diff --git a/hw/piix_pci.c b/hw/piix_pci.c
index 80d6665..28a3ee2 100644
--- a/hw/piix_pci.c
+++ b/hw/piix_pci.c
@@ -242,7 +242,8 @@
                                   PCII440FXState **pi440fx_state,
                                   int *piix3_devfn,
                                   qemu_irq *pic,
-                                  MemoryRegion *address_space,
+                                  MemoryRegion *address_space_mem,
+                                  MemoryRegion *address_space_io,
                                   ram_addr_t ram_size)
 {
     DeviceState *dev;
@@ -253,8 +254,9 @@
 
     dev = qdev_create(NULL, "i440FX-pcihost");
     s = FROM_SYSBUS(I440FXState, sysbus_from_qdev(dev));
-    s->address_space = address_space;
-    b = pci_bus_new(&s->busdev.qdev, NULL, s->address_space, 0);
+    s->address_space = address_space_mem;
+    b = pci_bus_new(&s->busdev.qdev, NULL, s->address_space,
+                    address_space_io, 0);
     s->bus = b;
     qdev_init_nofail(dev);
 
@@ -291,13 +293,15 @@
 }
 
 PCIBus *i440fx_init(PCII440FXState **pi440fx_state, int *piix3_devfn,
-                    qemu_irq *pic, MemoryRegion *address_space,
+                    qemu_irq *pic,
+                    MemoryRegion *address_space_mem,
+                    MemoryRegion *address_space_io,
                     ram_addr_t ram_size)
 {
     PCIBus *b;
 
     b = i440fx_common_init("i440FX", pi440fx_state, piix3_devfn, pic,
-                           address_space, ram_size);
+                           address_space_mem, address_space_io, ram_size);
     return b;
 }