[RFC PATCH 15/24] vhost-vdpa: introduce uAPI to get the number of address spaces

[Jason Wang]

A new uAPI is introduced for the userspace to know the address spaces
that is supported by a specific device.

Signed-off-by: Jason Wang <jasow...@redhat.com>
---
 drivers/vhost/vdpa.c       | 3 +++
 include/uapi/linux/vhost.h | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 4b8882f55bc9..4d97a59824a1 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -532,6 +532,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
                r = copy_to_user(argp, &v->vdpa->ngroups,
                                 sizeof(v->vdpa->ngroups));
                break;
+       case VHOST_VDPA_GET_AS_NUM:
+               r = copy_to_user(argp, &v->vdpa->nas, sizeof(v->vdpa->nas));
+               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 19f1acdfe3ea..99bdf50efc50 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -145,4 +145,6 @@
 /* Get the number of virtqueue groups. */
 #define VHOST_VDPA_GET_GROUP_NUM       _IOR(VHOST_VIRTIO, 0x78, unsigned int)
 
+/* Get the number of address spaces. */
+#define VHOST_VDPA_GET_AS_NUM          _IOR(VHOST_VIRTIO, 0x79, unsigned int)
 #endif
-- 
2.20.1