vhost-vdpa: introduce uAPI to set group ASID

Follows the vDPA support for associating ASID to a specific virtqueue
group. This patch adds a uAPI to support setting them from userspace.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Gautam Dawar <gdawar@xilinx.com>
Message-Id: <20220330180436.24644-15-gdawar@xilinx.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vdpa.c

@@ -473,6 +473,14 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 		else if (copy_to_user(argp, &s, sizeof(s)))
 			return -EFAULT;
 		return 0;
+	case VHOST_VDPA_SET_GROUP_ASID:
+		if (copy_from_user(&s, argp, sizeof(s)))
+			return -EFAULT;
+		if (s.num >= vdpa->nas)
+			return -EINVAL;
+		if (!ops->set_group_asid)
+			return -EOPNOTSUPP;
+		return ops->set_group_asid(vdpa, idx, s.num);
 	case VHOST_GET_VRING_BASE:
 		r = ops->get_vq_state(v->vdpa, idx, &vq_state);
 		if (r)

include/uapi/linux/vhost.h

@@ -164,4 +164,11 @@
  */
 #define VHOST_VDPA_GET_VRING_GROUP	_IOWR(VHOST_VIRTIO, 0x7B,	\
 					      struct vhost_vring_state)
+/* Set the ASID for a virtqueue group. The group index is stored in
+ * the index field of vhost_vring_state, the ASID associated with this
+ * group is stored at num field of vhost_vring_state.
+ */
+#define VHOST_VDPA_SET_GROUP_ASID	_IOW(VHOST_VIRTIO, 0x7C, \
+					     struct vhost_vring_state)
+
 #endif