[qemu-xen stable-4.13] vhost: Fix memory region section comparison

[patchbot@xxxxxxx]

commit 145b562990d252aeca7c37c21eb7e7110cfceffc
Author:     Dr. David Alan Gilbert <dgilbert@xxxxxxxxxx>
AuthorDate: Wed Aug 14 18:55:35 2019 +0100
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Tue Nov 12 16:23:54 2019 -0600

    vhost: Fix memory region section comparison
    
    Using memcmp to compare structures wasn't safe,
    as I found out on ARM when I was getting falce miscompares.
    
    Use the helper function for comparing the MRSs.
    
    Fixes: ade6d081fc33948e56e6 ("vhost: Regenerate region list from changed 
sections list")
    Cc: qemu-stable@xxxxxxxxxx
    Signed-off-by: Dr. David Alan Gilbert <dgilbert@xxxxxxxxxx>
    Message-Id: <20190814175535.2023-4-dgilbert@xxxxxxxxxx>
    Reviewed-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    (cherry picked from commit 3fc4a64cbaed2ddee4c60ddc06740b320e18ab82)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 hw/virtio/vhost.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index bc899fc60e..2ef4bc720f 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -451,8 +451,13 @@ static void vhost_commit(MemoryListener *listener)
         changed = true;
     } else {
         /* Same size, lets check the contents */
-        changed = n_old_sections && memcmp(dev->mem_sections, old_sections,
-                         n_old_sections * sizeof(old_sections[0])) != 0;
+        for (int i = 0; i < n_old_sections; i++) {
+            if (!MemoryRegionSection_eq(&old_sections[i],
+                                        &dev->mem_sections[i])) {
+                changed = true;
+                break;
+            }
+        }
     }
 
     trace_vhost_commit(dev->started, changed);
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.13