diff --git a/hw/cuda.c b/hw/cuda.c
index 065c362..5c92d81 100644
--- a/hw/cuda.c
+++ b/hw/cuda.c
@@ -117,6 +117,7 @@ typedef struct CUDATimer {
 } CUDATimer;
 
 typedef struct CUDAState {
+    MemoryRegion mem;
     /* cuda registers */
     uint8_t b;      /* B-side data */
     uint8_t a;      /* A-side data */
@@ -722,7 +723,7 @@ static void cuda_reset(void *opaque)
     set_counter(s, &s->timers[1], 0xffff);
 }
 
-void cuda_init (int *cuda_mem_index, qemu_irq irq)
+void cuda_init (MemoryRegion **cuda_mem, qemu_irq irq)
 {
     struct tm tm;
     CUDAState *s = &cuda_state;
@@ -738,8 +739,9 @@ void cuda_init (int *cuda_mem_index, qemu_irq irq)
     s->tick_offset = (uint32_t)mktimegm(&tm) + RTC_OFFSET;
 
     s->adb_poll_timer = qemu_new_timer_ns(vm_clock, cuda_adb_poll, s);
-    *cuda_mem_index = cpu_register_io_memory(cuda_read, cuda_write, s,
+    cpu_register_io_memory(cuda_read, cuda_write, s,
                                              DEVICE_NATIVE_ENDIAN);
+    *cuda_mem = &s->mem;
     vmstate_register(NULL, -1, &vmstate_cuda, s);
     qemu_register_reset(cuda_reset, s);
 }
diff --git a/hw/escc.c b/hw/escc.c
index f6fd919..bea5873 100644
--- a/hw/escc.c
+++ b/hw/escc.c
@@ -126,7 +126,7 @@ struct SerialState {
     SysBusDevice busdev;
     struct ChannelState chn[2];
     uint32_t it_shift;
-    int mmio_index;
+    MemoryRegion mmio;
     uint32_t disabled;
     uint32_t frequency;
 };
@@ -490,7 +490,8 @@ static void escc_update_parameters(ChannelState *s)
     qemu_chr_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
 }
 
-static void escc_mem_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)
+static void escc_mem_write(void *opaque, target_phys_addr_t addr,
+                           uint64_t val, unsigned size)
 {
     SerialState *serial = opaque;
     ChannelState *s;
@@ -592,7 +593,8 @@ static void escc_mem_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)
     }
 }
 
-static uint32_t escc_mem_readb(void *opaque, target_phys_addr_t addr)
+static uint64_t escc_mem_read(void *opaque, target_phys_addr_t addr,
+                              unsigned size)
 {
     SerialState *serial = opaque;
     ChannelState *s;
@@ -627,6 +629,16 @@ static uint32_t escc_mem_readb(void *opaque, target_phys_addr_t addr)
     return 0;
 }
 
+static const MemoryRegionOps escc_mem_ops = {
+    .read = escc_mem_read,
+    .write = escc_mem_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+};
+
 static int serial_can_receive(void *opaque)
 {
     ChannelState *s = opaque;
@@ -668,18 +680,6 @@ static void serial_event(void *opaque, int event)
         serial_receive_break(s);
 }
 
-static CPUReadMemoryFunc * const escc_mem_read[3] = {
-    escc_mem_readb,
-    NULL,
-    NULL,
-};
-
-static CPUWriteMemoryFunc * const escc_mem_write[3] = {
-    escc_mem_writeb,
-    NULL,
-    NULL,
-};
-
 static const VMStateDescription vmstate_escc_chn = {
     .name ="escc_chn",
     .version_id = 2,
@@ -712,7 +712,7 @@ static const VMStateDescription vmstate_escc = {
     }
 };
 
-int escc_init(target_phys_addr_t base, qemu_irq irqA, qemu_irq irqB,
+MemoryRegion *escc_init(target_phys_addr_t base, qemu_irq irqA, qemu_irq irqB,
               CharDriverState *chrA, CharDriverState *chrB,
               int clock, int it_shift)
 {
@@ -737,7 +737,7 @@ int escc_init(target_phys_addr_t base, qemu_irq irqA, qemu_irq irqB,
     }
 
     d = FROM_SYSBUS(SerialState, s);
-    return d->mmio_index;
+    return &d->mmio;
 }
 
 static const uint8_t keycodes[128] = {
@@ -901,7 +901,6 @@ void slavio_serial_ms_kbd_init(target_phys_addr_t base, qemu_irq irq,
 static int escc_init1(SysBusDevice *dev)
 {
     SerialState *s = FROM_SYSBUS(SerialState, dev);
-    int io;
     unsigned int i;
 
     s->chn[0].disabled = s->disabled;
@@ -918,10 +917,9 @@ static int escc_init1(SysBusDevice *dev)
     s->chn[0].otherchn = &s->chn[1];
     s->chn[1].otherchn = &s->chn[0];
 
-    io = cpu_register_io_memory(escc_mem_read, escc_mem_write, s,
-                                DEVICE_NATIVE_ENDIAN);
-    sysbus_init_mmio(dev, ESCC_SIZE << s->it_shift, io);
-    s->mmio_index = io;
+    memory_region_init_io(&s->mmio, &escc_mem_ops, s, "escc",
+                          ESCC_SIZE << s->it_shift);
+    sysbus_init_mmio_region(dev, &s->mmio);
 
     if (s->chn[0].type == mouse) {
         qemu_add_mouse_event_handler(sunmouse_event, &s->chn[0], 0,
diff --git a/hw/escc.h b/hw/escc.h
index 015b9d0..d1da46f 100644
--- a/hw/escc.h
+++ b/hw/escc.h
@@ -1,6 +1,6 @@
 /* escc.c */
 #define ESCC_SIZE 4
-int escc_init(target_phys_addr_t base, qemu_irq irqA, qemu_irq irqB,
+MemoryRegion *escc_init(target_phys_addr_t base, qemu_irq irqA, qemu_irq irqB,
               CharDriverState *chrA, CharDriverState *chrB,
               int clock, int it_shift);
 
diff --git a/hw/heathrow_pic.c b/hw/heathrow_pic.c
index 5fd71a0..3ba0b0e 100644
--- a/hw/heathrow_pic.c
+++ b/hw/heathrow_pic.c
@@ -43,6 +43,7 @@ typedef struct HeathrowPIC {
 } HeathrowPIC;
 
 typedef struct HeathrowPICS {
+    MemoryRegion mem;
     HeathrowPIC pics[2];
     qemu_irq *irqs;
 } HeathrowPICS;
@@ -62,7 +63,8 @@ static void heathrow_pic_update(HeathrowPICS *s)
     }
 }
 
-static void pic_writel (void *opaque, target_phys_addr_t addr, uint32_t value)
+static void pic_write(void *opaque, target_phys_addr_t addr,
+                      uint64_t value, unsigned size)
 {
     HeathrowPICS *s = opaque;
     HeathrowPIC *pic;
@@ -89,7 +91,8 @@ static void pic_writel (void *opaque, target_phys_addr_t addr, uint32_t value)
     }
 }
 
-static uint32_t pic_readl (void *opaque, target_phys_addr_t addr)
+static uint64_t pic_read(void *opaque, target_phys_addr_t addr,
+                         unsigned size)
 {
     HeathrowPICS *s = opaque;
     HeathrowPIC *pic;
@@ -120,19 +123,12 @@ static uint32_t pic_readl (void *opaque, target_phys_addr_t addr)
     return value;
 }
 
-static CPUWriteMemoryFunc * const pic_write[] = {
-    &pic_writel,
-    &pic_writel,
-    &pic_writel,
+static const MemoryRegionOps heathrow_pic_ops = {
+    .read = pic_read,
+    .write = pic_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static CPUReadMemoryFunc * const pic_read[] = {
-    &pic_readl,
-    &pic_readl,
-    &pic_readl,
-};
-
-
 static void heathrow_pic_set_irq(void *opaque, int num, int level)
 {
     HeathrowPICS *s = opaque;
@@ -201,7 +197,7 @@ static void heathrow_pic_reset(void *opaque)
     s->pics[1].level_triggered = 0x1ff00000;
 }
 
-qemu_irq *heathrow_pic_init(int *pmem_index,
+qemu_irq *heathrow_pic_init(MemoryRegion **pmem,
                             int nb_cpus, qemu_irq **irqs)
 {
     HeathrowPICS *s;
@@ -209,8 +205,9 @@ qemu_irq *heathrow_pic_init(int *pmem_index,
     s = qemu_mallocz(sizeof(HeathrowPICS));
     /* only 1 CPU */
     s->irqs = irqs[0];
-    *pmem_index = cpu_register_io_memory(pic_read, pic_write, s,
-                                         DEVICE_LITTLE_ENDIAN);
+    memory_region_init_io(&s->mem, &heathrow_pic_ops, s,
+                          "heathrow-pic", 0x1000);
+    *pmem = &s->mem;
 
     vmstate_register(NULL, -1, &vmstate_heathrow_pic, s);
     qemu_register_reset(heathrow_pic_reset, s);
diff --git a/hw/ide.h b/hw/ide.h
index a490cbb..9059aae 100644
--- a/hw/ide.h
+++ b/hw/ide.h
@@ -19,7 +19,7 @@ PCIDevice *pci_piix4_ide_init(PCIBus *bus, DriveInfo **hd_table, int devfn);
 void vt82c686b_ide_init(PCIBus *bus, DriveInfo **hd_table, int devfn);
 
 /* ide-macio.c */
-int pmac_ide_init (DriveInfo **hd_table, qemu_irq irq,
+MemoryRegion *pmac_ide_init (DriveInfo **hd_table, qemu_irq irq,
 		   void *dbdma, int channel, qemu_irq dma_irq);
 
 /* ide-mmio.c */
diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index 7daeb31..7ee35e9 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c
@@ -35,6 +35,7 @@
 /* MacIO based PowerPC IDE */
 
 typedef struct MACIOIDEState {
+    MemoryRegion mem;
     IDEBus bus;
     BlockDriverAIOCB *aiocb;
 } MACIOIDEState;
@@ -281,16 +282,20 @@ static uint32_t pmac_ide_readl (void *opaque,target_phys_addr_t addr)
     return retval;
 }
 
-static CPUWriteMemoryFunc * const pmac_ide_write[] = {
-    pmac_ide_writeb,
-    pmac_ide_writew,
-    pmac_ide_writel,
-};
-
-static CPUReadMemoryFunc * const pmac_ide_read[] = {
-    pmac_ide_readb,
-    pmac_ide_readw,
-    pmac_ide_readl,
+static MemoryRegionOps pmac_ide_ops = {
+    .old_mmio = {
+        .write = {
+            pmac_ide_writeb,
+            pmac_ide_writew,
+            pmac_ide_writel,
+        },
+        .read = {
+            pmac_ide_readb,
+            pmac_ide_readw,
+            pmac_ide_readl,
+        },
+    },
+    .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
 static const VMStateDescription vmstate_pmac = {
@@ -315,11 +320,10 @@ static void pmac_ide_reset(void *opaque)
 /* hd_table must contain 4 block drivers */
 /* PowerMac uses memory mapped registers, not I/O. Return the memory
    I/O index to access the ide. */
-int pmac_ide_init (DriveInfo **hd_table, qemu_irq irq,
-		   void *dbdma, int channel, qemu_irq dma_irq)
+MemoryRegion *pmac_ide_init (DriveInfo **hd_table, qemu_irq irq,
+                             void *dbdma, int channel, qemu_irq dma_irq)
 {
     MACIOIDEState *d;
-    int pmac_ide_memory;
 
     d = qemu_mallocz(sizeof(MACIOIDEState));
     ide_init2_with_non_qdev_drives(&d->bus, hd_table[0], hd_table[1], irq);
@@ -327,11 +331,9 @@ int pmac_ide_init (DriveInfo **hd_table, qemu_irq irq,
     if (dbdma)
         DBDMA_register_channel(dbdma, channel, dma_irq, pmac_ide_transfer, pmac_ide_flush, d);
 
-    pmac_ide_memory = cpu_register_io_memory(pmac_ide_read,
-                                             pmac_ide_write, d,
-                                             DEVICE_NATIVE_ENDIAN);
+    memory_region_init_io(&d->mem, &pmac_ide_ops, d, "pmac-ide", 0x1000);
     vmstate_register(NULL, 0, &vmstate_pmac, d);
     qemu_register_reset(pmac_ide_reset, d);
 
-    return pmac_ide_memory;
+    return &d->mem;
 }
diff --git a/hw/mac_dbdma.c b/hw/mac_dbdma.c
index ed4458e..350d901 100644
--- a/hw/mac_dbdma.c
+++ b/hw/mac_dbdma.c
@@ -166,6 +166,7 @@ typedef struct DBDMA_channel {
 } DBDMA_channel;
 
 typedef struct {
+    MemoryRegion mem;
     DBDMA_channel channels[DBDMA_CHANNELS];
 } DBDMAState;
 
@@ -703,8 +704,8 @@ dbdma_control_write(DBDMA_channel *ch)
         ch->flush(&ch->io);
 }
 
-static void dbdma_writel (void *opaque,
-                          target_phys_addr_t addr, uint32_t value)
+static void dbdma_write(void *opaque, target_phys_addr_t addr,
+                        uint64_t value, unsigned size)
 {
     int channel = addr >> DBDMA_CHANNEL_SHIFT;
     DBDMAState *s = opaque;
@@ -753,7 +754,8 @@ static void dbdma_writel (void *opaque,
     }
 }
 
-static uint32_t dbdma_readl (void *opaque, target_phys_addr_t addr)
+static uint64_t dbdma_read(void *opaque, target_phys_addr_t addr,
+                           unsigned size)
 {
     uint32_t value;
     int channel = addr >> DBDMA_CHANNEL_SHIFT;
@@ -798,16 +800,14 @@ static uint32_t dbdma_readl (void *opaque, target_phys_addr_t addr)
     return value;
 }
 
-static CPUWriteMemoryFunc * const dbdma_write[] = {
-    NULL,
-    NULL,
-    dbdma_writel,
-};
-
-static CPUReadMemoryFunc * const dbdma_read[] = {
-    NULL,
-    NULL,
-    dbdma_readl,
+static const MemoryRegionOps dbdma_ops = {
+    .read = dbdma_read,
+    .write = dbdma_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
 };
 
 static const VMStateDescription vmstate_dbdma_channel = {
@@ -842,14 +842,14 @@ static void dbdma_reset(void *opaque)
         memset(s->channels[i].regs, 0, DBDMA_SIZE);
 }
 
-void* DBDMA_init (int *dbdma_mem_index)
+void* DBDMA_init (MemoryRegion **dbdma_mem)
 {
     DBDMAState *s;
 
     s = qemu_mallocz(sizeof(DBDMAState));
 
-    *dbdma_mem_index = cpu_register_io_memory(dbdma_read, dbdma_write, s,
-                                              DEVICE_LITTLE_ENDIAN);
+    memory_region_init_io(&s->mem, &dbdma_ops, s, "dbdma", 0x1000);
+    *dbdma_mem = &s->mem;
     vmstate_register(NULL, -1, &vmstate_dbdma, s);
     qemu_register_reset(dbdma_reset, s);
 
diff --git a/hw/mac_dbdma.h b/hw/mac_dbdma.h
index d236c5b..933e17c 100644
--- a/hw/mac_dbdma.h
+++ b/hw/mac_dbdma.h
@@ -20,6 +20,8 @@
  * THE SOFTWARE.
  */
 
+#include "memory.h"
+
 typedef struct DBDMA_io DBDMA_io;
 
 typedef void (*DBDMA_flush)(DBDMA_io *io);
@@ -40,4 +42,4 @@ void DBDMA_register_channel(void *dbdma, int nchan, qemu_irq irq,
                             DBDMA_rw rw, DBDMA_flush flush,
                             void *opaque);
 void DBDMA_schedule(void);
-void* DBDMA_init (int *dbdma_mem_index);
+void* DBDMA_init (MemoryRegion **dbdma_mem);
diff --git a/hw/mac_nvram.c b/hw/mac_nvram.c
index 61e53d2..ced1e58 100644
--- a/hw/mac_nvram.c
+++ b/hw/mac_nvram.c
@@ -39,7 +39,7 @@
 
 struct MacIONVRAMState {
     uint32_t size;
-    int mem_index;
+    MemoryRegion mem;
     unsigned int it_shift;
     uint8_t *data;
 };
@@ -71,8 +71,8 @@ void macio_nvram_write (void *opaque, uint32_t addr, uint32_t val)
 }
 
 /* macio style NVRAM device */
-static void macio_nvram_writeb (void *opaque,
-                                target_phys_addr_t addr, uint32_t value)
+static void macio_nvram_writeb(void *opaque, target_phys_addr_t addr,
+                               uint64_t value, unsigned size)
 {
     MacIONVRAMState *s = opaque;
 
@@ -81,7 +81,8 @@ static void macio_nvram_writeb (void *opaque,
     NVR_DPRINTF("writeb addr %04x val %x\n", (int)addr, value);
 }
 
-static uint32_t macio_nvram_readb (void *opaque, target_phys_addr_t addr)
+static uint64_t macio_nvram_readb(void *opaque, target_phys_addr_t addr,
+                                  unsigned size)
 {
     MacIONVRAMState *s = opaque;
     uint32_t value;
@@ -93,16 +94,10 @@ static uint32_t macio_nvram_readb (void *opaque, target_phys_addr_t addr)
     return value;
 }
 
-static CPUWriteMemoryFunc * const nvram_write[] = {
-    &macio_nvram_writeb,
-    &macio_nvram_writeb,
-    &macio_nvram_writeb,
-};
-
-static CPUReadMemoryFunc * const nvram_read[] = {
-    &macio_nvram_readb,
-    &macio_nvram_readb,
-    &macio_nvram_readb,
+static const MemoryRegionOps macio_nvram_ops = {
+    .read = macio_nvram_readb,
+    .write = macio_nvram_writeb,
+    .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
 static const VMStateDescription vmstate_macio_nvram = {
@@ -121,7 +116,7 @@ static void macio_nvram_reset(void *opaque)
 {
 }
 
-MacIONVRAMState *macio_nvram_init (int *mem_index, target_phys_addr_t size,
+MacIONVRAMState *macio_nvram_init (target_phys_addr_t size,
                                    unsigned int it_shift)
 {
     MacIONVRAMState *s;
@@ -131,22 +126,18 @@ MacIONVRAMState *macio_nvram_init (int *mem_index, target_phys_addr_t size,
     s->size = size;
     s->it_shift = it_shift;
 
-    s->mem_index = cpu_register_io_memory(nvram_read, nvram_write, s,
-                                          DEVICE_NATIVE_ENDIAN);
-    *mem_index = s->mem_index;
+    memory_region_init_io(&s->mem, &macio_nvram_ops, s, "macio-nvram",
+                          size << it_shift);
     vmstate_register(NULL, -1, &vmstate_macio_nvram, s);
     qemu_register_reset(macio_nvram_reset, s);
 
     return s;
 }
 
-void macio_nvram_map (void *opaque, target_phys_addr_t mem_base)
+void macio_nvram_setup_bar(MacIONVRAMState *s, MemoryRegion *bar,
+                           target_phys_addr_t mem_base)
 {
-    MacIONVRAMState *s;
-
-    s = opaque;
-    cpu_register_physical_memory(mem_base, s->size << s->it_shift,
-                                 s->mem_index);
+    memory_region_add_subregion(bar, mem_base, &s->mem);
 }
 
 /* Set up a system OpenBIOS NVRAM partition */
diff --git a/hw/macio.c b/hw/macio.c
index 789ca55..71fa2a8 100644
--- a/hw/macio.c
+++ b/hw/macio.c
@@ -30,58 +30,55 @@
 typedef struct macio_state_t macio_state_t;
 struct macio_state_t {
     int is_oldworld;
-    int pic_mem_index;
-    int dbdma_mem_index;
-    int cuda_mem_index;
-    int escc_mem_index;
+    MemoryRegion bar;
+    MemoryRegion *pic_mem;
+    MemoryRegion *dbdma_mem;
+    MemoryRegion *cuda_mem;
+    MemoryRegion *escc_mem;
     void *nvram;
     int nb_ide;
-    int ide_mem_index[4];
+    MemoryRegion *ide_mem[4];
 };
 
-static void macio_map (PCIDevice *pci_dev, int region_num,
-                       pcibus_t addr, pcibus_t size, int type)
+static void macio_bar_setup(macio_state_t *macio_state)
 {
-    macio_state_t *macio_state;
     int i;
+    MemoryRegion *bar = &macio_state->bar;
 
-    macio_state = (macio_state_t *)(pci_dev + 1);
-    if (macio_state->pic_mem_index >= 0) {
+    memory_region_init(bar, "macio", 0x80000);
+    if (macio_state->pic_mem) {
         if (macio_state->is_oldworld) {
             /* Heathrow PIC */
-            cpu_register_physical_memory(addr + 0x00000, 0x1000,
-                                         macio_state->pic_mem_index);
+            memory_region_add_subregion(bar, 0x00000, macio_state->pic_mem);
         } else {
             /* OpenPIC */
-            cpu_register_physical_memory(addr + 0x40000, 0x40000,
-                                         macio_state->pic_mem_index);
+            memory_region_add_subregion(bar, 0x40000, macio_state->pic_mem);
         }
     }
-    if (macio_state->dbdma_mem_index >= 0) {
-        cpu_register_physical_memory(addr + 0x08000, 0x1000,
-                                     macio_state->dbdma_mem_index);
+    if (macio_state->dbdma_mem) {
+        memory_region_add_subregion(bar, 0x08000, macio_state->dbdma_mem);
     }
-    if (macio_state->escc_mem_index >= 0) {
-        cpu_register_physical_memory(addr + 0x13000, ESCC_SIZE << 4,
-                                     macio_state->escc_mem_index);
+    if (macio_state->escc_mem) {
+        memory_region_add_subregion(bar, 0x13000, macio_state->escc_mem);
     }
-    if (macio_state->cuda_mem_index >= 0) {
-        cpu_register_physical_memory(addr + 0x16000, 0x2000,
-                                     macio_state->cuda_mem_index);
+    if (macio_state->cuda_mem) {
+        memory_region_add_subregion(bar, 0x16000, macio_state->cuda_mem);
     }
     for (i = 0; i < macio_state->nb_ide; i++) {
-        if (macio_state->ide_mem_index[i] >= 0) {
-            cpu_register_physical_memory(addr + 0x1f000 + (i * 0x1000), 0x1000,
-                                         macio_state->ide_mem_index[i]);
+        if (macio_state->ide_mem[i]) {
+            memory_region_add_subregion(bar, 0x1f000 + (i * 0x1000),
+                                        macio_state->ide_mem[i]);
         }
     }
     if (macio_state->nvram != NULL)
-        macio_nvram_map(macio_state->nvram, addr + 0x60000);
+        macio_nvram_setup_bar(macio_state->nvram, bar, 0x60000);
 }
 
-void macio_init (PCIBus *bus, int device_id, int is_oldworld, int pic_mem_index,
-                 int dbdma_mem_index, int cuda_mem_index, void *nvram,
-                 int nb_ide, int *ide_mem_index, int escc_mem_index)
+void macio_init (PCIBus *bus, int device_id, int is_oldworld,
+                 MemoryRegion *pic_mem, MemoryRegion *dbdma_mem,
+                 MemoryRegion *cuda_mem, void *nvram,
+                 int nb_ide, MemoryRegion **ide_mem,
+                 MemoryRegion *escc_mem)
 {
     PCIDevice *d;
     macio_state_t *macio_state;
@@ -92,18 +89,18 @@ void macio_init (PCIBus *bus, int device_id, int is_oldworld, int pic_mem_index,
                             -1, NULL, NULL);
     macio_state = (macio_state_t *)(d + 1);
     macio_state->is_oldworld = is_oldworld;
-    macio_state->pic_mem_index = pic_mem_index;
-    macio_state->dbdma_mem_index = dbdma_mem_index;
-    macio_state->cuda_mem_index = cuda_mem_index;
-    macio_state->escc_mem_index = escc_mem_index;
+    macio_state->pic_mem = pic_mem;
+    macio_state->dbdma_mem = dbdma_mem;
+    macio_state->cuda_mem = cuda_mem;
+    macio_state->escc_mem = escc_mem;
     macio_state->nvram = nvram;
     if (nb_ide > 4)
         nb_ide = 4;
     macio_state->nb_ide = nb_ide;
     for (i = 0; i < nb_ide; i++)
-        macio_state->ide_mem_index[i] = ide_mem_index[i];
+        macio_state->ide_mem[i] = ide_mem[i];
     for (; i < 4; i++)
-        macio_state->ide_mem_index[i] = -1;
+        macio_state->ide_mem[i] = NULL;
     /* Note: this code is strongly inspirated from the corresponding code
        in PearPC */
 
@@ -113,6 +110,7 @@ void macio_init (PCIBus *bus, int device_id, int is_oldworld, int pic_mem_index,
 
     d->config[0x3d] = 0x01; // interrupt on pin 1
 
-    pci_register_bar(d, 0, 0x80000,
-                           PCI_BASE_ADDRESS_SPACE_MEMORY, macio_map);
+    macio_bar_setup(macio_state);
+    pci_register_bar_region(d, 0, PCI_BASE_ADDRESS_SPACE_MEMORY,
+                            &macio_state->bar);
 }
diff --git a/hw/openpic.c b/hw/openpic.c
index 6d2cf99..c2b04a3 100644
--- a/hw/openpic.c
+++ b/hw/openpic.c
@@ -205,7 +205,7 @@ typedef struct IRQ_dst_t {
 
 typedef struct openpic_t {
     PCIDevice pci_dev;
-    int mem_index;
+    MemoryRegion mem;
     /* Global registers */
     uint32_t frep; /* Feature reporting register */
     uint32_t glbc; /* Global configuration register  */
@@ -984,47 +984,34 @@ static uint32_t openpic_readl (void *opaque,target_phys_addr_t addr)
     return retval;
 }
 
-static CPUWriteMemoryFunc * const openpic_write[] = {
-    &openpic_buggy_write,
-    &openpic_buggy_write,
-    &openpic_writel,
-};
+static uint64_t openpic_read(void *opaque, target_phys_addr_t addr,
+                             unsigned size)
+{
+    openpic_t *opp = opaque;
 
-static CPUReadMemoryFunc * const openpic_read[] = {
-    &openpic_buggy_read,
-    &openpic_buggy_read,
-    &openpic_readl,
-};
+    switch (size) {
+    case 4: return openpic_readl(opp, addr);
+    default: return openpic_buggy_read(opp, addr);
+    }
+}
 
-static void openpic_map(PCIDevice *pci_dev, int region_num,
-                        pcibus_t addr, pcibus_t size, int type)
+static void openpic_write(void *opaque, target_phys_addr_t addr,
+                          uint64_t data, unsigned size)
 {
-    openpic_t *opp;
+    openpic_t *opp = opaque;
 
-    DPRINTF("Map OpenPIC\n");
-    opp = (openpic_t *)pci_dev;
-    /* Global registers */
-    DPRINTF("Register OPENPIC gbl   %08x => %08x\n",
-            addr + 0x1000, addr + 0x1000 + 0x100);
-    /* Timer registers */
-    DPRINTF("Register OPENPIC timer %08x => %08x\n",
-            addr + 0x1100, addr + 0x1100 + 0x40 * MAX_TMR);
-    /* Interrupt source registers */
-    DPRINTF("Register OPENPIC src   %08x => %08x\n",
-            addr + 0x10000, addr + 0x10000 + 0x20 * (OPENPIC_EXT_IRQ + 2));
-    /* Per CPU registers */
-    DPRINTF("Register OPENPIC dst   %08x => %08x\n",
-            addr + 0x20000, addr + 0x20000 + 0x1000 * MAX_CPU);
-    cpu_register_physical_memory(addr, 0x40000, opp->mem_index);
-#if 0 // Don't implement ISU for now
-    opp_io_memory = cpu_register_io_memory(openpic_src_read,
-                                           openpic_src_write, NULL
-                                           DEVICE_NATIVE_ENDIAN);
-    cpu_register_physical_memory(isu_base, 0x20 * (EXT_IRQ + 2),
-                                 opp_io_memory);
-#endif
+    switch (size) {
+    case 4: return openpic_writel(opp, addr, data);
+    default: return openpic_buggy_write(opp, addr, data);
+    }
 }
 
+static const MemoryRegionOps openpic_ops = {
+    .read = openpic_read,
+    .write = openpic_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
 static void openpic_save_IRQ_queue(QEMUFile* f, IRQ_queue_t *q)
 {
     unsigned int i;
@@ -1161,7 +1148,7 @@ static void openpic_irq_raise(openpic_t *opp, int n_CPU, IRQ_src_t *src)
     qemu_irq_raise(opp->dst[n_CPU].irqs[OPENPIC_OUTPUT_INT]);
 }
 
-qemu_irq *openpic_init (PCIBus *bus, int *pmem_index, int nb_cpus,
+qemu_irq *openpic_init (PCIBus *bus, MemoryRegion **pmem, int nb_cpus,
                         qemu_irq **irqs, qemu_irq irq_out)
 {
     openpic_t *opp;
@@ -1180,14 +1167,22 @@ qemu_irq *openpic_init (PCIBus *bus, int *pmem_index, int nb_cpus,
         pci_config_set_class(pci_conf, PCI_CLASS_SYSTEM_OTHER); // FIXME?
         pci_conf[0x3d] = 0x00; // no interrupt pin
 
+        memory_region_init_io(&opp->mem, &openpic_ops, opp, "openpic", 0x40000);
+#if 0 // Don't implement ISU for now
+        opp_io_memory = cpu_register_io_memory(openpic_src_read,
+                                               openpic_src_write, NULL
+                                               DEVICE_NATIVE_ENDIAN);
+        cpu_register_physical_memory(isu_base, 0x20 * (EXT_IRQ + 2),
+                                     opp_io_memory);
+#endif
+
         /* Register I/O spaces */
-        pci_register_bar(&opp->pci_dev, 0, 0x40000,
-                               PCI_BASE_ADDRESS_SPACE_MEMORY, &openpic_map);
+        pci_register_bar_region(&opp->pci_dev, 0,
+                                PCI_BASE_ADDRESS_SPACE_MEMORY, &opp->mem);
     } else {
         opp = qemu_mallocz(sizeof(openpic_t));
+        memory_region_init_io(&opp->mem, &openpic_ops, opp, "openpic", 0x40000);
     }
-    opp->mem_index = cpu_register_io_memory(openpic_read, openpic_write, opp,
-                                            DEVICE_LITTLE_ENDIAN);
 
     //    isu_base &= 0xFFFC0000;
     opp->nb_cpus = nb_cpus;
@@ -1223,8 +1218,8 @@ qemu_irq *openpic_init (PCIBus *bus, int *pmem_index, int nb_cpus,
     opp->irq_raise = openpic_irq_raise;
     opp->reset = openpic_reset;
 
-    if (pmem_index)
-        *pmem_index = opp->mem_index;
+    if (pmem)
+        *pmem = &opp->mem;
 
     return qemu_allocate_irqs(openpic_set_irq, opp, opp->max_irq);
 }
diff --git a/hw/openpic.h b/hw/openpic.h
index 0957c1f..75de361 100644
--- a/hw/openpic.h
+++ b/hw/openpic.h
@@ -11,7 +11,7 @@ enum {
     OPENPIC_OUTPUT_NB,
 };
 
-qemu_irq *openpic_init (PCIBus *bus, int *pmem_index, int nb_cpus,
+qemu_irq *openpic_init (PCIBus *bus, MemoryRegion **pmem, int nb_cpus,
                         qemu_irq **irqs, qemu_irq irq_out);
 qemu_irq *mpic_init (target_phys_addr_t base, int nb_cpus,
                         qemu_irq **irqs, qemu_irq irq_out);
diff --git a/hw/ppc_mac.h b/hw/ppc_mac.h
index 25a2274..7351bb6 100644
--- a/hw/ppc_mac.h
+++ b/hw/ppc_mac.h
@@ -42,15 +42,16 @@
 #define ESCC_CLOCK 3686400
 
 /* Cuda */
-void cuda_init (int *cuda_mem_index, qemu_irq irq);
+void cuda_init (MemoryRegion **cuda_mem, qemu_irq irq);
 
 /* MacIO */
-void macio_init (PCIBus *bus, int device_id, int is_oldworld, int pic_mem_index,
-                 int dbdma_mem_index, int cuda_mem_index, void *nvram,
-                 int nb_ide, int *ide_mem_index, int escc_mem_index);
+void macio_init (PCIBus *bus, int device_id, int is_oldworld,
+                 MemoryRegion *pic_mem, MemoryRegion *dbdma_mem,
+                 MemoryRegion *cuda_mem, void *nvram,
+                 int nb_ide, MemoryRegion **ide_mem, MemoryRegion *escc_mem);
 
 /* Heathrow PIC */
-qemu_irq *heathrow_pic_init(int *pmem_index,
+qemu_irq *heathrow_pic_init(MemoryRegion **pmem,
                             int nb_cpus, qemu_irq **irqs);
 
 /* Grackle PCI */
@@ -69,9 +70,10 @@ PCIBus *pci_pmac_u3_init(qemu_irq *pic,
 /* Mac NVRAM */
 typedef struct MacIONVRAMState MacIONVRAMState;
 
-MacIONVRAMState *macio_nvram_init (int *mem_index, target_phys_addr_t size,
+MacIONVRAMState *macio_nvram_init (target_phys_addr_t size,
                                    unsigned int it_shift);
-void macio_nvram_map (void *opaque, target_phys_addr_t mem_base);
+void macio_nvram_setup_bar(MacIONVRAMState *s, MemoryRegion *bar,
+                           target_phys_addr_t mem_base);
 void pmac_format_nvram_partition (MacIONVRAMState *nvr, int len);
 uint32_t macio_nvram_read (void *opaque, uint32_t addr);
 void macio_nvram_write (void *opaque, uint32_t addr, uint32_t val);
diff --git a/hw/ppc_newworld.c b/hw/ppc_newworld.c
index 94a21f9..3039022 100644
--- a/hw/ppc_newworld.c
+++ b/hw/ppc_newworld.c
@@ -144,10 +144,9 @@ static void ppc_core99_init (ram_addr_t ram_size,
     long kernel_size, initrd_size;
     PCIBus *pci_bus;
     MacIONVRAMState *nvr;
-    int nvram_mem_index;
     int bios_size;
-    int pic_mem_index, dbdma_mem_index, cuda_mem_index, escc_mem_index;
-    int ide_mem_index[3];
+    MemoryRegion *pic_mem, *dbdma_mem, *cuda_mem, *escc_mem;
+    MemoryRegion *ide_mem[3];
     int ppc_boot_device;
     DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
     void *fw_cfg;
@@ -315,7 +314,7 @@ static void ppc_core99_init (ram_addr_t ram_size,
             exit(1);
         }
     }
-    pic = openpic_init(NULL, &pic_mem_index, smp_cpus, openpic_irqs, NULL);
+    pic = openpic_init(NULL, &pic_mem, smp_cpus, openpic_irqs, NULL);
     if (PPC_INPUT(env) == PPC_FLAGS_INPUT_970) {
         /* 970 gets a U3 bus */
         pci_bus = pci_pmac_u3_init(pic, get_system_memory(), get_system_io());
@@ -327,32 +326,31 @@ static void ppc_core99_init (ram_addr_t ram_size,
     /* init basic PC hardware */
     pci_vga_init(pci_bus);
 
-    escc_mem_index = escc_init(0x80013000, pic[0x25], pic[0x24],
-                               serial_hds[0], serial_hds[1], ESCC_CLOCK, 4);
+    escc_mem = escc_init(0x80013000, pic[0x25], pic[0x24],
+                         serial_hds[0], serial_hds[1], ESCC_CLOCK, 4);
 
     for(i = 0; i < nb_nics; i++)
         pci_nic_init_nofail(&nd_table[i], "ne2k_pci", NULL);
 
     ide_drive_get(hd, MAX_IDE_BUS);
-    dbdma = DBDMA_init(&dbdma_mem_index);
+    dbdma = DBDMA_init(&dbdma_mem);
 
     /* We only emulate 2 out of 3 IDE controllers for now */
-    ide_mem_index[0] = -1;
-    ide_mem_index[1] = pmac_ide_init(hd, pic[0x0d], dbdma, 0x16, pic[0x02]);
-    ide_mem_index[2] = pmac_ide_init(&hd[MAX_IDE_DEVS], pic[0x0e], dbdma, 0x1a, pic[0x02]);
+    ide_mem[0] = NULL;
+    ide_mem[1] = pmac_ide_init(hd, pic[0x0d], dbdma, 0x16, pic[0x02]);
+    ide_mem[2] = pmac_ide_init(&hd[MAX_IDE_DEVS], pic[0x0e], dbdma, 0x1a, pic[0x02]);
 
     /* cuda also initialize ADB */
     if (machine_arch == ARCH_MAC99_U3) {
         usb_enabled = 1;
     }
-    cuda_init(&cuda_mem_index, pic[0x19]);
+    cuda_init(&cuda_mem, pic[0x19]);
 
     adb_kbd_init(&adb_bus);
     adb_mouse_init(&adb_bus);
 
-    macio_init(pci_bus, PCI_DEVICE_ID_APPLE_UNI_N_KEYL, 0, pic_mem_index,
-               dbdma_mem_index, cuda_mem_index, NULL, 3, ide_mem_index,
-               escc_mem_index);
+    macio_init(pci_bus, PCI_DEVICE_ID_APPLE_UNI_N_KEYL, 0, pic_mem,
+               dbdma_mem, cuda_mem, NULL, 3, ide_mem, escc_mem);
 
     if (usb_enabled) {
         usb_ohci_init_pci(pci_bus, -1);
@@ -369,9 +367,9 @@ static void ppc_core99_init (ram_addr_t ram_size,
         graphic_depth = 15;
 
     /* The NewWorld NVRAM is not located in the MacIO device */
-    nvr = macio_nvram_init(&nvram_mem_index, 0x2000, 1);
+    nvr = macio_nvram_init(0x2000, 1);
     pmac_format_nvram_partition(nvr, 0x2000);
-    macio_nvram_map(nvr, 0xFFF04000);
+    macio_nvram_setup_bar(nvr, get_system_memory(), 0xFFF04000);
     /* No PCI init: the BIOS will do it */
 
     fw_cfg = fw_cfg_init(0, 0, CFG_ADDR, CFG_ADDR + 2);
diff --git a/hw/ppc_oldworld.c b/hw/ppc_oldworld.c
index 0f99eef..41703a7 100644
--- a/hw/ppc_oldworld.c
+++ b/hw/ppc_oldworld.c
@@ -82,8 +82,8 @@ static void ppc_heathrow_init (ram_addr_t ram_size,
     PCIBus *pci_bus;
     MacIONVRAMState *nvr;
     int bios_size;
-    int pic_mem_index, nvram_mem_index, dbdma_mem_index, cuda_mem_index;
-    int escc_mem_index, ide_mem_index[2];
+    MemoryRegion *pic_mem, *dbdma_mem, *cuda_mem;
+    MemoryRegion *escc_mem, *ide_mem[2];
     uint16_t ppc_boot_device;
     DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
     void *fw_cfg;
@@ -233,13 +233,13 @@ static void ppc_heathrow_init (ram_addr_t ram_size,
     if (PPC_INPUT(env) != PPC_FLAGS_INPUT_6xx) {
         hw_error("Only 6xx bus is supported on heathrow machine\n");
     }
-    pic = heathrow_pic_init(&pic_mem_index, 1, heathrow_irqs);
+    pic = heathrow_pic_init(&pic_mem, 1, heathrow_irqs);
     pci_bus = pci_grackle_init(0xfec00000, pic,
                                get_system_memory(),
                                get_system_io());
     pci_vga_init(pci_bus);
 
-    escc_mem_index = escc_init(0x80013000, pic[0x0f], pic[0x10], serial_hds[0],
+    escc_mem = escc_init(0x80013000, pic[0x0f], pic[0x10], serial_hds[0],
                                serial_hds[1], ESCC_CLOCK, 4);
 
     for(i = 0; i < nb_nics; i++)
@@ -249,9 +249,9 @@ static void ppc_heathrow_init (ram_addr_t ram_size,
     ide_drive_get(hd, MAX_IDE_BUS);
 
     /* First IDE channel is a MAC IDE on the MacIO bus */
-    dbdma = DBDMA_init(&dbdma_mem_index);
-    ide_mem_index[0] = -1;
-    ide_mem_index[1] = pmac_ide_init(hd, pic[0x0D], dbdma, 0x16, pic[0x02]);
+    dbdma = DBDMA_init(&dbdma_mem);
+    ide_mem[0] = NULL;
+    ide_mem[1] = pmac_ide_init(hd, pic[0x0D], dbdma, 0x16, pic[0x02]);
 
     /* Second IDE channel is a CMD646 on the PCI bus */
     hd[0] = hd[MAX_IDE_DEVS];
@@ -260,17 +260,16 @@ static void ppc_heathrow_init (ram_addr_t ram_size,
     pci_cmd646_ide_init(pci_bus, hd, 0);
 
     /* cuda also initialize ADB */
-    cuda_init(&cuda_mem_index, pic[0x12]);
+    cuda_init(&cuda_mem, pic[0x12]);
 
     adb_kbd_init(&adb_bus);
     adb_mouse_init(&adb_bus);
 
-    nvr = macio_nvram_init(&nvram_mem_index, 0x2000, 4);
+    nvr = macio_nvram_init(0x2000, 4);
     pmac_format_nvram_partition(nvr, 0x2000);
 
-    macio_init(pci_bus, PCI_DEVICE_ID_APPLE_343S1201, 1, pic_mem_index,
-               dbdma_mem_index, cuda_mem_index, nvr, 2, ide_mem_index,
-               escc_mem_index);
+    macio_init(pci_bus, PCI_DEVICE_ID_APPLE_343S1201, 1, pic_mem,
+               dbdma_mem, cuda_mem, nvr, 2, ide_mem, escc_mem);
 
     if (usb_enabled) {
         usb_ohci_init_pci(pci_bus, -1);
