[PATCH v5 0/6] Add multiple address spaces support to VDUSE

[PATCH v5 0/6] Add multiple address spaces support to VDUSE

[Eugenio Pérez]

When used by vhost-vDPA bus driver for VM, the control virtqueue
should be shadowed via userspace VMM (QEMU) instead of being assigned
directly to Guest. This is because QEMU needs to know the device state
in order to start and stop device correctly (e.g for Live Migration).

This requies to isolate the memory mapping for control virtqueue
presented by vhost-vDPA to prevent guest from accessing it directly.

This series add support to multiple address spaces in VDUSE device
allowing selective virtqueue isolation through address space IDs (ASID).

The VDUSE device needs to report:
* Number of virtqueue groups
* Association of each vq group with each virtqueue
* Number of address spaces supported.

Then, the vDPA driver can modify the ASID assigned to each VQ group to
isolate the memory AS.  This aligns VDUSE with vdpa_sim and nvidia mlx5
devices which already support ASID.

This helps to isolate the environments for the virtqueues that will not
be assigned directly. E.g in the case of virtio-net, the control
virtqueue will not be assigned directly to guest.

This series depends on the series that reworks the VDUSE mapping API:
https://lore-kernel.gnuweeb.org/all/20250924070045.10361-1-jasowang@redhat.com/

Also, to be able to test this patch, the user needs to manually revert
56e71885b034 ("vduse: Temporarily fail if control queue feature requested").

PATCH 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).
* Revert core vdpa changes (Jason).
* Fix group == ngroup case in checking VQ_SETUP argument (Jason).
* Exclude "padding" member from the only >V1 members in
  vduse_dev_request.

PATCH v4:
* Consider config->nas == 0 and config->ngroups == 0 as a fail (Jason).
* Revert the "invalid vq group" concept and assume 0 if not set.
* 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).

PATCH v3:
* Make the default group an invalid group as long as VDUSE device does
  not set it to some valid u32 value.  Modify the vdpa core to take that
  into account (Jason).  Adapt all the virtio_map_ops callbacks to it.
* Make setting status DRIVER_OK fail if vq group is not valid.
* Create the VDUSE_DEV_MAX_GROUPS and VDUSE_DEV_MAX_AS instead of using a magic
  number
* Remove the _int name suffix from struct vduse_vq_group.
* Get the vduse domain through the vduse_as in the map functions (Jason).
* Squash the patch implementing the AS logic with the patch creating the
  vduse_as struct (Jason).

PATCH v2:
* Now the vq group is in vduse_vq_config struct instead of issuing one
  VDUSE message per vq.
* Convert the use of mutex to rwlock (Xie Yongji).

PATCH v1:
* Fix: Remove BIT_ULL(VIRTIO_S_*), as _S_ is already the bit (Maxime)
* Using vduse_vq_group_int directly instead of an empty struct in union
  virtio_map.

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.  Also, it's
  a dynamic array now.  Same with ASID.
* Move the valid vq groups range check to vduse_validate_config.
* Embed vduse_iotlb_entry into vduse_iotlb_entry_v2.
* Use of array_index_nospec in VDUSE device ioctls.
* Move the umem mutex to asid struct so there is no contention between
  ASIDs.
* Remove the descs vq group capability as it will not be used and we can
  add it on top.
* Do not ask for vq groups in number of vq groups < 2.
* Remove TODO about merging VDUSE_IOTLB_GET_FD ioctl with
  VDUSE_IOTLB_GET_INFO.

RFC v2:
* Cache group information in kernel, as we need to provide the vq map
  tokens properly.
* Add descs vq group to optimize SVQ forwarding and support indirect
  descriptors out of the box.
* Make iotlb entry the last one of vduse_iotlb_entry_v2 so the first
  part of the struct is the same.
* Fixes detected testing with OVS+VDUSE.

Eugenio Pérez (6):
  vduse: make domain_lock an rwlock
  vduse: add v1 API definition
  vduse: add vq group support
  vduse: return internal vq group struct as map token
  vduse: add vq group asid support
  vduse: bump version number

 drivers/vdpa/vdpa_user/vduse_dev.c | 492 ++++++++++++++++++++++-------
 include/linux/virtio.h             |   6 +-
 include/uapi/linux/vduse.h         |  67 +++-
 3 files changed, 441 insertions(+), 124 deletions(-)

-- 
2.51.0

[PATCH v5 1/6] vduse: make domain_lock an rwlock

[Eugenio Pérez]

It will be used in a few more scenarios read-only so make it more
scalable.

Suggested-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
v2: New in v2
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 41 +++++++++++++++---------------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index e7bced0b5542..2b6a8958ffe0 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -14,6 +14,7 @@
 #include <linux/cdev.h>
 #include <linux/device.h>
 #include <linux/eventfd.h>
+#include <linux/rwlock.h>
 #include <linux/slab.h>
 #include <linux/wait.h>
 #include <linux/dma-map-ops.h>
@@ -117,7 +118,7 @@ struct vduse_dev {
 	struct vduse_umem *umem;
 	struct mutex mem_lock;
 	unsigned int bounce_size;
-	struct mutex domain_lock;
+	rwlock_t domain_lock;
 };
 
 struct vduse_dev_msg {
@@ -1176,9 +1177,9 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		if (entry.start > entry.last)
 			break;
 
-		mutex_lock(&dev->domain_lock);
+		read_lock(&dev->domain_lock);
 		if (!dev->domain) {
-			mutex_unlock(&dev->domain_lock);
+			read_unlock(&dev->domain_lock);
 			break;
 		}
 		spin_lock(&dev->domain->iotlb_lock);
@@ -1193,7 +1194,7 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 			entry.perm = map->perm;
 		}
 		spin_unlock(&dev->domain->iotlb_lock);
-		mutex_unlock(&dev->domain_lock);
+		read_unlock(&dev->domain_lock);
 		ret = -EINVAL;
 		if (!f)
 			break;
@@ -1346,10 +1347,10 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 				 sizeof(umem.reserved)))
 			break;
 
-		mutex_lock(&dev->domain_lock);
+		write_lock(&dev->domain_lock);
 		ret = vduse_dev_reg_umem(dev, umem.iova,
 					 umem.uaddr, umem.size);
-		mutex_unlock(&dev->domain_lock);
+		write_unlock(&dev->domain_lock);
 		break;
 	}
 	case VDUSE_IOTLB_DEREG_UMEM: {
@@ -1363,10 +1364,10 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		if (!is_mem_zero((const char *)umem.reserved,
 				 sizeof(umem.reserved)))
 			break;
-		mutex_lock(&dev->domain_lock);
+		write_lock(&dev->domain_lock);
 		ret = vduse_dev_dereg_umem(dev, umem.iova,
 					   umem.size);
-		mutex_unlock(&dev->domain_lock);
+		write_unlock(&dev->domain_lock);
 		break;
 	}
 	case VDUSE_IOTLB_GET_INFO: {
@@ -1385,9 +1386,9 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 				 sizeof(info.reserved)))
 			break;
 
-		mutex_lock(&dev->domain_lock);
+		read_lock(&dev->domain_lock);
 		if (!dev->domain) {
-			mutex_unlock(&dev->domain_lock);
+			read_unlock(&dev->domain_lock);
 			break;
 		}
 		spin_lock(&dev->domain->iotlb_lock);
@@ -1402,7 +1403,7 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 				info.capability |= VDUSE_IOVA_CAP_UMEM;
 		}
 		spin_unlock(&dev->domain->iotlb_lock);
-		mutex_unlock(&dev->domain_lock);
+		read_unlock(&dev->domain_lock);
 		if (!map)
 			break;
 
@@ -1425,10 +1426,10 @@ static int vduse_dev_release(struct inode *inode, struct file *file)
 {
 	struct vduse_dev *dev = file->private_data;
 
-	mutex_lock(&dev->domain_lock);
+	write_lock(&dev->domain_lock);
 	if (dev->domain)
 		vduse_dev_dereg_umem(dev, 0, dev->domain->bounce_size);
-	mutex_unlock(&dev->domain_lock);
+	write_unlock(&dev->domain_lock);
 	spin_lock(&dev->msg_lock);
 	/* Make sure the inflight messages can processed after reconncection */
 	list_splice_init(&dev->recv_list, &dev->send_list);
@@ -1647,7 +1648,7 @@ static struct vduse_dev *vduse_dev_create(void)
 
 	mutex_init(&dev->lock);
 	mutex_init(&dev->mem_lock);
-	mutex_init(&dev->domain_lock);
+	rwlock_init(&dev->domain_lock);
 	spin_lock_init(&dev->msg_lock);
 	INIT_LIST_HEAD(&dev->send_list);
 	INIT_LIST_HEAD(&dev->recv_list);
@@ -1805,7 +1806,7 @@ static ssize_t bounce_size_store(struct device *device,
 	int ret;
 
 	ret = -EPERM;
-	mutex_lock(&dev->domain_lock);
+	write_lock(&dev->domain_lock);
 	if (dev->domain)
 		goto unlock;
 
@@ -1821,7 +1822,7 @@ static ssize_t bounce_size_store(struct device *device,
 	dev->bounce_size = bounce_size & PAGE_MASK;
 	ret = count;
 unlock:
-	mutex_unlock(&dev->domain_lock);
+	write_unlock(&dev->domain_lock);
 	return ret;
 }
 
@@ -2045,11 +2046,11 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 	if (ret)
 		return ret;
 
-	mutex_lock(&dev->domain_lock);
+	write_lock(&dev->domain_lock);
 	if (!dev->domain)
 		dev->domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
 						  dev->bounce_size);
-	mutex_unlock(&dev->domain_lock);
+	write_unlock(&dev->domain_lock);
 	if (!dev->domain) {
 		put_device(&dev->vdev->vdpa.dev);
 		return -ENOMEM;
@@ -2059,10 +2060,10 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
 	if (ret) {
 		put_device(&dev->vdev->vdpa.dev);
-		mutex_lock(&dev->domain_lock);
+		write_lock(&dev->domain_lock);
 		vduse_domain_destroy(dev->domain);
 		dev->domain = NULL;
-		mutex_unlock(&dev->domain_lock);
+		write_unlock(&dev->domain_lock);
 		return ret;
 	}
 
-- 
2.51.0

[PATCH v5 2/6] vduse: add v1 API definition

[Eugenio Pérez]

This allows the kernel to detect whether the userspace VDUSE device
supports the VQ group and ASID features.  VDUSE devices that don't set
the V1 API will not receive the new messages, and vdpa device will be
created with only one vq group and asid.

The next patches implement the new feature incrementally, only enabling
the VDUSE device to set the V1 API version by the end of the series.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/uapi/linux/vduse.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index 10ad71aa00d6..ccb92a1efce0 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -10,6 +10,10 @@
 
 #define VDUSE_API_VERSION	0
 
+/* VQ groups and ASID support */
+
+#define VDUSE_API_VERSION_1	1
+
 /*
  * Get the version of VDUSE API that kernel supported (VDUSE_API_VERSION).
  * This is used for future extension.
-- 
2.51.0

[PATCH v5 3/6] vduse: add vq group support

[Eugenio Pérez]

This allows sepparate the different virtqueues in groups that shares the
same address space.  Asking the VDUSE device for the groups of the vq at
the beginning as they're needed for the DMA API.

Allocating 3 vq groups as net is the device that need the most groups:
* Dataplane (guest passthrough)
* CVQ
* Shadowed vrings.

Future versions of the series can include dynamic allocation of the
groups array so VDUSE can declare more groups.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
v5:
* Revert core vdpa changes (Jason).
* Fix group == ngroup case in checking VQ_SETUP argument (Jason).

v4:
* Revert the "invalid vq group" concept and assume 0 if not set (Jason).
* Make config->ngroups == 0 invalid (Jason).

v3:
* Make the default group an invalid group as long as VDUSE device does
  not set it to some valid u32 value.  Modify the vdpa core to take that
  into account (Jason).
* Create the VDUSE_DEV_MAX_GROUPS instead of using a magic number

v2:
* Now the vq group is in vduse_vq_config struct instead of issuing one
  VDUSE message per vq.

v1:
* Fix: Remove BIT_ULL(VIRTIO_S_*), as _S_ is already the bit (Maxime)

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 the descs vq group capability as it will not be used and we can
  add it on top.
* Do not ask for vq groups in number of vq groups < 2.
* Move the valid vq groups range check to vduse_validate_config.

RFC v2:
* Cache group information in kernel, as we need to provide the vq map
  tokens properly.
* Add descs vq group to optimize SVQ forwarding and support indirect
  descriptors out of the box.
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 46 ++++++++++++++++++++++++++----
 include/uapi/linux/vduse.h         | 12 ++++++--
 2 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 2b6a8958ffe0..99e37def7a83 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -40,6 +40,7 @@
 #define DRV_LICENSE  "GPL v2"
 
 #define VDUSE_DEV_MAX (1U << MINORBITS)
+#define VDUSE_DEV_MAX_GROUPS 0xffff
 #define VDUSE_MAX_BOUNCE_SIZE (1024 * 1024 * 1024)
 #define VDUSE_MIN_BOUNCE_SIZE (1024 * 1024)
 #define VDUSE_BOUNCE_SIZE (64 * 1024 * 1024)
@@ -59,6 +60,7 @@ struct vduse_virtqueue {
 	struct vdpa_vq_state state;
 	bool ready;
 	bool kicked;
+	u32 vq_group;
 	spinlock_t kick_lock;
 	spinlock_t irq_lock;
 	struct eventfd_ctx *kickfd;
@@ -115,6 +117,7 @@ struct vduse_dev {
 	u8 status;
 	u32 vq_num;
 	u32 vq_align;
+	u32 ngroups;
 	struct vduse_umem *umem;
 	struct mutex mem_lock;
 	unsigned int bounce_size;
@@ -456,6 +459,7 @@ static void vduse_dev_reset(struct vduse_dev *dev)
 		vq->driver_addr = 0;
 		vq->device_addr = 0;
 		vq->num = 0;
+		vq->vq_group = 0;
 		memset(&vq->state, 0, sizeof(vq->state));
 
 		spin_lock(&vq->kick_lock);
@@ -593,6 +597,16 @@ static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
 	return 0;
 }
 
+static u32 vduse_get_vq_group(struct vdpa_device *vdpa, u16 idx)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+
+	if (dev->api_version < VDUSE_API_VERSION_1)
+		return 0;
+
+	return dev->vqs[idx]->vq_group;
+}
+
 static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
 				struct vdpa_vq_state *state)
 {
@@ -790,6 +804,7 @@ static const struct vdpa_config_ops vduse_vdpa_config_ops = {
 	.set_vq_cb		= vduse_vdpa_set_vq_cb,
 	.set_vq_num             = vduse_vdpa_set_vq_num,
 	.get_vq_size		= vduse_vdpa_get_vq_size,
+	.get_vq_group		= vduse_get_vq_group,
 	.set_vq_ready		= vduse_vdpa_set_vq_ready,
 	.get_vq_ready		= vduse_vdpa_get_vq_ready,
 	.set_vq_state		= vduse_vdpa_set_vq_state,
@@ -1253,12 +1268,24 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		if (config.index >= dev->vq_num)
 			break;
 
-		if (!is_mem_zero((const char *)config.reserved,
-				 sizeof(config.reserved)))
+		if (dev->api_version < VDUSE_API_VERSION_1 && config.group)
+			break;
+
+		if (dev->api_version >= VDUSE_API_VERSION_1) {
+			if (config.group >= dev->ngroups)
+				break;
+			if (dev->status & VIRTIO_CONFIG_S_DRIVER_OK)
+				break;
+		}
+
+		if (config.reserved1 ||
+		    !is_mem_zero((const char *)config.reserved2,
+				 sizeof(config.reserved2)))
 			break;
 
 		index = array_index_nospec(config.index, dev->vq_num);
 		dev->vqs[index]->num_max = config.max_size;
+		dev->vqs[index]->vq_group = config.group;
 		ret = 0;
 		break;
 	}
@@ -1738,12 +1765,20 @@ static bool features_is_valid(struct vduse_dev_config *config)
 	return true;
 }
 
-static bool vduse_validate_config(struct vduse_dev_config *config)
+static bool vduse_validate_config(struct vduse_dev_config *config,
+				  u64 api_version)
 {
 	if (!is_mem_zero((const char *)config->reserved,
 			 sizeof(config->reserved)))
 		return false;
 
+	if (api_version < VDUSE_API_VERSION_1 && config->ngroups)
+		return false;
+
+	if (api_version >= VDUSE_API_VERSION_1 &&
+	    (!config->ngroups || config->ngroups > VDUSE_DEV_MAX_GROUPS))
+		return false;
+
 	if (config->vq_align > PAGE_SIZE)
 		return false;
 
@@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
 	dev->name = kstrdup(config->name, GFP_KERNEL);
 	if (!dev->name)
 		goto err_str;
@@ -1937,7 +1973,7 @@ static long vduse_ioctl(struct file *file, unsigned int cmd,
 			break;
 
 		ret = -EINVAL;
-		if (vduse_validate_config(&config) == false)
+		if (!vduse_validate_config(&config, control->api_version))
 			break;
 
 		buf = vmemdup_user(argp + size, config.config_size);
@@ -2018,7 +2054,7 @@ 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,
-				 1, 1, name, true);
+				 dev->ngroups, 1, name, true);
 	if (IS_ERR(vdev))
 		return PTR_ERR(vdev);
 
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index ccb92a1efce0..a3d51cf6df3a 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -31,6 +31,7 @@
  * @features: virtio features
  * @vq_num: the number of virtqueues
  * @vq_align: the allocation alignment of virtqueue's metadata
+ * @ngroups: number of vq groups 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
@@ -45,7 +46,8 @@ struct vduse_dev_config {
 	__u64 features;
 	__u32 vq_num;
 	__u32 vq_align;
-	__u32 reserved[13];
+	__u32 ngroups; /* if VDUSE_API_VERSION >= 1 */
+	__u32 reserved[12];
 	__u32 config_size;
 	__u8 config[];
 };
@@ -122,14 +124,18 @@ struct vduse_config_data {
  * struct vduse_vq_config - basic configuration of a virtqueue
  * @index: virtqueue index
  * @max_size: the max size of virtqueue
- * @reserved: for future use, needs to be initialized to zero
+ * @reserved1: for future use, needs to be initialized to zero
+ * @group: virtqueue group
+ * @reserved2: for future use, needs to be initialized to zero
  *
  * Structure used by VDUSE_VQ_SETUP ioctl to setup a virtqueue.
  */
 struct vduse_vq_config {
 	__u32 index;
 	__u16 max_size;
-	__u16 reserved[13];
+	__u16 reserved1;
+	__u32 group;
+	__u16 reserved2[10];
 };
 
 /*
-- 
2.51.0

[PATCH v5 4/6] vduse: return internal vq group struct as map token

[Eugenio Pérez]

Return the internal struct that represents the vq group as virtqueue map
token, instead of the device.  This allows the map functions to access
the information per group.

At this moment all the virtqueues share the same vq group, that only
can point to ASID 0.  This change prepares the infrastructure for actual
per-group address space handling

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
v4:
* Revert the "invalid vq group" concept, and assume 0 by default.
* Revert unnecesary blank line addition (Jason)

v3:
* Adapt all virtio_map_ops callbacks to handle empty tokens in case of
  invalid groups.
* Make setting status DRIVER_OK fail if vq group is not valid.
* Remove the _int name suffix from struct vduse_vq_group.

RFC v3:
* Make the vq groups a dynamic array to support an arbitrary number of
  them.
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 100 ++++++++++++++++++++++++++---
 include/linux/virtio.h             |   6 +-
 2 files changed, 94 insertions(+), 12 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 99e37def7a83..3ce70e6524d5 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -23,6 +23,7 @@
 #include <linux/uio.h>
 #include <linux/vdpa.h>
 #include <linux/nospec.h>
+#include <linux/virtio.h>
 #include <linux/vmalloc.h>
 #include <linux/sched/mm.h>
 #include <uapi/linux/vduse.h>
@@ -86,6 +87,10 @@ struct vduse_umem {
 	struct mm_struct *mm;
 };
 
+struct vduse_vq_group {
+	struct vduse_dev *dev;
+};
+
 struct vduse_dev {
 	struct vduse_vdpa *vdev;
 	struct device *dev;
@@ -119,6 +124,7 @@ struct vduse_dev {
 	u32 vq_align;
 	u32 ngroups;
 	struct vduse_umem *umem;
+	struct vduse_vq_group *groups;
 	struct mutex mem_lock;
 	unsigned int bounce_size;
 	rwlock_t domain_lock;
@@ -607,6 +613,17 @@ static u32 vduse_get_vq_group(struct vdpa_device *vdpa, u16 idx)
 	return dev->vqs[idx]->vq_group;
 }
 
+static union virtio_map vduse_get_vq_map(struct vdpa_device *vdpa, u16 idx)
+{
+	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+	u32 vq_group = vduse_get_vq_group(vdpa, idx);
+	union virtio_map ret = {
+		.group = &dev->groups[vq_group],
+	};
+
+	return ret;
+}
+
 static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
 				struct vdpa_vq_state *state)
 {
@@ -827,6 +844,7 @@ 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,
+	.get_vq_map		= vduse_get_vq_map,
 	.free			= vduse_vdpa_free,
 };
 
@@ -834,7 +852,14 @@ 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_iova_domain *domain = token.iova_domain;
+	struct vduse_dev *vdev;
+	struct vduse_iova_domain *domain;
+
+	if (!token.group)
+		return;
+
+	vdev = token.group->dev;
+	domain = vdev->domain;
 
 	vduse_domain_sync_single_for_device(domain, dma_addr, size, dir);
 }
@@ -843,7 +868,14 @@ 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_iova_domain *domain = token.iova_domain;
+	struct vduse_dev *vdev;
+	struct vduse_iova_domain *domain;
+
+	if (!token.group)
+		return;
+
+	vdev = token.group->dev;
+	domain = vdev->domain;
 
 	vduse_domain_sync_single_for_cpu(domain, dma_addr, size, dir);
 }
@@ -853,7 +885,14 @@ 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_iova_domain *domain = token.iova_domain;
+	struct vduse_dev *vdev;
+	struct vduse_iova_domain *domain;
+
+	if (!token.group)
+		return DMA_MAPPING_ERROR;
+
+	vdev = token.group->dev;
+	domain = vdev->domain;
 
 	return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
 }
@@ -862,7 +901,14 @@ 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_iova_domain *domain = token.iova_domain;
+	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);
 }
@@ -870,11 +916,17 @@ static void vduse_dev_unmap_page(union virtio_map token, dma_addr_t dma_addr,
 static void *vduse_dev_alloc_coherent(union virtio_map token, size_t size,
 				      dma_addr_t *dma_addr, gfp_t flag)
 {
-	struct vduse_iova_domain *domain = token.iova_domain;
+	struct vduse_dev *vdev;
+	struct vduse_iova_domain *domain;
 	unsigned long iova;
 	void *addr;
 
 	*dma_addr = DMA_MAPPING_ERROR;
+	if (!token.group)
+		return NULL;
+
+	vdev = token.group->dev;
+	domain = vdev->domain;
 	addr = vduse_domain_alloc_coherent(domain, size,
 					   (dma_addr_t *)&iova, flag);
 	if (!addr)
@@ -889,14 +941,28 @@ 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_iova_domain *domain = token.iova_domain;
+	struct vduse_dev *vdev;
+	struct vduse_iova_domain *domain;
+
+	if (!token.group)
+		return;
+
+	vdev = token.group->dev;
+	domain = vdev->domain;
 
 	vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
 }
 
 static bool vduse_dev_need_sync(union virtio_map token, dma_addr_t dma_addr)
 {
-	struct vduse_iova_domain *domain = token.iova_domain;
+	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;
 }
@@ -910,7 +976,14 @@ 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_iova_domain *domain = token.iova_domain;
+	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;
 }
@@ -1728,6 +1801,7 @@ static int vduse_destroy_dev(char *name)
 	if (dev->domain)
 		vduse_domain_destroy(dev->domain);
 	kfree(dev->name);
+	kfree(dev->groups);
 	vduse_dev_destroy(dev);
 	module_put(THIS_MODULE);
 
@@ -1895,6 +1969,13 @@ static int vduse_create_dev(struct vduse_dev_config *config,
 	dev->device_id = config->device_id;
 	dev->vendor_id = config->vendor_id;
 	dev->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
+	dev->groups = kcalloc(dev->ngroups, sizeof(dev->groups[0]),
+			      GFP_KERNEL);
+	if (!dev->groups)
+		goto err_vq_groups;
+	for (u32 i = 0; i < dev->ngroups; ++i)
+		dev->groups[i].dev = dev;
+
 	dev->name = kstrdup(config->name, GFP_KERNEL);
 	if (!dev->name)
 		goto err_str;
@@ -1931,6 +2012,8 @@ static int vduse_create_dev(struct vduse_dev_config *config,
 err_idr:
 	kfree(dev->name);
 err_str:
+	kfree(dev->groups);
+err_vq_groups:
 	vduse_dev_destroy(dev);
 err:
 	return ret;
@@ -2092,7 +2175,6 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 		return -ENOMEM;
 	}
 
-	dev->vdev->vdpa.vmap.iova_domain = dev->domain;
 	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
 	if (ret) {
 		put_device(&dev->vdev->vdpa.dev);
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 96c66126c074..302109029700 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -41,13 +41,13 @@ struct virtqueue {
 	void *priv;
 };
 
-struct vduse_iova_domain;
+struct vduse_vq_group;
 
 union virtio_map {
 	/* Device that performs DMA */
 	struct device *dma_dev;
-	/* VDUSE specific mapping data */
-	struct vduse_iova_domain *iova_domain;
+	/* VDUSE specific virtqueue group for doing map */
+	struct vduse_vq_group *group;
 };
 
 int virtqueue_add_outbuf(struct virtqueue *vq,
-- 
2.51.0

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

[Eugenio Pérez]

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

[PATCH v5 6/6] vduse: bump version number

[Eugenio Pérez]

Finalize the series by advertising VDUSE API v1 support to userspace.

Now that all required infrastructure for v1 (ASIDs, VQ groups,
update_iotlb_v2) is in place, VDUSE devices can opt in to the new
features.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 731de08bb692..7f24a1af6cca 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -2165,7 +2165,7 @@ static long vduse_ioctl(struct file *file, unsigned int cmd,
 			break;
 
 		ret = -EINVAL;
-		if (api_version > VDUSE_API_VERSION)
+		if (api_version > VDUSE_API_VERSION_1)
 			break;
 
 		ret = 0;
@@ -2232,7 +2232,7 @@ static int vduse_open(struct inode *inode, struct file *file)
 	if (!control)
 		return -ENOMEM;
 
-	control->api_version = VDUSE_API_VERSION;
+	control->api_version = VDUSE_API_VERSION_1;
 	file->private_data = control;
 
 	return 0;
-- 
2.51.0

Re: [PATCH v5 0/6] Add multiple address spaces support to VDUSE

[Michael S. Tsirkin]

On Fri, Sep 26, 2025 at 12:14:26PM +0200, Eugenio Pérez wrote:
> PATCH v5:
> * Properly return errno if copy_to_user returns >0 in VDUSE_IOTLB_GET_FD
>   ioctl (Jason).

???

I think copy_to_user returns an unsigned value: the number of bytes copied.


static __always_inline unsigned long __must_check
copy_from_user(void *to, const void __user *from, unsigned long n)
{
        if (!check_copy_size(to, n, false))
                return n;
#ifdef INLINE_COPY_FROM_USER
        return _inline_copy_from_user(to, from, n);
#else
        return _copy_from_user(to, from, n);
#endif
}


so, how does the patch work then?

-- 
MST

Re: [PATCH v5 3/6] vduse: add vq group support

[Michael S. Tsirkin]

On Fri, Sep 26, 2025 at 12:14:29PM +0200, Eugenio Pérez wrote:
> This allows sepparate the different virtqueues in groups that shares the

separate

> same address space.  Asking the VDUSE device for the groups of the vq at
> the beginning as they're needed for the DMA API.
> 
> Allocating 3 vq groups as net is the device that need the most groups:
> * Dataplane (guest passthrough)
> * CVQ
> * Shadowed vrings.
> 
> Future versions of the series can include dynamic allocation of the
> groups array so VDUSE can declare more groups.
> 
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
> v5:
> * Revert core vdpa changes (Jason).
> * Fix group == ngroup case in checking VQ_SETUP argument (Jason).
> 
> v4:
> * Revert the "invalid vq group" concept and assume 0 if not set (Jason).
> * Make config->ngroups == 0 invalid (Jason).
> 
> v3:
> * Make the default group an invalid group as long as VDUSE device does
>   not set it to some valid u32 value.  Modify the vdpa core to take that
>   into account (Jason).
> * Create the VDUSE_DEV_MAX_GROUPS instead of using a magic number
> 
> v2:
> * Now the vq group is in vduse_vq_config struct instead of issuing one
>   VDUSE message per vq.
> 
> v1:
> * Fix: Remove BIT_ULL(VIRTIO_S_*), as _S_ is already the bit (Maxime)
> 
> 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 the descs vq group capability as it will not be used and we can
>   add it on top.
> * Do not ask for vq groups in number of vq groups < 2.
> * Move the valid vq groups range check to vduse_validate_config.
> 
> RFC v2:
> * Cache group information in kernel, as we need to provide the vq map
>   tokens properly.
> * Add descs vq group to optimize SVQ forwarding and support indirect
>   descriptors out of the box.
> ---
>  drivers/vdpa/vdpa_user/vduse_dev.c | 46 ++++++++++++++++++++++++++----
>  include/uapi/linux/vduse.h         | 12 ++++++--
>  2 files changed, 50 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index 2b6a8958ffe0..99e37def7a83 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -40,6 +40,7 @@
>  #define DRV_LICENSE  "GPL v2"
>  
>  #define VDUSE_DEV_MAX (1U << MINORBITS)
> +#define VDUSE_DEV_MAX_GROUPS 0xffff
>  #define VDUSE_MAX_BOUNCE_SIZE (1024 * 1024 * 1024)
>  #define VDUSE_MIN_BOUNCE_SIZE (1024 * 1024)
>  #define VDUSE_BOUNCE_SIZE (64 * 1024 * 1024)
> @@ -59,6 +60,7 @@ struct vduse_virtqueue {
>  	struct vdpa_vq_state state;
>  	bool ready;
>  	bool kicked;
> +	u32 vq_group;
>  	spinlock_t kick_lock;
>  	spinlock_t irq_lock;
>  	struct eventfd_ctx *kickfd;
> @@ -115,6 +117,7 @@ struct vduse_dev {
>  	u8 status;
>  	u32 vq_num;
>  	u32 vq_align;
> +	u32 ngroups;
>  	struct vduse_umem *umem;
>  	struct mutex mem_lock;
>  	unsigned int bounce_size;
> @@ -456,6 +459,7 @@ static void vduse_dev_reset(struct vduse_dev *dev)
>  		vq->driver_addr = 0;
>  		vq->device_addr = 0;
>  		vq->num = 0;
> +		vq->vq_group = 0;
>  		memset(&vq->state, 0, sizeof(vq->state));
>  
>  		spin_lock(&vq->kick_lock);
> @@ -593,6 +597,16 @@ static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
>  	return 0;
>  }
>  
> +static u32 vduse_get_vq_group(struct vdpa_device *vdpa, u16 idx)
> +{
> +	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> +
> +	if (dev->api_version < VDUSE_API_VERSION_1)
> +		return 0;
> +
> +	return dev->vqs[idx]->vq_group;
> +}
> +
>  static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
>  				struct vdpa_vq_state *state)
>  {
> @@ -790,6 +804,7 @@ static const struct vdpa_config_ops vduse_vdpa_config_ops = {
>  	.set_vq_cb		= vduse_vdpa_set_vq_cb,
>  	.set_vq_num             = vduse_vdpa_set_vq_num,
>  	.get_vq_size		= vduse_vdpa_get_vq_size,
> +	.get_vq_group		= vduse_get_vq_group,
>  	.set_vq_ready		= vduse_vdpa_set_vq_ready,
>  	.get_vq_ready		= vduse_vdpa_get_vq_ready,
>  	.set_vq_state		= vduse_vdpa_set_vq_state,
> @@ -1253,12 +1268,24 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
>  		if (config.index >= dev->vq_num)
>  			break;
>  
> -		if (!is_mem_zero((const char *)config.reserved,
> -				 sizeof(config.reserved)))
> +		if (dev->api_version < VDUSE_API_VERSION_1 && config.group)
> +			break;
> +
> +		if (dev->api_version >= VDUSE_API_VERSION_1) {
> +			if (config.group >= dev->ngroups)
> +				break;
> +			if (dev->status & VIRTIO_CONFIG_S_DRIVER_OK)
> +				break;
> +		}
> +
> +		if (config.reserved1 ||
> +		    !is_mem_zero((const char *)config.reserved2,
> +				 sizeof(config.reserved2)))
>  			break;
>  
>  		index = array_index_nospec(config.index, dev->vq_num);
>  		dev->vqs[index]->num_max = config.max_size;
> +		dev->vqs[index]->vq_group = config.group;
>  		ret = 0;
>  		break;
>  	}
> @@ -1738,12 +1765,20 @@ static bool features_is_valid(struct vduse_dev_config *config)
>  	return true;
>  }
>  
> -static bool vduse_validate_config(struct vduse_dev_config *config)
> +static bool vduse_validate_config(struct vduse_dev_config *config,
> +				  u64 api_version)
>  {
>  	if (!is_mem_zero((const char *)config->reserved,
>  			 sizeof(config->reserved)))
>  		return false;
>  
> +	if (api_version < VDUSE_API_VERSION_1 && config->ngroups)
> +		return false;
> +
> +	if (api_version >= VDUSE_API_VERSION_1 &&
> +	    (!config->ngroups || config->ngroups > VDUSE_DEV_MAX_GROUPS))
> +		return false;
> +
>  	if (config->vq_align > PAGE_SIZE)
>  		return false;
>  
> @@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
>  	dev->name = kstrdup(config->name, GFP_KERNEL);
>  	if (!dev->name)
>  		goto err_str;
> @@ -1937,7 +1973,7 @@ static long vduse_ioctl(struct file *file, unsigned int cmd,
>  			break;
>  
>  		ret = -EINVAL;
> -		if (vduse_validate_config(&config) == false)
> +		if (!vduse_validate_config(&config, control->api_version))
>  			break;
>  
>  		buf = vmemdup_user(argp + size, config.config_size);
> @@ -2018,7 +2054,7 @@ 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,
> -				 1, 1, name, true);
> +				 dev->ngroups, 1, name, true);
>  	if (IS_ERR(vdev))
>  		return PTR_ERR(vdev);
>  
> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> index ccb92a1efce0..a3d51cf6df3a 100644
> --- a/include/uapi/linux/vduse.h
> +++ b/include/uapi/linux/vduse.h
> @@ -31,6 +31,7 @@
>   * @features: virtio features
>   * @vq_num: the number of virtqueues
>   * @vq_align: the allocation alignment of virtqueue's metadata
> + * @ngroups: number of vq groups 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
> @@ -45,7 +46,8 @@ struct vduse_dev_config {
>  	__u64 features;
>  	__u32 vq_num;
>  	__u32 vq_align;
> -	__u32 reserved[13];
> +	__u32 ngroups; /* if VDUSE_API_VERSION >= 1 */
> +	__u32 reserved[12];
>  	__u32 config_size;
>  	__u8 config[];
>  };
> @@ -122,14 +124,18 @@ struct vduse_config_data {
>   * struct vduse_vq_config - basic configuration of a virtqueue
>   * @index: virtqueue index
>   * @max_size: the max size of virtqueue
> - * @reserved: for future use, needs to be initialized to zero
> + * @reserved1: for future use, needs to be initialized to zero
> + * @group: virtqueue group
> + * @reserved2: for future use, needs to be initialized to zero
>   *
>   * Structure used by VDUSE_VQ_SETUP ioctl to setup a virtqueue.
>   */
>  struct vduse_vq_config {
>  	__u32 index;
>  	__u16 max_size;
> -	__u16 reserved[13];
> +	__u16 reserved1;
> +	__u32 group;
> +	__u16 reserved2[10];
>  };
>  
>  /*
> -- 
> 2.51.0

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

[Michael S. Tsirkin]

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

[Michael S. Tsirkin]

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 3/6] vduse: add vq group support

[Michael S. Tsirkin]

On Fri, Sep 26, 2025 at 12:14:29PM +0200, Eugenio Pérez wrote:
> @@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;

Is this < 1 same as VDUSE_API_VERSION_1? If so, maybe use that?

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

[Michael S. Tsirkin]

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 0/6] Add multiple address spaces support to VDUSE

[Eugenio Perez Martin]

On Fri, Sep 26, 2025 at 4:37 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Sep 26, 2025 at 12:14:26PM +0200, Eugenio Pérez wrote:
> > PATCH v5:
> > * Properly return errno if copy_to_user returns >0 in VDUSE_IOTLB_GET_FD
> >   ioctl (Jason).
>
> ???
>
> I think copy_to_user returns an unsigned value: the number of bytes copied.
>
>
> static __always_inline unsigned long __must_check
> copy_from_user(void *to, const void __user *from, unsigned long n)
> {
>         if (!check_copy_size(to, n, false))
>                 return n;
> #ifdef INLINE_COPY_FROM_USER
>         return _inline_copy_from_user(to, from, n);
> #else
>         return _copy_from_user(to, from, n);
> #endif
> }
>
>
> so, how does the patch work then?
>

copy_from_user returns the number of bytes that could not be copied.
For example when the object size in the kernel is less than n bytes
long, check_copy_size returns false and copy_from_user returns n, the
amount of size requested to copy.

Re: [PATCH v5 3/6] vduse: add vq group support

[Eugenio Perez Martin]

On Fri, Sep 26, 2025 at 4:59 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Sep 26, 2025 at 12:14:29PM +0200, Eugenio Pérez wrote:
> > This allows sepparate the different virtqueues in groups that shares the
>
> separate
>

Fixing, thanks!

> > same address space.  Asking the VDUSE device for the groups of the vq at
> > the beginning as they're needed for the DMA API.
> >
> > Allocating 3 vq groups as net is the device that need the most groups:
> > * Dataplane (guest passthrough)
> > * CVQ
> > * Shadowed vrings.
> >
> > Future versions of the series can include dynamic allocation of the
> > groups array so VDUSE can declare more groups.
> >
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > ---
> > v5:
> > * Revert core vdpa changes (Jason).
> > * Fix group == ngroup case in checking VQ_SETUP argument (Jason).
> >
> > v4:
> > * Revert the "invalid vq group" concept and assume 0 if not set (Jason).
> > * Make config->ngroups == 0 invalid (Jason).
> >
> > v3:
> > * Make the default group an invalid group as long as VDUSE device does
> >   not set it to some valid u32 value.  Modify the vdpa core to take that
> >   into account (Jason).
> > * Create the VDUSE_DEV_MAX_GROUPS instead of using a magic number
> >
> > v2:
> > * Now the vq group is in vduse_vq_config struct instead of issuing one
> >   VDUSE message per vq.
> >
> > v1:
> > * Fix: Remove BIT_ULL(VIRTIO_S_*), as _S_ is already the bit (Maxime)
> >
> > 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 the descs vq group capability as it will not be used and we can
> >   add it on top.
> > * Do not ask for vq groups in number of vq groups < 2.
> > * Move the valid vq groups range check to vduse_validate_config.
> >
> > RFC v2:
> > * Cache group information in kernel, as we need to provide the vq map
> >   tokens properly.
> > * Add descs vq group to optimize SVQ forwarding and support indirect
> >   descriptors out of the box.
> > ---
> >  drivers/vdpa/vdpa_user/vduse_dev.c | 46 ++++++++++++++++++++++++++----
> >  include/uapi/linux/vduse.h         | 12 ++++++--
> >  2 files changed, 50 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> > index 2b6a8958ffe0..99e37def7a83 100644
> > --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> > @@ -40,6 +40,7 @@
> >  #define DRV_LICENSE  "GPL v2"
> >
> >  #define VDUSE_DEV_MAX (1U << MINORBITS)
> > +#define VDUSE_DEV_MAX_GROUPS 0xffff
> >  #define VDUSE_MAX_BOUNCE_SIZE (1024 * 1024 * 1024)
> >  #define VDUSE_MIN_BOUNCE_SIZE (1024 * 1024)
> >  #define VDUSE_BOUNCE_SIZE (64 * 1024 * 1024)
> > @@ -59,6 +60,7 @@ struct vduse_virtqueue {
> >       struct vdpa_vq_state state;
> >       bool ready;
> >       bool kicked;
> > +     u32 vq_group;
> >       spinlock_t kick_lock;
> >       spinlock_t irq_lock;
> >       struct eventfd_ctx *kickfd;
> > @@ -115,6 +117,7 @@ struct vduse_dev {
> >       u8 status;
> >       u32 vq_num;
> >       u32 vq_align;
> > +     u32 ngroups;
> >       struct vduse_umem *umem;
> >       struct mutex mem_lock;
> >       unsigned int bounce_size;
> > @@ -456,6 +459,7 @@ static void vduse_dev_reset(struct vduse_dev *dev)
> >               vq->driver_addr = 0;
> >               vq->device_addr = 0;
> >               vq->num = 0;
> > +             vq->vq_group = 0;
> >               memset(&vq->state, 0, sizeof(vq->state));
> >
> >               spin_lock(&vq->kick_lock);
> > @@ -593,6 +597,16 @@ static int vduse_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 idx,
> >       return 0;
> >  }
> >
> > +static u32 vduse_get_vq_group(struct vdpa_device *vdpa, u16 idx)
> > +{
> > +     struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > +
> > +     if (dev->api_version < VDUSE_API_VERSION_1)
> > +             return 0;
> > +
> > +     return dev->vqs[idx]->vq_group;
> > +}
> > +
> >  static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
> >                               struct vdpa_vq_state *state)
> >  {
> > @@ -790,6 +804,7 @@ static const struct vdpa_config_ops vduse_vdpa_config_ops = {
> >       .set_vq_cb              = vduse_vdpa_set_vq_cb,
> >       .set_vq_num             = vduse_vdpa_set_vq_num,
> >       .get_vq_size            = vduse_vdpa_get_vq_size,
> > +     .get_vq_group           = vduse_get_vq_group,
> >       .set_vq_ready           = vduse_vdpa_set_vq_ready,
> >       .get_vq_ready           = vduse_vdpa_get_vq_ready,
> >       .set_vq_state           = vduse_vdpa_set_vq_state,
> > @@ -1253,12 +1268,24 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> >               if (config.index >= dev->vq_num)
> >                       break;
> >
> > -             if (!is_mem_zero((const char *)config.reserved,
> > -                              sizeof(config.reserved)))
> > +             if (dev->api_version < VDUSE_API_VERSION_1 && config.group)
> > +                     break;
> > +
> > +             if (dev->api_version >= VDUSE_API_VERSION_1) {
> > +                     if (config.group >= dev->ngroups)
> > +                             break;
> > +                     if (dev->status & VIRTIO_CONFIG_S_DRIVER_OK)
> > +                             break;
> > +             }
> > +
> > +             if (config.reserved1 ||
> > +                 !is_mem_zero((const char *)config.reserved2,
> > +                              sizeof(config.reserved2)))
> >                       break;
> >
> >               index = array_index_nospec(config.index, dev->vq_num);
> >               dev->vqs[index]->num_max = config.max_size;
> > +             dev->vqs[index]->vq_group = config.group;
> >               ret = 0;
> >               break;
> >       }
> > @@ -1738,12 +1765,20 @@ static bool features_is_valid(struct vduse_dev_config *config)
> >       return true;
> >  }
> >
> > -static bool vduse_validate_config(struct vduse_dev_config *config)
> > +static bool vduse_validate_config(struct vduse_dev_config *config,
> > +                               u64 api_version)
> >  {
> >       if (!is_mem_zero((const char *)config->reserved,
> >                        sizeof(config->reserved)))
> >               return false;
> >
> > +     if (api_version < VDUSE_API_VERSION_1 && config->ngroups)
> > +             return false;
> > +
> > +     if (api_version >= VDUSE_API_VERSION_1 &&
> > +         (!config->ngroups || config->ngroups > VDUSE_DEV_MAX_GROUPS))
> > +             return false;
> > +
> >       if (config->vq_align > PAGE_SIZE)
> >               return false;
> >
> > @@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
> >       dev->name = kstrdup(config->name, GFP_KERNEL);
> >       if (!dev->name)
> >               goto err_str;
> > @@ -1937,7 +1973,7 @@ static long vduse_ioctl(struct file *file, unsigned int cmd,
> >                       break;
> >
> >               ret = -EINVAL;
> > -             if (vduse_validate_config(&config) == false)
> > +             if (!vduse_validate_config(&config, control->api_version))
> >                       break;
> >
> >               buf = vmemdup_user(argp + size, config.config_size);
> > @@ -2018,7 +2054,7 @@ 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,
> > -                              1, 1, name, true);
> > +                              dev->ngroups, 1, name, true);
> >       if (IS_ERR(vdev))
> >               return PTR_ERR(vdev);
> >
> > diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> > index ccb92a1efce0..a3d51cf6df3a 100644
> > --- a/include/uapi/linux/vduse.h
> > +++ b/include/uapi/linux/vduse.h
> > @@ -31,6 +31,7 @@
> >   * @features: virtio features
> >   * @vq_num: the number of virtqueues
> >   * @vq_align: the allocation alignment of virtqueue's metadata
> > + * @ngroups: number of vq groups 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
> > @@ -45,7 +46,8 @@ struct vduse_dev_config {
> >       __u64 features;
> >       __u32 vq_num;
> >       __u32 vq_align;
> > -     __u32 reserved[13];
> > +     __u32 ngroups; /* if VDUSE_API_VERSION >= 1 */
> > +     __u32 reserved[12];
> >       __u32 config_size;
> >       __u8 config[];
> >  };
> > @@ -122,14 +124,18 @@ struct vduse_config_data {
> >   * struct vduse_vq_config - basic configuration of a virtqueue
> >   * @index: virtqueue index
> >   * @max_size: the max size of virtqueue
> > - * @reserved: for future use, needs to be initialized to zero
> > + * @reserved1: for future use, needs to be initialized to zero
> > + * @group: virtqueue group
> > + * @reserved2: for future use, needs to be initialized to zero
> >   *
> >   * Structure used by VDUSE_VQ_SETUP ioctl to setup a virtqueue.
> >   */
> >  struct vduse_vq_config {
> >       __u32 index;
> >       __u16 max_size;
> > -     __u16 reserved[13];
> > +     __u16 reserved1;
> > +     __u32 group;
> > +     __u16 reserved2[10];
> >  };
> >
> >  /*
> > --
> > 2.51.0
>

Re: [PATCH v5 3/6] vduse: add vq group support

[Eugenio Perez Martin]

On Fri, Sep 26, 2025 at 5:27 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Sep 26, 2025 at 12:14:29PM +0200, Eugenio Pérez wrote:
> > @@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
>
> Is this < 1 same as VDUSE_API_VERSION_1? If so, maybe use that?
>

The macro for v0 is called VDUSE_API_VERSION, so I think it is less
intuitive to put:
dev->api_version == VDUSE_API_VERSION

But I'm ok with the change if you want.

Re: [PATCH v5 3/6] vduse: add vq group support

[Michael S. Tsirkin]

On Mon, Sep 29, 2025 at 07:55:59AM +0200, Eugenio Perez Martin wrote:
> On Fri, Sep 26, 2025 at 5:27 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Fri, Sep 26, 2025 at 12:14:29PM +0200, Eugenio Pérez wrote:
> > > @@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
> >
> > Is this < 1 same as VDUSE_API_VERSION_1? If so, maybe use that?
> >
> 
> The macro for v0 is called VDUSE_API_VERSION, so I think it is less
> intuitive to put:
> dev->api_version == VDUSE_API_VERSION
> 
> But I'm ok with the change if you want.

Confused. You mean "more intuitive"?

Re: [PATCH v5 0/6] Add multiple address spaces support to VDUSE

[Michael S. Tsirkin]

On Mon, Sep 29, 2025 at 07:41:13AM +0200, Eugenio Perez Martin wrote:
> On Fri, Sep 26, 2025 at 4:37 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Fri, Sep 26, 2025 at 12:14:26PM +0200, Eugenio Pérez wrote:
> > > PATCH v5:
> > > * Properly return errno if copy_to_user returns >0 in VDUSE_IOTLB_GET_FD
> > >   ioctl (Jason).
> >
> > ???
> >
> > I think copy_to_user returns an unsigned value: the number of bytes copied.
> >
> >
> > static __always_inline unsigned long __must_check
> > copy_from_user(void *to, const void __user *from, unsigned long n)
> > {
> >         if (!check_copy_size(to, n, false))
> >                 return n;
> > #ifdef INLINE_COPY_FROM_USER
> >         return _inline_copy_from_user(to, from, n);
> > #else
> >         return _copy_from_user(to, from, n);
> > #endif
> > }
> >
> >
> > so, how does the patch work then?
> >
> 
> copy_from_user returns the number of bytes that could not be copied.
> For example when the object size in the kernel is less than n bytes
> long, check_copy_size returns false and copy_from_user returns n, the
> amount of size requested to copy.

oh, right. thanks!

Re: [PATCH v5 3/6] vduse: add vq group support

[Eugenio Perez Martin]

On Mon, Sep 29, 2025 at 9:55 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Mon, Sep 29, 2025 at 07:55:59AM +0200, Eugenio Perez Martin wrote:
> > On Fri, Sep 26, 2025 at 5:27 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > >
> > > On Fri, Sep 26, 2025 at 12:14:29PM +0200, Eugenio Pérez wrote:
> > > > @@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
> > >
> > > Is this < 1 same as VDUSE_API_VERSION_1? If so, maybe use that?
> > >
> >
> > The macro for v0 is called VDUSE_API_VERSION, so I think it is less
> > intuitive to put:
> > dev->api_version == VDUSE_API_VERSION
> >
> > But I'm ok with the change if you want.
>
> Confused. You mean "more intuitive"?
>

Ok think I misread your comment,

I find

(dev->api_version < 1) ? ...

more intuitive than

(dev->api_version == VDUSE_API_VERSION) ? ...

But now I think you meant

(dev->api_version < VDUSE_API_VERSION_1) ? ...

Is that right?

Re: [PATCH v5 3/6] vduse: add vq group support

[Michael S. Tsirkin]

On Mon, Sep 29, 2025 at 10:52:45AM +0200, Eugenio Perez Martin wrote:
> On Mon, Sep 29, 2025 at 9:55 AM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Mon, Sep 29, 2025 at 07:55:59AM +0200, Eugenio Perez Martin wrote:
> > > On Fri, Sep 26, 2025 at 5:27 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > > >
> > > > On Fri, Sep 26, 2025 at 12:14:29PM +0200, Eugenio Pérez wrote:
> > > > > @@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
> > > >
> > > > Is this < 1 same as VDUSE_API_VERSION_1? If so, maybe use that?
> > > >
> > >
> > > The macro for v0 is called VDUSE_API_VERSION, so I think it is less
> > > intuitive to put:
> > > dev->api_version == VDUSE_API_VERSION
> > >
> > > But I'm ok with the change if you want.
> >
> > Confused. You mean "more intuitive"?
> >
> 
> Ok think I misread your comment,
> 
> I find
> 
> (dev->api_version < 1) ? ...
> 
> more intuitive than
> 
> (dev->api_version == VDUSE_API_VERSION) ? ...
> 
> But now I think you meant
> 
> (dev->api_version < VDUSE_API_VERSION_1) ? ...
> 
> Is that right?

That's right.

Re: [PATCH v5 3/6] vduse: add vq group support

[Eugenio Perez Martin]

On Mon, Sep 29, 2025 at 11:29 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Mon, Sep 29, 2025 at 10:52:45AM +0200, Eugenio Perez Martin wrote:
> > On Mon, Sep 29, 2025 at 9:55 AM Michael S. Tsirkin <mst@redhat.com> wrote:
> > >
> > > On Mon, Sep 29, 2025 at 07:55:59AM +0200, Eugenio Perez Martin wrote:
> > > > On Fri, Sep 26, 2025 at 5:27 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > > > >
> > > > > On Fri, Sep 26, 2025 at 12:14:29PM +0200, Eugenio Pérez wrote:
> > > > > > @@ -1859,6 +1894,7 @@ 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->ngroups = (dev->api_version < 1) ? 1 : config->ngroups;
> > > > >
> > > > > Is this < 1 same as VDUSE_API_VERSION_1? If so, maybe use that?
> > > > >
> > > >
> > > > The macro for v0 is called VDUSE_API_VERSION, so I think it is less
> > > > intuitive to put:
> > > > dev->api_version == VDUSE_API_VERSION
> > > >
> > > > But I'm ok with the change if you want.
> > >
> > > Confused. You mean "more intuitive"?
> > >
> >
> > Ok think I misread your comment,
> >
> > I find
> >
> > (dev->api_version < 1) ? ...
> >
> > more intuitive than
> >
> > (dev->api_version == VDUSE_API_VERSION) ? ...
> >
> > But now I think you meant
> >
> > (dev->api_version < VDUSE_API_VERSION_1) ? ...
> >
> > Is that right?
>
> That's right.
>

Ok, take it for granted in v6!

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

[Eugenio Perez Martin]

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

[Eugenio Perez Martin]

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

[Eugenio Perez Martin]

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.