diff --git a/sys/amd64/vmm/vmm_instruction_emul.c b/sys/amd64/vmm/vmm_instruction_emul.c
index 809fa16bce46..06dffe6a80b9 100644
--- a/sys/amd64/vmm/vmm_instruction_emul.c
+++ b/sys/amd64/vmm/vmm_instruction_emul.c
@@ -58,6 +58,7 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 #include <strings.h>
 #include <vmmapi.h>
+#define	__diagused
 #define	KASSERT(exp,msg)	assert((exp))
 #define	panic(...)		errx(4, __VA_ARGS__)
 #endif	/* _KERNEL */