diff --git a/include/uapi/linux/hyperv.h b/include/uapi/linux/hyperv.h
index 0a8e6badb29bcf05f9a1c968a9c2e2c2d271df1e..bb1cb73c927ae78c84e3ea5a7f253be6040cfed7 100644
--- a/include/uapi/linux/hyperv.h
+++ b/include/uapi/linux/hyperv.h
@@ -134,6 +134,7 @@ struct hv_start_fcopy {
 
 struct hv_do_fcopy {
 	struct hv_fcopy_hdr hdr;
+	__u32   pad;
 	__u64	offset;
 	__u32	size;
 	__u8	data[DATA_FRAGMENT];