[PATCH v5 5/6] vduse: add vq group asid support

Eugenio Pérez posted 6 patches 5 days, 12 hours ago
There is a newer version of this series
[PATCH v5 5/6] vduse: add vq group asid support
Posted by Eugenio Pérez 5 days, 12 hours ago
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 <eperezma@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

Re: [PATCH v5 5/6] vduse: add vq group asid support
Posted by Michael S. Tsirkin 4 days, 2 hours ago
On Fri, Sep 26, 2025 at 12:14:31PM +0200, Eugenio Pérez wrote:
> @@ -166,6 +179,16 @@ struct vduse_vq_state_packed {
>  	__u16 last_used_idx;
>  };
>  
> +/**
> + * struct vduse_vq_group - virtqueue group

comment does not match struct name.


> + * @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
Re: [PATCH v5 5/6] vduse: add vq group asid support
Posted by Eugenio Perez Martin 2 days, 10 hours ago
On Sat, Sep 27, 2025 at 10:00 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Sep 26, 2025 at 12:14:31PM +0200, Eugenio Pérez wrote:
> > @@ -166,6 +179,16 @@ struct vduse_vq_state_packed {
> >       __u16 last_used_idx;
> >  };
> >
> > +/**
> > + * struct vduse_vq_group - virtqueue group
>
> comment does not match struct name.
>

Fixing in v6!
Re: [PATCH v5 5/6] vduse: add vq group asid support
Posted by Michael S. Tsirkin 5 days, 7 hours ago
On Fri, Sep 26, 2025 at 12:14:31PM +0200, Eugenio Pérez wrote:
> 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 <eperezma@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;

Is this "< 1" here same as VDUSE_API_VERSION_1 ? Maybe use that then.


> +	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
Re: [PATCH v5 5/6] vduse: add vq group asid support
Posted by Eugenio Perez Martin 2 days, 10 hours ago
On Fri, Sep 26, 2025 at 5:25 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Sep 26, 2025 at 12:14:31PM +0200, Eugenio Pérez wrote:
> > 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 <eperezma@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;
>
> Is this "< 1" here same as VDUSE_API_VERSION_1 ? Maybe use that then.
>

Right, fixing in v6, thanks!
Re: [PATCH v5 5/6] vduse: add vq group asid support
Posted by Michael S. Tsirkin 5 days, 7 hours ago
On Fri, Sep 26, 2025 at 12:14:31PM +0200, Eugenio Pérez wrote:
> 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 <eperezma@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);


I don't get this kind of error handling.

So on error, you destroy all domains 0 to i? Then proceed to
create another domain? But that one will not be destroyed,
will it? Will that leak resources?


This is hard to understand even if correct.
I suggest you switch to use the standard goto error; error handling
idiom insead of integrating error handling and good path in this funky
way.




> +		}
> +	}
> +
>  	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
Re: [PATCH v5 5/6] vduse: add vq group asid support
Posted by Eugenio Perez Martin 2 days, 10 hours ago
On Fri, Sep 26, 2025 at 5:23 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Sep 26, 2025 at 12:14:31PM +0200, Eugenio Pérez wrote:
> > 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 <eperezma@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);
>
>
> I don't get this kind of error handling.
>
> So on error, you destroy all domains 0 to i? Then proceed to
> create another domain? But that one will not be destroyed,
> will it? Will that leak resources?
>
>
> This is hard to understand even if correct.
> I suggest you switch to use the standard goto error; error handling
> idiom insead of integrating error handling and good path in this funky
> way.
>
>

It's bad actually, thanks for the catch!. The reason I didn't use the
goto was because of the locking, but I can adapt the code.