vhost: allocate SVQ device file descriptors at device start

The next patches will start control SVQ if possible. However, we don't
know if that will be possible at qemu boot anymore.

Delay device file descriptors until we know it at device start. This
will avoid to create them if the device does not support SVQ.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20221215113144.322011-4-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 2 insertions, 29 deletions

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 264ddc166d..3b05bab44d 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -715,43 +715,18 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
  * @iova_tree: Tree to perform descriptors translations
  * @ops: SVQ owner callbacks
  * @ops_opaque: ops opaque pointer
- *
- * Returns the new virtqueue or NULL.
- *
- * In case of error, reason is reported through error_report.
  */
 VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree,
                                     const VhostShadowVirtqueueOps *ops,
                                     void *ops_opaque)
 {
-    g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
-    int r;
-
-    r = event_notifier_init(&svq->hdev_kick, 0);
-    if (r != 0) {
-        error_report("Couldn't create kick event notifier: %s (%d)",
-                     g_strerror(errno), errno);
-        goto err_init_hdev_kick;
-    }
-
-    r = event_notifier_init(&svq->hdev_call, 0);
-    if (r != 0) {
-        error_report("Couldn't create call event notifier: %s (%d)",
-                     g_strerror(errno), errno);
-        goto err_init_hdev_call;
-    }
+    VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
 
     event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
     svq->iova_tree = iova_tree;
     svq->ops = ops;
     svq->ops_opaque = ops_opaque;
-    return g_steal_pointer(&svq);
-
-err_init_hdev_call:
-    event_notifier_cleanup(&svq->hdev_kick);
-
-err_init_hdev_kick:
-    return NULL;
+    return svq;
 }
 
 /**
@@ -763,7 +738,5 @@ void vhost_svq_free(gpointer pvq)
 {
     VhostShadowVirtqueue *vq = pvq;
     vhost_svq_stop(vq);
-    event_notifier_cleanup(&vq->hdev_kick);
-    event_notifier_cleanup(&vq->hdev_call);
     g_free(vq);
 }