[Qemu-devel] [PATCH v5 09/21] vhost-user: add a migration blocker

[marcandre.lureau@redhat.com]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

If VHOST_USER_PROTOCOL_F_LOG_SHMFD is not announced, block vhost-user
migration.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost-user.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 6420efd..ff87e87 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -15,6 +15,7 @@
 #include "qemu/error-report.h"
 #include "qemu/sockets.h"
 #include "exec/ram_addr.h"
+#include "migration/migration.h"
 
 #include <fcntl.h>
 #include <unistd.h>
@@ -442,6 +443,14 @@ static int vhost_user_init(struct vhost_dev *dev, void *opaque)
         }
     }
 
+    if (!virtio_has_feature(dev->protocol_features,
+                            VHOST_USER_PROTOCOL_F_LOG_SHMFD)) {
+        migrate_add_blocker(dev->migration_blocker);
+        error_setg(&dev->migration_blocker,
+                   "Migration disabled: vhost-user backend lacks "
+                   "VHOST_USER_PROTOCOL_F_LOG_SHMFD feature.");
+    }
+
     return 0;
 }
 
@@ -466,6 +475,10 @@ static int vhost_user_cleanup(struct vhost_dev *dev)
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
 
     dev->opaque = 0;
+    if (dev->migration_blocker) {
+        migrate_del_blocker(dev->migration_blocker);
+        error_free(dev->migration_blocker);
+    }
 
     return 0;
 }
-- 
2.4.3