diff --git a/hw/core/machine.c b/hw/core/machine.c
index 2fe6ff6f30..e5a456f21d 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -65,6 +65,9 @@ static void machine_set_kernel_irqchip(Object *obj, Visitor *v,
             ms->kernel_irqchip_split = true;
             break;
         default:
+            /* The value was checked in visit_type_OnOffSplit() above. If
+             * we get here, then something is wrong in QEMU.
+             */
             abort();
         }
     }