diff --git a/xen/include/public/io/blkif.h b/xen/include/public/io/blkif.h
index 664345ac2b..a5b0147b39 100644
--- a/xen/include/public/io/blkif.h
+++ b/xen/include/public/io/blkif.h
@@ -11,7 +11,9 @@
 
 #include "ring.h"
 
+#ifndef blkif_vdev_t
 #define blkif_vdev_t   u16
+#endif
 #define blkif_sector_t u64
 
 #define BLKIF_OP_READ      0
diff --git a/xen/include/public/io/domain_controller.h b/xen/include/public/io/domain_controller.h
index 418d714e60..3a9f2e8bf7 100644
--- a/xen/include/public/io/domain_controller.h
+++ b/xen/include/public/io/domain_controller.h
@@ -87,10 +87,10 @@ typedef struct control_if {
 #define CMSG_BLKIF_FE_INTERFACE_DISCONNECT      34
 #define CMSG_BLKIF_FE_INTERFACE_QUERY           35
 
-/* These are used by both front-end and back-end drivers. */
+#ifndef blkif_vdev_t
 #define blkif_vdev_t   u16
+#endif
 #define blkif_pdev_t   u32
-#define blkif_sector_t u64
 
 /*
  * CMSG_BLKIF_FE_INTERFACE_STATUS: