Add support for assigning Address Space Identifiers (ASIDs) to each VQ
group.  This enables mapping each group into a distinct memory space.

Now that the driver can change ASID in the middle of operation, the
domain that each vq address point is also protected by domain_lock.

Signed-off-by: Eugenio Pérez <epere...@redhat.com>
---
v5:
* Properly return errno if copy_to_user returns >0 in VDUSE_IOTLB_GET_FD
  ioctl (Jason).
* Properly set domain bounce size to divide equally between nas (Jason).
* Exclude "padding" member from the only >V1 members in
  vduse_dev_request.

v4:
* Divide each domain bounce size between the device bounce size (Jason).
* revert unneeded addr = NULL assignment (Jason)
* Change if (x && (y || z)) return to if (x) { if (y) return; if (z)
  return; } (Jason)
* Change a bad multiline comment, using @ caracter instead of * (Jason).
* Consider config->nas == 0 as a fail (Jason).

v3:
* Get the vduse domain through the vduse_as in the map functions
  (Jason).
* Squash with the patch creating the vduse_as struct (Jason).
* Create VDUSE_DEV_MAX_AS instead of comparing agains a magic number
  (Jason)

v2:
* Convert the use of mutex to rwlock.

RFC v3:
* Increase VDUSE_MAX_VQ_GROUPS to 0xffff (Jason). It was set to a lower
  value to reduce memory consumption, but vqs are already limited to
  that value and userspace VDUSE is able to allocate that many vqs.
* Remove TODO about merging VDUSE_IOTLB_GET_FD ioctl with
  VDUSE_IOTLB_GET_INFO.
* Use of array_index_nospec in VDUSE device ioctls.
* Embed vduse_iotlb_entry into vduse_iotlb_entry_v2.
* Move the umem mutex to asid struct so there is no contention between
  ASIDs.

RFC v2:
* Make iotlb entry the last one of vduse_iotlb_entry_v2 so the first
  part of the struct is the same.
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 335 ++++++++++++++++++++---------
 include/uapi/linux/vduse.h         |  53 ++++-
 2 files changed, 288 insertions(+), 100 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c 
b/drivers/vdpa/vdpa_user/vduse_dev.c
index 3ce70e6524d5..731de08bb692 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -42,6 +42,7 @@
 
 #define VDUSE_DEV_MAX (1U << MINORBITS)
 #define VDUSE_DEV_MAX_GROUPS 0xffff
+#define VDUSE_DEV_MAX_AS 0xffff
 #define VDUSE_MAX_BOUNCE_SIZE (1024 * 1024 * 1024)
 #define VDUSE_MIN_BOUNCE_SIZE (1024 * 1024)
 #define VDUSE_BOUNCE_SIZE (64 * 1024 * 1024)
@@ -87,7 +88,14 @@ struct vduse_umem {
        struct mm_struct *mm;
 };
 
+struct vduse_as {
+       struct vduse_iova_domain *domain;
+       struct vduse_umem *umem;
+       struct mutex mem_lock;
+};
+
 struct vduse_vq_group {
+       struct vduse_as *as;
        struct vduse_dev *dev;
 };
 
@@ -95,7 +103,7 @@ struct vduse_dev {
        struct vduse_vdpa *vdev;
        struct device *dev;
        struct vduse_virtqueue **vqs;
-       struct vduse_iova_domain *domain;
+       struct vduse_as *as;
        char *name;
        struct mutex lock;
        spinlock_t msg_lock;
@@ -123,9 +131,8 @@ struct vduse_dev {
        u32 vq_num;
        u32 vq_align;
        u32 ngroups;
-       struct vduse_umem *umem;
+       u32 nas;
        struct vduse_vq_group *groups;
-       struct mutex mem_lock;
        unsigned int bounce_size;
        rwlock_t domain_lock;
 };
@@ -315,7 +322,7 @@ static int vduse_dev_set_status(struct vduse_dev *dev, u8 
status)
        return vduse_dev_msg_sync(dev, &msg);
 }
 
-static int vduse_dev_update_iotlb(struct vduse_dev *dev,
+static int vduse_dev_update_iotlb(struct vduse_dev *dev, u32 asid,
                                  u64 start, u64 last)
 {
        struct vduse_dev_msg msg = { 0 };
@@ -324,8 +331,14 @@ static int vduse_dev_update_iotlb(struct vduse_dev *dev,
                return -EINVAL;
 
        msg.req.type = VDUSE_UPDATE_IOTLB;
-       msg.req.iova.start = start;
-       msg.req.iova.last = last;
+       if (dev->api_version < VDUSE_API_VERSION_1) {
+               msg.req.iova.start = start;
+               msg.req.iova.last = last;
+       } else {
+               msg.req.iova_v2.start = start;
+               msg.req.iova_v2.last = last;
+               msg.req.iova_v2.asid = asid;
+       }
 
        return vduse_dev_msg_sync(dev, &msg);
 }
@@ -437,14 +450,29 @@ static __poll_t vduse_dev_poll(struct file *file, 
poll_table *wait)
        return mask;
 }
 
+/* Force set the asid to a vq group without a message to the VDUSE device */
+static void vduse_set_group_asid_nomsg(struct vduse_dev *dev,
+                                      unsigned int group, unsigned int asid)
+{
+       write_lock(&dev->domain_lock);
+       dev->groups[group].as = &dev->as[asid];
+       write_unlock(&dev->domain_lock);
+}
+
 static void vduse_dev_reset(struct vduse_dev *dev)
 {
        int i;
-       struct vduse_iova_domain *domain = dev->domain;
 
        /* The coherent mappings are handled in vduse_dev_free_coherent() */
-       if (domain && domain->bounce_map)
-               vduse_domain_reset_bounce_map(domain);
+       for (i = 0; i < dev->nas; i++) {
+               struct vduse_iova_domain *domain = dev->as[i].domain;
+
+               if (domain && domain->bounce_map)
+                       vduse_domain_reset_bounce_map(domain);
+       }
+
+       for (i = 0; i < dev->ngroups; i++)
+               vduse_set_group_asid_nomsg(dev, i, 0);
 
        down_write(&dev->rwsem);
 
@@ -624,6 +652,29 @@ static union virtio_map vduse_get_vq_map(struct 
vdpa_device *vdpa, u16 idx)
        return ret;
 }
 
+static int vduse_set_group_asid(struct vdpa_device *vdpa, unsigned int group,
+                               unsigned int asid)
+{
+       struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+       struct vduse_dev_msg msg = { 0 };
+       int r;
+
+       if (dev->api_version < VDUSE_API_VERSION_1 ||
+           group >= dev->ngroups || asid >= dev->nas)
+               return -EINVAL;
+
+       msg.req.type = VDUSE_SET_VQ_GROUP_ASID;
+       msg.req.vq_group_asid.group = group;
+       msg.req.vq_group_asid.asid = asid;
+
+       r = vduse_dev_msg_sync(dev, &msg);
+       if (r < 0)
+               return r;
+
+       vduse_set_group_asid_nomsg(dev, group, asid);
+       return 0;
+}
+
 static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
                                struct vdpa_vq_state *state)
 {
@@ -795,13 +846,13 @@ static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
        struct vduse_dev *dev = vdpa_to_vduse(vdpa);
        int ret;
 
-       ret = vduse_domain_set_map(dev->domain, iotlb);
+       ret = vduse_domain_set_map(dev->as[asid].domain, iotlb);
        if (ret)
                return ret;
 
-       ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
+       ret = vduse_dev_update_iotlb(dev, asid, 0ULL, ULLONG_MAX);
        if (ret) {
-               vduse_domain_clear_map(dev->domain, iotlb);
+               vduse_domain_clear_map(dev->as[asid].domain, iotlb);
                return ret;
        }
 
@@ -844,6 +895,7 @@ static const struct vdpa_config_ops vduse_vdpa_config_ops = 
{
        .get_vq_affinity        = vduse_vdpa_get_vq_affinity,
        .reset                  = vduse_vdpa_reset,
        .set_map                = vduse_vdpa_set_map,
+       .set_group_asid         = vduse_set_group_asid,
        .get_vq_map             = vduse_get_vq_map,
        .free                   = vduse_vdpa_free,
 };
@@ -859,9 +911,10 @@ static void vduse_dev_sync_single_for_device(union 
virtio_map token,
                return;
 
        vdev = token.group->dev;
-       domain = vdev->domain;
-
+       read_lock(&vdev->domain_lock);
+       domain = token.group->as->domain;
        vduse_domain_sync_single_for_device(domain, dma_addr, size, dir);
+       read_unlock(&vdev->domain_lock);
 }
 
 static void vduse_dev_sync_single_for_cpu(union virtio_map token,
@@ -875,9 +928,10 @@ static void vduse_dev_sync_single_for_cpu(union virtio_map 
token,
                return;
 
        vdev = token.group->dev;
-       domain = vdev->domain;
-
+       read_lock(&vdev->domain_lock);
+       domain = token.group->as->domain;
        vduse_domain_sync_single_for_cpu(domain, dma_addr, size, dir);
+       read_unlock(&vdev->domain_lock);
 }
 
 static dma_addr_t vduse_dev_map_page(union virtio_map token, struct page *page,
@@ -887,14 +941,18 @@ static dma_addr_t vduse_dev_map_page(union virtio_map 
token, struct page *page,
 {
        struct vduse_dev *vdev;
        struct vduse_iova_domain *domain;
+       dma_addr_t r;
 
        if (!token.group)
                return DMA_MAPPING_ERROR;
 
        vdev = token.group->dev;
-       domain = vdev->domain;
+       read_lock(&vdev->domain_lock);
+       domain = token.group->as->domain;
+       r = vduse_domain_map_page(domain, page, offset, size, dir, attrs);
+       read_unlock(&vdev->domain_lock);
 
-       return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
+       return r;
 }
 
 static void vduse_dev_unmap_page(union virtio_map token, dma_addr_t dma_addr,
@@ -908,9 +966,10 @@ static void vduse_dev_unmap_page(union virtio_map token, 
dma_addr_t dma_addr,
                return;
 
        vdev = token.group->dev;
-       domain = vdev->domain;
-
-       return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
+       read_lock(&vdev->domain_lock);
+       domain = token.group->as->domain;
+       vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
+       read_unlock(&vdev->domain_lock);
 }
 
 static void *vduse_dev_alloc_coherent(union virtio_map token, size_t size,
@@ -926,14 +985,14 @@ static void *vduse_dev_alloc_coherent(union virtio_map 
token, size_t size,
                return NULL;
 
        vdev = token.group->dev;
-       domain = vdev->domain;
+       read_lock(&vdev->domain_lock);
+       domain = token.group->as->domain;
        addr = vduse_domain_alloc_coherent(domain, size,
                                           (dma_addr_t *)&iova, flag);
-       if (!addr)
-               return NULL;
-
-       *dma_addr = (dma_addr_t)iova;
+       if (addr)
+               *dma_addr = (dma_addr_t)iova;
 
+       read_unlock(&vdev->domain_lock);
        return addr;
 }
 
@@ -948,23 +1007,28 @@ static void vduse_dev_free_coherent(union virtio_map 
token, size_t size,
                return;
 
        vdev = token.group->dev;
-       domain = vdev->domain;
-
+       read_lock(&vdev->domain_lock);
+       domain = token.group->as->domain;
        vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
+       read_unlock(&vdev->domain_lock);
 }
 
 static bool vduse_dev_need_sync(union virtio_map token, dma_addr_t dma_addr)
 {
        struct vduse_dev *vdev;
        struct vduse_iova_domain *domain;
+       size_t bounce_size;
 
        if (!token.group)
                return false;
 
        vdev = token.group->dev;
-       domain = vdev->domain;
+       read_lock(&vdev->domain_lock);
+       domain = token.group->as->domain;
+       bounce_size = domain->bounce_size;
+       read_unlock(&vdev->domain_lock);
 
-       return dma_addr < domain->bounce_size;
+       return dma_addr < bounce_size;
 }
 
 static int vduse_dev_mapping_error(union virtio_map token, dma_addr_t dma_addr)
@@ -978,14 +1042,18 @@ static size_t vduse_dev_max_mapping_size(union 
virtio_map token)
 {
        struct vduse_dev *vdev;
        struct vduse_iova_domain *domain;
+       size_t bounce_size;
 
        if (!token.group)
                return 0;
 
        vdev = token.group->dev;
-       domain = vdev->domain;
+       read_lock(&vdev->domain_lock);
+       domain = token.group->as->domain;
+       bounce_size = domain->bounce_size;
+       read_unlock(&vdev->domain_lock);
 
-       return domain->bounce_size;
+       return bounce_size;
 }
 
 static const struct virtio_map_ops vduse_map_ops = {
@@ -1125,39 +1193,40 @@ static int vduse_dev_queue_irq_work(struct vduse_dev 
*dev,
        return ret;
 }
 
-static int vduse_dev_dereg_umem(struct vduse_dev *dev,
+static int vduse_dev_dereg_umem(struct vduse_dev *dev, u32 asid,
                                u64 iova, u64 size)
 {
        int ret;
 
-       mutex_lock(&dev->mem_lock);
+       mutex_lock(&dev->as[asid].mem_lock);
        ret = -ENOENT;
-       if (!dev->umem)
+       if (!dev->as[asid].umem)
                goto unlock;
 
        ret = -EINVAL;
-       if (!dev->domain)
+       if (!dev->as[asid].domain)
                goto unlock;
 
-       if (dev->umem->iova != iova || size != dev->domain->bounce_size)
+       if (dev->as[asid].umem->iova != iova ||
+           size != dev->as[asid].domain->bounce_size)
                goto unlock;
 
-       vduse_domain_remove_user_bounce_pages(dev->domain);
-       unpin_user_pages_dirty_lock(dev->umem->pages,
-                                   dev->umem->npages, true);
-       atomic64_sub(dev->umem->npages, &dev->umem->mm->pinned_vm);
-       mmdrop(dev->umem->mm);
-       vfree(dev->umem->pages);
-       kfree(dev->umem);
-       dev->umem = NULL;
+       vduse_domain_remove_user_bounce_pages(dev->as[asid].domain);
+       unpin_user_pages_dirty_lock(dev->as[asid].umem->pages,
+                                   dev->as[asid].umem->npages, true);
+       atomic64_sub(dev->as[asid].umem->npages, 
&dev->as[asid].umem->mm->pinned_vm);
+       mmdrop(dev->as[asid].umem->mm);
+       vfree(dev->as[asid].umem->pages);
+       kfree(dev->as[asid].umem);
+       dev->as[asid].umem = NULL;
        ret = 0;
 unlock:
-       mutex_unlock(&dev->mem_lock);
+       mutex_unlock(&dev->as[asid].mem_lock);
        return ret;
 }
 
 static int vduse_dev_reg_umem(struct vduse_dev *dev,
-                             u64 iova, u64 uaddr, u64 size)
+                             u32 asid, u64 iova, u64 uaddr, u64 size)
 {
        struct page **page_list = NULL;
        struct vduse_umem *umem = NULL;
@@ -1165,14 +1234,14 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
        unsigned long npages, lock_limit;
        int ret;
 
-       if (!dev->domain || !dev->domain->bounce_map ||
-           size != dev->domain->bounce_size ||
+       if (!dev->as[asid].domain || !dev->as[asid].domain->bounce_map ||
+           size != dev->as[asid].domain->bounce_size ||
            iova != 0 || uaddr & ~PAGE_MASK)
                return -EINVAL;
 
-       mutex_lock(&dev->mem_lock);
+       mutex_lock(&dev->as[asid].mem_lock);
        ret = -EEXIST;
-       if (dev->umem)
+       if (dev->as[asid].umem)
                goto unlock;
 
        ret = -ENOMEM;
@@ -1196,7 +1265,7 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
                goto out;
        }
 
-       ret = vduse_domain_add_user_bounce_pages(dev->domain,
+       ret = vduse_domain_add_user_bounce_pages(dev->as[asid].domain,
                                                 page_list, pinned);
        if (ret)
                goto out;
@@ -1209,7 +1278,7 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
        umem->mm = current->mm;
        mmgrab(current->mm);
 
-       dev->umem = umem;
+       dev->as[asid].umem = umem;
 out:
        if (ret && pinned > 0)
                unpin_user_pages(page_list, pinned);
@@ -1220,7 +1289,7 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
                vfree(page_list);
                kfree(umem);
        }
-       mutex_unlock(&dev->mem_lock);
+       mutex_unlock(&dev->as[asid].mem_lock);
        return ret;
 }
 
@@ -1252,47 +1321,66 @@ static long vduse_dev_ioctl(struct file *file, unsigned 
int cmd,
 
        switch (cmd) {
        case VDUSE_IOTLB_GET_FD: {
-               struct vduse_iotlb_entry entry;
+               struct vduse_iotlb_entry_v2 entry;
                struct vhost_iotlb_map *map;
                struct vdpa_map_file *map_file;
                struct file *f = NULL;
+               u32 asid;
 
                ret = -EFAULT;
-               if (copy_from_user(&entry, argp, sizeof(entry)))
-                       break;
+               if (dev->api_version >= VDUSE_API_VERSION_1) {
+                       if (copy_from_user(&entry, argp, sizeof(entry)))
+                               break;
+               } else {
+                       entry.asid = 0;
+                       if (copy_from_user(&entry.v1, argp,
+                                          sizeof(entry.v1)))
+                               break;
+               }
 
                ret = -EINVAL;
-               if (entry.start > entry.last)
+               if (entry.v1.start > entry.v1.last)
+                       break;
+
+               if (entry.asid >= dev->nas)
                        break;
 
                read_lock(&dev->domain_lock);
-               if (!dev->domain) {
+               asid = array_index_nospec(entry.asid, dev->nas);
+               if (!dev->as[asid].domain) {
                        read_unlock(&dev->domain_lock);
                        break;
                }
-               spin_lock(&dev->domain->iotlb_lock);
-               map = vhost_iotlb_itree_first(dev->domain->iotlb,
-                                             entry.start, entry.last);
+               spin_lock(&dev->as[asid].domain->iotlb_lock);
+               map = vhost_iotlb_itree_first(dev->as[asid].domain->iotlb,
+                                             entry.v1.start, entry.v1.last);
                if (map) {
                        map_file = (struct vdpa_map_file *)map->opaque;
                        f = get_file(map_file->file);
-                       entry.offset = map_file->offset;
-                       entry.start = map->start;
-                       entry.last = map->last;
-                       entry.perm = map->perm;
+                       entry.v1.offset = map_file->offset;
+                       entry.v1.start = map->start;
+                       entry.v1.last = map->last;
+                       entry.v1.perm = map->perm;
                }
-               spin_unlock(&dev->domain->iotlb_lock);
+               spin_unlock(&dev->as[asid].domain->iotlb_lock);
                read_unlock(&dev->domain_lock);
                ret = -EINVAL;
                if (!f)
                        break;
 
-               ret = -EFAULT;
-               if (copy_to_user(argp, &entry, sizeof(entry))) {
+               if (dev->api_version >= VDUSE_API_VERSION_1)
+                       ret = copy_to_user(argp, &entry,
+                                          sizeof(entry));
+               else
+                       ret = copy_to_user(argp, &entry.v1,
+                                          sizeof(entry.v1));
+
+               if (ret) {
+                       ret = -EFAULT;
                        fput(f);
                        break;
                }
-               ret = receive_fd(f, NULL, perm_to_file_flags(entry.perm));
+               ret = receive_fd(f, NULL, perm_to_file_flags(entry.v1.perm));
                fput(f);
                break;
        }
@@ -1437,6 +1525,7 @@ static long vduse_dev_ioctl(struct file *file, unsigned 
int cmd,
        }
        case VDUSE_IOTLB_REG_UMEM: {
                struct vduse_iova_umem umem;
+               u32 asid;
 
                ret = -EFAULT;
                if (copy_from_user(&umem, argp, sizeof(umem)))
@@ -1444,17 +1533,21 @@ static long vduse_dev_ioctl(struct file *file, unsigned 
int cmd,
 
                ret = -EINVAL;
                if (!is_mem_zero((const char *)umem.reserved,
-                                sizeof(umem.reserved)))
+                                sizeof(umem.reserved)) ||
+                   (dev->api_version < VDUSE_API_VERSION_1 &&
+                    umem.asid != 0) || umem.asid >= dev->nas)
                        break;
 
                write_lock(&dev->domain_lock);
-               ret = vduse_dev_reg_umem(dev, umem.iova,
+               asid = array_index_nospec(umem.asid, dev->nas);
+               ret = vduse_dev_reg_umem(dev, asid, umem.iova,
                                         umem.uaddr, umem.size);
                write_unlock(&dev->domain_lock);
                break;
        }
        case VDUSE_IOTLB_DEREG_UMEM: {
                struct vduse_iova_umem umem;
+               u32 asid;
 
                ret = -EFAULT;
                if (copy_from_user(&umem, argp, sizeof(umem)))
@@ -1462,10 +1555,15 @@ static long vduse_dev_ioctl(struct file *file, unsigned 
int cmd,
 
                ret = -EINVAL;
                if (!is_mem_zero((const char *)umem.reserved,
-                                sizeof(umem.reserved)))
+                                sizeof(umem.reserved)) ||
+                   (dev->api_version < VDUSE_API_VERSION_1 &&
+                    umem.asid != 0) ||
+                    umem.asid >= dev->nas)
                        break;
+
                write_lock(&dev->domain_lock);
-               ret = vduse_dev_dereg_umem(dev, umem.iova,
+               asid = array_index_nospec(umem.asid, dev->nas);
+               ret = vduse_dev_dereg_umem(dev, asid, umem.iova,
                                           umem.size);
                write_unlock(&dev->domain_lock);
                break;
@@ -1473,6 +1571,7 @@ static long vduse_dev_ioctl(struct file *file, unsigned 
int cmd,
        case VDUSE_IOTLB_GET_INFO: {
                struct vduse_iova_info info;
                struct vhost_iotlb_map *map;
+               u32 asid;
 
                ret = -EFAULT;
                if (copy_from_user(&info, argp, sizeof(info)))
@@ -1486,23 +1585,31 @@ static long vduse_dev_ioctl(struct file *file, unsigned 
int cmd,
                                 sizeof(info.reserved)))
                        break;
 
+               if (dev->api_version < VDUSE_API_VERSION_1) {
+                       if (info.asid)
+                               break;
+               } else if (info.asid >= dev->nas)
+                       break;
+
                read_lock(&dev->domain_lock);
-               if (!dev->domain) {
+               asid = array_index_nospec(info.asid, dev->nas);
+               if (!dev->as[asid].domain) {
                        read_unlock(&dev->domain_lock);
                        break;
                }
-               spin_lock(&dev->domain->iotlb_lock);
-               map = vhost_iotlb_itree_first(dev->domain->iotlb,
+               spin_lock(&dev->as[asid].domain->iotlb_lock);
+               map = vhost_iotlb_itree_first(dev->as[asid].domain->iotlb,
                                              info.start, info.last);
                if (map) {
                        info.start = map->start;
                        info.last = map->last;
                        info.capability = 0;
-                       if (dev->domain->bounce_map && map->start == 0 &&
-                           map->last == dev->domain->bounce_size - 1)
+                       if (dev->as[asid].domain->bounce_map &&
+                           map->start == 0 &&
+                           map->last == dev->as[asid].domain->bounce_size - 1)
                                info.capability |= VDUSE_IOVA_CAP_UMEM;
                }
-               spin_unlock(&dev->domain->iotlb_lock);
+               spin_unlock(&dev->as[asid].domain->iotlb_lock);
                read_unlock(&dev->domain_lock);
                if (!map)
                        break;
@@ -1527,8 +1634,10 @@ static int vduse_dev_release(struct inode *inode, struct 
file *file)
        struct vduse_dev *dev = file->private_data;
 
        write_lock(&dev->domain_lock);
-       if (dev->domain)
-               vduse_dev_dereg_umem(dev, 0, dev->domain->bounce_size);
+       for (int i = 0; i < dev->nas; i++)
+               if (dev->as[i].domain)
+                       vduse_dev_dereg_umem(dev, i, 0,
+                                            dev->as[i].domain->bounce_size);
        write_unlock(&dev->domain_lock);
        spin_lock(&dev->msg_lock);
        /* Make sure the inflight messages can processed after reconncection */
@@ -1747,7 +1856,6 @@ static struct vduse_dev *vduse_dev_create(void)
                return NULL;
 
        mutex_init(&dev->lock);
-       mutex_init(&dev->mem_lock);
        rwlock_init(&dev->domain_lock);
        spin_lock_init(&dev->msg_lock);
        INIT_LIST_HEAD(&dev->send_list);
@@ -1798,8 +1906,11 @@ static int vduse_destroy_dev(char *name)
        idr_remove(&vduse_idr, dev->minor);
        kvfree(dev->config);
        vduse_dev_deinit_vqs(dev);
-       if (dev->domain)
-               vduse_domain_destroy(dev->domain);
+       for (int i = 0; i < dev->nas; i++) {
+               if (dev->as[i].domain)
+                       vduse_domain_destroy(dev->as[i].domain);
+       }
+       kfree(dev->as);
        kfree(dev->name);
        kfree(dev->groups);
        vduse_dev_destroy(dev);
@@ -1846,12 +1957,17 @@ static bool vduse_validate_config(struct 
vduse_dev_config *config,
                         sizeof(config->reserved)))
                return false;
 
-       if (api_version < VDUSE_API_VERSION_1 && config->ngroups)
+       if (api_version < VDUSE_API_VERSION_1 &&
+           (config->ngroups || config->nas))
                return false;
 
-       if (api_version >= VDUSE_API_VERSION_1 &&
-           (!config->ngroups || config->ngroups > VDUSE_DEV_MAX_GROUPS))
-               return false;
+       if (api_version >= VDUSE_API_VERSION_1) {
+               if (!config->ngroups || config->ngroups > VDUSE_DEV_MAX_GROUPS)
+                       return false;
+
+               if (!config->nas || config->nas > VDUSE_DEV_MAX_AS)
+                       return false;
+       }
 
        if (config->vq_align > PAGE_SIZE)
                return false;
@@ -1916,7 +2032,8 @@ static ssize_t bounce_size_store(struct device *device,
 
        ret = -EPERM;
        write_lock(&dev->domain_lock);
-       if (dev->domain)
+       /* Assuming that if the first domain is allocated, all are allocated */
+       if (dev->as[0].domain)
                goto unlock;
 
        ret = kstrtouint(buf, 10, &bounce_size);
@@ -1976,6 +2093,13 @@ static int vduse_create_dev(struct vduse_dev_config 
*config,
        for (u32 i = 0; i < dev->ngroups; ++i)
                dev->groups[i].dev = dev;
 
+       dev->nas = (dev->api_version < 1) ? 1 : config->nas;
+       dev->as = kcalloc(dev->nas, sizeof(dev->as[0]), GFP_KERNEL);
+       if (!dev->as)
+               goto err_as;
+       for (int i = 0; i < dev->nas; i++)
+               mutex_init(&dev->as[i].mem_lock);
+
        dev->name = kstrdup(config->name, GFP_KERNEL);
        if (!dev->name)
                goto err_str;
@@ -2012,6 +2136,8 @@ static int vduse_create_dev(struct vduse_dev_config 
*config,
 err_idr:
        kfree(dev->name);
 err_str:
+       kfree(dev->as);
+err_as:
        kfree(dev->groups);
 err_vq_groups:
        vduse_dev_destroy(dev);
@@ -2137,7 +2263,7 @@ static int vduse_dev_init_vdpa(struct vduse_dev *dev, 
const char *name)
 
        vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, dev->dev,
                                 &vduse_vdpa_config_ops, &vduse_map_ops,
-                                dev->ngroups, 1, name, true);
+                                dev->ngroups, dev->nas, name, true);
        if (IS_ERR(vdev))
                return PTR_ERR(vdev);
 
@@ -2152,6 +2278,7 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const 
char *name,
                        const struct vdpa_dev_set_config *config)
 {
        struct vduse_dev *dev;
+       size_t domain_bounce_size;
        int ret;
 
        mutex_lock(&vduse_lock);
@@ -2166,11 +2293,21 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, 
const char *name,
                return ret;
 
        write_lock(&dev->domain_lock);
-       if (!dev->domain)
-               dev->domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
-                                                 dev->bounce_size);
+       ret = 0;
+
+       domain_bounce_size = dev->bounce_size / dev->nas;
+       for (int i = 0; i < dev->nas; ++i) {
+               dev->as[i].domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
+                                                       domain_bounce_size);
+               if (!dev->as[i].domain) {
+                       ret = -ENOMEM;
+                       for (int j = 0; j < i; ++j)
+                               vduse_domain_destroy(dev->as[j].domain);
+               }
+       }
+
        write_unlock(&dev->domain_lock);
-       if (!dev->domain) {
+       if (ret == -ENOMEM) {
                put_device(&dev->vdev->vdpa.dev);
                return -ENOMEM;
        }
@@ -2179,8 +2316,12 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, 
const char *name,
        if (ret) {
                put_device(&dev->vdev->vdpa.dev);
                write_lock(&dev->domain_lock);
-               vduse_domain_destroy(dev->domain);
-               dev->domain = NULL;
+               for (int i = 0; i < dev->nas; i++) {
+                       if (dev->as[i].domain) {
+                               vduse_domain_destroy(dev->as[i].domain);
+                               dev->as[i].domain = NULL;
+                       }
+               }
                write_unlock(&dev->domain_lock);
                return ret;
        }
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index a3d51cf6df3a..3d71a3d6593c 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -47,7 +47,8 @@ struct vduse_dev_config {
        __u32 vq_num;
        __u32 vq_align;
        __u32 ngroups; /* if VDUSE_API_VERSION >= 1 */
-       __u32 reserved[12];
+       __u32 nas; /* if VDUSE_API_VERSION >= 1 */
+       __u32 reserved[11];
        __u32 config_size;
        __u8 config[];
 };
@@ -82,6 +83,18 @@ struct vduse_iotlb_entry {
        __u8 perm;
 };
 
+/**
+ * struct vduse_iotlb_entry_v2 - entry of IOTLB to describe one IOVA region in 
an ASID
+ * @v1: the original vduse_iotlb_entry
+ * @asid: address space ID of the IOVA region
+ *
+ * Structure used by VDUSE_IOTLB_GET_FD ioctl to find an overlapped IOVA 
region.
+ */
+struct vduse_iotlb_entry_v2 {
+       struct vduse_iotlb_entry v1;
+       __u32 asid;
+};
+
 /*
  * Find the first IOVA region that overlaps with the range [start, last]
  * and return the corresponding file descriptor. Return -EINVAL means the
@@ -166,6 +179,16 @@ struct vduse_vq_state_packed {
        __u16 last_used_idx;
 };
 
+/**
+ * struct vduse_vq_group - virtqueue group
+ * @group: Index of the virtqueue group
+ * @asid: Address space ID of the group
+ */
+struct vduse_vq_group_asid {
+       __u32 group;
+       __u32 asid;
+};
+
 /**
  * struct vduse_vq_info - information of a virtqueue
  * @index: virtqueue index
@@ -225,6 +248,7 @@ struct vduse_vq_eventfd {
  * @uaddr: start address of userspace memory, it must be aligned to page size
  * @iova: start of the IOVA region
  * @size: size of the IOVA region
+ * @asid: Address space ID of the IOVA region
  * @reserved: for future use, needs to be initialized to zero
  *
  * Structure used by VDUSE_IOTLB_REG_UMEM and VDUSE_IOTLB_DEREG_UMEM
@@ -234,7 +258,8 @@ struct vduse_iova_umem {
        __u64 uaddr;
        __u64 iova;
        __u64 size;
-       __u64 reserved[3];
+       __u32 asid;
+       __u32 reserved[5];
 };
 
 /* Register userspace memory for IOVA regions */
@@ -248,6 +273,7 @@ struct vduse_iova_umem {
  * @start: start of the IOVA region
  * @last: last of the IOVA region
  * @capability: capability of the IOVA region
+ * @asid: Address space ID of the IOVA region, only if device API version >= 1
  * @reserved: for future use, needs to be initialized to zero
  *
  * Structure used by VDUSE_IOTLB_GET_INFO ioctl to get information of
@@ -258,7 +284,8 @@ struct vduse_iova_info {
        __u64 last;
 #define VDUSE_IOVA_CAP_UMEM (1 << 0)
        __u64 capability;
-       __u64 reserved[3];
+       __u32 asid; /* Only if device API version >= 1 */
+       __u32 reserved[5];
 };
 
 /*
@@ -280,6 +307,7 @@ enum vduse_req_type {
        VDUSE_GET_VQ_STATE,
        VDUSE_SET_STATUS,
        VDUSE_UPDATE_IOTLB,
+       VDUSE_SET_VQ_GROUP_ASID,
 };
 
 /**
@@ -314,6 +342,18 @@ struct vduse_iova_range {
        __u64 last;
 };
 
+/**
+ * struct vduse_iova_range - IOVA range [start, last] if API_VERSION >= 1
+ * @start: start of the IOVA range
+ * @last: last of the IOVA range
+ * @asid: address space ID of the IOVA range
+ */
+struct vduse_iova_range_v2 {
+       __u64 start;
+       __u64 last;
+       __u32 asid;
+};
+
 /**
  * struct vduse_dev_request - control request
  * @type: request type
@@ -322,6 +362,8 @@ struct vduse_iova_range {
  * @vq_state: virtqueue state, only index field is available
  * @s: device status
  * @iova: IOVA range for updating
+ * @iova_v2: IOVA range for updating if API_VERSION >= 1
+ * @vq_group_asid: ASID of a virtqueue group
  * @padding: padding
  *
  * Structure used by read(2) on /dev/vduse/$NAME.
@@ -334,6 +376,11 @@ struct vduse_dev_request {
                struct vduse_vq_state vq_state;
                struct vduse_dev_status s;
                struct vduse_iova_range iova;
+               /* Following members but padding exist only if vduse api
+                * version >= 1
+                */;
+               struct vduse_iova_range_v2 iova_v2;
+               struct vduse_vq_group_asid vq_group_asid;
                __u32 padding[32];
        };
 };
-- 
2.51.0


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