diff --git a/hw/ub/ub_ummu.c b/hw/ub/ub_ummu.c
index 5eff0c1f6ed4b6f64814454046c8877af960844a..23f2c6c7985804a75a12b9ed37b51cfd685a039e 100644
--- a/hw/ub/ub_ummu.c
+++ b/hw/ub/ub_ummu.c
@@ -918,7 +918,9 @@ static void ummu_glb_int_enable(UMMUState *u, UMMUUSIVectorType type)
     KVMRouteChange route_change;
     USIMessage msg;
     uint32_t interrupt_id = UMMU_INTERRUPT_ID;
-
+    if (!kvm_state) {
+        return;
+    }
     if (type == UMMU_USI_VECTOR_EVETQ) {
         msg = ummu_get_eventq_usi_message(u);
     } else {
diff --git a/hw/vfio/ub.c b/hw/vfio/ub.c
index 1f0d511bc0d9241612402b857da6986e6479d62f..ab2beea49298b67532034b9b4803a80516542396 100644
--- a/hw/vfio/ub.c
+++ b/hw/vfio/ub.c
@@ -536,7 +536,7 @@ static int vfio_usi_vector_do_use(UBDevice *udev, uint16_t nr, USIMessage *msg,
             vfio_update_kvm_usi_virq(vector, *msg, udev);
         }
     } else {
-        if (msg) {
+        if (msg && kvm_state) {
             vfio_route_change = kvm_irqchip_begin_route_changes(kvm_state);
             vfio_add_kvm_usi_virq(vdev, vector, nr);
             kvm_irqchip_commit_route_changes(&vfio_route_change);
@@ -1283,4 +1283,4 @@ static void register_vfio_ub_dev_types(void)
     type_register_static(&vfio_ub_dev_info);
 }
 
-type_init(register_vfio_ub_dev_types)
\ No newline at end of file
+type_init(register_vfio_ub_dev_types)