diff --git a/include/system/memory.h b/include/system/memory.h
index fbbf4cf911..fc35a0dcad 100644
--- a/include/system/memory.h
+++ b/include/system/memory.h
@@ -183,6 +183,7 @@ struct IOMMUNotifier {
     hwaddr start;
     hwaddr end;
     int iommu_idx;
+    void *opaque;
     QLIST_ENTRY(IOMMUNotifier) node;
 };
 typedef struct IOMMUNotifier IOMMUNotifier;