virtio-blk: propagate the required alignment

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

hw/virtio-blk.c

@@ -540,6 +540,7 @@ VirtIODevice *virtio_blk_init(DeviceState *dev, BlockConf *conf)
     register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
                     virtio_blk_save, virtio_blk_load, s);
     bdrv_set_removable(s->bs, 0);
+    s->bs->buffer_alignment = conf->logical_block_size;
 
     return &s->vdev;
 }