diff --git a/xen/include/xen/keyhandler.h b/xen/include/xen/keyhandler.h
index 39052b5e99..06c05c8723 100644
--- a/xen/include/xen/keyhandler.h
+++ b/xen/include/xen/keyhandler.h
@@ -24,6 +24,7 @@ typedef void (keyhandler_fn_t)(unsigned char key);
  *
  * Called in hardirq context with interrupts disabled.
  */
+struct cpu_user_regs;
 typedef void (irq_keyhandler_fn_t)(unsigned char key,
                                    struct cpu_user_regs *regs);