diff --git a/hw/i386/x86-iommu.c b/hw/i386/x86-iommu.c
index 51de519ec30896ba206fef47d49648942c975f5b..8a01a2dd25de8fa4f19631a14c8f7000217eb0c2 100644
--- a/hw/i386/x86-iommu.c
+++ b/hw/i386/x86-iommu.c
@@ -88,7 +88,7 @@ static void x86_iommu_realize(DeviceState *dev, Error **errp)
         PC_MACHINE(object_dynamic_cast(OBJECT(ms), TYPE_PC_MACHINE));
     QLIST_INIT(&x86_iommu->iec_notifiers);
 
-    if (!pcms) {
+    if (!pcms || !pcms->bus) {
         error_setg(errp, "Machine-type '%s' not supported by IOMMU",
                    mc->name);
         return;