diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h
index fb22bccfbc8a..7ef45a4a3cba 100644
--- a/tools/virtio/linux/kernel.h
+++ b/tools/virtio/linux/kernel.h
@@ -23,6 +23,10 @@
 #define PAGE_MASK (~(PAGE_SIZE-1))
 #define PAGE_ALIGN(x) ((x + PAGE_SIZE - 1) & PAGE_MASK)
 
+/* generic data direction definitions */
+#define READ                    0
+#define WRITE                   1
+
 typedef unsigned long long phys_addr_t;
 typedef unsigned long long dma_addr_t;
 typedef size_t __kernel_size_t;