diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
index a3cbfb6..f027521 100644
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -263,6 +263,18 @@ static QEMUMachine s390_machine_v0_12 = {
     .use_virtcon = 1,
     .no_vga = 1,
     .max_cpus = 255,
+    .compat_props = (GlobalProperty[]) {
+        {
+            .driver   = "virtio-serial-s390",
+            .property = "max_nr_ports",
+            .value    = stringify(1),
+        },{
+            .driver   = "virtio-serial-s390",
+            .property = "vectors",
+            .value    = stringify(0),
+        },
+        { /* end of list */ }
+  },
 };
 
 static void s390_machine_init(void)