diff --git a/hw/pci-host/prep.c b/hw/pci-host/prep.c
index 84d50ca..629735e 100644
--- a/hw/pci-host/prep.c
+++ b/hw/pci-host/prep.c
@@ -54,8 +54,12 @@ typedef struct PRePPCIState {
 
     qemu_irq irq[PCI_NUM_PINS];
     PCIBus pci_bus;
+    AddressSpace pci_io_as;
+    MemoryRegion pci_io_non_contiguous;
     MemoryRegion pci_intack;
     RavenPCIState pci_dev;
+
+    int contiguous_map;
 } PREPPCIState;
 
 #define BIOS_SIZE (1024 * 1024)
@@ -107,6 +111,71 @@ static const MemoryRegionOps PPC_intack_ops = {
     },
 };
 
+static inline hwaddr raven_io_address(PREPPCIState *s,
+                                      hwaddr addr)
+{
+    if (s->contiguous_map == 0) {
+        /* 64 KB contiguous space for IOs */
+        addr &= 0xFFFF;
+    } else {
+        /* 8 MB non-contiguous space for IOs */
+        addr = (addr & 0x1F) | ((addr & 0x007FFF000) >> 7);
+    }
+
+    /* FIXME: handle endianness switch */
+
+    return addr;
+}
+
+static uint64_t raven_io_read(void *opaque, hwaddr addr,
+                              unsigned int size)
+{
+    PREPPCIState *s = opaque;
+    uint8_t buf[4];
+
+    addr = raven_io_address(s, addr);
+    address_space_read(&s->pci_io_as, addr, buf, size);
+
+    if (size == 1) {
+        return buf[0];
+    } else if (size == 2) {
+        return lduw_p(buf);
+    } else if (size == 4) {
+        return ldl_p(buf);
+    } else {
+        g_assert_not_reached();
+    }
+}
+
+static void raven_io_write(void *opaque, hwaddr addr,
+                           uint64_t val, unsigned int size)
+{
+    PREPPCIState *s = opaque;
+    uint8_t buf[4];
+
+    addr = raven_io_address(s, addr);
+
+    if (size == 1) {
+        buf[0] = val;
+    } else if (size == 2) {
+        stw_p(buf, val);
+    } else if (size == 4) {
+        stl_p(buf, val);
+    } else {
+        g_assert_not_reached();
+    }
+
+    address_space_write(&s->pci_io_as, addr, buf, size);
+}
+
+static const MemoryRegionOps raven_io_ops = {
+    .read = raven_io_read,
+    .write = raven_io_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .impl.max_access_size = 4,
+    .valid.unaligned = true,
+};
+
 static int prep_map_irq(PCIDevice *pci_dev, int irq_num)
 {
     return (irq_num + (pci_dev->devfn >> 3)) & 1;
@@ -119,6 +188,13 @@ static void prep_set_irq(void *opaque, int irq_num, int level)
     qemu_set_irq(pic[irq_num] , level);
 }
 
+static void raven_change_gpio(void *opaque, int n, int level)
+{
+    PREPPCIState *s = opaque;
+
+    s->contiguous_map = level;
+}
+
 static void raven_pcihost_realizefn(DeviceState *d, Error **errp)
 {
     SysBusDevice *dev = SYS_BUS_DEVICE(d);
@@ -133,6 +209,8 @@ static void raven_pcihost_realizefn(DeviceState *d, Error **errp)
         sysbus_init_irq(dev, &s->irq[i]);
     }
 
+    qdev_init_gpio_in(d, raven_change_gpio, 1);
+
     pci_bus_irqs(&s->pci_bus, prep_set_irq, prep_map_irq, s->irq, PCI_NUM_PINS);
 
     memory_region_init_io(&h->conf_mem, OBJECT(h), &pci_host_conf_be_ops, s,
@@ -164,6 +242,13 @@ static void raven_pcihost_initfn(Object *obj)
     MemoryRegion *address_space_io = get_system_io();
     DeviceState *pci_dev;
 
+    memory_region_init_io(&s->pci_io_non_contiguous, obj, &raven_io_ops, s,
+                          "pci-io-non-contiguous", 0x00800000);
+    address_space_init(&s->pci_io_as, get_system_io(), "raven-io");
+
+    /* CPU address space */
+    memory_region_add_subregion_overlap(address_space_mem, 0x80000000,
+                                        &s->pci_io_non_contiguous, 1);
     pci_bus_new_inplace(&s->pci_bus, sizeof(s->pci_bus), DEVICE(obj), NULL,
                         address_space_mem, address_space_io, 0, TYPE_PCI_BUS);
     h->bus = &s->pci_bus;
diff --git a/hw/ppc/prep.c b/hw/ppc/prep.c
index 81e13cb..035b5b2 100644
--- a/hw/ppc/prep.c
+++ b/hw/ppc/prep.c
@@ -185,6 +185,7 @@ typedef struct sysctrl_t {
     uint8_t state;
     uint8_t syscontrol;
     int contiguous_map;
+    qemu_irq contiguous_map_irq;
     int endian;
 } sysctrl_t;
 
@@ -253,6 +254,7 @@ static void PREP_io_800_writeb (void *opaque, uint32_t addr, uint32_t val)
     case 0x0850:
         /* I/O map type register */
         sysctrl->contiguous_map = val & 0x01;
+        qemu_set_irq(sysctrl->contiguous_map_irq, sysctrl->contiguous_map);
         break;
     default:
         printf("ERROR: unaffected IO port write: %04" PRIx32
@@ -327,91 +329,6 @@ static uint32_t PREP_io_800_readb (void *opaque, uint32_t addr)
     return retval;
 }
 
-static inline hwaddr prep_IO_address(sysctrl_t *sysctrl,
-                                                 hwaddr addr)
-{
-    if (sysctrl->contiguous_map == 0) {
-        /* 64 KB contiguous space for IOs */
-        addr &= 0xFFFF;
-    } else {
-        /* 8 MB non-contiguous space for IOs */
-        addr = (addr & 0x1F) | ((addr & 0x007FFF000) >> 7);
-    }
-
-    return addr;
-}
-
-static void PPC_prep_io_writeb (void *opaque, hwaddr addr,
-                                uint32_t value)
-{
-    sysctrl_t *sysctrl = opaque;
-
-    addr = prep_IO_address(sysctrl, addr);
-    cpu_outb(addr, value);
-}
-
-static uint32_t PPC_prep_io_readb (void *opaque, hwaddr addr)
-{
-    sysctrl_t *sysctrl = opaque;
-    uint32_t ret;
-
-    addr = prep_IO_address(sysctrl, addr);
-    ret = cpu_inb(addr);
-
-    return ret;
-}
-
-static void PPC_prep_io_writew (void *opaque, hwaddr addr,
-                                uint32_t value)
-{
-    sysctrl_t *sysctrl = opaque;
-
-    addr = prep_IO_address(sysctrl, addr);
-    PPC_IO_DPRINTF("0x" TARGET_FMT_plx " => 0x%08" PRIx32 "\n", addr, value);
-    cpu_outw(addr, value);
-}
-
-static uint32_t PPC_prep_io_readw (void *opaque, hwaddr addr)
-{
-    sysctrl_t *sysctrl = opaque;
-    uint32_t ret;
-
-    addr = prep_IO_address(sysctrl, addr);
-    ret = cpu_inw(addr);
-    PPC_IO_DPRINTF("0x" TARGET_FMT_plx " <= 0x%08" PRIx32 "\n", addr, ret);
-
-    return ret;
-}
-
-static void PPC_prep_io_writel (void *opaque, hwaddr addr,
-                                uint32_t value)
-{
-    sysctrl_t *sysctrl = opaque;
-
-    addr = prep_IO_address(sysctrl, addr);
-    PPC_IO_DPRINTF("0x" TARGET_FMT_plx " => 0x%08" PRIx32 "\n", addr, value);
-    cpu_outl(addr, value);
-}
-
-static uint32_t PPC_prep_io_readl (void *opaque, hwaddr addr)
-{
-    sysctrl_t *sysctrl = opaque;
-    uint32_t ret;
-
-    addr = prep_IO_address(sysctrl, addr);
-    ret = cpu_inl(addr);
-    PPC_IO_DPRINTF("0x" TARGET_FMT_plx " <= 0x%08" PRIx32 "\n", addr, ret);
-
-    return ret;
-}
-
-static const MemoryRegionOps PPC_prep_io_ops = {
-    .old_mmio = {
-        .read = { PPC_prep_io_readb, PPC_prep_io_readw, PPC_prep_io_readl },
-        .write = { PPC_prep_io_writeb, PPC_prep_io_writew, PPC_prep_io_writel },
-    },
-    .endianness = DEVICE_NATIVE_ENDIAN,
-};
 
 #define NVRAM_SIZE        0x2000
 
@@ -458,7 +375,6 @@ static void ppc_prep_init(QEMUMachineInitArgs *args)
     CPUPPCState *env = NULL;
     nvram_t nvram;
     M48t59State *m48t59;
-    MemoryRegion *PPC_io_memory = g_new(MemoryRegion, 1);
     PortioList *port_list = g_new(PortioList, 1);
 #if 0
     MemoryRegion *xcsr = g_new(MemoryRegion, 1);
@@ -567,6 +483,7 @@ static void ppc_prep_init(QEMUMachineInitArgs *args)
         fprintf(stderr, "Couldn't create PCI host controller.\n");
         exit(1);
     }
+    sysctrl->contiguous_map_irq = qdev_get_gpio_in(dev, 0);
 
     /* PCI -> ISA bridge */
     pci = pci_create_simple(pci_bus, PCI_DEVFN(1, 0), "i82378");
@@ -587,11 +504,6 @@ static void ppc_prep_init(QEMUMachineInitArgs *args)
     qdev_prop_set_uint8(dev, "config", 13); /* fdc, ser0, ser1, par0 */
     qdev_init_nofail(dev);
 
-    /* Register 8 MB of ISA IO space (needed for non-contiguous map) */
-    memory_region_init_io(PPC_io_memory, NULL, &PPC_prep_io_ops, sysctrl,
-                          "ppc-io", 0x00800000);
-    memory_region_add_subregion(sysmem, 0x80000000, PPC_io_memory);
-
     /* init basic PC hardware */
     pci_vga_init(pci_bus);
 
