[PATCH v5 10/14] vdpa net: block migration if the device has CVQ

["Eugenio Pérez" <eperezma@redhat.com>]

Devices with CVQ need to migrate state beyond vq state.  Leaving this to
future series.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
v5: Fix comment (s/v/s->vhost_vdpa/).
v3: Migration blocker is registered in vhost_dev.
---
 include/hw/virtio/vhost-vdpa.h | 1 +
 hw/virtio/vhost-vdpa.c         | 1 +
 net/vhost-vdpa.c               | 9 +++++++++
 3 files changed, 11 insertions(+)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index 4a7d396674..c278a2a8de 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -50,6 +50,7 @@ typedef struct vhost_vdpa {
     const VhostShadowVirtqueueOps *shadow_vq_ops;
     void *shadow_vq_ops_opaque;
     struct vhost_dev *dev;
+    Error *migration_blocker;
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostVDPA;
 
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 49afa59261..e9167977d5 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -438,6 +438,7 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
     v->msg_type = VHOST_IOTLB_MSG_V2;
     vhost_vdpa_init_svq(dev, v);
 
+    error_propagate(&dev->migration_blocker, v->migration_blocker);
     if (!vhost_vdpa_first_dev(dev)) {
         return 0;
     }
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 167b43679d..533ba54317 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -828,6 +828,15 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
 
         s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
         s->vhost_vdpa.shadow_vq_ops_opaque = s;
+
+        /*
+         * TODO: We cannot migrate devices with CVQ as there is no way to set
+         * the device state (MAC, MQ, etc) before starting the datapath.
+         *
+         * Migration blocker ownership now belongs to s->vhost_vdpa.
+         */
+        error_setg(&s->vhost_vdpa.migration_blocker,
+                   "net vdpa cannot migrate with CVQ feature");
     }
     ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
     if (ret) {
-- 
2.31.1