[PATCH 12/21] vhost-vdpa: introduce uAPI to get the number of virtqueue groups

[Jason Wang]

Follows the vDPA support for multiple address spaces, this patch
introduce uAPI for the userspace to know the number of virtqueue
groups supported by the vDPA device.

Signed-off-by: Jason Wang <jasow...@redhat.com>
---
 drivers/vhost/vdpa.c       | 4 ++++
 include/uapi/linux/vhost.h | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 060d5b5b7e64..1ba5901b28e7 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -536,6 +536,10 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
        case VHOST_VDPA_GET_VRING_NUM:
                r = vhost_vdpa_get_vring_num(v, argp);
                break;
+       case VHOST_VDPA_GET_GROUP_NUM:
+               r = copy_to_user(argp, &v->vdpa->ngroups,
+                                sizeof(v->vdpa->ngroups));
+               break;
        case VHOST_SET_LOG_BASE:
        case VHOST_SET_LOG_FD:
                r = -ENOIOCTLCMD;
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index 59c6c0fbaba1..8a4e6e426bbf 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -145,4 +145,7 @@
 /* Get the valid iova range */
 #define VHOST_VDPA_GET_IOVA_RANGE      _IOR(VHOST_VIRTIO, 0x78, \
                                             struct vhost_vdpa_iova_range)
+/* Get the number of virtqueue groups. */
+#define VHOST_VDPA_GET_GROUP_NUM       _IOR(VHOST_VIRTIO, 0x79, unsigned int)
+
 #endif
-- 
2.25.1