virtio-blk: store opt_io_size with correct size

The width of opt_io_size in virtio_blk_config is 32bit.  However, it's
written with virtio_stw_p; this may result in value truncation, and on
big-endian systems with legacy virtio in completely bogus readings in
the guest.

Use the appropriate accessor to store it.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200528225516.1676602-2-rvkagan@yandex-team.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 8882a1d1d429726d07be3e336eea259704a387f0..6938a75aa527d6b719f31d8181d0f7d8a8cff731 100644 (file)
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -930,7 +930,7 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
     virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls);
     virtio_stl_p(vdev, &blkcfg.blk_size, blk_size);
     virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size);
-    virtio_stw_p(vdev, &blkcfg.opt_io_size, conf->opt_io_size / blk_size);
+    virtio_stl_p(vdev, &blkcfg.opt_io_size, conf->opt_io_size / blk_size);
     blkcfg.geometry.heads = conf->heads;
     /*
      * We must ensure that the block device capacity is a multiple of