diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 2a7807578e..30de25de5c 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -850,11 +850,31 @@ static void spapr_reset_htab(sPAPREnvironment *spapr)
     }
 }
 
+static int find_unknown_sysbus_device(SysBusDevice *sbdev, void *opaque)
+{
+    bool matched = false;
+
+    if (object_dynamic_cast(OBJECT(sbdev), TYPE_SPAPR_PCI_HOST_BRIDGE)) {
+        matched = true;
+    }
+
+    if (!matched) {
+        error_report("Device %s is not supported by this machine yet.",
+                     qdev_fw_name(DEVICE(sbdev)));
+        exit(1);
+    }
+
+    return 0;
+}
+
 static void ppc_spapr_reset(void)
 {
     PowerPCCPU *first_ppc_cpu;
     uint32_t rtas_limit;
 
+    /* Check for unknown sysbus devices */
+    foreach_dynamic_sysbus_device(find_unknown_sysbus_device, NULL);
+
     /* Reset the hash table & recalc the RMA */
     spapr_reset_htab(spapr);
 
@@ -1667,6 +1687,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     mc->no_parallel = 1;
     mc->default_boot_order = NULL;
     mc->kvm_type = spapr_kvm_type;
+    mc->has_dynamic_sysbus = true;
 
     fwc->get_dev_path = spapr_get_fw_dev_path;
     nc->nmi_monitor_handler = spapr_nmi;