From 8010d3fce008dd13f155bc0babfe236ea44a2712 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Fri, 11 Oct 2019 15:58:03 +0200
Subject: [PATCH] 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>
(cherry picked from commit 1dd713837cac8ec5a97d3b8492d72ce5ac94803c)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/virtio/virtio.c         | 7 +++++++
 include/hw/virtio/virtio.h | 6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index a94ea18a9c..7c3822c3a0 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2287,6 +2287,13 @@ 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 b189788cb2..f9f62370e9 100644
--- 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;
 
-- 
2.23.0