diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index 1b6e5065a3..2d7d3a4645 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -715,6 +715,7 @@ static void vfio_listener_region_del(MemoryListener *listener,
         bool unmap_all = false;
 
         if (int128_eq(llsize, int128_2_64())) {
+            assert(!iova);
             unmap_all = true;
             llsize = int128_zero();
         }