diff --git a/hw/input/pckbd.c b/hw/input/pckbd.c
index c04a2c5..a70442e 100644
--- a/hw/input/pckbd.c
+++ b/hw/input/pckbd.c
@@ -675,6 +675,7 @@
 
 static Property i8042_mmio_properties[] = {
     DEFINE_PROP_UINT64("mask", MMIOKBDState, kbd.mask, UINT64_MAX),
+    DEFINE_PROP_UINT32("size", MMIOKBDState, size, -1),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -696,6 +697,7 @@
 
     dev = qdev_new(TYPE_I8042_MMIO);
     qdev_prop_set_uint64(dev, "mask", mask);
+    qdev_prop_set_uint32(dev, "size", size);
     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
     s = &I8042_MMIO(dev)->kbd;