) {
> +                       for (iova = start; iova < end; iova += PAGE_SIZE) {
> +                               riscv_iommu_cmd_inval_set_addr(&cmd, iova);
> +                               riscv_iommu_cmd_send(iommu, &cmd, 0);
> +                       }
> +               } else {
> +                       riscv_iommu_cmd_send(iommu, &cmd, 0);
> +               }
> +               prev = iommu;
> +       }
> +
> +       prev = NULL;
> +       list_for_each_entry_rcu(bond, &domain->bonds, list) {
> +               iommu = dev_to_iommu(bond->dev);
> +               if (iommu == prev)
> +                       continue;
> +
> +               riscv_iommu_cmd_iofence(&cmd);

I was wondering why we need many 'iofence' commands following
invalidation commands. Could we just use one iofence to guarantees
that all previous invalidation commands have been completed?

> +               riscv_iommu_cmd_send(iommu, &cmd, RISCV_IOMMU_QUEUE_TIMEOUT);
> +               prev = iommu;
> +       }
> +       rcu_read_unlock();
> +}
> +
>  #define RISCV_IOMMU_FSC_BARE 0
>
>  /*
> @@ -785,10 +926,29 @@ static void riscv_iommu_iodir_update(struct riscv_iommu_device *iommu,
>  {
>         struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>         struct riscv_iommu_dc *dc;
> +       struct riscv_iommu_command cmd;
> +       bool sync_required = false;
>         u64 tc;
>         int i;
>
> -       /* Device context invalidation ignored for now. */
> +       for (i = 0; i < fwspec->num_ids; i++) {
> +               dc = riscv_iommu_get_dc(iommu, fwspec->ids[i]);
> +               tc = READ_ONCE(dc->tc);
> +               if (tc & RISCV_IOMMU_DC_TC_V) {
> +                       WRITE_ONCE(dc->tc, tc & ~RISCV_IOMMU_DC_TC_V);
> +
> +                       /* Invalidate device context cached values */
> +                       riscv_iommu_cmd_iodir_inval_ddt(&cmd);
> +                       riscv_iommu_cmd_iodir_set_did(&cmd, fwspec->ids[i]);
> +                       riscv_iommu_cmd_send(iommu, &cmd, 0);
> +                       sync_required = true;
> +               }
> +       }
> +
> +       if (sync_required) {
> +               riscv_iommu_cmd_iofence(&cmd);
> +               riscv_iommu_cmd_send(iommu, &cmd, RISCV_IOMMU_IOTINVAL_TIMEOUT);
> +       }
>
>         /*
>          * For device context with DC_TC_PDTV = 0, translation attributes valid bit
> @@ -806,12 +966,415 @@ static void riscv_iommu_iodir_update(struct riscv_iommu_device *iommu,
>         }
>  }
>
> +/*
> + * IOVA page translation tree management.
> + */
> +
> +#define IOMMU_PAGE_SIZE_4K     BIT_ULL(12)
> +#define IOMMU_PAGE_SIZE_2M     BIT_ULL(21)
> +#define IOMMU_PAGE_SIZE_1G     BIT_ULL(30)
> +#define IOMMU_PAGE_SIZE_512G   BIT_ULL(39)
> +
> +#define PT_SHIFT (PAGE_SHIFT - ilog2(sizeof(pte_t)))
> +
> +static void riscv_iommu_iotlb_flush_all(struct iommu_domain *iommu_domain)
> +{
> +       struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> +
> +       riscv_iommu_iotlb_inval(domain, 0, ULONG_MAX);
> +}
> +
> +static void riscv_iommu_iotlb_sync(struct iommu_domain *iommu_domain,
> +                                  struct iommu_iotlb_gather *gather)
> +{
> +       struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> +
> +       riscv_iommu_iotlb_inval(domain, gather->start, gather->end);
> +}
> +
> +static inline size_t get_page_size(size_t size)
> +{
> +       if (size >= IOMMU_PAGE_SIZE_512G)
> +               return IOMMU_PAGE_SIZE_512G;
> +       if (size >= IOMMU_PAGE_SIZE_1G)
> +               return IOMMU_PAGE_SIZE_1G;
> +       if (size >= IOMMU_PAGE_SIZE_2M)
> +               return IOMMU_PAGE_SIZE_2M;
> +       return IOMMU_PAGE_SIZE_4K;
> +}
> +
> +#define _io_pte_present(pte)   ((pte) & (_PAGE_PRESENT | _PAGE_PROT_NONE))
> +#define _io_pte_leaf(pte)      ((pte) & _PAGE_LEAF)
> +#define _io_pte_none(pte)      ((pte) == 0)
> +#define _io_pte_entry(pn, prot)        ((_PAGE_PFN_MASK & ((pn) << _PAGE_PFN_SHIFT)) | (prot))
> +
> +static void riscv_iommu_pte_free(struct riscv_iommu_domain *domain,
> +                                unsigned long pte, struct list_head *freelist)
> +{
> +       unsigned long *ptr;
> +       int i;
> +
> +       if (!_io_pte_present(pte) || _io_pte_leaf(pte))
> +               return;
> +
> +       ptr = (unsigned long *)pfn_to_virt(__page_val_to_pfn(pte));
> +
> +       /* Recursively free all sub page table pages */
> +       for (i = 0; i < PTRS_PER_PTE; i++) {
> +               pte = READ_ONCE(ptr[i]);
> +               if (!_io_pte_none(pte) && cmpxchg_relaxed(ptr + i, pte, 0) == pte)
> +                       riscv_iommu_pte_free(domain, pte, freelist);
> +       }
> +
> +       if (freelist)
> +               list_add_tail(&virt_to_page(ptr)->lru, freelist);
> +       else
> +               iommu_free_page(ptr);
> +}
> +
> +static unsigned long *riscv_iommu_pte_alloc(struct riscv_iommu_domain *domain,
> +                                           unsigned long iova, size_t pgsize,
> +                                           gfp_t gfp)
> +{
> +       unsigned long *ptr = domain->pgd_root;
> +       unsigned long pte, old;
> +       int level = domain->pgd_mode - RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39 + 2;
> +       void *addr;
> +
> +       do {
> +               const int shift = PAGE_SHIFT + PT_SHIFT * level;
> +
> +               ptr += ((iova >> shift) & (PTRS_PER_PTE - 1));
> +               /*
> +                * Note: returned entry might be a non-leaf if there was
> +                * existing mapping with smaller granularity. Up to the caller
> +                * to replace and invalidate.
> +                */
> +               if (((size_t)1 << shift) == pgsize)
> +                       return ptr;
> +pte_retry:
> +               pte = READ_ONCE(*ptr);
> +               /*
> +                * This is very likely incorrect as we should not be adding
> +                * new mapping with smaller granularity on top
> +                * of existing 2M/1G mapping. Fail.
> +                */
> +               if (_io_pte_present(pte) && _io_pte_leaf(pte))
> +                       return NULL;
> +               /*
> +                * Non-leaf entry is missing, allocate and try to add to the
> +                * page table. This might race with other mappings, retry.
> +                */
> +               if (_io_pte_none(pte)) {
> +                       addr = iommu_alloc_page_node(domain->numa_node, gfp);
> +                       if (!addr)
> +                               return NULL;
> +                       old = pte;
> +                       pte = _io_pte_entry(virt_to_pfn(addr), _PAGE_TABLE);
> +                       if (cmpxchg_relaxed(ptr, old, pte) != old) {
> +                               iommu_free_page(addr);
> +                               goto pte_retry;
> +                       }
> +               }
> +               ptr = (unsigned long *)pfn_to_virt(__page_val_to_pfn(pte));
> +       } while (level-- > 0);
> +
> +       return NULL;
> +}
> +
> +static unsigned long *riscv_iommu_pte_fetch(struct riscv_iommu_domain *domain,
> +                                           unsigned long iova, size_t *pte_pgsize)
> +{
> +       unsigned long *ptr = domain->pgd_root;
> +       unsigned long pte;
> +       int level = domain->pgd_mode - RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39 + 2;
> +
> +       do {
> +               const int shift = PAGE_SHIFT + PT_SHIFT * level;
> +
> +               ptr += ((iova >> shift) & (PTRS_PER_PTE - 1));
> +               pte = READ_ONCE(*ptr);
> +               if (_io_pte_present(pte) && _io_pte_leaf(pte)) {
> +                       *pte_pgsize = (size_t)1 << shift;
> +                       return ptr;
> +               }
> +               if (_io_pte_none(pte))
> +                       return NULL;
> +               ptr = (unsigned long *)pfn_to_virt(__page_val_to_pfn(pte));
> +       } while (level-- > 0);
> +
> +       return NULL;
> +}
> +
> +static int riscv_iommu_map_pages(struct iommu_domain *iommu_domain,
> +                                unsigned long iova, phys_addr_t phys,
> +                                size_t pgsize, size_t pgcount, int prot,
> +                                gfp_t gfp, size_t *mapped)
> +{
> +       struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> +       size_t size = 0;
> +       size_t page_size = get_page_size(pgsize);
> +       unsigned long *ptr;
> +       unsigned long pte, old, pte_prot;
> +       int rc = 0;
> +       LIST_HEAD(freelist);
> +
> +       if (!(prot & IOMMU_WRITE))
> +               pte_prot = _PAGE_BASE | _PAGE_READ;
> +       else if (domain->amo_enabled)
> +               pte_prot = _PAGE_BASE | _PAGE_READ | _PAGE_WRITE;
> +       else
> +               pte_prot = _PAGE_BASE | _PAGE_READ | _PAGE_WRITE | _PAGE_DIRTY;
> +
> +       while (pgcount) {
> +               ptr = riscv_iommu_pte_alloc(domain, iova, page_size, gfp);
> +               if (!ptr) {
> +                       rc = -ENOMEM;
> +                       break;
> +               }
> +
> +               old = READ_ONCE(*ptr);
> +               pte = _io_pte_entry(phys_to_pfn(phys), pte_prot);
> +               if (cmpxchg_relaxed(ptr, old, pte) != old)
> +                       continue;
> +
> +               riscv_iommu_pte_free(domain, old, &freelist);
> +
> +               size += page_size;
> +               iova += page_size;
> +               phys += page_size;
> +               --pgcount;
> +       }
> +
> +       *mapped = size;
> +
> +       if (!list_empty(&freelist)) {
> +               /*
> +                * In 1.0 spec version, the smallest scope we can use to
> +                * invalidate all levels of page table (i.e. leaf and non-leaf)
> +                * is an invalidate-all-PSCID IOTINVAL.VMA with AV=0.
> +                * This will be updated with hardware support for
> +                * capability.NL (non-leaf) IOTINVAL command.
> +                */
> +               riscv_iommu_iotlb_inval(domain, 0, ULONG_MAX);
> +               iommu_put_pages_list(&freelist);
> +       }
> +
> +       return rc;
> +}
> +
> +static size_t riscv_iommu_unmap_pages(struct iommu_domain *iommu_domain,
> +                                     unsigned long iova, size_t pgsize,
> +                                     size_t pgcount,
> +                                     struct iommu_iotlb_gather *gather)
> +{
> +       struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> +       size_t size = pgcount << __ffs(pgsize);
> +       unsigned long *ptr, old;
> +       size_t unmapped = 0;
> +       size_t pte_size;
> +
> +       while (unmapped < size) {
> +               ptr = riscv_iommu_pte_fetch(domain, iova, &pte_size);
> +               if (!ptr)
> +                       return unmapped;
> +
> +               /* partial unmap is not allowed, fail. */
> +               if (iova & (pte_size - 1))
> +                       return unmapped;
> +
> +               old = READ_ONCE(*ptr);
> +               if (cmpxchg_relaxed(ptr, old, 0) != old)
> +                       continue;
> +
> +               iommu_iotlb_gather_add_page(&domain->domain, gather, iova,
> +                                           pte_size);
> +
> +               iova += pte_size;
> +               unmapped += pte_size;
> +       }
> +
> +       return unmapped;
> +}
> +
> +static phys_addr_t riscv_iommu_iova_to_phys(struct iommu_domain *iommu_domain,
> +                                           dma_addr_t iova)
> +{
> +       struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> +       unsigned long pte_size;
> +       unsigned long *ptr;
> +
> +       ptr = riscv_iommu_pte_fetch(domain, iova, &pte_size);
> +       if (_io_pte_none(*ptr) || !_io_pte_present(*ptr))
> +               return 0;
> +
> +       return pfn_to_phys(__page_val_to_pfn(*ptr)) | (iova & (pte_size - 1));
> +}
> +
> +static void riscv_iommu_free_paging_domain(struct iommu_domain *iommu_domain)
> +{
> +       struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> +       const unsigned long pfn = virt_to_pfn(domain->pgd_root);
> +
> +       WARN_ON(!list_empty(&domain->bonds));
> +
> +       if ((int)domain->pscid > 0)
> +               ida_free(&riscv_iommu_pscids, domain->pscid);
> +
> +       riscv_iommu_pte_free(domain, _io_pte_entry(pfn, _PAGE_TABLE), NULL);
> +       kfree(domain);
> +}
> +
> +static bool riscv_iommu_pt_supported(struct riscv_iommu_device *iommu, int pgd_mode)
> +{
> +       switch (pgd_mode) {
> +       case RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39:
> +               return iommu->caps & RISCV_IOMMU_CAP_S_SV39;
> +
> +       case RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV48:
> +               return iommu->caps & RISCV_IOMMU_CAP_S_SV48;
> +
> +       case RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV57:
> +               return iommu->caps & RISCV_IOMMU_CAP_S_SV57;
> +       }
> +       return false;
> +}
> +
> +static int riscv_iommu_attach_paging_domain(struct iommu_domain *iommu_domain,
> +                                           struct device *dev)
> +{
> +       struct riscv_iommu_domain *domain = iommu_domain_to_riscv(iommu_domain);
> +       struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> +       struct riscv_iommu_info *info = dev_iommu_priv_get(dev);
> +       u64 fsc, ta;
> +
> +       if (!riscv_iommu_pt_supported(iommu, domain->pgd_mode))
> +               return -ENODEV;
> +
> +       if (domain->numa_node == NUMA_NO_NODE)
> +               domain->numa_node = dev_to_node(iommu->dev);
> +
> +       if (riscv_iommu_bond_link(domain, dev))
> +               return -ENOMEM;
> +
> +       /*
> +        * Invalidate PSCID.
> +        * This invalidation might be redundant if IOATC has been already cleared,
> +        * however we are not keeping track for domains not linked to a device.
> +        */
> +       riscv_iommu_iotlb_inval(domain, 0, ULONG_MAX);
> +
> +       fsc = FIELD_PREP(RISCV_IOMMU_PC_FSC_MODE, domain->pgd_mode) |
> +             FIELD_PREP(RISCV_IOMMU_PC_FSC_PPN, virt_to_pfn(domain->pgd_root));
> +       ta = FIELD_PREP(RISCV_IOMMU_PC_TA_PSCID, domain->pscid) |
> +            RISCV_IOMMU_PC_TA_V;
> +
> +       riscv_iommu_iodir_update(iommu, dev, fsc, ta);
> +       riscv_iommu_bond_unlink(info->domain, dev);

Should we unlink bond before link it?

> +       info->domain = domain;
> +
> +       return 0;
> +}
> +
> +static const struct iommu_domain_ops riscv_iommu_paging_domain_ops = {
> +       .attach_dev = riscv_iommu_attach_paging_domain,
> +       .free = riscv_iommu_free_paging_domain,
> +       .map_pages = riscv_iommu_map_pages,
> +       .unmap_pages = riscv_iommu_unmap_pages,
> +       .iova_to_phys = riscv_iommu_iova_to_phys,
> +       .iotlb_sync = riscv_iommu_iotlb_sync,
> +       .flush_iotlb_all = riscv_iommu_iotlb_flush_all,
> +};
> +
> +static struct iommu_domain *riscv_iommu_alloc_paging_domain(struct device *dev)
> +{
> +       struct riscv_iommu_domain *domain;
> +       struct riscv_iommu_device *iommu;
> +       unsigned int pgd_mode;
> +       int va_bits;
> +
> +       iommu = dev ? dev_to_iommu(dev) : NULL;
> +
> +       /*
> +        * In unlikely case when dev or iommu is not known, use system
> +        * SATP mode to configure paging domain radix tree depth.
> +        * Use highest available if actual IOMMU hardware capabilities
> +        * are known here.
> +        */
> +       if (!iommu) {
> +               pgd_mode = satp_mode >> SATP_MODE_SHIFT;
> +               va_bits = VA_BITS;
> +       } else if (iommu->caps & RISCV_IOMMU_CAP_S_SV57) {
> +               pgd_mode = RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV57;
> +               va_bits = 57;
> +       } else if (iommu->caps & RISCV_IOMMU_CAP_S_SV48) {
> +               pgd_mode = RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV48;
> +               va_bits = 48;
> +       } else if (iommu->caps & RISCV_IOMMU_CAP_S_SV39) {
> +               pgd_mode =  RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39;
> +               va_bits = 39;
> +       } else {
> +               dev_err(dev, "cannot find supported page table mode\n");
> +               return ERR_PTR(-ENODEV);
> +       }
> +
> +       domain = kzalloc(sizeof(*domain), GFP_KERNEL);
> +       if (!domain)
> +               return ERR_PTR(-ENOMEM);
> +
> +       INIT_LIST_HEAD_RCU(&domain->bonds);
> +       spin_lock_init(&domain->lock);
> +       domain->numa_node = NUMA_NO_NODE;
> +
> +       if (iommu) {
> +               domain->numa_node = dev_to_node(iommu->dev);
> +               domain->amo_enabled = !!(iommu->caps & RISCV_IOMMU_CAP_AMO_HWAD);
> +       }
> +
> +       domain->pgd_mode = pgd_mode;
> +       domain->pgd_root = iommu_alloc_page_node(domain->numa_node,
> +                                                GFP_KERNEL_ACCOUNT);
> +       if (!domain->pgd_root) {
> +               kfree(domain);
> +               return ERR_PTR(-ENOMEM);
> +       }
> +
> +       domain->pscid = ida_alloc_range(&riscv_iommu_pscids, 1,
> +                                       RISCV_IOMMU_MAX_PSCID, GFP_KERNEL);
> +       if (domain->pscid < 0) {
> +               iommu_free_page(domain->pgd_root);
> +               kfree(domain);
> +               return ERR_PTR(-ENOMEM);
> +       }
> +
> +       /*
> +        * Note: RISC-V Privilege spec mandates that virtual addresses
> +        * need to be sign-extended, so if (VA_BITS - 1) is set, all
> +        * bits >= VA_BITS need to also be set or else we'll get a
> +        * page fault. However the code that creates the mappings
> +        * above us (e.g. iommu_dma_alloc_iova()) won't do that for us
> +        * for now, so we'll end up with invalid virtual addresses
> +        * to map. As a workaround until we get this sorted out
> +        * limit the available virtual addresses to VA_BITS - 1.
> +        */
> +       domain->domain.geometry.aperture_start = 0;
> +       domain->domain.geometry.aperture_end = DMA_BIT_MASK(va_bits - 1);
> +       domain->domain.geometry.force_aperture = true;
> +
> +       domain->domain.ops = &riscv_iommu_paging_domain_ops;
> +
> +       return &domain->domain;
> +}
> +
>  static int riscv_iommu_attach_blocking_domain(struct iommu_domain *iommu_domain,
>                                               struct device *dev)
>  {
>         struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> +       struct riscv_iommu_info *info = dev_iommu_priv_get(dev);
>
>         riscv_iommu_iodir_update(iommu, dev, RISCV_IOMMU_FSC_BARE, 0);
> +       riscv_iommu_bond_unlink(info->domain, dev);
> +       info->domain = NULL;
>
>         return 0;
>  }
> @@ -827,8 +1390,11 @@ static int riscv_iommu_attach_identity_domain(struct iommu_domain *iommu_domain,
>                                               struct device *dev)
>  {
>         struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> +       struct riscv_iommu_info *info = dev_iommu_priv_get(dev);
>
>         riscv_iommu_iodir_update(iommu, dev, RISCV_IOMMU_FSC_BARE, RISCV_IOMMU_PC_TA_V);
> +       riscv_iommu_bond_unlink(info->domain, dev);
> +       info->domain = NULL;
>
>         return 0;
>  }
> @@ -842,7 +1408,7 @@ static struct iommu_domain riscv_iommu_identity_domain = {
>
>  static int riscv_iommu_device_domain_type(struct device *dev)
>  {
> -       return IOMMU_DOMAIN_IDENTITY;
> +       return 0;
>  }
>
>  static struct iommu_group *riscv_iommu_device_group(struct device *dev)
> @@ -861,6 +1427,7 @@ static struct iommu_device *riscv_iommu_probe_device(struct device *dev)
>  {
>         struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>         struct riscv_iommu_device *iommu;
> +       struct riscv_iommu_info *info;
>         struct riscv_iommu_dc *dc;
>         u64 tc;
>         int i;
> @@ -895,17 +1462,33 @@ static struct iommu_device *riscv_iommu_probe_device(struct device *dev)
>                 WRITE_ONCE(dc->tc, tc);
>         }
>
> +       info = kzalloc(sizeof(*info), GFP_KERNEL);
> +       if (!info)
> +               return ERR_PTR(-ENOMEM);
> +       dev_iommu_priv_set(dev, info);
> +
>         return &iommu->iommu;
>  }
>
> +static void riscv_iommu_release_device(struct device *dev)
> +{
> +       struct riscv_iommu_info *info = dev_iommu_priv_get(dev);
> +
> +       synchronize_rcu();
> +       kfree(info);
> +}
> +
>  static const struct iommu_ops riscv_iommu_ops = {
> +       .pgsize_bitmap = SZ_4K,
>         .of_xlate = riscv_iommu_of_xlate,
>         .identity_domain = &riscv_iommu_identity_domain,
>         .blocked_domain = &riscv_iommu_blocking_domain,
>         .release_domain = &riscv_iommu_blocking_domain,
> +       .domain_alloc_paging = riscv_iommu_alloc_paging_domain,
>         .def_domain_type = riscv_iommu_device_domain_type,
>         .device_group = riscv_iommu_device_group,
>         .probe_device = riscv_iommu_probe_device,
> +       .release_device = riscv_iommu_release_device,
>  };
>
>  static int riscv_iommu_init_check(struct riscv_iommu_device *iommu)
> --
> 2.34.1
>
>
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