vdpa: do not set virtio status bits if unneeded

Next commits will set DRIVER and ACKNOWLEDGE flags repeatedly in the case of a migration destination. Let's save ioctls with this. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Message-Id: <20231215172830.2540987-2-eperezma@redhat.com>
qemu · Dec 26, 2023 · bc865bf · bc865bf
1 parent 410cefb
commit bc865bf
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
@@ -511,6 +511,10 @@ static int vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
     if (ret < 0) {
         return ret;
     }
+    if ((s & status) == status) {
+        /* Don't set bits already set */
+        return 0;
+    }
 
     s |= status;