diff --git a/hw/mips/gt64xxx_pci.c b/hw/mips/gt64xxx_pci.c
index 815ef0711dea4c5b86ac877cc0b84d02b31e1baf..2fa313f49883d4007ba94e0f199ab713b63462e6 100644
--- a/hw/mips/gt64xxx_pci.c
+++ b/hw/mips/gt64xxx_pci.c
@@ -23,6 +23,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/units.h"
 #include "qemu/log.h"
 #include "hw/hw.h"
 #include "hw/mips/mips.h"
@@ -1201,7 +1202,7 @@ PCIBus *gt64120_register(qemu_irq *pic)
     dev = qdev_create(NULL, TYPE_GT64120_PCI_HOST_BRIDGE);
     d = GT64120_PCI_HOST_BRIDGE(dev);
     phb = PCI_HOST_BRIDGE(dev);
-    memory_region_init(&d->pci0_mem, OBJECT(dev), "pci0-mem", UINT32_MAX);
+    memory_region_init(&d->pci0_mem, OBJECT(dev), "pci0-mem", 4 * GiB);
     address_space_init(&d->pci0_mem_as, &d->pci0_mem, "pci0-mem");
     phb->bus = pci_register_root_bus(dev, "pci",
                                      gt64120_pci_set_irq, gt64120_pci_map_irq,