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>

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 264ddc166d6e879ca3dfcd3c7e070b9f67ff37b1..3b05bab44ddb7403de52c2c68ea36d699d55498a 100644 (file)
--- 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);
 }

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 220a9a2e6eb638f3d5d2d4b93bd31f6d2bccb37c..65f896314b54c1f5e8acbbb0bd0dd835b46f7d1d 100644 (file)
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -428,15 +428,11 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
 
     shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_svq_free);
     for (unsigned n = 0; n < hdev->nvqs; ++n) {
-        g_autoptr(VhostShadowVirtqueue) svq;
+        VhostShadowVirtqueue *svq;
 
         svq = vhost_svq_new(v->iova_tree, v->shadow_vq_ops,
                             v->shadow_vq_ops_opaque);
-        if (unlikely(!svq)) {
-            error_setg(errp, "Cannot create svq %u", n);
-            return -1;
-        }
-        g_ptr_array_add(shadow_vqs, g_steal_pointer(&svq));
+        g_ptr_array_add(shadow_vqs, svq);
     }
 
     v->shadow_vqs = g_steal_pointer(&shadow_vqs);
@@ -864,11 +860,23 @@ static int vhost_vdpa_svq_set_fds(struct vhost_dev *dev,
     const EventNotifier *event_notifier = &svq->hdev_kick;
     int r;
 
+    r = event_notifier_init(&svq->hdev_kick, 0);
+    if (r != 0) {
+        error_setg_errno(errp, -r, "Couldn't create kick event notifier");
+        goto err_init_hdev_kick;
+    }
+
+    r = event_notifier_init(&svq->hdev_call, 0);
+    if (r != 0) {
+        error_setg_errno(errp, -r, "Couldn't create call event notifier");
+        goto err_init_hdev_call;
+    }
+
     file.fd = event_notifier_get_fd(event_notifier);
     r = vhost_vdpa_set_vring_dev_kick(dev, &file);
     if (unlikely(r != 0)) {
         error_setg_errno(errp, -r, "Can't set device kick fd");
-        return r;
+        goto err_init_set_dev_fd;
     }
 
     event_notifier = &svq->hdev_call;
@@ -876,8 +884,18 @@ static int vhost_vdpa_svq_set_fds(struct vhost_dev *dev,
     r = vhost_vdpa_set_vring_dev_call(dev, &file);
     if (unlikely(r != 0)) {
         error_setg_errno(errp, -r, "Can't set device call fd");
+        goto err_init_set_dev_fd;
     }
 
+    return 0;
+
+err_init_set_dev_fd:
+    event_notifier_set_handler(&svq->hdev_call, NULL);
+
+err_init_hdev_call:
+    event_notifier_cleanup(&svq->hdev_kick);
+
+err_init_hdev_kick:
     return r;
 }
 
@@ -1089,6 +1107,9 @@ static void vhost_vdpa_svqs_stop(struct vhost_dev *dev)
     for (unsigned i = 0; i < v->shadow_vqs->len; ++i) {
         VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
         vhost_vdpa_svq_unmap_rings(dev, svq);
+
+        event_notifier_cleanup(&svq->hdev_kick);
+        event_notifier_cleanup(&svq->hdev_call);
     }
 }