diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index f2a4e863fc..cb0143ea77 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -508,7 +508,12 @@ struct BlockDriver {
         BlockDriverState *bs, BlockdevAmendOptions *opts, bool force,
         Error **errp);
 
-    /* aio */
+    /*
+     * AIO
+     * The given completion callback will be run in the same AioContext as the
+     * one in which the AIO function was called.
+     */
+
     BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_preadv)(BlockDriverState *bs,
         int64_t offset, int64_t bytes, QEMUIOVector *qiov,
         BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque);