virtio: new post_load hook

Post load hook in virtio vmsd is called early while device is processed,
and when VirtIODevice core isn't fully initialized.  Most device
specific code isn't ready to deal with a device in such state, and
behaves weirdly.

Add a new post_load hook in a device class instead.  Devices should use
this unless they specifically want to verify the migration stream as
it's processed, e.g. for bounds checking.

Cc: qemu-stable@nongnu.org
Suggested-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mikhail Sennikovsky <mikhail.sennikovskii@cloud.ionos.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 527df03bfd0a88d3a9c5c44f08b17c630698ec0e..54a46e204cb32266d3dbbd32ee027250b8dfda24 100644 (file)
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2291,6 +2291,13 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
     }
     rcu_read_unlock();
 
+    if (vdc->post_load) {
+        ret = vdc->post_load(vdev);
+        if (ret) {
+            return ret;
+        }
+    }
+
     return 0;
 }
 

diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 48e8d04ff6fc49b3c3bc8dd6aaebe1ad6decd198..ca4f9c0bcc2e31da7d1cd7ecc0dd547dc8bb7393 100644 (file)
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -158,6 +158,12 @@ typedef struct VirtioDeviceClass {
      */
     void (*save)(VirtIODevice *vdev, QEMUFile *f);
     int (*load)(VirtIODevice *vdev, QEMUFile *f, int version_id);
+    /* Post load hook in vmsd is called early while device is processed, and
+     * when VirtIODevice isn't fully initialized.  Devices should use this instead,
+     * unless they specifically want to verify the migration stream as it's
+     * processed, e.g. for bounds checking.
+     */
+    int (*post_load)(VirtIODevice *vdev);
     const VMStateDescription *vmsd;
 } VirtioDeviceClass;