vduse: add vq group asid support

Add support for assigning Address Space Identifiers (ASIDs) to each VQ group. This enables mapping each group into a distinct memory space. The vq group to ASID association is protected by a rwlock now. But the mutex domain_lock keeps protecting the domains of all ASIDs, as some operations like the one related with the bounce buffer size still requires to lock all the ASIDs. Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20260119143306.1818855-12-eperezma@redhat.com>
2026-02-28 19:06:51 +01:00 · 2026-01-19 15:33:04 +01:00
parent f3dc3a8a3e
commit 079212f687
2 changed files with 315 additions and 136 deletions
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -9,6 +9,7 @@
 */

 #include "linux/virtio_net.h"
+#include <linux/cleanup.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/cdev.h>
@@ -41,6 +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)
@@ -86,7 +88,15 @@ 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 {
+	rwlock_t as_lock;
+	struct vduse_as *as; /* Protected by as_lock */
 	struct vduse_dev *dev;
 };

@@ -94,7 +104,7 @@ 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;
@@ -122,9 +132,8 @@ 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;
 	struct mutex domain_lock;
 };
@@ -314,7 +323,7 @@ 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 };
@@ -323,8 +332,14 @@ 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);
 }
@@ -439,11 +454,14 @@ static __poll_t vduse_dev_poll(struct file *file, poll_table *wait)
 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);
+	}

 	down_write(&dev->rwsem);

@@ -622,6 +640,42 @@ static union virtio_map vduse_get_vq_map(struct vdpa_device *vdpa, u16 idx)
 	return ret;
 }

+DEFINE_GUARD(vq_group_as_read_lock, struct vduse_vq_group *,
+	if (_T->dev->nas > 1)
+		read_lock(&_T->as_lock),
+	if (_T->dev->nas > 1)
+		read_unlock(&_T->as_lock))
+
+DEFINE_GUARD(vq_group_as_write_lock, struct vduse_vq_group *,
+	if (_T->dev->nas > 1)
+		write_lock(&_T->as_lock),
+	if (_T->dev->nas > 1)
+		write_unlock(&_T->as_lock))
+
+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)
+		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;
+
+	guard(vq_group_as_write_lock)(&dev->groups[group]);
+	dev->groups[group].as = &dev->as[asid];
+
+	return 0;
+}
+
 static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
 				struct vdpa_vq_state *state)
 {
@@ -793,13 +847,13 @@ 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;
 	}

@@ -842,6 +896,7 @@ 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,
 };
@@ -850,15 +905,13 @@ static void vduse_dev_sync_single_for_device(union virtio_map token,
 					     dma_addr_t dma_addr, size_t size,
 					     enum dma_data_direction dir)
 {
-	struct vduse_dev *vdev;
 	struct vduse_iova_domain *domain;

 	if (!token.group)
 		return;

-	vdev = token.group->dev;
-	domain = vdev->domain;
-
+	guard(vq_group_as_read_lock)(token.group);
+	domain = token.group->as->domain;
 	vduse_domain_sync_single_for_device(domain, dma_addr, size, dir);
 }

@@ -866,15 +919,13 @@ static void vduse_dev_sync_single_for_cpu(union virtio_map token,
 					     dma_addr_t dma_addr, size_t size,
 					     enum dma_data_direction dir)
 {
-	struct vduse_dev *vdev;
 	struct vduse_iova_domain *domain;

 	if (!token.group)
 		return;

-	vdev = token.group->dev;
-	domain = vdev->domain;
-
+	guard(vq_group_as_read_lock)(token.group);
+	domain = token.group->as->domain;
 	vduse_domain_sync_single_for_cpu(domain, dma_addr, size, dir);
 }

@@ -883,15 +934,13 @@ static dma_addr_t vduse_dev_map_page(union virtio_map token, struct page *page,
 				     enum dma_data_direction dir,
 				     unsigned long attrs)
 {
-	struct vduse_dev *vdev;
 	struct vduse_iova_domain *domain;

 	if (!token.group)
 		return DMA_MAPPING_ERROR;

-	vdev = token.group->dev;
-	domain = vdev->domain;
-
+	guard(vq_group_as_read_lock)(token.group);
+	domain = token.group->as->domain;
 	return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
 }

@@ -899,23 +948,19 @@ static void vduse_dev_unmap_page(union virtio_map token, dma_addr_t dma_addr,
 				 size_t size, enum dma_data_direction dir,
 				 unsigned long attrs)
 {
-	struct vduse_dev *vdev;
 	struct vduse_iova_domain *domain;

 	if (!token.group)
 		return;

-	vdev = token.group->dev;
-	domain = vdev->domain;
-
-	return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
+	guard(vq_group_as_read_lock)(token.group);
+	domain = token.group->as->domain;
+	vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
 }

 static void *vduse_dev_alloc_coherent(union virtio_map token, size_t size,
 				      dma_addr_t *dma_addr, gfp_t flag)
 {
-	struct vduse_dev *vdev;
-	struct vduse_iova_domain *domain;
 	void *addr;

 	*dma_addr = DMA_MAPPING_ERROR;
@@ -926,11 +971,15 @@ static void *vduse_dev_alloc_coherent(union virtio_map token, size_t size,
 	if (!addr)
 		return NULL;

-	vdev = token.group->dev;
-	domain = vdev->domain;
-	*dma_addr = vduse_domain_alloc_coherent(domain, size, addr);
-	if (*dma_addr == DMA_MAPPING_ERROR)
-		goto err;
+	{
+		struct vduse_iova_domain *domain;
+
+		guard(vq_group_as_read_lock)(token.group);
+		domain = token.group->as->domain;
+		*dma_addr = vduse_domain_alloc_coherent(domain, size, addr);
+		if (*dma_addr == DMA_MAPPING_ERROR)
+			goto err;
+	}

 	return addr;

@@ -943,31 +992,27 @@ static void vduse_dev_free_coherent(union virtio_map token, size_t size,
 				    void *vaddr, dma_addr_t dma_addr,
 				    unsigned long attrs)
 {
-	struct vduse_dev *vdev;
-	struct vduse_iova_domain *domain;
-
 	if (!token.group)
 		return;

-	vdev = token.group->dev;
-	domain = vdev->domain;
+	{
+		struct vduse_iova_domain *domain;
+
+		guard(vq_group_as_read_lock)(token.group);
+		domain = token.group->as->domain;
+		vduse_domain_free_coherent(domain, size, dma_addr, attrs);
+	}

-	vduse_domain_free_coherent(domain, size, dma_addr, attrs);
 	free_pages_exact(vaddr, size);
 }

 static bool vduse_dev_need_sync(union virtio_map token, dma_addr_t dma_addr)
 {
-	struct vduse_dev *vdev;
-	struct vduse_iova_domain *domain;
-
 	if (!token.group)
 		return false;

-	vdev = token.group->dev;
-	domain = vdev->domain;
-
-	return dma_addr < domain->bounce_size;
+	guard(vq_group_as_read_lock)(token.group);
+	return dma_addr < token.group->as->domain->bounce_size;
 }

 static int vduse_dev_mapping_error(union virtio_map token, dma_addr_t dma_addr)
@@ -979,16 +1024,11 @@ static int vduse_dev_mapping_error(union virtio_map token, dma_addr_t dma_addr)

 static size_t vduse_dev_max_mapping_size(union virtio_map token)
 {
-	struct vduse_dev *vdev;
-	struct vduse_iova_domain *domain;
-
 	if (!token.group)
 		return 0;

-	vdev = token.group->dev;
-	domain = vdev->domain;
-
-	return domain->bounce_size;
+	guard(vq_group_as_read_lock)(token.group);
+	return token.group->as->domain->bounce_size;
 }

 static const struct virtio_map_ops vduse_map_ops = {
@@ -1128,39 +1168,40 @@ unlock:
 	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;
@@ -1168,14 +1209,14 @@ 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;
@@ -1199,7 +1240,7 @@ 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;
@@ -1212,7 +1253,7 @@ 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);
@@ -1223,7 +1264,7 @@ unlock:
 		vfree(page_list);
 		kfree(umem);
 	}
-	mutex_unlock(&dev->mem_lock);
+	mutex_unlock(&dev->as[asid].mem_lock);
 	return ret;
 }

@@ -1244,44 +1285,47 @@ static void vduse_vq_update_effective_cpu(struct vduse_virtqueue *vq)
 }

 static int vduse_dev_iotlb_entry(struct vduse_dev *dev,
-				 struct vduse_iotlb_entry *entry,
+				 struct vduse_iotlb_entry_v2 *entry,
 				 struct file **f, uint64_t *capability)
 {
+	u32 asid;
 	int r = -EINVAL;
 	struct vhost_iotlb_map *map;

-	if (entry->start > entry->last)
+	if (entry->v1.start > entry->v1.last || entry->asid >= dev->nas)
 		return -EINVAL;

+	asid = array_index_nospec(entry->asid, dev->nas);
 	mutex_lock(&dev->domain_lock);
-	if (!dev->domain)
+
+	if (!dev->as[asid].domain)
 		goto out;

-	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) {
 		if (f) {
 			const struct vdpa_map_file *map_file;

 			map_file = (struct vdpa_map_file *)map->opaque;
-			entry->offset = map_file->offset;
+			entry->v1.offset = map_file->offset;
 			*f = get_file(map_file->file);
 		}
-		entry->start = map->start;
-		entry->last = map->last;
-		entry->perm = map->perm;
+		entry->v1.start = map->start;
+		entry->v1.last = map->last;
+		entry->v1.perm = map->perm;
 		if (capability) {
 			*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)
 				*capability |= VDUSE_IOVA_CAP_UMEM;
 		}

 		r = 0;
 	}
-	spin_unlock(&dev->domain->iotlb_lock);
+	spin_unlock(&dev->as[asid].domain->iotlb_lock);

 out:
 	mutex_unlock(&dev->domain_lock);
@@ -1299,12 +1343,29 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		return -EPERM;

 	switch (cmd) {
-	case VDUSE_IOTLB_GET_FD: {
-		struct vduse_iotlb_entry entry;
+	case VDUSE_IOTLB_GET_FD:
+	case VDUSE_IOTLB_GET_FD2: {
+		struct vduse_iotlb_entry_v2 entry = {0};
 		struct file *f = NULL;

+		ret = -ENOIOCTLCMD;
+		if (dev->api_version < VDUSE_API_VERSION_1 &&
+		    cmd == VDUSE_IOTLB_GET_FD2)
+			break;
+
 		ret = -EFAULT;
-		if (copy_from_user(&entry, argp, sizeof(entry)))
+		if (cmd == VDUSE_IOTLB_GET_FD2) {
+			if (copy_from_user(&entry, argp, sizeof(entry)))
+				break;
+		} else {
+			if (copy_from_user(&entry.v1, argp,
+					   sizeof(entry.v1)))
+				break;
+		}
+
+		ret = -EINVAL;
+		if (!is_mem_zero((const char *)entry.reserved,
+				 sizeof(entry.reserved)))
 			break;

 		ret = vduse_dev_iotlb_entry(dev, &entry, &f, NULL);
@@ -1315,12 +1376,19 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		if (!f)
 			break;

-		ret = -EFAULT;
-		if (copy_to_user(argp, &entry, sizeof(entry))) {
+		if (cmd == VDUSE_IOTLB_GET_FD2)
+			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;
 	}
@@ -1465,6 +1533,7 @@ 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)))
@@ -1472,17 +1541,21 @@ 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;

 		mutex_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);
 		mutex_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)))
@@ -1490,17 +1563,22 @@ 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;
+
 		mutex_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);
 		mutex_unlock(&dev->domain_lock);
 		break;
 	}
 	case VDUSE_IOTLB_GET_INFO: {
 		struct vduse_iova_info info;
-		struct vduse_iotlb_entry entry;
+		struct vduse_iotlb_entry_v2 entry;

 		ret = -EFAULT;
 		if (copy_from_user(&info, argp, sizeof(info)))
@@ -1510,15 +1588,23 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 				 sizeof(info.reserved)))
 			break;

-		entry.start = info.start;
-		entry.last = info.last;
+		if (dev->api_version < VDUSE_API_VERSION_1) {
+			if (info.asid)
+				break;
+		} else if (info.asid >= dev->nas)
+			break;
+
+		entry.v1.start = info.start;
+		entry.v1.last = info.last;
+		entry.asid = info.asid;
 		ret = vduse_dev_iotlb_entry(dev, &entry, NULL,
 					    &info.capability);
 		if (ret < 0)
 			break;

-		info.start = entry.start;
-		info.last = entry.last;
+		info.start = entry.v1.start;
+		info.last = entry.v1.last;
+		info.asid = entry.asid;

 		ret = -EFAULT;
 		if (copy_to_user(argp, &info, sizeof(info)))
@@ -1540,8 +1626,10 @@ static int vduse_dev_release(struct inode *inode, struct file *file)
 	struct vduse_dev *dev = file->private_data;

 	mutex_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);
 	mutex_unlock(&dev->domain_lock);
 	spin_lock(&dev->msg_lock);
 	/* Make sure the inflight messages can processed after reconncection */
@@ -1760,7 +1848,6 @@ static struct vduse_dev *vduse_dev_create(void)
 		return NULL;

 	mutex_init(&dev->lock);
-	mutex_init(&dev->mem_lock);
 	mutex_init(&dev->domain_lock);
 	spin_lock_init(&dev->msg_lock);
 	INIT_LIST_HEAD(&dev->send_list);
@@ -1811,8 +1898,11 @@ 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);
@@ -1859,12 +1949,17 @@ 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;
@@ -1929,7 +2024,8 @@ static ssize_t bounce_size_store(struct device *device,

 	ret = -EPERM;
 	mutex_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);
@@ -1981,6 +2077,14 @@ static int vduse_create_dev(struct vduse_dev_config *config,
 	dev->device_features = config->features;
 	dev->device_id = config->device_id;
 	dev->vendor_id = config->vendor_id;
+
+	dev->nas = (dev->api_version < VDUSE_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->ngroups = (dev->api_version < VDUSE_API_VERSION_1)
 		       ? 1
 		       : config->ngroups;
@@ -1988,8 +2092,11 @@ static int vduse_create_dev(struct vduse_dev_config *config,
 			      GFP_KERNEL);
 	if (!dev->groups)
 		goto err_vq_groups;
-	for (u32 i = 0; i < dev->ngroups; ++i)
+	for (u32 i = 0; i < dev->ngroups; ++i) {
 		dev->groups[i].dev = dev;
+		rwlock_init(&dev->groups[i].as_lock);
+		dev->groups[i].as = &dev->as[0];
+	}

 	dev->name = kstrdup(config->name, GFP_KERNEL);
 	if (!dev->name)
@@ -2029,6 +2136,8 @@ err_idr:
 err_str:
 	kfree(dev->groups);
 err_vq_groups:
+	kfree(dev->as);
+err_as:
 	vduse_dev_destroy(dev);
 err:
 	return ret;
@@ -2152,7 +2261,7 @@ 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);

@@ -2167,7 +2276,8 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 			const struct vdpa_dev_set_config *config)
 {
 	struct vduse_dev *dev;
-	int ret;
+	size_t domain_bounce_size;
+	int ret, i;

 	mutex_lock(&vduse_lock);
 	dev = vduse_find_dev(name);
@@ -2181,29 +2291,38 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 		return ret;

 	mutex_lock(&dev->domain_lock);
-	if (!dev->domain)
-		dev->domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
-						  dev->bounce_size);
-	mutex_unlock(&dev->domain_lock);
-	if (!dev->domain) {
-		ret = -ENOMEM;
-		goto domain_err;
+	ret = 0;
+
+	domain_bounce_size = dev->bounce_size / dev->nas;
+	for (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;
+			goto err;
+		}
 	}

+	mutex_unlock(&dev->domain_lock);
+
 	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
-	if (ret) {
-		goto register_err;
-	}
+	if (ret)
+		goto err_register;

 	return 0;

-register_err:
+err_register:
 	mutex_lock(&dev->domain_lock);
-	vduse_domain_destroy(dev->domain);
-	dev->domain = NULL;
+
+err:
+	for (int j = 0; j < i; j++) {
+		if (dev->as[j].domain) {
+			vduse_domain_destroy(dev->as[j].domain);
+			dev->as[j].domain = NULL;
+		}
+	}
 	mutex_unlock(&dev->domain_lock);

-domain_err:
 	put_device(&dev->vdev->vdpa.dev);

 	return ret;
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -32,6 +32,7 @@
 * @vq_num: the number of virtqueues
 * @vq_align: the allocation alignment of virtqueue's metadata
 * @ngroups: number of vq groups that VDUSE device declares
+ * @nas: number of address spaces that VDUSE device declares
 * @reserved: for future use, needs to be initialized to zero
 * @config_size: the size of the configuration space
 * @config: the buffer of the configuration space
@@ -47,7 +48,8 @@ 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[];
 };
@@ -166,6 +168,16 @@ struct vduse_vq_state_packed {
 	__u16 last_used_idx;
 };

+/**
+ * struct vduse_vq_group_asid - virtqueue group ASID
+ * @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 +237,7 @@ 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 +247,8 @@ 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 +262,7 @@ 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 +273,8 @@ 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];
 };

 /*
@@ -267,6 +283,28 @@ struct vduse_iova_info {
 */
 #define VDUSE_IOTLB_GET_INFO	_IOWR(VDUSE_BASE, 0x1a, struct vduse_iova_info)

+/**
+ * struct vduse_iotlb_entry_v2 - entry of IOTLB to describe one IOVA region
+ *
+ * @v1: the original vduse_iotlb_entry
+ * @asid: address space ID of the IOVA region
+ * @reserved: for future use, needs to be initialized to zero
+ *
+ * Structure used by VDUSE_IOTLB_GET_FD2 ioctl to find an overlapped IOVA region.
+ */
+struct vduse_iotlb_entry_v2 {
+	struct vduse_iotlb_entry v1;
+	__u32 asid;
+	__u32 reserved[12];
+};
+
+/*
+ * Same as VDUSE_IOTLB_GET_FD but with vduse_iotlb_entry_v2 argument that
+ * support extra fields.
+ */
+#define VDUSE_IOTLB_GET_FD2	_IOWR(VDUSE_BASE, 0x1b, struct vduse_iotlb_entry_v2)
+
+
 /* The control messages definition for read(2)/write(2) on /dev/vduse/$NAME */

 /**
@@ -275,11 +313,14 @@ struct vduse_iova_info {
 * @VDUSE_SET_STATUS: set the device status
 * @VDUSE_UPDATE_IOTLB: Notify userspace to update the memory mapping for
 *                      specified IOVA range via VDUSE_IOTLB_GET_FD ioctl
+ * @VDUSE_SET_VQ_GROUP_ASID: Notify userspace to update the address space of a
+ *                           virtqueue group.
 */
 enum vduse_req_type {
 	VDUSE_GET_VQ_STATE,
 	VDUSE_SET_STATUS,
 	VDUSE_UPDATE_IOTLB,
+	VDUSE_SET_VQ_GROUP_ASID,
 };

 /**
@@ -314,6 +355,18 @@ struct vduse_iova_range {
 	__u64 last;
 };

+/**
+ * struct vduse_iova_range_v2 - 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 +375,8 @@ 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 +389,11 @@ 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];
 	};
 };