vhost-user: add a new message to disable/enable a specific virt queue.

Add a new message, VHOST_USER_SET_VRING_ENABLE, to enable or disable
a specific virt queue, which is similar to attach/detach queue for
tap device.

virtio driver on guest doesn't have to use max virt queue pair, it
could enable any number of virt queue ranging from 1 to max virt
queue pair.

Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Tested-by: Marcel Apfelbaum <marcel@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
index e1dfc6d..3a0f6e2 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -25,6 +25,7 @@ typedef int (*vhost_call)(struct vhost_dev *dev, unsigned long int request,
 typedef int (*vhost_backend_init)(struct vhost_dev *dev, void *opaque);
 typedef int (*vhost_backend_cleanup)(struct vhost_dev *dev);
 typedef int (*vhost_backend_get_vq_index)(struct vhost_dev *dev, int idx);
+typedef int (*vhost_backend_set_vring_enable)(struct vhost_dev *dev, int enable);
 
 typedef struct VhostOps {
     VhostBackendType backend_type;
@@ -32,6 +33,7 @@ typedef struct VhostOps {
     vhost_backend_init vhost_backend_init;
     vhost_backend_cleanup vhost_backend_cleanup;
     vhost_backend_get_vq_index vhost_backend_get_vq_index;
+    vhost_backend_set_vring_enable vhost_backend_set_vring_enable;
 } VhostOps;
 
 extern const VhostOps user_ops;