diff --git a/sys/amd64/vmm/vmm_instruction_emul.c b/sys/amd64/vmm/vmm_instruction_emul.c
index ae022210893..809fa16bce4 100644
--- a/sys/amd64/vmm/vmm_instruction_emul.c
+++ b/sys/amd64/vmm/vmm_instruction_emul.c
@@ -717,7 +717,7 @@ get_gla(void *vm, int vcpuid, struct vie *vie, struct vm_guest_paging *paging,
 {
 	struct seg_desc desc;
 	uint64_t cr0, val, rflags;
-	int error;
+	int error __diagused;
 
 	error = vie_read_register(vm, vcpuid, VM_REG_GUEST_CR0, &cr0);
 	KASSERT(error == 0, ("%s: error %d getting cr0", __func__, error));