diff --git a/cpu-common.h b/cpu-common.h
index 4640924..8f89325 100644
--- a/cpu-common.h
+++ b/cpu-common.h
@@ -41,8 +41,7 @@
 /* This should not be used by devices.  */
 ram_addr_t qemu_ram_addr_from_host(void *ptr);
 
-int cpu_register_io_memory(int io_index,
-                           CPUReadMemoryFunc **mem_read,
+int cpu_register_io_memory(CPUReadMemoryFunc **mem_read,
                            CPUWriteMemoryFunc **mem_write,
                            void *opaque);
 void cpu_unregister_io_memory(int table_address);
diff --git a/exec.c b/exec.c
index 9e7d66a..cf2583e 100644
--- a/exec.c
+++ b/exec.c
@@ -3004,7 +3004,7 @@
     mmio = qemu_mallocz(sizeof(subpage_t));
 
     mmio->base = base;
-    subpage_memory = cpu_register_io_memory(0, subpage_read, subpage_write, mmio);
+    subpage_memory = cpu_register_io_memory(subpage_read, subpage_write, mmio);
 #if defined(DEBUG_SUBPAGE)
     printf("%s: %p base " TARGET_FMT_plx " len %08x %d\n", __func__,
            mmio, base, TARGET_PAGE_SIZE, subpage_memory);
@@ -3029,17 +3029,22 @@
     return -1;
 }
 
+static int cpu_register_io_memory_fixed(int io_index,
+                                        CPUReadMemoryFunc **mem_read,
+                                        CPUWriteMemoryFunc **mem_write,
+                                        void *opaque);
+
 static void io_mem_init(void)
 {
     int i;
 
-    cpu_register_io_memory(IO_MEM_ROM >> IO_MEM_SHIFT, error_mem_read, unassigned_mem_write, NULL);
-    cpu_register_io_memory(IO_MEM_UNASSIGNED >> IO_MEM_SHIFT, unassigned_mem_read, unassigned_mem_write, NULL);
-    cpu_register_io_memory(IO_MEM_NOTDIRTY >> IO_MEM_SHIFT, error_mem_read, notdirty_mem_write, NULL);
+    cpu_register_io_memory_fixed(IO_MEM_ROM, error_mem_read, unassigned_mem_write, NULL);
+    cpu_register_io_memory_fixed(IO_MEM_UNASSIGNED, unassigned_mem_read, unassigned_mem_write, NULL);
+    cpu_register_io_memory_fixed(IO_MEM_NOTDIRTY, error_mem_read, notdirty_mem_write, NULL);
     for (i=0; i<5; i++)
         io_mem_used[i] = 1;
 
-    io_mem_watch = cpu_register_io_memory(0, watch_mem_read,
+    io_mem_watch = cpu_register_io_memory(watch_mem_read,
                                           watch_mem_write, NULL);
 #ifdef CONFIG_KQEMU
     if (kqemu_phys_ram_base) {
@@ -3057,10 +3062,10 @@
    modified. If it is zero, a new io zone is allocated. The return
    value can be used with cpu_register_physical_memory(). (-1) is
    returned if error. */
-int cpu_register_io_memory(int io_index,
-                           CPUReadMemoryFunc **mem_read,
-                           CPUWriteMemoryFunc **mem_write,
-                           void *opaque)
+static int cpu_register_io_memory_fixed(int io_index,
+                                        CPUReadMemoryFunc **mem_read,
+                                        CPUWriteMemoryFunc **mem_write,
+                                        void *opaque)
 {
     int i, subwidth = 0;
 
@@ -3069,6 +3074,7 @@
         if (io_index == -1)
             return io_index;
     } else {
+        io_index >>= IO_MEM_SHIFT;
         if (io_index >= IO_MEM_NB_ENTRIES)
             return -1;
     }
@@ -3083,6 +3089,13 @@
     return (io_index << IO_MEM_SHIFT) | subwidth;
 }
 
+int cpu_register_io_memory(CPUReadMemoryFunc **mem_read,
+                           CPUWriteMemoryFunc **mem_write,
+                           void *opaque)
+{
+    return cpu_register_io_memory_fixed(0, mem_read, mem_write, opaque);
+}
+
 void cpu_unregister_io_memory(int io_table_address)
 {
     int i;
diff --git a/hw/apb_pci.c b/hw/apb_pci.c
index dac5cd3..b63ccd1 100644
--- a/hw/apb_pci.c
+++ b/hw/apb_pci.c
@@ -234,13 +234,13 @@
     s->bus = pci_register_bus(NULL, "pci",
                               pci_apb_set_irq, pci_pbm_map_irq, pic, 0, 32);
 
-    pci_mem_config = cpu_register_io_memory(0, pci_apb_config_read,
+    pci_mem_config = cpu_register_io_memory(pci_apb_config_read,
                                             pci_apb_config_write, s);
-    apb_config = cpu_register_io_memory(0, apb_config_read,
+    apb_config = cpu_register_io_memory(apb_config_read,
                                         apb_config_write, s);
-    pci_mem_data = cpu_register_io_memory(0, pci_apb_read,
+    pci_mem_data = cpu_register_io_memory(pci_apb_read,
                                           pci_apb_write, s);
-    pci_ioport = cpu_register_io_memory(0, pci_apb_ioread,
+    pci_ioport = cpu_register_io_memory(pci_apb_ioread,
                                           pci_apb_iowrite, s);
 
     cpu_register_physical_memory(special_base + 0x2000ULL, 0x40, apb_config);
diff --git a/hw/apic.c b/hw/apic.c
index 000339b..3e04132 100644
--- a/hw/apic.c
+++ b/hw/apic.c
@@ -936,7 +936,7 @@
     if (apic_io_memory == 0) {
         /* NOTE: the APIC is directly connected to the CPU - it is not
            on the global memory bus. */
-        apic_io_memory = cpu_register_io_memory(0, apic_mem_read,
+        apic_io_memory = cpu_register_io_memory(apic_mem_read,
                                                 apic_mem_write, NULL);
         cpu_register_physical_memory(s->apicbase & ~0xfff, 0x1000,
                                      apic_io_memory);
diff --git a/hw/arm_gic.c b/hw/arm_gic.c
index 817234d..563397d 100644
--- a/hw/arm_gic.c
+++ b/hw/arm_gic.c
@@ -725,7 +725,7 @@
     for (i = 0; i < NCPU; i++) {
         sysbus_init_irq(&s->busdev, &s->parent_irq[i]);
     }
-    s->iomemtype = cpu_register_io_memory(0, gic_dist_readfn,
+    s->iomemtype = cpu_register_io_memory(gic_dist_readfn,
                                           gic_dist_writefn, s);
     gic_reset(s);
     register_savevm("arm_gic", -1, 1, gic_save, gic_load, s);
diff --git a/hw/arm_sysctl.c b/hw/arm_sysctl.c
index 1ddb4a2..c9d1e3f 100644
--- a/hw/arm_sysctl.c
+++ b/hw/arm_sysctl.c
@@ -198,7 +198,7 @@
     /* The MPcore bootloader uses these flags to start secondary CPUs.
        We don't use a bootloader, so do this here.  */
     s->flags = 3;
-    iomemtype = cpu_register_io_memory(0, arm_sysctl_readfn,
+    iomemtype = cpu_register_io_memory(arm_sysctl_readfn,
                                        arm_sysctl_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     /* ??? Save/restore.  */
diff --git a/hw/arm_timer.c b/hw/arm_timer.c
index 226ecc4..572804f 100644
--- a/hw/arm_timer.c
+++ b/hw/arm_timer.c
@@ -268,7 +268,7 @@
     s->timer[1] = arm_timer_init(1000000);
     s->timer[0]->irq = qi[0];
     s->timer[1]->irq = qi[1];
-    iomemtype = cpu_register_io_memory(0, sp804_readfn,
+    iomemtype = cpu_register_io_memory(sp804_readfn,
                                        sp804_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     register_savevm("sp804", -1, 1, sp804_save, sp804_load, s);
@@ -338,7 +338,7 @@
     sysbus_init_irq(dev, &s->timer[1]->irq);
     sysbus_init_irq(dev, &s->timer[2]->irq);
 
-    iomemtype = cpu_register_io_memory(0, icp_pit_readfn,
+    iomemtype = cpu_register_io_memory(icp_pit_readfn,
                                        icp_pit_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     /* This device has no state to save/restore.  The component timers will
diff --git a/hw/armv7m.c b/hw/armv7m.c
index c3c5b9e..297a3e1 100644
--- a/hw/armv7m.c
+++ b/hw/armv7m.c
@@ -128,7 +128,7 @@
     int iomemtype;
 
     s->base = qdev_get_prop_int(&dev->qdev, "base", 0);
-    iomemtype = cpu_register_io_memory(0, bitband_readfn, bitband_writefn,
+    iomemtype = cpu_register_io_memory(bitband_readfn, bitband_writefn,
                                        &s->base);
     sysbus_init_mmio(dev, 0x02000000, iomemtype);
 }
diff --git a/hw/axis_dev88.c b/hw/axis_dev88.c
index c4e09dd..2b1925f 100644
--- a/hw/axis_dev88.c
+++ b/hw/axis_dev88.c
@@ -286,11 +286,11 @@
 
       /* Attach a NAND flash to CS1.  */
     nand_state.nand = nand_init(NAND_MFR_STMICRO, 0x39);
-    nand_regs = cpu_register_io_memory(0, nand_read, nand_write, &nand_state);
+    nand_regs = cpu_register_io_memory(nand_read, nand_write, &nand_state);
     cpu_register_physical_memory(0x10000000, 0x05000000, nand_regs);
 
     gpio_state.nand = &nand_state;
-    gpio_regs = cpu_register_io_memory(0, gpio_read, gpio_write, &gpio_state);
+    gpio_regs = cpu_register_io_memory(gpio_read, gpio_write, &gpio_state);
     cpu_register_physical_memory(0x3001a000, 0x5c, gpio_regs);
 
 
diff --git a/hw/cirrus_vga.c b/hw/cirrus_vga.c
index f0bb8d9..5591149 100644
--- a/hw/cirrus_vga.c
+++ b/hw/cirrus_vga.c
@@ -3196,7 +3196,7 @@
     register_ioport_read(0x3ba, 1, 1, vga_ioport_read, s);
     register_ioport_read(0x3da, 1, 1, vga_ioport_read, s);
 
-    s->vga.vga_io_memory = cpu_register_io_memory(0, cirrus_vga_mem_read,
+    s->vga.vga_io_memory = cpu_register_io_memory(cirrus_vga_mem_read,
                                                   cirrus_vga_mem_write, s);
     cpu_register_physical_memory(isa_mem_base + 0x000a0000, 0x20000,
                                  s->vga.vga_io_memory);
@@ -3204,16 +3204,16 @@
 
     /* I/O handler for LFB */
     s->cirrus_linear_io_addr =
-        cpu_register_io_memory(0, cirrus_linear_read, cirrus_linear_write, s);
+        cpu_register_io_memory(cirrus_linear_read, cirrus_linear_write, s);
 
     /* I/O handler for LFB */
     s->cirrus_linear_bitblt_io_addr =
-        cpu_register_io_memory(0, cirrus_linear_bitblt_read,
+        cpu_register_io_memory(cirrus_linear_bitblt_read,
                                cirrus_linear_bitblt_write, s);
 
     /* I/O handler for memory-mapped I/O */
     s->cirrus_mmio_io_addr =
-        cpu_register_io_memory(0, cirrus_mmio_read, cirrus_mmio_write, s);
+        cpu_register_io_memory(cirrus_mmio_read, cirrus_mmio_write, s);
 
     s->real_vram_size =
         (s->device_id == CIRRUS_ID_CLGD5446) ? 4096 * 1024 : 2048 * 1024;
diff --git a/hw/cs4231.c b/hw/cs4231.c
index a5ba221..6d7e4b1 100644
--- a/hw/cs4231.c
+++ b/hw/cs4231.c
@@ -172,7 +172,7 @@
 
     s = qemu_mallocz(sizeof(CSState));
 
-    cs_io_memory = cpu_register_io_memory(0, cs_mem_read, cs_mem_write, s);
+    cs_io_memory = cpu_register_io_memory(cs_mem_read, cs_mem_write, s);
     cpu_register_physical_memory(base, CS_SIZE, cs_io_memory);
     register_savevm("cs4231", base, 1, cs_save, cs_load, s);
     qemu_register_reset(cs_reset, 0, s);
diff --git a/hw/cuda.c b/hw/cuda.c
index 828ccf7..edc3d4a 100644
--- a/hw/cuda.c
+++ b/hw/cuda.c
@@ -760,7 +760,7 @@
     s->tick_offset = (uint32_t)mktimegm(&tm) + RTC_OFFSET;
 
     s->adb_poll_timer = qemu_new_timer(vm_clock, cuda_adb_poll, s);
-    *cuda_mem_index = cpu_register_io_memory(0, cuda_read, cuda_write, s);
+    *cuda_mem_index = cpu_register_io_memory(cuda_read, cuda_write, s);
     register_savevm("cuda", -1, 1, cuda_save, cuda_load, s);
     qemu_register_reset(cuda_reset, 0, s);
     cuda_reset(s);
diff --git a/hw/dp8393x.c b/hw/dp8393x.c
index cff84aa..f326a10 100644
--- a/hw/dp8393x.c
+++ b/hw/dp8393x.c
@@ -897,6 +897,6 @@
     qemu_register_reset(nic_reset, 0, s);
     nic_reset(s);
 
-    s->mmio_index = cpu_register_io_memory(0, dp8393x_read, dp8393x_write, s);
+    s->mmio_index = cpu_register_io_memory(dp8393x_read, dp8393x_write, s);
     cpu_register_physical_memory(base, 0x40 << it_shift, s->mmio_index);
 }
diff --git a/hw/ds1225y.c b/hw/ds1225y.c
index 458a7d5..4475717 100644
--- a/hw/ds1225y.c
+++ b/hw/ds1225y.c
@@ -171,10 +171,10 @@
     }
 
     /* Read/write memory */
-    mem_indexRW = cpu_register_io_memory(0, nvram_read, nvram_write, s);
+    mem_indexRW = cpu_register_io_memory(nvram_read, nvram_write, s);
     cpu_register_physical_memory(mem_base, s->chip_size, mem_indexRW);
     /* Read/write protected memory */
-    mem_indexRP = cpu_register_io_memory(0, nvram_read, nvram_write_protected, s);
+    mem_indexRP = cpu_register_io_memory(nvram_read, nvram_write_protected, s);
     cpu_register_physical_memory(mem_base + s->chip_size, s->chip_size, mem_indexRP);
     return s;
 }
diff --git a/hw/e1000.c b/hw/e1000.c
index eed02a6..0dd3a12 100644
--- a/hw/e1000.c
+++ b/hw/e1000.c
@@ -1101,7 +1101,7 @@
 
     pci_conf[0x3d] = 1; // interrupt pin 0
 
-    d->mmio_index = cpu_register_io_memory(0, e1000_mmio_read,
+    d->mmio_index = cpu_register_io_memory(e1000_mmio_read,
             e1000_mmio_write, d);
 
     pci_register_io_region((PCIDevice *)d, 0, PNPMMIO_SIZE,
diff --git a/hw/eccmemctl.c b/hw/eccmemctl.c
index aa4218d..356b803 100644
--- a/hw/eccmemctl.c
+++ b/hw/eccmemctl.c
@@ -325,10 +325,10 @@
     s->regs[0] = version;
     s->irq = irq;
 
-    ecc_io_memory = cpu_register_io_memory(0, ecc_mem_read, ecc_mem_write, s);
+    ecc_io_memory = cpu_register_io_memory(ecc_mem_read, ecc_mem_write, s);
     cpu_register_physical_memory(base, ECC_SIZE, ecc_io_memory);
     if (version == ECC_MCC) { // SS-600MP only
-        ecc_io_memory = cpu_register_io_memory(0, ecc_diag_mem_read,
+        ecc_io_memory = cpu_register_io_memory(ecc_diag_mem_read,
                                                ecc_diag_mem_write, s);
         cpu_register_physical_memory(base + 0x1000, ECC_DIAG_SIZE,
                                      ecc_io_memory);
diff --git a/hw/eepro100.c b/hw/eepro100.c
index a6355dc..5045e5c 100644
--- a/hw/eepro100.c
+++ b/hw/eepro100.c
@@ -1750,7 +1750,7 @@
 
     /* Handler for memory-mapped I/O */
     d->eepro100.mmio_index =
-        cpu_register_io_memory(0, pci_mmio_read, pci_mmio_write, s);
+        cpu_register_io_memory(pci_mmio_read, pci_mmio_write, s);
 
     pci_register_io_region(&d->dev, 0, PCI_MEM_SIZE,
                            PCI_ADDRESS_SPACE_MEM |
diff --git a/hw/escc.c b/hw/escc.c
index 3d982b5..1911e7d 100644
--- a/hw/escc.c
+++ b/hw/escc.c
@@ -728,7 +728,7 @@
 
     s = qemu_mallocz(sizeof(SerialState));
 
-    escc_io_memory = cpu_register_io_memory(0, escc_mem_read,
+    escc_io_memory = cpu_register_io_memory(escc_mem_read,
                                             escc_mem_write,
                                             s);
     if (base)
@@ -922,7 +922,7 @@
     s->chn[0].disabled = disabled;
     s->chn[1].disabled = disabled;
 
-    slavio_serial_io_memory = cpu_register_io_memory(0, escc_mem_read,
+    slavio_serial_io_memory = cpu_register_io_memory(escc_mem_read,
                                                      escc_mem_write,
                                                      s);
     cpu_register_physical_memory(base, ESCC_SIZE << it_shift,
diff --git a/hw/esp.c b/hw/esp.c
index ffb2225..5fa910c 100644
--- a/hw/esp.c
+++ b/hw/esp.c
@@ -676,7 +676,7 @@
     s->dma_memory_write = qdev_get_prop_ptr(&dev->qdev, "dma_memory_write");
     s->dma_opaque = qdev_get_prop_ptr(&dev->qdev, "dma_opaque");
 
-    esp_io_memory = cpu_register_io_memory(0, esp_mem_read, esp_mem_write, s);
+    esp_io_memory = cpu_register_io_memory(esp_mem_read, esp_mem_write, s);
     sysbus_init_mmio(dev, ESP_REGS << s->it_shift, esp_io_memory);
 
     esp_reset(s);
diff --git a/hw/etraxfs_dma.c b/hw/etraxfs_dma.c
index 1b65d03..4117535 100644
--- a/hw/etraxfs_dma.c
+++ b/hw/etraxfs_dma.c
@@ -750,7 +750,7 @@
 	ctrl->nr_channels = nr_channels;
 	ctrl->channels = qemu_mallocz(sizeof ctrl->channels[0] * nr_channels);
 
-	ctrl->map = cpu_register_io_memory(0, dma_read, dma_write, ctrl);
+	ctrl->map = cpu_register_io_memory(dma_read, dma_write, ctrl);
 	cpu_register_physical_memory(base, nr_channels * 0x2000, ctrl->map);
 	return ctrl;
 }
diff --git a/hw/etraxfs_eth.c b/hw/etraxfs_eth.c
index 469be55..58f9f4e 100644
--- a/hw/etraxfs_eth.c
+++ b/hw/etraxfs_eth.c
@@ -587,7 +587,7 @@
 	tdk_init(&eth->phy);
 	mdio_attach(&eth->mdio_bus, &eth->phy, eth->phyaddr);
 
-	eth->ethregs = cpu_register_io_memory(0, eth_read, eth_write, eth);
+	eth->ethregs = cpu_register_io_memory(eth_read, eth_write, eth);
 	cpu_register_physical_memory (base, 0x5c, eth->ethregs);
 
 	eth->vc = qemu_new_vlan_client(nd->vlan, nd->model, nd->name,
diff --git a/hw/etraxfs_pic.c b/hw/etraxfs_pic.c
index 585e785..1c67427 100644
--- a/hw/etraxfs_pic.c
+++ b/hw/etraxfs_pic.c
@@ -145,7 +145,7 @@
     sysbus_init_irq(dev, &s->parent_irq);
     sysbus_init_irq(dev, &s->parent_nmi);
 
-    intr_vect_regs = cpu_register_io_memory(0, pic_read, pic_write, s);
+    intr_vect_regs = cpu_register_io_memory(pic_read, pic_write, s);
     sysbus_init_mmio(dev, R_MAX * 4, intr_vect_regs);
 }
 
diff --git a/hw/etraxfs_ser.c b/hw/etraxfs_ser.c
index e74d11a..7cb5e71 100644
--- a/hw/etraxfs_ser.c
+++ b/hw/etraxfs_ser.c
@@ -171,7 +171,7 @@
     s->regs[RS_STAT_DIN] |= (1 << STAT_TR_IDLE);
 
     sysbus_init_irq(dev, &s->irq);
-    ser_regs = cpu_register_io_memory(0, ser_read, ser_write, s);
+    ser_regs = cpu_register_io_memory(ser_read, ser_write, s);
     sysbus_init_mmio(dev, R_MAX * 4, ser_regs);
     s->chr = qdev_init_chardev(&dev->qdev);
     if (s->chr)
diff --git a/hw/etraxfs_timer.c b/hw/etraxfs_timer.c
index 79eceb8..78fa810 100644
--- a/hw/etraxfs_timer.c
+++ b/hw/etraxfs_timer.c
@@ -323,7 +323,7 @@
     sysbus_init_irq(dev, &t->irq);
     sysbus_init_irq(dev, &t->nmi);
 
-    timer_regs = cpu_register_io_memory(0, timer_read, timer_write, t);
+    timer_regs = cpu_register_io_memory(timer_read, timer_write, t);
     sysbus_init_mmio(dev, 0x5c, timer_regs);
 
     qemu_register_reset(etraxfs_timer_reset, 0, t);
diff --git a/hw/fdc.c b/hw/fdc.c
index 4c6284c..aa89db3 100644
--- a/hw/fdc.c
+++ b/hw/fdc.c
@@ -1902,7 +1902,7 @@
 
     fdctrl->sun4m = 0;
     if (mem_mapped) {
-        io_mem = cpu_register_io_memory(0, fdctrl_mem_read, fdctrl_mem_write,
+        io_mem = cpu_register_io_memory(fdctrl_mem_read, fdctrl_mem_write,
                                         fdctrl);
         cpu_register_physical_memory(io_base, 0x08, io_mem);
     } else {
@@ -1927,7 +1927,7 @@
 
     fdctrl = fdctrl_init_common(irq, -1, io_base, fds);
     fdctrl->sun4m = 1;
-    io_mem = cpu_register_io_memory(0, fdctrl_mem_read_strict,
+    io_mem = cpu_register_io_memory(fdctrl_mem_read_strict,
                                     fdctrl_mem_write_strict,
                                     fdctrl);
     cpu_register_physical_memory(io_base, 0x08, io_mem);
diff --git a/hw/fw_cfg.c b/hw/fw_cfg.c
index 8ac0e9d..276c396 100644
--- a/hw/fw_cfg.c
+++ b/hw/fw_cfg.c
@@ -266,12 +266,12 @@
         register_ioport_write(data_port, 1, 1, fw_cfg_io_writeb, s);
     }
     if (ctl_addr) {
-        io_ctl_memory = cpu_register_io_memory(0, fw_cfg_ctl_mem_read,
+        io_ctl_memory = cpu_register_io_memory(fw_cfg_ctl_mem_read,
                                            fw_cfg_ctl_mem_write, s);
         cpu_register_physical_memory(ctl_addr, FW_CFG_SIZE, io_ctl_memory);
     }
     if (data_addr) {
-        io_data_memory = cpu_register_io_memory(0, fw_cfg_data_mem_read,
+        io_data_memory = cpu_register_io_memory(fw_cfg_data_mem_read,
                                            fw_cfg_data_mem_write, s);
         cpu_register_physical_memory(data_addr, FW_CFG_SIZE, io_data_memory);
     }
diff --git a/hw/g364fb.c b/hw/g364fb.c
index b9bb318..8afc603 100644
--- a/hw/g364fb.c
+++ b/hw/g364fb.c
@@ -608,7 +608,7 @@
 
     cpu_register_physical_memory(vram_base, s->vram_size, s->vram_offset);
 
-    io_ctrl = cpu_register_io_memory(0, g364fb_ctrl_read, g364fb_ctrl_write, s);
+    io_ctrl = cpu_register_io_memory(g364fb_ctrl_read, g364fb_ctrl_write, s);
     cpu_register_physical_memory(ctrl_base, 0x200000, io_ctrl);
 
     return 0;
diff --git a/hw/grackle_pci.c b/hw/grackle_pci.c
index 581d1c5..f08dc01 100644
--- a/hw/grackle_pci.c
+++ b/hw/grackle_pci.c
@@ -137,9 +137,9 @@
                               pci_grackle_set_irq, pci_grackle_map_irq,
                               pic, 0, 4);
 
-    pci_mem_config = cpu_register_io_memory(0, pci_grackle_config_read,
+    pci_mem_config = cpu_register_io_memory(pci_grackle_config_read,
                                             pci_grackle_config_write, s);
-    pci_mem_data = cpu_register_io_memory(0, pci_grackle_read,
+    pci_mem_data = cpu_register_io_memory(pci_grackle_read,
                                           pci_grackle_write, s);
     cpu_register_physical_memory(base, 0x1000, pci_mem_config);
     cpu_register_physical_memory(base + 0x00200000, 0x1000, pci_mem_data);
diff --git a/hw/gt64xxx.c b/hw/gt64xxx.c
index ce3ffe2..3b44fc9 100644
--- a/hw/gt64xxx.c
+++ b/hw/gt64xxx.c
@@ -1131,7 +1131,7 @@
     s->pci->bus = pci_register_bus(NULL, "pci",
                                    pci_gt64120_set_irq, pci_gt64120_map_irq,
                                    pic, 144, 4);
-    s->ISD_handle = cpu_register_io_memory(0, gt64120_read, gt64120_write, s);
+    s->ISD_handle = cpu_register_io_memory(gt64120_read, gt64120_write, s);
     d = pci_register_device(s->pci->bus, "GT64120 PCI Bus", sizeof(PCIDevice),
                             0, gt64120_read_config, gt64120_write_config);
 
diff --git a/hw/heathrow_pic.c b/hw/heathrow_pic.c
index 38ebe99..5bee0ce 100644
--- a/hw/heathrow_pic.c
+++ b/hw/heathrow_pic.c
@@ -226,7 +226,7 @@
     s = qemu_mallocz(sizeof(HeathrowPICS));
     /* only 1 CPU */
     s->irqs = irqs[0];
-    *pmem_index = cpu_register_io_memory(0, pic_read, pic_write, s);
+    *pmem_index = cpu_register_io_memory(pic_read, pic_write, s);
 
     register_savevm("heathrow_pic", -1, 1, heathrow_pic_save,
                     heathrow_pic_load, s);
diff --git a/hw/hpet.c b/hw/hpet.c
index 29db325..e0be486 100644
--- a/hw/hpet.c
+++ b/hw/hpet.c
@@ -582,7 +582,7 @@
     register_savevm("hpet", -1, 1, hpet_save, hpet_load, s);
     qemu_register_reset(hpet_reset, 0, s);
     /* HPET Area */
-    iomemtype = cpu_register_io_memory(0, hpet_ram_read,
+    iomemtype = cpu_register_io_memory(hpet_ram_read,
                                        hpet_ram_write, s);
     cpu_register_physical_memory(HPET_BASE, 0x400, iomemtype);
 }
diff --git a/hw/ide.c b/hw/ide.c
index f8da7c9..dd76aa1 100644
--- a/hw/ide.c
+++ b/hw/ide.c
@@ -3751,7 +3751,7 @@
     if (dbdma)
         DBDMA_register_channel(dbdma, channel, dma_irq, pmac_ide_transfer, pmac_ide_flush, d);
 
-    pmac_ide_memory = cpu_register_io_memory(0, pmac_ide_read,
+    pmac_ide_memory = cpu_register_io_memory(pmac_ide_read,
                                              pmac_ide_write, d);
     register_savevm("ide", 0, 1, pmac_ide_save, pmac_ide_load, d);
     qemu_register_reset(pmac_ide_reset, 0, d);
@@ -3847,8 +3847,8 @@
     s->dev = ide;
     s->shift = shift;
 
-    mem1 = cpu_register_io_memory(0, mmio_ide_reads, mmio_ide_writes, s);
-    mem2 = cpu_register_io_memory(0, mmio_ide_status, mmio_ide_cmd, s);
+    mem1 = cpu_register_io_memory(mmio_ide_reads, mmio_ide_writes, s);
+    mem2 = cpu_register_io_memory(mmio_ide_status, mmio_ide_cmd, s);
     cpu_register_physical_memory(membase, 16 << shift, mem1);
     cpu_register_physical_memory(membase2, 2 << shift, mem2);
 }
diff --git a/hw/integratorcp.c b/hw/integratorcp.c
index b6fbe15..50eae0c 100644
--- a/hw/integratorcp.c
+++ b/hw/integratorcp.c
@@ -256,7 +256,7 @@
     s->cm_init = 0x00000112;
     s->flash_offset = qemu_ram_alloc(0x100000);
 
-    iomemtype = cpu_register_io_memory(0, integratorcm_readfn,
+    iomemtype = cpu_register_io_memory(integratorcm_readfn,
                                        integratorcm_writefn, s);
     sysbus_init_mmio(dev, 0x00800000, iomemtype);
     integratorcm_do_remap(s, 1);
@@ -381,7 +381,7 @@
     qdev_init_gpio_in(&dev->qdev, icp_pic_set_irq, 32);
     sysbus_init_irq(dev, &s->parent_irq);
     sysbus_init_irq(dev, &s->parent_fiq);
-    iomemtype = cpu_register_io_memory(0, icp_pic_readfn,
+    iomemtype = cpu_register_io_memory(icp_pic_readfn,
                                        icp_pic_writefn, s);
     sysbus_init_mmio(dev, 0x00800000, iomemtype);
 }
@@ -433,7 +433,7 @@
 {
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, icp_control_readfn,
+    iomemtype = cpu_register_io_memory(icp_control_readfn,
                                        icp_control_writefn, NULL);
     cpu_register_physical_memory(base, 0x00800000, iomemtype);
     /* ??? Save/restore.  */
diff --git a/hw/ioapic.c b/hw/ioapic.c
index 83ac25e..b179e6e 100644
--- a/hw/ioapic.c
+++ b/hw/ioapic.c
@@ -250,7 +250,7 @@
     s = qemu_mallocz(sizeof(IOAPICState));
     ioapic_reset(s);
 
-    io_memory = cpu_register_io_memory(0, ioapic_mem_read,
+    io_memory = cpu_register_io_memory(ioapic_mem_read,
                                        ioapic_mem_write, s);
     cpu_register_physical_memory(0xfec00000, 0x1000, io_memory);
 
diff --git a/hw/iommu.c b/hw/iommu.c
index ae0c56d..694adbd 100644
--- a/hw/iommu.c
+++ b/hw/iommu.c
@@ -375,7 +375,7 @@
     s->version = version;
     s->irq = irq;
 
-    iommu_io_memory = cpu_register_io_memory(0, iommu_mem_read,
+    iommu_io_memory = cpu_register_io_memory(iommu_mem_read,
                                              iommu_mem_write, s);
     cpu_register_physical_memory(addr, IOMMU_NREGS * 4, iommu_io_memory);
 
diff --git a/hw/isa_mmio.c b/hw/isa_mmio.c
index 3519611..1d5e8dc 100644
--- a/hw/isa_mmio.c
+++ b/hw/isa_mmio.c
@@ -96,7 +96,7 @@
 void isa_mmio_init(target_phys_addr_t base, target_phys_addr_t size)
 {
     if (!isa_mmio_iomemtype) {
-        isa_mmio_iomemtype = cpu_register_io_memory(0, isa_mmio_read,
+        isa_mmio_iomemtype = cpu_register_io_memory(isa_mmio_read,
                                                     isa_mmio_write, NULL);
     }
     cpu_register_physical_memory(base, size, isa_mmio_iomemtype);
diff --git a/hw/jazz_led.c b/hw/jazz_led.c
index 8e20369..9fdaf8f 100644
--- a/hw/jazz_led.c
+++ b/hw/jazz_led.c
@@ -307,7 +307,7 @@
 
     s->state = REDRAW_SEGMENTS | REDRAW_BACKGROUND;
 
-    io = cpu_register_io_memory(0, led_read, led_write, s);
+    io = cpu_register_io_memory(led_read, led_write, s);
     cpu_register_physical_memory(base, 1, io);
 
     s->ds = graphic_console_init(jazz_led_update_display,
diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
index 9b9f761..5bae70a 100644
--- a/hw/lsi53c895a.c
+++ b/hw/lsi53c895a.c
@@ -1998,9 +1998,9 @@
     /* Interrupt pin 1 */
     pci_conf[0x3d] = 0x01;
 
-    s->mmio_io_addr = cpu_register_io_memory(0, lsi_mmio_readfn,
+    s->mmio_io_addr = cpu_register_io_memory(lsi_mmio_readfn,
                                              lsi_mmio_writefn, s);
-    s->ram_io_addr = cpu_register_io_memory(0, lsi_ram_readfn,
+    s->ram_io_addr = cpu_register_io_memory(lsi_ram_readfn,
                                             lsi_ram_writefn, s);
 
     pci_register_io_region((struct PCIDevice *)s, 0, 256,
diff --git a/hw/m48t59.c b/hw/m48t59.c
index 4804443..455da3d 100644
--- a/hw/m48t59.c
+++ b/hw/m48t59.c
@@ -632,7 +632,7 @@
         register_ioport_write(io_base, 0x04, 1, NVRAM_writeb, s);
     }
     if (mem_base != 0) {
-        s->mem_index = cpu_register_io_memory(0, nvram_read, nvram_write, s);
+        s->mem_index = cpu_register_io_memory(nvram_read, nvram_write, s);
         cpu_register_physical_memory(mem_base, size, s->mem_index);
     }
     if (type == 59) {
diff --git a/hw/mac_dbdma.c b/hw/mac_dbdma.c
index 75a9f17..eeceb7d 100644
--- a/hw/mac_dbdma.c
+++ b/hw/mac_dbdma.c
@@ -837,7 +837,7 @@
 
     s = qemu_mallocz(sizeof(DBDMA_channel) * DBDMA_CHANNELS);
 
-    *dbdma_mem_index = cpu_register_io_memory(0, dbdma_read, dbdma_write, s);
+    *dbdma_mem_index = cpu_register_io_memory(dbdma_read, dbdma_write, s);
     register_savevm("dbdma", -1, 1, dbdma_save, dbdma_load, s);
     qemu_register_reset(dbdma_reset, 0, s);
     dbdma_reset(s);
diff --git a/hw/mac_nvram.c b/hw/mac_nvram.c
index 1a1ca0d..7301145 100644
--- a/hw/mac_nvram.c
+++ b/hw/mac_nvram.c
@@ -138,7 +138,7 @@
     s->size = size;
     s->it_shift = it_shift;
 
-    s->mem_index = cpu_register_io_memory(0, nvram_read, nvram_write, s);
+    s->mem_index = cpu_register_io_memory(nvram_read, nvram_write, s);
     *mem_index = s->mem_index;
     register_savevm("macio_nvram", -1, 1, macio_nvram_save, macio_nvram_load,
                     s);
diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
index 8c446e1..d0597ac 100644
--- a/hw/mc146818rtc.c
+++ b/hw/mc146818rtc.c
@@ -735,7 +735,7 @@
     s->next_second_time = qemu_get_clock(vm_clock) + (ticks_per_sec * 99) / 100;
     qemu_mod_timer(s->second_timer2, s->next_second_time);
 
-    io_memory = cpu_register_io_memory(0, rtc_mm_read, rtc_mm_write, s);
+    io_memory = cpu_register_io_memory(rtc_mm_read, rtc_mm_write, s);
     cpu_register_physical_memory(base, 2 << it_shift, io_memory);
 
     register_savevm("mc146818rtc", base, 1, rtc_save, rtc_load, s);
diff --git a/hw/mcf5206.c b/hw/mcf5206.c
index b570376..049099e 100644
--- a/hw/mcf5206.c
+++ b/hw/mcf5206.c
@@ -524,7 +524,7 @@
     int iomemtype;
 
     s = (m5206_mbar_state *)qemu_mallocz(sizeof(m5206_mbar_state));
-    iomemtype = cpu_register_io_memory(0, m5206_mbar_readfn,
+    iomemtype = cpu_register_io_memory(m5206_mbar_readfn,
                                        m5206_mbar_writefn, s);
     cpu_register_physical_memory(base, 0x00001000, iomemtype);
 
diff --git a/hw/mcf5208.c b/hw/mcf5208.c
index 47a0f3e..1ee9680 100644
--- a/hw/mcf5208.c
+++ b/hw/mcf5208.c
@@ -176,7 +176,7 @@
     QEMUBH *bh;
     int i;
 
-    iomemtype = cpu_register_io_memory(0, m5208_sys_readfn,
+    iomemtype = cpu_register_io_memory(m5208_sys_readfn,
                                        m5208_sys_writefn, NULL);
     /* SDRAMC.  */
     cpu_register_physical_memory(0xfc0a8000, 0x00004000, iomemtype);
@@ -185,7 +185,7 @@
         s = (m5208_timer_state *)qemu_mallocz(sizeof(m5208_timer_state));
         bh = qemu_bh_new(m5208_timer_trigger, s);
         s->timer = ptimer_init(bh);
-        iomemtype = cpu_register_io_memory(0, m5208_timer_readfn,
+        iomemtype = cpu_register_io_memory(m5208_timer_readfn,
                                            m5208_timer_writefn, s);
         cpu_register_physical_memory(0xfc080000 + 0x4000 * i, 0x00004000,
                                      iomemtype);
diff --git a/hw/mcf_fec.c b/hw/mcf_fec.c
index 179ec19..1676bcb 100644
--- a/hw/mcf_fec.c
+++ b/hw/mcf_fec.c
@@ -458,7 +458,7 @@
 
     s = (mcf_fec_state *)qemu_mallocz(sizeof(mcf_fec_state));
     s->irq = irq;
-    s->mmio_index = cpu_register_io_memory(0, mcf_fec_readfn,
+    s->mmio_index = cpu_register_io_memory(mcf_fec_readfn,
                                            mcf_fec_writefn, s);
     cpu_register_physical_memory(base, 0x400, s->mmio_index);
 
diff --git a/hw/mcf_intc.c b/hw/mcf_intc.c
index ce378c2..e291280 100644
--- a/hw/mcf_intc.c
+++ b/hw/mcf_intc.c
@@ -148,7 +148,7 @@
     s->env = env;
     mcf_intc_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, mcf_intc_readfn,
+    iomemtype = cpu_register_io_memory(mcf_intc_readfn,
                                        mcf_intc_writefn, s);
     cpu_register_physical_memory(base, 0x100, iomemtype);
 
diff --git a/hw/mcf_uart.c b/hw/mcf_uart.c
index a65cc77..8300fe8 100644
--- a/hw/mcf_uart.c
+++ b/hw/mcf_uart.c
@@ -303,7 +303,7 @@
     int iomemtype;
 
     s = mcf_uart_init(irq, chr);
-    iomemtype = cpu_register_io_memory(0, mcf_uart_readfn,
+    iomemtype = cpu_register_io_memory(mcf_uart_readfn,
                                        mcf_uart_writefn, s);
     cpu_register_physical_memory(base, 0x40, iomemtype);
 }
diff --git a/hw/mips_jazz.c b/hw/mips_jazz.c
index e683421..2b4e1e0 100644
--- a/hw/mips_jazz.c
+++ b/hw/mips_jazz.c
@@ -181,7 +181,7 @@
 
     /* Chipset */
     rc4030_opaque = rc4030_init(env->irq[6], env->irq[3], &rc4030, &dmas);
-    s_dma_dummy = cpu_register_io_memory(0, dma_dummy_read, dma_dummy_write, NULL);
+    s_dma_dummy = cpu_register_io_memory(dma_dummy_read, dma_dummy_write, NULL);
     cpu_register_physical_memory(0x8000d000, 0x00001000, s_dma_dummy);
 
     /* ISA devices */
@@ -245,7 +245,7 @@
 
     /* Real time clock */
     rtc_init(0x70, i8259[8], 1980);
-    s_rtc = cpu_register_io_memory(0, rtc_read, rtc_write, env);
+    s_rtc = cpu_register_io_memory(rtc_read, rtc_write, env);
     cpu_register_physical_memory(0x80004000, 0x00001000, s_rtc);
 
     /* Keyboard (i8042) */
diff --git a/hw/mips_malta.c b/hw/mips_malta.c
index 970da4e..ed104f0 100644
--- a/hw/mips_malta.c
+++ b/hw/mips_malta.c
@@ -435,7 +435,7 @@
 
     s = (MaltaFPGAState *)qemu_mallocz(sizeof(MaltaFPGAState));
 
-    malta = cpu_register_io_memory(0, malta_fpga_read,
+    malta = cpu_register_io_memory(malta_fpga_read,
                                    malta_fpga_write, s);
 
     cpu_register_physical_memory(base, 0x900, malta);
diff --git a/hw/mips_r4k.c b/hw/mips_r4k.c
index 71832d5..a2bdd36 100644
--- a/hw/mips_r4k.c
+++ b/hw/mips_r4k.c
@@ -185,7 +185,7 @@
     cpu_register_physical_memory(0, ram_size, ram_offset | IO_MEM_RAM);
 
     if (!mips_qemu_iomemtype) {
-        mips_qemu_iomemtype = cpu_register_io_memory(0, mips_qemu_read,
+        mips_qemu_iomemtype = cpu_register_io_memory(mips_qemu_read,
                                                      mips_qemu_write, NULL);
     }
     cpu_register_physical_memory(0x1fbf0000, 0x10000, mips_qemu_iomemtype);
diff --git a/hw/mpcore.c b/hw/mpcore.c
index a5eddd9..907bd99 100644
--- a/hw/mpcore.c
+++ b/hw/mpcore.c
@@ -268,7 +268,7 @@
     int i;
 
     gic_init(&s->gic);
-    s->iomemtype = cpu_register_io_memory(0, mpcore_priv_readfn,
+    s->iomemtype = cpu_register_io_memory(mpcore_priv_readfn,
                                           mpcore_priv_writefn, s);
     sysbus_init_mmio_cb(dev, 0x2000, mpcore_priv_map);
     for (i = 0; i < 8; i++) {
diff --git a/hw/mst_fpga.c b/hw/mst_fpga.c
index 84eedb7..c77328f 100644
--- a/hw/mst_fpga.c
+++ b/hw/mst_fpga.c
@@ -231,7 +231,7 @@
 	qi  = qemu_allocate_irqs(mst_fpga_set_irq, s, MST_NUM_IRQS);
 	s->pins = qi;
 
-	iomemtype = cpu_register_io_memory(0, mst_fpga_readfn,
+	iomemtype = cpu_register_io_memory(mst_fpga_readfn,
 		mst_fpga_writefn, s);
 	cpu_register_physical_memory(base, 0x00100000, iomemtype);
 	register_savevm("mainstone_fpga", 0, 0, mst_fpga_save, mst_fpga_load, s);
diff --git a/hw/musicpal.c b/hw/musicpal.c
index 8c70a2b..42fdf45 100644
--- a/hw/musicpal.c
+++ b/hw/musicpal.c
@@ -437,7 +437,7 @@
     s->wm = i2c_create_slave(i2c->bus, "wm8750", MP_WM_ADDR);
     wm8750_data_req_set(s->wm, audio_callback, s);
 
-    iomemtype = cpu_register_io_memory(0, musicpal_audio_readfn,
+    iomemtype = cpu_register_io_memory(musicpal_audio_readfn,
                        musicpal_audio_writefn, s);
     cpu_register_physical_memory(MP_AUDIO_BASE, MP_AUDIO_SIZE, iomemtype);
 
@@ -756,7 +756,7 @@
     s->vc = qdev_get_vlan_client(&dev->qdev,
                                  eth_can_receive, eth_receive, NULL,
                                  eth_cleanup, s);
-    s->mmio_index = cpu_register_io_memory(0, mv88w8618_eth_readfn,
+    s->mmio_index = cpu_register_io_memory(mv88w8618_eth_readfn,
                                            mv88w8618_eth_writefn, s);
     sysbus_init_mmio(dev, MP_ETH_SIZE, s->mmio_index);
 }
@@ -946,7 +946,7 @@
     musicpal_lcd_state *s = FROM_SYSBUS(musicpal_lcd_state, dev);
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, musicpal_lcd_readfn,
+    iomemtype = cpu_register_io_memory(musicpal_lcd_readfn,
                                        musicpal_lcd_writefn, s);
     sysbus_init_mmio(dev, MP_LCD_SIZE, iomemtype);
     cpu_register_physical_memory(MP_LCD_BASE, MP_LCD_SIZE, iomemtype);
@@ -1043,7 +1043,7 @@
 
     qdev_init_gpio_in(&dev->qdev, mv88w8618_pic_set_irq, 32);
     sysbus_init_irq(dev, &s->parent_irq);
-    iomemtype = cpu_register_io_memory(0, mv88w8618_pic_readfn,
+    iomemtype = cpu_register_io_memory(mv88w8618_pic_readfn,
                                        mv88w8618_pic_writefn, s);
     sysbus_init_mmio(dev, MP_PIC_SIZE, iomemtype);
 
@@ -1167,7 +1167,7 @@
         mv88w8618_timer_init(dev, &s->timer[i], 1000000);
     }
 
-    iomemtype = cpu_register_io_memory(0, mv88w8618_pit_readfn,
+    iomemtype = cpu_register_io_memory(mv88w8618_pit_readfn,
                                        mv88w8618_pit_writefn, s);
     sysbus_init_mmio(dev, MP_PIT_SIZE, iomemtype);
 }
@@ -1224,7 +1224,7 @@
     mv88w8618_flashcfg_state *s = FROM_SYSBUS(mv88w8618_flashcfg_state, dev);
 
     s->cfgr0 = 0xfffe4285; /* Default as set by U-Boot for 8 MB flash */
-    iomemtype = cpu_register_io_memory(0, mv88w8618_flashcfg_readfn,
+    iomemtype = cpu_register_io_memory(mv88w8618_flashcfg_readfn,
                        mv88w8618_flashcfg_writefn, s);
     sysbus_init_mmio(dev, MP_FLASHCFG_SIZE, iomemtype);
 }
@@ -1266,7 +1266,7 @@
 {
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, musicpal_misc_readfn,
+    iomemtype = cpu_register_io_memory(musicpal_misc_readfn,
                                        musicpal_misc_writefn, NULL);
     cpu_register_physical_memory(MP_MISC_BASE, MP_MISC_SIZE, iomemtype);
 }
@@ -1311,7 +1311,7 @@
 {
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, mv88w8618_wlan_readfn,
+    iomemtype = cpu_register_io_memory(mv88w8618_wlan_readfn,
                                        mv88w8618_wlan_writefn, NULL);
     sysbus_init_mmio(dev, MP_WLAN_SIZE, iomemtype);
 }
@@ -1412,7 +1412,7 @@
 {
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, musicpal_gpio_readfn,
+    iomemtype = cpu_register_io_memory(musicpal_gpio_readfn,
                                        musicpal_gpio_writefn, NULL);
     cpu_register_physical_memory(MP_GPIO_BASE, MP_GPIO_SIZE, iomemtype);
 }
diff --git a/hw/omap.h b/hw/omap.h
index 231049d..e25904c 100644
--- a/hw/omap.h
+++ b/hw/omap.h
@@ -1116,7 +1116,7 @@
 static CPUReadMemoryFunc *io_readfn[] = { io_readb, io_readh, io_readw, };
 static CPUWriteMemoryFunc *io_writefn[] = { io_writeb, io_writeh, io_writew, };
 
-inline static int debug_register_io_memory(int io_index,
+inline static int debug_register_io_memory(
                 CPUReadMemoryFunc **mem_read, CPUWriteMemoryFunc **mem_write,
                 void *opaque)
 {
@@ -1126,7 +1126,7 @@
     s->mem_write = mem_write;
     s->opaque = opaque;
     s->in = 0;
-    return cpu_register_io_memory(io_index, io_readfn, io_writefn, s);
+    return cpu_register_io_memory(io_readfn, io_writefn, s);
 }
 #  define cpu_register_io_memory	debug_register_io_memory
 # endif
@@ -1136,7 +1136,7 @@
 
 # ifdef L4_MUX_HACK
 #  undef l4_register_io_memory
-int l4_register_io_memory(int io_index, CPUReadMemoryFunc **mem_read,
+int l4_register_io_memory(CPUReadMemoryFunc **mem_read,
                 CPUWriteMemoryFunc **mem_write, void *opaque);
 # endif
 
diff --git a/hw/omap1.c b/hw/omap1.c
index 4a479b4..857677d 100644
--- a/hw/omap1.c
+++ b/hw/omap1.c
@@ -425,7 +425,7 @@
 
     omap_inth_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_inth_readfn,
+    iomemtype = cpu_register_io_memory(omap_inth_readfn,
                     omap_inth_writefn, s);
     cpu_register_physical_memory(base, size, iomemtype);
 
@@ -645,7 +645,7 @@
 
     omap_inth_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap2_inth_readfn,
+    iomemtype = cpu_register_io_memory(omap2_inth_readfn,
                     omap2_inth_writefn, s);
     cpu_register_physical_memory(base, size, iomemtype);
 
@@ -834,7 +834,7 @@
     omap_mpu_timer_reset(s);
     omap_timer_clk_setup(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_mpu_timer_readfn,
+    iomemtype = cpu_register_io_memory(omap_mpu_timer_readfn,
                     omap_mpu_timer_writefn, s);
     cpu_register_physical_memory(base, 0x100, iomemtype);
 
@@ -957,7 +957,7 @@
     omap_wd_timer_reset(s);
     omap_timer_clk_setup(&s->timer);
 
-    iomemtype = cpu_register_io_memory(0, omap_wd_timer_readfn,
+    iomemtype = cpu_register_io_memory(omap_wd_timer_readfn,
                     omap_wd_timer_writefn, s);
     cpu_register_physical_memory(base, 0x100, iomemtype);
 
@@ -1059,7 +1059,7 @@
     omap_os_timer_reset(s);
     omap_timer_clk_setup(&s->timer);
 
-    iomemtype = cpu_register_io_memory(0, omap_os_timer_readfn,
+    iomemtype = cpu_register_io_memory(omap_os_timer_readfn,
                     omap_os_timer_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -1286,7 +1286,7 @@
 static void omap_ulpd_pm_init(target_phys_addr_t base,
                 struct omap_mpu_state_s *mpu)
 {
-    int iomemtype = cpu_register_io_memory(0, omap_ulpd_pm_readfn,
+    int iomemtype = cpu_register_io_memory(omap_ulpd_pm_readfn,
                     omap_ulpd_pm_writefn, mpu);
 
     cpu_register_physical_memory(base, 0x800, iomemtype);
@@ -1501,7 +1501,7 @@
 static void omap_pin_cfg_init(target_phys_addr_t base,
                 struct omap_mpu_state_s *mpu)
 {
-    int iomemtype = cpu_register_io_memory(0, omap_pin_cfg_readfn,
+    int iomemtype = cpu_register_io_memory(omap_pin_cfg_readfn,
                     omap_pin_cfg_writefn, mpu);
 
     cpu_register_physical_memory(base, 0x800, iomemtype);
@@ -1571,7 +1571,7 @@
 
 static void omap_id_init(struct omap_mpu_state_s *mpu)
 {
-    int iomemtype = cpu_register_io_memory(0, omap_id_readfn,
+    int iomemtype = cpu_register_io_memory(omap_id_readfn,
                     omap_id_writefn, mpu);
     cpu_register_physical_memory_offset(0xfffe1800, 0x800, iomemtype, 0xfffe1800);
     cpu_register_physical_memory_offset(0xfffed400, 0x100, iomemtype, 0xfffed400);
@@ -1654,7 +1654,7 @@
 static void omap_mpui_init(target_phys_addr_t base,
                 struct omap_mpu_state_s *mpu)
 {
-    int iomemtype = cpu_register_io_memory(0, omap_mpui_readfn,
+    int iomemtype = cpu_register_io_memory(omap_mpui_readfn,
                     omap_mpui_writefn, mpu);
 
     cpu_register_physical_memory(base, 0x100, iomemtype);
@@ -1763,7 +1763,7 @@
     s->abort = abort_irq;
     omap_tipb_bridge_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_tipb_bridge_readfn,
+    iomemtype = cpu_register_io_memory(omap_tipb_bridge_readfn,
                     omap_tipb_bridge_writefn, s);
     cpu_register_physical_memory(base, 0x100, iomemtype);
 
@@ -1869,7 +1869,7 @@
 static void omap_tcmi_init(target_phys_addr_t base,
                 struct omap_mpu_state_s *mpu)
 {
-    int iomemtype = cpu_register_io_memory(0, omap_tcmi_readfn,
+    int iomemtype = cpu_register_io_memory(omap_tcmi_readfn,
                     omap_tcmi_writefn, mpu);
 
     cpu_register_physical_memory(base, 0x100, iomemtype);
@@ -1942,7 +1942,7 @@
 static void omap_dpll_init(struct dpll_ctl_s *s, target_phys_addr_t base,
                 omap_clk clk)
 {
-    int iomemtype = cpu_register_io_memory(0, omap_dpll_readfn,
+    int iomemtype = cpu_register_io_memory(omap_dpll_readfn,
                     omap_dpll_writefn, s);
 
     s->dpll = clk;
@@ -2089,7 +2089,7 @@
     target_phys_addr_t base = omap_l4_attach(ta, 0, 0);
     struct omap_uart_s *s = omap_uart_init(base, irq,
                     fclk, iclk, txdma, rxdma, chr);
-    int iomemtype = cpu_register_io_memory(0, omap_uart_readfn,
+    int iomemtype = cpu_register_io_memory(omap_uart_readfn,
                     omap_uart_writefn, s);
 
     s->ta = ta;
@@ -2504,8 +2504,8 @@
                 target_phys_addr_t dsp_base, struct omap_mpu_state_s *s)
 {
     int iomemtype[2] = {
-        cpu_register_io_memory(0, omap_clkm_readfn, omap_clkm_writefn, s),
-        cpu_register_io_memory(0, omap_clkdsp_readfn, omap_clkdsp_writefn, s),
+        cpu_register_io_memory(omap_clkm_readfn, omap_clkm_writefn, s),
+        cpu_register_io_memory(omap_clkdsp_readfn, omap_clkdsp_writefn, s),
     };
 
     s->clkm.arm_idlect1 = 0x03ff;
@@ -2758,7 +2758,7 @@
     s->in = qemu_allocate_irqs(omap_mpuio_set, s, 16);
     omap_mpuio_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_mpuio_readfn,
+    iomemtype = cpu_register_io_memory(omap_mpuio_readfn,
                     omap_mpuio_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -2954,7 +2954,7 @@
     s->in = qemu_allocate_irqs(omap_gpio_set, s, 16);
     omap_gpio_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_gpio_readfn,
+    iomemtype = cpu_register_io_memory(omap_gpio_readfn,
                     omap_gpio_writefn, s);
     cpu_register_physical_memory(base, 0x1000, iomemtype);
 
@@ -3124,7 +3124,7 @@
     s->txdrq = dma;
     omap_uwire_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_uwire_readfn,
+    iomemtype = cpu_register_io_memory(omap_uwire_readfn,
                     omap_uwire_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -3225,7 +3225,7 @@
 
     omap_pwl_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_pwl_readfn,
+    iomemtype = cpu_register_io_memory(omap_pwl_readfn,
                     omap_pwl_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -3320,7 +3320,7 @@
     s->pwt.clk = clk;
     omap_pwt_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_pwt_readfn,
+    iomemtype = cpu_register_io_memory(omap_pwt_readfn,
                     omap_pwt_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 }
@@ -3743,7 +3743,7 @@
 
     omap_rtc_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_rtc_readfn,
+    iomemtype = cpu_register_io_memory(omap_rtc_readfn,
                     omap_rtc_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -4263,7 +4263,7 @@
     s->source_timer = qemu_new_timer(vm_clock, omap_mcbsp_source_tick, s);
     omap_mcbsp_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_mcbsp_readfn,
+    iomemtype = cpu_register_io_memory(omap_mcbsp_readfn,
                     omap_mcbsp_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -4435,7 +4435,7 @@
 
     omap_lpg_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_lpg_readfn,
+    iomemtype = cpu_register_io_memory(omap_lpg_readfn,
                     omap_lpg_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -4468,7 +4468,7 @@
 
 static void omap_setup_mpui_io(struct omap_mpu_state_s *mpu)
 {
-    int iomemtype = cpu_register_io_memory(0, omap_mpui_io_readfn,
+    int iomemtype = cpu_register_io_memory(omap_mpui_io_readfn,
                     omap_mpui_io_writefn, mpu);
     cpu_register_physical_memory(OMAP_MPUI_BASE, 0x7fff, iomemtype);
 }
diff --git a/hw/omap2.c b/hw/omap2.c
index 6fccca4..71483da 100644
--- a/hw/omap2.c
+++ b/hw/omap2.c
@@ -483,7 +483,7 @@
     omap_gp_timer_reset(s);
     omap_gp_timer_clk_setup(s);
 
-    iomemtype = l4_register_io_memory(0, omap_gp_timer_readfn,
+    iomemtype = l4_register_io_memory(omap_gp_timer_readfn,
                     omap_gp_timer_writefn, s);
     omap_l4_attach(ta, 0, iomemtype);
 
@@ -554,7 +554,7 @@
     struct omap_synctimer_s *s = &mpu->synctimer;
 
     omap_synctimer_reset(s);
-    omap_l4_attach(ta, 0, l4_register_io_memory(0,
+    omap_l4_attach(ta, 0, l4_register_io_memory(
                       omap_synctimer_readfn, omap_synctimer_writefn, s));
 }
 
@@ -952,7 +952,7 @@
     s->wkup = wkup;
     s->in = qemu_allocate_irqs(omap_gpio_module_set, s, 32);
 
-    iomemtype = l4_register_io_memory(0, omap_gpio_module_readfn,
+    iomemtype = l4_register_io_memory(omap_gpio_module_readfn,
                     omap_gpio_module_writefn, s);
     omap_l4_attach(ta, region, iomemtype);
 }
@@ -1060,7 +1060,7 @@
 
     omap_gpif_reset(s);
 
-    iomemtype = l4_register_io_memory(0, omap_gpif_top_readfn,
+    iomemtype = l4_register_io_memory(omap_gpif_top_readfn,
                     omap_gpif_top_writefn, s);
     omap_l4_attach(ta, 1, iomemtype);
 
@@ -1386,7 +1386,7 @@
     }
     omap_mcspi_reset(s);
 
-    iomemtype = l4_register_io_memory(0, omap_mcspi_readfn,
+    iomemtype = l4_register_io_memory(omap_mcspi_readfn,
                     omap_mcspi_writefn, s);
     omap_l4_attach(ta, 0, iomemtype);
 
@@ -1975,7 +1975,7 @@
 #ifdef HAS_AUDIO
     AUD_register_card("OMAP EAC", &s->codec.card);
 
-    iomemtype = cpu_register_io_memory(0, omap_eac_readfn,
+    iomemtype = cpu_register_io_memory(omap_eac_readfn,
                     omap_eac_writefn, s);
     omap_l4_attach(ta, 0, iomemtype);
 #endif
@@ -2160,11 +2160,11 @@
 
     s->chr = chr ?: qemu_chr_open("null", "null", NULL);
 
-    iomemtype = l4_register_io_memory(0, omap_sti_readfn,
+    iomemtype = l4_register_io_memory(omap_sti_readfn,
                     omap_sti_writefn, s);
     omap_l4_attach(ta, 0, iomemtype);
 
-    iomemtype = cpu_register_io_memory(0, omap_sti_fifo_readfn,
+    iomemtype = cpu_register_io_memory(omap_sti_fifo_readfn,
                     omap_sti_fifo_writefn, s);
     cpu_register_physical_memory(channel_base, 0x10000, iomemtype);
 
@@ -2204,7 +2204,7 @@
 static CPUWriteMemoryFunc **omap_l4_io_writew_fn;
 static void **omap_l4_io_opaque;
 
-int l4_register_io_memory(int io_index, CPUReadMemoryFunc **mem_read,
+int l4_register_io_memory(CPUReadMemoryFunc **mem_read,
                 CPUWriteMemoryFunc **mem_write, void *opaque)
 {
     omap_l4_io_entry[omap_l4_io_entries].mem_read = mem_read;
@@ -2285,7 +2285,7 @@
     omap_l4_io_entry = qemu_mallocz(125 * sizeof(*omap_l4_io_entry));
 
     omap_cpu_io_entry =
-            cpu_register_io_memory(0, omap_l4_io_readfn,
+            cpu_register_io_memory(omap_l4_io_readfn,
                             omap_l4_io_writefn, bus);
 # define L4_PAGES	(0xb4000 / TARGET_PAGE_SIZE)
     omap_l4_io_readb_fn = qemu_mallocz(sizeof(void *) * L4_PAGES);
@@ -2578,7 +2578,7 @@
     ta->status = 0x00000000;
     ta->control = 0x00000200;	/* XXX 01000200 for L4TAO */
 
-    iomemtype = l4_register_io_memory(0, omap_l4ta_readfn,
+    iomemtype = l4_register_io_memory(omap_l4ta_readfn,
                     omap_l4ta_writefn, ta);
     ta->base = omap_l4_attach(ta, info->ta_region, iomemtype);
 
@@ -2708,7 +2708,7 @@
 void omap_tap_init(struct omap_target_agent_s *ta,
                 struct omap_mpu_state_s *mpu)
 {
-    omap_l4_attach(ta, 0, l4_register_io_memory(0,
+    omap_l4_attach(ta, 0, l4_register_io_memory(
                             omap_tap_readfn, omap_tap_writefn, mpu));
 }
 
@@ -3521,7 +3521,7 @@
     s->mpu = mpu;
     omap_prcm_coldreset(s);
 
-    iomemtype = l4_register_io_memory(0, omap_prcm_readfn,
+    iomemtype = l4_register_io_memory(omap_prcm_readfn,
                     omap_prcm_writefn, s);
     omap_l4_attach(ta, 0, iomemtype);
     omap_l4_attach(ta, 1, iomemtype);
@@ -3891,7 +3891,7 @@
     s->mpu = mpu;
     omap_sysctl_reset(s);
 
-    iomemtype = l4_register_io_memory(0, omap_sysctl_readfn,
+    iomemtype = l4_register_io_memory(omap_sysctl_readfn,
                     omap_sysctl_writefn, s);
     omap_l4_attach(ta, 0, iomemtype);
 
@@ -4035,7 +4035,7 @@
 
     omap_sdrc_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_sdrc_readfn,
+    iomemtype = cpu_register_io_memory(omap_sdrc_readfn,
                     omap_sdrc_writefn, s);
     cpu_register_physical_memory(base, 0x1000, iomemtype);
 
@@ -4409,7 +4409,7 @@
 
     omap_gpmc_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_gpmc_readfn,
+    iomemtype = cpu_register_io_memory(omap_gpmc_readfn,
                     omap_gpmc_writefn, s);
     cpu_register_physical_memory(base, 0x1000, iomemtype);
 
diff --git a/hw/omap_dma.c b/hw/omap_dma.c
index 6df3800..e31a14b 100644
--- a/hw/omap_dma.c
+++ b/hw/omap_dma.c
@@ -1655,7 +1655,7 @@
     omap_dma_reset(s->dma);
     omap_dma_clk_update(s, 0, 1);
 
-    iomemtype = cpu_register_io_memory(0, omap_dma_readfn,
+    iomemtype = cpu_register_io_memory(omap_dma_readfn,
                     omap_dma_writefn, s);
     cpu_register_physical_memory(base, memsize, iomemtype);
 
@@ -2062,7 +2062,7 @@
     omap_dma_reset(s->dma);
     omap_dma_clk_update(s, 0, !!s->dma->freq);
 
-    iomemtype = cpu_register_io_memory(0, omap_dma4_readfn,
+    iomemtype = cpu_register_io_memory(omap_dma4_readfn,
                     omap_dma4_writefn, s);
     cpu_register_physical_memory(base, 0x1000, iomemtype);
 
diff --git a/hw/omap_dss.c b/hw/omap_dss.c
index d8c2977..c69b91b 100644
--- a/hw/omap_dss.c
+++ b/hw/omap_dss.c
@@ -1037,15 +1037,15 @@
     s->drq = drq;
     omap_dss_reset(s);
 
-    iomemtype[0] = l4_register_io_memory(0, omap_diss1_readfn,
+    iomemtype[0] = l4_register_io_memory(omap_diss1_readfn,
                     omap_diss1_writefn, s);
-    iomemtype[1] = l4_register_io_memory(0, omap_disc1_readfn,
+    iomemtype[1] = l4_register_io_memory(omap_disc1_readfn,
                     omap_disc1_writefn, s);
-    iomemtype[2] = l4_register_io_memory(0, omap_rfbi1_readfn,
+    iomemtype[2] = l4_register_io_memory(omap_rfbi1_readfn,
                     omap_rfbi1_writefn, s);
-    iomemtype[3] = l4_register_io_memory(0, omap_venc1_readfn,
+    iomemtype[3] = l4_register_io_memory(omap_venc1_readfn,
                     omap_venc1_writefn, s);
-    iomemtype[4] = cpu_register_io_memory(0, omap_im3_readfn,
+    iomemtype[4] = cpu_register_io_memory(omap_im3_readfn,
                     omap_im3_writefn, s);
     omap_l4_attach(ta, 0, iomemtype[0]);
     omap_l4_attach(ta, 1, iomemtype[1]);
diff --git a/hw/omap_i2c.c b/hw/omap_i2c.c
index c0dd3a5..60da574 100644
--- a/hw/omap_i2c.c
+++ b/hw/omap_i2c.c
@@ -436,7 +436,7 @@
     s->bus = i2c_init_bus(NULL, "i2c");
     omap_i2c_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_i2c_readfn,
+    iomemtype = cpu_register_io_memory(omap_i2c_readfn,
                     omap_i2c_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -457,7 +457,7 @@
     s->bus = i2c_init_bus(NULL, "i2c");
     omap_i2c_reset(s);
 
-    iomemtype = l4_register_io_memory(0, omap_i2c_readfn,
+    iomemtype = l4_register_io_memory(omap_i2c_readfn,
                     omap_i2c_writefn, s);
     omap_l4_attach(ta, 0, iomemtype);
 
diff --git a/hw/omap_lcdc.c b/hw/omap_lcdc.c
index 6a91b27..5458f2a 100644
--- a/hw/omap_lcdc.c
+++ b/hw/omap_lcdc.c
@@ -450,7 +450,7 @@
     s->emiff_base = emiff_base;
     omap_lcdc_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_lcdc_readfn,
+    iomemtype = cpu_register_io_memory(omap_lcdc_readfn,
                     omap_lcdc_writefn, s);
     cpu_register_physical_memory(base, 0x100, iomemtype);
 
diff --git a/hw/omap_mmc.c b/hw/omap_mmc.c
index 81c003c..93dbff6 100644
--- a/hw/omap_mmc.c
+++ b/hw/omap_mmc.c
@@ -586,7 +586,7 @@
 
     omap_mmc_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, omap_mmc_readfn,
+    iomemtype = cpu_register_io_memory(omap_mmc_readfn,
                     omap_mmc_writefn, s);
     cpu_register_physical_memory(base, 0x800, iomemtype);
 
@@ -612,7 +612,7 @@
 
     omap_mmc_reset(s);
 
-    iomemtype = l4_register_io_memory(0, omap_mmc_readfn,
+    iomemtype = l4_register_io_memory(omap_mmc_readfn,
                     omap_mmc_writefn, s);
     omap_l4_attach(ta, 0, iomemtype);
 
diff --git a/hw/omap_sx1.c b/hw/omap_sx1.c
index ee8e39d..0f6ed9e 100644
--- a/hw/omap_sx1.c
+++ b/hw/omap_sx1.c
@@ -142,12 +142,12 @@
     cpu_register_physical_memory(OMAP_CS0_BASE, flash_size,
                     (phys_flash = qemu_ram_alloc(flash_size)) | IO_MEM_ROM);
 
-    io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs0val);
+    io = cpu_register_io_memory(static_readfn, static_writefn, &cs0val);
     cpu_register_physical_memory(OMAP_CS0_BASE + flash_size,
                     OMAP_CS0_SIZE - flash_size, io);
-    io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs2val);
+    io = cpu_register_io_memory(static_readfn, static_writefn, &cs2val);
     cpu_register_physical_memory(OMAP_CS2_BASE, OMAP_CS2_SIZE, io);
-    io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs3val);
+    io = cpu_register_io_memory(static_readfn, static_writefn, &cs3val);
     cpu_register_physical_memory(OMAP_CS3_BASE, OMAP_CS3_SIZE, io);
 
     fl_idx = 0;
@@ -167,7 +167,7 @@
         cpu_register_physical_memory(OMAP_CS1_BASE, flash1_size,
                         (phys_flash = qemu_ram_alloc(flash1_size)) |
                         IO_MEM_ROM);
-        io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs1val);
+        io = cpu_register_io_memory(static_readfn, static_writefn, &cs1val);
         cpu_register_physical_memory(OMAP_CS1_BASE + flash1_size,
                         OMAP_CS1_SIZE - flash1_size, io);
 
@@ -179,7 +179,7 @@
         }
         fl_idx++;
     } else {
-        io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs1val);
+        io = cpu_register_io_memory(static_readfn, static_writefn, &cs1val);
         cpu_register_physical_memory(OMAP_CS1_BASE, OMAP_CS1_SIZE, io);
     }
 
diff --git a/hw/onenand.c b/hw/onenand.c
index 9803a07..7388e7c 100644
--- a/hw/onenand.c
+++ b/hw/onenand.c
@@ -631,7 +631,7 @@
     s->secs = size >> 9;
     s->blockwp = qemu_malloc(s->blocks);
     s->density_mask = (id & (1 << 11)) ? (1 << (6 + ((id >> 12) & 7))) : 0;
-    s->iomemtype = cpu_register_io_memory(0, onenand_readfn,
+    s->iomemtype = cpu_register_io_memory(onenand_readfn,
                     onenand_writefn, s);
     if (bdrv_index == -1)
         s->image = memset(qemu_malloc(size + (size >> 5)),
diff --git a/hw/openpic.c b/hw/openpic.c
index 51c8ad8..269b965 100644
--- a/hw/openpic.c
+++ b/hw/openpic.c
@@ -1046,7 +1046,7 @@
             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(0, openpic_src_read,
+    opp_io_memory = cpu_register_io_memory(openpic_src_read,
                                            openpic_src_write);
     cpu_register_physical_memory(isu_base, 0x20 * (EXT_IRQ + 2),
                                  opp_io_memory);
@@ -1217,7 +1217,7 @@
     } else {
         opp = qemu_mallocz(sizeof(openpic_t));
     }
-    opp->mem_index = cpu_register_io_memory(0, openpic_read,
+    opp->mem_index = cpu_register_io_memory(openpic_read,
                                             openpic_write, opp);
 
     //    isu_base &= 0xFFFC0000;
@@ -1687,7 +1687,7 @@
     for (i = 0; i < sizeof(list)/sizeof(list[0]); i++) {
         int mem_index;
 
-        mem_index = cpu_register_io_memory(0, list[i].read, list[i].write, mpp);
+        mem_index = cpu_register_io_memory(list[i].read, list[i].write, mpp);
         if (mem_index < 0) {
             goto free;
         }
diff --git a/hw/palm.c b/hw/palm.c
index e9be058..8b3a2ba 100644
--- a/hw/palm.c
+++ b/hw/palm.c
@@ -216,14 +216,14 @@
     cpu_register_physical_memory(OMAP_CS0_BASE, flash_size,
                     (phys_flash = qemu_ram_alloc(flash_size)) | IO_MEM_ROM);
 
-    io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs0val);
+    io = cpu_register_io_memory(static_readfn, static_writefn, &cs0val);
     cpu_register_physical_memory(OMAP_CS0_BASE + flash_size,
                     OMAP_CS0_SIZE - flash_size, io);
-    io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs1val);
+    io = cpu_register_io_memory(static_readfn, static_writefn, &cs1val);
     cpu_register_physical_memory(OMAP_CS1_BASE, OMAP_CS1_SIZE, io);
-    io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs2val);
+    io = cpu_register_io_memory(static_readfn, static_writefn, &cs2val);
     cpu_register_physical_memory(OMAP_CS2_BASE, OMAP_CS2_SIZE, io);
-    io = cpu_register_io_memory(0, static_readfn, static_writefn, &cs3val);
+    io = cpu_register_io_memory(static_readfn, static_writefn, &cs3val);
     cpu_register_physical_memory(OMAP_CS3_BASE, OMAP_CS3_SIZE, io);
 
     palmte_microwire_setup(cpu);
diff --git a/hw/parallel.c b/hw/parallel.c
index f66e5eb..a23686a 100644
--- a/hw/parallel.c
+++ b/hw/parallel.c
@@ -543,7 +543,7 @@
     parallel_reset(s);
     qemu_register_reset(parallel_reset, 0, s);
 
-    io_sw = cpu_register_io_memory(0, parallel_mm_read_sw, parallel_mm_write_sw, s);
+    io_sw = cpu_register_io_memory(parallel_mm_read_sw, parallel_mm_write_sw, s);
     cpu_register_physical_memory(base, 8 << it_shift, io_sw);
     return s;
 }
diff --git a/hw/pckbd.c b/hw/pckbd.c
index 3ef3594..092d1ba 100644
--- a/hw/pckbd.c
+++ b/hw/pckbd.c
@@ -430,7 +430,7 @@
 
     kbd_reset(s);
     register_savevm("pckbd", 0, 3, kbd_save, kbd_load, s);
-    s_io_memory = cpu_register_io_memory(0, kbd_mm_read, kbd_mm_write, s);
+    s_io_memory = cpu_register_io_memory(kbd_mm_read, kbd_mm_write, s);
     cpu_register_physical_memory(base, size, s_io_memory);
 
     s->kbd = ps2_kbd_init(kbd_update_kbd_irq, s);
diff --git a/hw/pcnet.c b/hw/pcnet.c
index b5793ff..51a00de 100644
--- a/hw/pcnet.c
+++ b/hw/pcnet.c
@@ -2048,7 +2048,7 @@
 
     /* Handler for memory-mapped I/O */
     s->mmio_index =
-      cpu_register_io_memory(0, pcnet_mmio_read, pcnet_mmio_write, &d->state);
+      cpu_register_io_memory(pcnet_mmio_read, pcnet_mmio_write, &d->state);
 
     pci_register_io_region((PCIDevice *)d, 0, PCNET_IOPORT_SIZE,
                            PCI_ADDRESS_SPACE_IO, pcnet_ioport_map);
@@ -2126,7 +2126,7 @@
     PCNetState *s = &d->state;
 
     s->mmio_index =
-        cpu_register_io_memory(0, lance_mem_read, lance_mem_write, d);
+        cpu_register_io_memory(lance_mem_read, lance_mem_write, d);
 
     s->dma_opaque = qdev_get_prop_ptr(&dev->qdev, "dma");
 
diff --git a/hw/pflash_cfi01.c b/hw/pflash_cfi01.c
index d696560..53ed97e 100644
--- a/hw/pflash_cfi01.c
+++ b/hw/pflash_cfi01.c
@@ -522,7 +522,7 @@
 
     /* FIXME: Allocate ram ourselves.  */
     pfl->storage = qemu_get_ram_ptr(off);
-    pfl->fl_mem = cpu_register_io_memory(0,
+    pfl->fl_mem = cpu_register_io_memory(
                     pflash_read_ops, pflash_write_ops, pfl);
     pfl->off = off;
     cpu_register_physical_memory(base, total_len,
diff --git a/hw/pflash_cfi02.c b/hw/pflash_cfi02.c
index 60edbf5..4b96364 100644
--- a/hw/pflash_cfi02.c
+++ b/hw/pflash_cfi02.c
@@ -559,7 +559,7 @@
     pfl = qemu_mallocz(sizeof(pflash_t));
     /* FIXME: Allocate ram ourselves.  */
     pfl->storage = qemu_get_ram_ptr(off);
-    pfl->fl_mem = cpu_register_io_memory(0, pflash_read_ops, pflash_write_ops,
+    pfl->fl_mem = cpu_register_io_memory(pflash_read_ops, pflash_write_ops,
                                          pfl);
     pfl->off = off;
     pfl->base = base;
diff --git a/hw/pl011.c b/hw/pl011.c
index 3a1a4cb..0528bfe 100644
--- a/hw/pl011.c
+++ b/hw/pl011.c
@@ -291,7 +291,7 @@
     int iomemtype;
     pl011_state *s = FROM_SYSBUS(pl011_state, dev);
 
-    iomemtype = cpu_register_io_memory(0, pl011_readfn,
+    iomemtype = cpu_register_io_memory(pl011_readfn,
                                        pl011_writefn, s);
     sysbus_init_mmio(dev, 0x1000,iomemtype);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/pl022.c b/hw/pl022.c
index 27cb7af..78076e0 100644
--- a/hw/pl022.c
+++ b/hw/pl022.c
@@ -293,7 +293,7 @@
     pl022_state *s = FROM_SYSBUS(pl022_state, dev);
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, pl022_readfn,
+    iomemtype = cpu_register_io_memory(pl022_readfn,
                                        pl022_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/pl031.c b/hw/pl031.c
index 11ecf73..5c9992e 100644
--- a/hw/pl031.c
+++ b/hw/pl031.c
@@ -189,7 +189,7 @@
     pl031_state *s = FROM_SYSBUS(pl031_state, dev);
     struct tm tm;
 
-    iomemtype = cpu_register_io_memory(0, pl031_readfn, pl031_writefn, s);
+    iomemtype = cpu_register_io_memory(pl031_readfn, pl031_writefn, s);
     if (iomemtype == -1) {
         hw_error("pl031_init: Can't register I/O memory\n");
     }
diff --git a/hw/pl050.c b/hw/pl050.c
index 1f8878c..c8818e0 100644
--- a/hw/pl050.c
+++ b/hw/pl050.c
@@ -127,7 +127,7 @@
     pl050_state *s = FROM_SYSBUS(pl050_state, dev);
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, pl050_readfn,
+    iomemtype = cpu_register_io_memory(pl050_readfn,
                                        pl050_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/pl061.c b/hw/pl061.c
index aa0a322..a003b97 100644
--- a/hw/pl061.c
+++ b/hw/pl061.c
@@ -296,7 +296,7 @@
     int iomemtype;
     pl061_state *s = FROM_SYSBUS(pl061_state, dev);
 
-    iomemtype = cpu_register_io_memory(0, pl061_readfn,
+    iomemtype = cpu_register_io_memory(pl061_readfn,
                                        pl061_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/pl080.c b/hw/pl080.c
index e43b11d..9c17be6 100644
--- a/hw/pl080.c
+++ b/hw/pl080.c
@@ -324,7 +324,7 @@
     int iomemtype;
     pl080_state *s = FROM_SYSBUS(pl080_state, dev);
 
-    iomemtype = cpu_register_io_memory(0, pl080_readfn,
+    iomemtype = cpu_register_io_memory(pl080_readfn,
                                        pl080_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/pl110.c b/hw/pl110.c
index b45204c..45b7dbe 100644
--- a/hw/pl110.c
+++ b/hw/pl110.c
@@ -354,7 +354,7 @@
     pl110_state *s = FROM_SYSBUS(pl110_state, dev);
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, pl110_readfn,
+    iomemtype = cpu_register_io_memory(pl110_readfn,
                                        pl110_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/pl181.c b/hw/pl181.c
index 2ba7f28..12f4ca7 100644
--- a/hw/pl181.c
+++ b/hw/pl181.c
@@ -451,7 +451,7 @@
     pl181_state *s = FROM_SYSBUS(pl181_state, dev);
     BlockDriverState *bd;
 
-    iomemtype = cpu_register_io_memory(0, pl181_readfn,
+    iomemtype = cpu_register_io_memory(pl181_readfn,
                                        pl181_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     sysbus_init_irq(dev, &s->irq[0]);
diff --git a/hw/pl190.c b/hw/pl190.c
index 1085768..f68fb42 100644
--- a/hw/pl190.c
+++ b/hw/pl190.c
@@ -232,7 +232,7 @@
     pl190_state *s = FROM_SYSBUS(pl190_state, dev);
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, pl190_readfn,
+    iomemtype = cpu_register_io_memory(pl190_readfn,
                                        pl190_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     qdev_init_gpio_in(&dev->qdev, pl190_set_irq, 32);
diff --git a/hw/ppc405_boards.c b/hw/ppc405_boards.c
index 0dec131..2ab170e 100644
--- a/hw/ppc405_boards.c
+++ b/hw/ppc405_boards.c
@@ -161,7 +161,7 @@
     int fpga_memory;
 
     fpga = qemu_mallocz(sizeof(ref405ep_fpga_t));
-    fpga_memory = cpu_register_io_memory(0, ref405ep_fpga_read,
+    fpga_memory = cpu_register_io_memory(ref405ep_fpga_read,
                                          ref405ep_fpga_write, fpga);
     cpu_register_physical_memory(base, 0x00000100, fpga_memory);
     ref405ep_fpga_reset(fpga);
@@ -485,7 +485,7 @@
     int cpld_memory;
 
     cpld = qemu_mallocz(sizeof(taihu_cpld_t));
-    cpld_memory = cpu_register_io_memory(0, taihu_cpld_read,
+    cpld_memory = cpu_register_io_memory(taihu_cpld_read,
                                          taihu_cpld_write, cpld);
     cpu_register_physical_memory(base, 0x00000100, cpld_memory);
     taihu_cpld_reset(cpld);
diff --git a/hw/ppc4xx_devs.c b/hw/ppc4xx_devs.c
index 5c8d273..81bab8e 100644
--- a/hw/ppc4xx_devs.c
+++ b/hw/ppc4xx_devs.c
@@ -247,7 +247,7 @@
 
     mmio = qemu_mallocz(sizeof(ppc4xx_mmio_t));
     mmio->base = base;
-    mmio_memory = cpu_register_io_memory(0, mmio_read, mmio_write, mmio);
+    mmio_memory = cpu_register_io_memory(mmio_read, mmio_write, mmio);
 #if defined(DEBUG_MMIO)
     printf("%s: base " PADDRX " len %08x %d\n", __func__,
            base, TARGET_PAGE_SIZE, mmio_memory);
diff --git a/hw/ppc4xx_pci.c b/hw/ppc4xx_pci.c
index 45ab3be..516fce9 100644
--- a/hw/ppc4xx_pci.c
+++ b/hw/ppc4xx_pci.c
@@ -384,14 +384,14 @@
     pci_config_set_class(pci_conf, PCI_CLASS_BRIDGE_OTHER);
 
     /* CFGADDR */
-    index = cpu_register_io_memory(0, pci4xx_cfgaddr_read,
+    index = cpu_register_io_memory(pci4xx_cfgaddr_read,
                                    pci4xx_cfgaddr_write, controller);
     if (index < 0)
         goto free;
     cpu_register_physical_memory(config_space + PCIC0_CFGADDR, 4, index);
 
     /* CFGDATA */
-    index = cpu_register_io_memory(0, pci4xx_cfgdata_read,
+    index = cpu_register_io_memory(pci4xx_cfgdata_read,
                                    pci4xx_cfgdata_write,
                                    &controller->pci_state);
     if (index < 0)
@@ -399,7 +399,7 @@
     cpu_register_physical_memory(config_space + PCIC0_CFGDATA, 4, index);
 
     /* Internal registers */
-    index = cpu_register_io_memory(0, pci_reg_read, pci_reg_write, controller);
+    index = cpu_register_io_memory(pci_reg_read, pci_reg_write, controller);
     if (index < 0)
         goto free;
     cpu_register_physical_memory(registers, PCI_REG_SIZE, index);
diff --git a/hw/ppc_newworld.c b/hw/ppc_newworld.c
index f0d167d..22beedb 100644
--- a/hw/ppc_newworld.c
+++ b/hw/ppc_newworld.c
@@ -246,7 +246,7 @@
     isa_mmio_init(0xf2000000, 0x00800000);
 
     /* UniN init */
-    unin_memory = cpu_register_io_memory(0, unin_read, unin_write, NULL);
+    unin_memory = cpu_register_io_memory(unin_read, unin_write, NULL);
     cpu_register_physical_memory(0xf8000000, 0x00001000, unin_memory);
 
     openpic_irqs = qemu_mallocz(smp_cpus * sizeof(qemu_irq *));
diff --git a/hw/ppc_prep.c b/hw/ppc_prep.c
index 2d308f3..83f2eca 100644
--- a/hw/ppc_prep.c
+++ b/hw/ppc_prep.c
@@ -659,7 +659,7 @@
     pci_bus = pci_prep_init(i8259);
     //    pci_bus = i440fx_init();
     /* Register 8 MB of ISA IO space (needed for non-contiguous map) */
-    PPC_io_memory = cpu_register_io_memory(0, PPC_prep_io_read,
+    PPC_io_memory = cpu_register_io_memory(PPC_prep_io_read,
                                            PPC_prep_io_write, sysctrl);
     cpu_register_physical_memory(0x80000000, 0x00800000, PPC_io_memory);
 
@@ -728,12 +728,12 @@
     register_ioport_read(0x0800, 0x52, 1, &PREP_io_800_readb, sysctrl);
     register_ioport_write(0x0800, 0x52, 1, &PREP_io_800_writeb, sysctrl);
     /* PCI intack location */
-    PPC_io_memory = cpu_register_io_memory(0, PPC_intack_read,
+    PPC_io_memory = cpu_register_io_memory(PPC_intack_read,
                                            PPC_intack_write, NULL);
     cpu_register_physical_memory(0xBFFFFFF0, 0x4, PPC_io_memory);
     /* PowerPC control and status register group */
 #if 0
-    PPC_io_memory = cpu_register_io_memory(0, PPC_XCSR_read, PPC_XCSR_write,
+    PPC_io_memory = cpu_register_io_memory(PPC_XCSR_read, PPC_XCSR_write,
                                            NULL);
     cpu_register_physical_memory(0xFEFF0000, 0x1000, PPC_io_memory);
 #endif
diff --git a/hw/ppce500_pci.c b/hw/ppce500_pci.c
index 79703a3..1a8a6c9 100644
--- a/hw/ppce500_pci.c
+++ b/hw/ppce500_pci.c
@@ -332,21 +332,21 @@
     controller->pci_dev = d;
 
     /* CFGADDR */
-    index = cpu_register_io_memory(0, pcie500_cfgaddr_read,
+    index = cpu_register_io_memory(pcie500_cfgaddr_read,
                                    pcie500_cfgaddr_write, controller);
     if (index < 0)
         goto free;
     cpu_register_physical_memory(registers + PCIE500_CFGADDR, 4, index);
 
     /* CFGDATA */
-    index = cpu_register_io_memory(0, pcie500_cfgdata_read,
+    index = cpu_register_io_memory(pcie500_cfgdata_read,
                                    pcie500_cfgdata_write,
                                    &controller->pci_state);
     if (index < 0)
         goto free;
     cpu_register_physical_memory(registers + PCIE500_CFGDATA, 4, index);
 
-    index = cpu_register_io_memory(0, e500_pci_reg_read,
+    index = cpu_register_io_memory(e500_pci_reg_read,
                                    e500_pci_reg_write, controller);
     if (index < 0)
         goto free;
diff --git a/hw/prep_pci.c b/hw/prep_pci.c
index e747e39..80058b1 100644
--- a/hw/prep_pci.c
+++ b/hw/prep_pci.c
@@ -149,7 +149,7 @@
     register_ioport_read(0xcfc, 4, 2, pci_host_data_readw, s);
     register_ioport_read(0xcfc, 4, 4, pci_host_data_readl, s);
 
-    PPC_io_memory = cpu_register_io_memory(0, PPC_PCIIO_read,
+    PPC_io_memory = cpu_register_io_memory(PPC_PCIIO_read,
                                            PPC_PCIIO_write, s);
     cpu_register_physical_memory(0x80800000, 0x00400000, PPC_io_memory);
 
diff --git a/hw/pxa2xx.c b/hw/pxa2xx.c
index e001d1f..f2e98ff 100644
--- a/hw/pxa2xx.c
+++ b/hw/pxa2xx.c
@@ -857,7 +857,7 @@
 
     sysbus_init_irq(dev, &s->irq);
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_ssp_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_ssp_readfn,
                                        pxa2xx_ssp_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     register_savevm("pxa2xx_ssp", -1, 0,
@@ -1509,7 +1509,7 @@
     s->bus = i2c_init_bus(NULL, "i2c");
     s->offset = base - (base & (~region_size) & TARGET_PAGE_MASK);
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_i2c_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_i2c_readfn,
                     pxa2xx_i2c_writefn, s);
     cpu_register_physical_memory(base & ~region_size,
                     region_size + 1, iomemtype);
@@ -1747,7 +1747,7 @@
 
     pxa2xx_i2s_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_i2s_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_i2s_readfn,
                     pxa2xx_i2s_writefn, s);
     cpu_register_physical_memory(base, 0x100000, iomemtype);
 
@@ -2006,7 +2006,7 @@
 
     pxa2xx_fir_reset(s);
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_fir_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_fir_readfn,
                     pxa2xx_fir_writefn, s);
     cpu_register_physical_memory(base, 0x1000, iomemtype);
 
@@ -2090,7 +2090,7 @@
     s->cm_base = 0x41300000;
     s->cm_regs[CCCR >> 2] = 0x02000210;	/* 416.0 MHz */
     s->clkcfg = 0x00000009;		/* Turbo mode active */
-    iomemtype = cpu_register_io_memory(0, pxa2xx_cm_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_cm_readfn,
                     pxa2xx_cm_writefn, s);
     cpu_register_physical_memory(s->cm_base, 0x1000, iomemtype);
     register_savevm("pxa2xx_cm", 0, 0, pxa2xx_cm_save, pxa2xx_cm_load, s);
@@ -2101,13 +2101,13 @@
     s->mm_regs[MDMRS >> 2] = 0x00020002;
     s->mm_regs[MDREFR >> 2] = 0x03ca4000;
     s->mm_regs[MECR >> 2] = 0x00000001;	/* Two PC Card sockets */
-    iomemtype = cpu_register_io_memory(0, pxa2xx_mm_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_mm_readfn,
                     pxa2xx_mm_writefn, s);
     cpu_register_physical_memory(s->mm_base, 0x1000, iomemtype);
     register_savevm("pxa2xx_mm", 0, 0, pxa2xx_mm_save, pxa2xx_mm_load, s);
 
     s->pm_base = 0x40f00000;
-    iomemtype = cpu_register_io_memory(0, pxa2xx_pm_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_pm_readfn,
                     pxa2xx_pm_writefn, s);
     cpu_register_physical_memory(s->pm_base, 0x100, iomemtype);
     register_savevm("pxa2xx_pm", 0, 0, pxa2xx_pm_save, pxa2xx_pm_load, s);
@@ -2129,7 +2129,7 @@
     s->pcmcia[1] = pxa2xx_pcmcia_init(0x30000000);
 
     s->rtc_base = 0x40900000;
-    iomemtype = cpu_register_io_memory(0, pxa2xx_rtc_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_rtc_readfn,
                     pxa2xx_rtc_writefn, s);
     cpu_register_physical_memory(s->rtc_base, 0x1000, iomemtype);
     pxa2xx_rtc_init(s);
@@ -2202,7 +2202,7 @@
     s->cm_base = 0x41300000;
     s->cm_regs[CCCR >> 2] = 0x02000210;	/* 416.0 MHz */
     s->clkcfg = 0x00000009;		/* Turbo mode active */
-    iomemtype = cpu_register_io_memory(0, pxa2xx_cm_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_cm_readfn,
                     pxa2xx_cm_writefn, s);
     cpu_register_physical_memory(s->cm_base, 0x1000, iomemtype);
     register_savevm("pxa2xx_cm", 0, 0, pxa2xx_cm_save, pxa2xx_cm_load, s);
@@ -2213,13 +2213,13 @@
     s->mm_regs[MDMRS >> 2] = 0x00020002;
     s->mm_regs[MDREFR >> 2] = 0x03ca4000;
     s->mm_regs[MECR >> 2] = 0x00000001;	/* Two PC Card sockets */
-    iomemtype = cpu_register_io_memory(0, pxa2xx_mm_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_mm_readfn,
                     pxa2xx_mm_writefn, s);
     cpu_register_physical_memory(s->mm_base, 0x1000, iomemtype);
     register_savevm("pxa2xx_mm", 0, 0, pxa2xx_mm_save, pxa2xx_mm_load, s);
 
     s->pm_base = 0x40f00000;
-    iomemtype = cpu_register_io_memory(0, pxa2xx_pm_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_pm_readfn,
                     pxa2xx_pm_writefn, s);
     cpu_register_physical_memory(s->pm_base, 0x100, iomemtype);
     register_savevm("pxa2xx_pm", 0, 0, pxa2xx_pm_save, pxa2xx_pm_load, s);
@@ -2241,7 +2241,7 @@
     s->pcmcia[1] = pxa2xx_pcmcia_init(0x30000000);
 
     s->rtc_base = 0x40900000;
-    iomemtype = cpu_register_io_memory(0, pxa2xx_rtc_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_rtc_readfn,
                     pxa2xx_rtc_writefn, s);
     cpu_register_physical_memory(s->rtc_base, 0x1000, iomemtype);
     pxa2xx_rtc_init(s);
diff --git a/hw/pxa2xx_dma.c b/hw/pxa2xx_dma.c
index 0b350a2..f0351c4 100644
--- a/hw/pxa2xx_dma.c
+++ b/hw/pxa2xx_dma.c
@@ -503,7 +503,7 @@
 
     memset(s->req, 0, sizeof(uint8_t) * PXA2XX_DMA_NUM_REQUESTS);
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_dma_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_dma_readfn,
                     pxa2xx_dma_writefn, s);
     cpu_register_physical_memory(base, 0x00010000, iomemtype);
 
diff --git a/hw/pxa2xx_gpio.c b/hw/pxa2xx_gpio.c
index 9749cb7..27f72ec 100644
--- a/hw/pxa2xx_gpio.c
+++ b/hw/pxa2xx_gpio.c
@@ -308,7 +308,7 @@
     s->cpu_env = env;
     s->in = qemu_allocate_irqs(pxa2xx_gpio_set, s, lines);
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_gpio_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_gpio_readfn,
                     pxa2xx_gpio_writefn, s);
     cpu_register_physical_memory(base, 0x00001000, iomemtype);
 
diff --git a/hw/pxa2xx_keypad.c b/hw/pxa2xx_keypad.c
index 07f8d20..80dcb58 100644
--- a/hw/pxa2xx_keypad.c
+++ b/hw/pxa2xx_keypad.c
@@ -313,7 +313,7 @@
     s = (PXA2xxKeyPadState *) qemu_mallocz(sizeof(PXA2xxKeyPadState));
     s->irq = irq;
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_keypad_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_keypad_readfn,
                     pxa2xx_keypad_writefn, s);
     cpu_register_physical_memory(base, 0x00100000, iomemtype);
 
diff --git a/hw/pxa2xx_lcd.c b/hw/pxa2xx_lcd.c
index 12bfc13..c9fefc3 100644
--- a/hw/pxa2xx_lcd.c
+++ b/hw/pxa2xx_lcd.c
@@ -928,7 +928,7 @@
 
     pxa2xx_lcdc_orientation(s, graphic_rotate);
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_lcdc_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_lcdc_readfn,
                     pxa2xx_lcdc_writefn, s);
     cpu_register_physical_memory(base, 0x00100000, iomemtype);
 
diff --git a/hw/pxa2xx_mmci.c b/hw/pxa2xx_mmci.c
index 8ce28f7..4c306cf 100644
--- a/hw/pxa2xx_mmci.c
+++ b/hw/pxa2xx_mmci.c
@@ -527,7 +527,7 @@
     s->irq = irq;
     s->dma = dma;
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_mmci_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_mmci_readfn,
                     pxa2xx_mmci_writefn, s);
     cpu_register_physical_memory(base, 0x00100000, iomemtype);
 
diff --git a/hw/pxa2xx_pcmcia.c b/hw/pxa2xx_pcmcia.c
index 6e9c956..cb13a26 100644
--- a/hw/pxa2xx_pcmcia.c
+++ b/hw/pxa2xx_pcmcia.c
@@ -139,19 +139,19 @@
             qemu_mallocz(sizeof(PXA2xxPCMCIAState));
 
     /* Socket I/O Memory Space */
-    iomemtype = cpu_register_io_memory(0, pxa2xx_pcmcia_io_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_pcmcia_io_readfn,
                     pxa2xx_pcmcia_io_writefn, s);
     cpu_register_physical_memory(base | 0x00000000, 0x04000000, iomemtype);
 
     /* Then next 64 MB is reserved */
 
     /* Socket Attribute Memory Space */
-    iomemtype = cpu_register_io_memory(0, pxa2xx_pcmcia_attr_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_pcmcia_attr_readfn,
                     pxa2xx_pcmcia_attr_writefn, s);
     cpu_register_physical_memory(base | 0x08000000, 0x04000000, iomemtype);
 
     /* Socket Common Memory Space */
-    iomemtype = cpu_register_io_memory(0, pxa2xx_pcmcia_common_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_pcmcia_common_readfn,
                     pxa2xx_pcmcia_common_writefn, s);
     cpu_register_physical_memory(base | 0x0c000000, 0x04000000, iomemtype);
 
diff --git a/hw/pxa2xx_pic.c b/hw/pxa2xx_pic.c
index aa17ba3..a4d56d8 100644
--- a/hw/pxa2xx_pic.c
+++ b/hw/pxa2xx_pic.c
@@ -299,7 +299,7 @@
     qi = qemu_allocate_irqs(pxa2xx_pic_set_irq, s, PXA2XX_PIC_SRCS);
 
     /* Enable IC memory-mapped registers access.  */
-    iomemtype = cpu_register_io_memory(0, pxa2xx_pic_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_pic_readfn,
                     pxa2xx_pic_writefn, s);
     cpu_register_physical_memory(base, 0x00100000, iomemtype);
 
diff --git a/hw/pxa2xx_timer.c b/hw/pxa2xx_timer.c
index 3725dd1..4d47e4d 100644
--- a/hw/pxa2xx_timer.c
+++ b/hw/pxa2xx_timer.c
@@ -451,7 +451,7 @@
                         pxa2xx_timer_tick, &s->timer[i]);
     }
 
-    iomemtype = cpu_register_io_memory(0, pxa2xx_timer_readfn,
+    iomemtype = cpu_register_io_memory(pxa2xx_timer_readfn,
                     pxa2xx_timer_writefn, s);
     cpu_register_physical_memory(base, 0x00001000, iomemtype);
 
diff --git a/hw/r2d.c b/hw/r2d.c
index 5b69c4f..a529ab4 100644
--- a/hw/r2d.c
+++ b/hw/r2d.c
@@ -176,7 +176,7 @@
 
     s->irl = irl;
 
-    iomemtype = cpu_register_io_memory(0, r2d_fpga_readfn,
+    iomemtype = cpu_register_io_memory(r2d_fpga_readfn,
 				       r2d_fpga_writefn, s);
     cpu_register_physical_memory(base, 0x40, iomemtype);
     return qemu_allocate_irqs(r2d_fpga_irq_set, s, NR_IRQS);
diff --git a/hw/rc4030.c b/hw/rc4030.c
index a35360a..40610c0 100644
--- a/hw/rc4030.c
+++ b/hw/rc4030.c
@@ -814,9 +814,9 @@
     register_savevm("rc4030", 0, 2, rc4030_save, rc4030_load, s);
     rc4030_reset(s);
 
-    s_chipset = cpu_register_io_memory(0, rc4030_read, rc4030_write, s);
+    s_chipset = cpu_register_io_memory(rc4030_read, rc4030_write, s);
     cpu_register_physical_memory(0x80000000, 0x300, s_chipset);
-    s_jazzio = cpu_register_io_memory(0, jazzio_read, jazzio_write, s);
+    s_jazzio = cpu_register_io_memory(jazzio_read, jazzio_write, s);
     cpu_register_physical_memory(0xf0000000, 0x00001000, s_jazzio);
 
     return s;
diff --git a/hw/realview_gic.c b/hw/realview_gic.c
index cae0f7e..089d94c 100644
--- a/hw/realview_gic.c
+++ b/hw/realview_gic.c
@@ -63,7 +63,7 @@
     RealViewGICState *s = FROM_SYSBUSGIC(RealViewGICState, dev);
 
     gic_init(&s->gic);
-    s->iomemtype = cpu_register_io_memory(0, realview_gic_cpu_readfn,
+    s->iomemtype = cpu_register_io_memory(realview_gic_cpu_readfn,
                                           realview_gic_cpu_writefn, s);
     sysbus_init_mmio_cb(dev, 0x2000, realview_gic_map);
 }
diff --git a/hw/rtl8139.c b/hw/rtl8139.c
index de5a68f..e2516ba 100644
--- a/hw/rtl8139.c
+++ b/hw/rtl8139.c
@@ -3469,7 +3469,7 @@
 
     /* I/O handler for memory-mapped I/O */
     s->rtl8139_mmio_io_addr =
-    cpu_register_io_memory(0, rtl8139_mmio_read, rtl8139_mmio_write, s);
+    cpu_register_io_memory(rtl8139_mmio_read, rtl8139_mmio_write, s);
 
     pci_register_io_region(&d->dev, 0, 0x100,
                            PCI_ADDRESS_SPACE_IO,  rtl8139_ioport_map);
diff --git a/hw/sbi.c b/hw/sbi.c
index a601a59..4350b6e 100644
--- a/hw/sbi.c
+++ b/hw/sbi.c
@@ -151,7 +151,7 @@
         s->cpu_irqs[i] = parent_irq[i];
     }
 
-    sbi_io_memory = cpu_register_io_memory(0, sbi_mem_read, sbi_mem_write, s);
+    sbi_io_memory = cpu_register_io_memory(sbi_mem_read, sbi_mem_write, s);
     cpu_register_physical_memory(addr, SBI_SIZE, sbi_io_memory);
 
     register_savevm("sbi", addr, 1, sbi_save, sbi_load, s);
diff --git a/hw/serial.c b/hw/serial.c
index 71f545d..b255ea9 100644
--- a/hw/serial.c
+++ b/hw/serial.c
@@ -831,7 +831,7 @@
     register_savevm("serial", base, 3, serial_save, serial_load, s);
 
     if (ioregister) {
-        s_io_memory = cpu_register_io_memory(0, serial_mm_read,
+        s_io_memory = cpu_register_io_memory(serial_mm_read,
                                              serial_mm_write, s);
         cpu_register_physical_memory(base, 8 << it_shift, s_io_memory);
     }
diff --git a/hw/sh7750.c b/hw/sh7750.c
index f079781..ac1cc01 100644
--- a/hw/sh7750.c
+++ b/hw/sh7750.c
@@ -709,8 +709,7 @@
     s = qemu_mallocz(sizeof(SH7750State));
     s->cpu = cpu;
     s->periph_freq = 60000000;	/* 60MHz */
-    sh7750_io_memory = cpu_register_io_memory(0,
-					      sh7750_mem_read,
+    sh7750_io_memory = cpu_register_io_memory(sh7750_mem_read,
 					      sh7750_mem_write, s);
     cpu_register_physical_memory_offset(0x1f000000, 0x1000,
                                         sh7750_io_memory, 0x1f000000);
@@ -725,8 +724,7 @@
     cpu_register_physical_memory_offset(0xffc00000, 0x1000,
                                         sh7750_io_memory, 0x1fc00000);
 
-    sh7750_mm_cache_and_tlb = cpu_register_io_memory(0,
-						     sh7750_mmct_read,
+    sh7750_mm_cache_and_tlb = cpu_register_io_memory(sh7750_mmct_read,
 						     sh7750_mmct_write, s);
     cpu_register_physical_memory(0xf0000000, 0x08000000,
 				 sh7750_mm_cache_and_tlb);
diff --git a/hw/sh_intc.c b/hw/sh_intc.c
index b75d794..9938160 100644
--- a/hw/sh_intc.c
+++ b/hw/sh_intc.c
@@ -442,7 +442,7 @@
 
     desc->irqs = qemu_allocate_irqs(sh_intc_set_irq, desc, nr_sources);
  
-    desc->iomemtype = cpu_register_io_memory(0, sh_intc_readfn,
+    desc->iomemtype = cpu_register_io_memory(sh_intc_readfn,
 					     sh_intc_writefn, desc);
     if (desc->mask_regs) {
         for (i = 0; i < desc->nr_mask_regs; i++) {
diff --git a/hw/sh_pci.c b/hw/sh_pci.c
index 2ec4b43..1b148ab 100644
--- a/hw/sh_pci.c
+++ b/hw/sh_pci.c
@@ -179,9 +179,9 @@
 
     p->dev = pci_register_device(p->bus, "SH PCIC", sizeof(PCIDevice),
                                  -1, NULL, NULL);
-    reg = cpu_register_io_memory(0, sh_pci_reg.r, sh_pci_reg.w, p);
-    iop = cpu_register_io_memory(0, sh_pci_iop.r, sh_pci_iop.w, p);
-    mem = cpu_register_io_memory(0, sh_pci_mem.r, sh_pci_mem.w, p);
+    reg = cpu_register_io_memory(sh_pci_reg.r, sh_pci_reg.w, p);
+    iop = cpu_register_io_memory(sh_pci_iop.r, sh_pci_iop.w, p);
+    mem = cpu_register_io_memory(sh_pci_mem.r, sh_pci_mem.w, p);
     cpu_register_physical_memory(0x1e200000, 0x224, reg);
     cpu_register_physical_memory(0x1e240000, 0x40000, iop);
     cpu_register_physical_memory(0x1d000000, 0x1000000, mem);
diff --git a/hw/sh_serial.c b/hw/sh_serial.c
index ee0c52c..ddf63d5 100644
--- a/hw/sh_serial.c
+++ b/hw/sh_serial.c
@@ -394,7 +394,7 @@
 
     sh_serial_clear_fifo(s);
 
-    s_io_memory = cpu_register_io_memory(0, sh_serial_readfn,
+    s_io_memory = cpu_register_io_memory(sh_serial_readfn,
 					 sh_serial_writefn, s);
     cpu_register_physical_memory(P4ADDR(base), 0x28, s_io_memory);
     cpu_register_physical_memory(A7ADDR(base), 0x28, s_io_memory);
diff --git a/hw/sh_timer.c b/hw/sh_timer.c
index 1a1404c..5b9c903 100644
--- a/hw/sh_timer.c
+++ b/hw/sh_timer.c
@@ -318,7 +318,7 @@
     if (feat & TMU012_FEAT_3CHAN)
         s->timer[2] = sh_timer_init(freq, timer_feat | TIMER_FEAT_CAPT,
 				    ch2_irq0); /* ch2_irq1 not supported */
-    iomemtype = cpu_register_io_memory(0, tmu012_readfn,
+    iomemtype = cpu_register_io_memory(tmu012_readfn,
                                        tmu012_writefn, s);
     cpu_register_physical_memory(P4ADDR(base), 0x00001000, iomemtype);
     cpu_register_physical_memory(A7ADDR(base), 0x00001000, iomemtype);
diff --git a/hw/slavio_intctl.c b/hw/slavio_intctl.c
index e39e4f9..a2f085f 100644
--- a/hw/slavio_intctl.c
+++ b/hw/slavio_intctl.c
@@ -388,8 +388,7 @@
         slave->cpu = i;
         slave->master = s;
 
-        slavio_intctl_io_memory = cpu_register_io_memory(0,
-                                                         slavio_intctl_mem_read,
+        slavio_intctl_io_memory = cpu_register_io_memory(slavio_intctl_mem_read,
                                                          slavio_intctl_mem_write,
                                                          slave);
         cpu_register_physical_memory(addr + i * TARGET_PAGE_SIZE, INTCTL_SIZE,
@@ -399,8 +398,7 @@
         s->cpu_irqs[i] = parent_irq[i];
     }
 
-    slavio_intctlm_io_memory = cpu_register_io_memory(0,
-                                                      slavio_intctlm_mem_read,
+    slavio_intctlm_io_memory = cpu_register_io_memory(slavio_intctlm_mem_read,
                                                       slavio_intctlm_mem_write,
                                                       s);
     cpu_register_physical_memory(addrg, INTCTLM_SIZE, slavio_intctlm_io_memory);
diff --git a/hw/slavio_misc.c b/hw/slavio_misc.c
index f335863..170dc10 100644
--- a/hw/slavio_misc.c
+++ b/hw/slavio_misc.c
@@ -448,28 +448,28 @@
         /* 8 bit registers */
 
         // Slavio control
-        io = cpu_register_io_memory(0, slavio_cfg_mem_read,
+        io = cpu_register_io_memory(slavio_cfg_mem_read,
                                     slavio_cfg_mem_write, s);
         cpu_register_physical_memory(base + MISC_CFG, MISC_SIZE, io);
 
         // Diagnostics
-        io = cpu_register_io_memory(0, slavio_diag_mem_read,
+        io = cpu_register_io_memory(slavio_diag_mem_read,
                                     slavio_diag_mem_write, s);
         cpu_register_physical_memory(base + MISC_DIAG, MISC_SIZE, io);
 
         // Modem control
-        io = cpu_register_io_memory(0, slavio_mdm_mem_read,
+        io = cpu_register_io_memory(slavio_mdm_mem_read,
                                     slavio_mdm_mem_write, s);
         cpu_register_physical_memory(base + MISC_MDM, MISC_SIZE, io);
 
         /* 16 bit registers */
-        io = cpu_register_io_memory(0, slavio_led_mem_read,
+        io = cpu_register_io_memory(slavio_led_mem_read,
                                     slavio_led_mem_write, s);
         /* ss600mp diag LEDs */
         cpu_register_physical_memory(base + MISC_LEDS, MISC_SIZE, io);
 
         /* 32 bit registers */
-        io = cpu_register_io_memory(0, slavio_sysctrl_mem_read,
+        io = cpu_register_io_memory(slavio_sysctrl_mem_read,
                                     slavio_sysctrl_mem_write, s);
         // System control
         cpu_register_physical_memory(base + MISC_SYS, SYSCTRL_SIZE, io);
@@ -477,21 +477,21 @@
 
     // AUX 1 (Misc System Functions)
     if (aux1_base) {
-        io = cpu_register_io_memory(0, slavio_aux1_mem_read,
+        io = cpu_register_io_memory(slavio_aux1_mem_read,
                                     slavio_aux1_mem_write, s);
         cpu_register_physical_memory(aux1_base, MISC_SIZE, io);
     }
 
     // AUX 2 (Software Powerdown Control)
     if (aux2_base) {
-        io = cpu_register_io_memory(0, slavio_aux2_mem_read,
+        io = cpu_register_io_memory(slavio_aux2_mem_read,
                                     slavio_aux2_mem_write, s);
         cpu_register_physical_memory(aux2_base, MISC_SIZE, io);
     }
 
     // Power management (APC) XXX: not a Slavio device
     if (power_base) {
-        io = cpu_register_io_memory(0, apc_mem_read, apc_mem_write, s);
+        io = cpu_register_io_memory(apc_mem_read, apc_mem_write, s);
         cpu_register_physical_memory(power_base, MISC_SIZE, io);
     }
 
diff --git a/hw/slavio_timer.c b/hw/slavio_timer.c
index b5f9ec3..08dc5ff 100644
--- a/hw/slavio_timer.c
+++ b/hw/slavio_timer.c
@@ -381,7 +381,7 @@
         ptimer_set_period(s->timer, TIMER_PERIOD);
     }
 
-    slavio_timer_io_memory = cpu_register_io_memory(0, slavio_timer_mem_read,
+    slavio_timer_io_memory = cpu_register_io_memory(slavio_timer_mem_read,
                                                     slavio_timer_mem_write, s);
     if (master)
         cpu_register_physical_memory(addr, CPU_TIMER_SIZE,
diff --git a/hw/sm501.c b/hw/sm501.c
index 4b0df8f..df40aaa 100644
--- a/hw/sm501.c
+++ b/hw/sm501.c
@@ -1080,11 +1080,11 @@
 
     /* map mmio */
     sm501_system_config_index
-	= cpu_register_io_memory(0, sm501_system_config_readfn,
+	= cpu_register_io_memory(sm501_system_config_readfn,
 				 sm501_system_config_writefn, s);
     cpu_register_physical_memory(base + MMIO_BASE_OFFSET,
 				 0x6c, sm501_system_config_index);
-    sm501_disp_ctrl_index = cpu_register_io_memory(0, sm501_disp_ctrl_readfn,
+    sm501_disp_ctrl_index = cpu_register_io_memory(sm501_disp_ctrl_readfn,
 						   sm501_disp_ctrl_writefn, s);
     cpu_register_physical_memory(base + MMIO_BASE_OFFSET + SM501_DC,
                                  0x1000, sm501_disp_ctrl_index);
diff --git a/hw/smc91c111.c b/hw/smc91c111.c
index 93a1fae..cf8d864 100644
--- a/hw/smc91c111.c
+++ b/hw/smc91c111.c
@@ -704,7 +704,7 @@
 {
     smc91c111_state *s = FROM_SYSBUS(smc91c111_state, dev);
 
-    s->mmio_index = cpu_register_io_memory(0, smc91c111_readfn,
+    s->mmio_index = cpu_register_io_memory(smc91c111_readfn,
                                            smc91c111_writefn, s);
     sysbus_init_mmio(dev, 16, s->mmio_index);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/sparc32_dma.c b/hw/sparc32_dma.c
index 6893b88..ce027cc 100644
--- a/hw/sparc32_dma.c
+++ b/hw/sparc32_dma.c
@@ -252,7 +252,7 @@
     s->irq = parent_irq;
     s->iommu = iommu;
 
-    dma_io_memory = cpu_register_io_memory(0, dma_mem_read, dma_mem_write, s);
+    dma_io_memory = cpu_register_io_memory(dma_mem_read, dma_mem_write, s);
     cpu_register_physical_memory(daddr, DMA_SIZE, dma_io_memory);
 
     register_savevm("sparc32_dma", daddr, 2, dma_save, dma_load, s);
diff --git a/hw/spitz.c b/hw/spitz.c
index 4da7060..d9ff85e 100644
--- a/hw/spitz.c
+++ b/hw/spitz.c
@@ -174,7 +174,7 @@
     else if (size == FLASH_1024M)
         s->nand = nand_init(NAND_MFR_SAMSUNG, 0xf1);
 
-    iomemtype = cpu_register_io_memory(0, sl_readfn,
+    iomemtype = cpu_register_io_memory(sl_readfn,
                     sl_writefn, s);
     cpu_register_physical_memory(FLASH_BASE, 0x40, iomemtype);
 
diff --git a/hw/stellaris.c b/hw/stellaris.c
index bf339e8..5f44bff 100644
--- a/hw/stellaris.c
+++ b/hw/stellaris.c
@@ -347,7 +347,7 @@
     sysbus_init_irq(dev, &s->irq);
     qdev_init_gpio_out(&dev->qdev, &s->trigger, 1);
 
-    iomemtype = cpu_register_io_memory(0, gptm_readfn,
+    iomemtype = cpu_register_io_memory(gptm_readfn,
                                        gptm_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
 
@@ -668,7 +668,7 @@
     s->user0 = macaddr[0] | (macaddr[1] << 8) | (macaddr[2] << 16);
     s->user1 = macaddr[3] | (macaddr[4] << 8) | (macaddr[5] << 16);
 
-    iomemtype = cpu_register_io_memory(0, ssys_readfn,
+    iomemtype = cpu_register_io_memory(ssys_readfn,
                                        ssys_writefn, s);
     cpu_register_physical_memory(base, 0x00001000, iomemtype);
     ssys_reset(s);
@@ -880,7 +880,7 @@
     bus = i2c_init_bus(&dev->qdev, "i2c");
     s->bus = bus;
 
-    iomemtype = cpu_register_io_memory(0, stellaris_i2c_readfn,
+    iomemtype = cpu_register_io_memory(stellaris_i2c_readfn,
                                        stellaris_i2c_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     /* ??? For now we only implement the master interface.  */
@@ -1188,7 +1188,7 @@
         sysbus_init_irq(dev, &s->irq[n]);
     }
 
-    iomemtype = cpu_register_io_memory(0, stellaris_adc_readfn,
+    iomemtype = cpu_register_io_memory(stellaris_adc_readfn,
                                        stellaris_adc_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     stellaris_adc_reset(s);
diff --git a/hw/stellaris_enet.c b/hw/stellaris_enet.c
index 8586db6..43fa305 100644
--- a/hw/stellaris_enet.c
+++ b/hw/stellaris_enet.c
@@ -400,7 +400,7 @@
 {
     stellaris_enet_state *s = FROM_SYSBUS(stellaris_enet_state, dev);
 
-    s->mmio_index = cpu_register_io_memory(0, stellaris_enet_readfn,
+    s->mmio_index = cpu_register_io_memory(stellaris_enet_readfn,
                                            stellaris_enet_writefn, s);
     sysbus_init_mmio(dev, 0x1000, s->mmio_index);
     sysbus_init_irq(dev, &s->irq);
diff --git a/hw/sun4c_intctl.c b/hw/sun4c_intctl.c
index 8978e48..caad661 100644
--- a/hw/sun4c_intctl.c
+++ b/hw/sun4c_intctl.c
@@ -205,7 +205,7 @@
 
     s = qemu_mallocz(sizeof(Sun4c_INTCTLState));
 
-    sun4c_intctl_io_memory = cpu_register_io_memory(0, sun4c_intctl_mem_read,
+    sun4c_intctl_io_memory = cpu_register_io_memory(sun4c_intctl_mem_read,
                                                     sun4c_intctl_mem_write, s);
     cpu_register_physical_memory(addr, INTCTL_SIZE, sun4c_intctl_io_memory);
     s->cpu_irqs = parent_irq;
diff --git a/hw/syborg_fb.c b/hw/syborg_fb.c
index 90254e4..42c6274 100644
--- a/hw/syborg_fb.c
+++ b/hw/syborg_fb.c
@@ -511,7 +511,7 @@
     int height;
 
     sysbus_init_irq(dev, &s->irq);
-    iomemtype = cpu_register_io_memory(0, syborg_fb_readfn,
+    iomemtype = cpu_register_io_memory(syborg_fb_readfn,
                                        syborg_fb_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
 
diff --git a/hw/syborg_interrupt.c b/hw/syborg_interrupt.c
index 29e0d1a..569c7f6 100644
--- a/hw/syborg_interrupt.c
+++ b/hw/syborg_interrupt.c
@@ -210,7 +210,7 @@
     sysbus_init_irq(dev, &s->parent_irq);
     s->num_irqs = qdev_get_prop_int(&dev->qdev, "num-interrupts", 64);
     qdev_init_gpio_in(&dev->qdev, syborg_int_set_irq, s->num_irqs);
-    iomemtype = cpu_register_io_memory(0, syborg_int_readfn,
+    iomemtype = cpu_register_io_memory(syborg_int_readfn,
                                        syborg_int_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     s->flags = qemu_mallocz(s->num_irqs * sizeof(syborg_int_flags));
diff --git a/hw/syborg_keyboard.c b/hw/syborg_keyboard.c
index 69976e4..84a099e 100644
--- a/hw/syborg_keyboard.c
+++ b/hw/syborg_keyboard.c
@@ -209,7 +209,7 @@
     int iomemtype;
 
     sysbus_init_irq(dev, &s->irq);
-    iomemtype = cpu_register_io_memory(0, syborg_keyboard_readfn,
+    iomemtype = cpu_register_io_memory(syborg_keyboard_readfn,
                                        syborg_keyboard_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     s->fifo_size = qdev_get_prop_int(&dev->qdev, "fifo-size", 16);
diff --git a/hw/syborg_pointer.c b/hw/syborg_pointer.c
index e5a72d3..e0a892d 100644
--- a/hw/syborg_pointer.c
+++ b/hw/syborg_pointer.c
@@ -205,7 +205,7 @@
     int iomemtype;
 
     sysbus_init_irq(dev, &s->irq);
-    iomemtype = cpu_register_io_memory(0, syborg_pointer_readfn,
+    iomemtype = cpu_register_io_memory(syborg_pointer_readfn,
 				       syborg_pointer_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
 
diff --git a/hw/syborg_rtc.c b/hw/syborg_rtc.c
index b480d53..48853f7 100644
--- a/hw/syborg_rtc.c
+++ b/hw/syborg_rtc.c
@@ -129,7 +129,7 @@
     struct tm tm;
     int iomemtype;
 
-    iomemtype = cpu_register_io_memory(0, syborg_rtc_readfn,
+    iomemtype = cpu_register_io_memory(syborg_rtc_readfn,
                                        syborg_rtc_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
 
diff --git a/hw/syborg_serial.c b/hw/syborg_serial.c
index 48f11e9..f430508 100644
--- a/hw/syborg_serial.c
+++ b/hw/syborg_serial.c
@@ -321,7 +321,7 @@
     int iomemtype;
 
     sysbus_init_irq(dev, &s->irq);
-    iomemtype = cpu_register_io_memory(0, syborg_serial_readfn,
+    iomemtype = cpu_register_io_memory(syborg_serial_readfn,
                                        syborg_serial_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     s->chr = qdev_init_chardev(&dev->qdev);
diff --git a/hw/syborg_timer.c b/hw/syborg_timer.c
index b6d7f0c..4f5e3a1 100644
--- a/hw/syborg_timer.c
+++ b/hw/syborg_timer.c
@@ -215,7 +215,7 @@
         exit(1);
     }
     sysbus_init_irq(dev, &s->irq);
-    iomemtype = cpu_register_io_memory(0, syborg_timer_readfn,
+    iomemtype = cpu_register_io_memory(syborg_timer_readfn,
                                        syborg_timer_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
 
diff --git a/hw/syborg_virtio.c b/hw/syborg_virtio.c
index 37c219c..8e665c6 100644
--- a/hw/syborg_virtio.c
+++ b/hw/syborg_virtio.c
@@ -249,7 +249,7 @@
     proxy->vdev = vdev;
 
     sysbus_init_irq(&proxy->busdev, &proxy->irq);
-    iomemtype = cpu_register_io_memory(0, syborg_virtio_readfn,
+    iomemtype = cpu_register_io_memory(syborg_virtio_readfn,
                                        syborg_virtio_writefn, proxy);
     sysbus_init_mmio(&proxy->busdev, 0x1000, iomemtype);
 
diff --git a/hw/tc6393xb.c b/hw/tc6393xb.c
index 7803a4c..3962d98 100644
--- a/hw/tc6393xb.c
+++ b/hw/tc6393xb.c
@@ -589,7 +589,7 @@
 
     s->flash = nand_init(NAND_MFR_TOSHIBA, 0x76);
 
-    iomemtype = cpu_register_io_memory(0, tc6393xb_readfn,
+    iomemtype = cpu_register_io_memory(tc6393xb_readfn,
                     tc6393xb_writefn, s);
     cpu_register_physical_memory(base, 0x10000, iomemtype);
 
diff --git a/hw/tcx.c b/hw/tcx.c
index 450ff9d..217a2a6 100644
--- a/hw/tcx.c
+++ b/hw/tcx.c
@@ -523,11 +523,11 @@
     vram_offset += size;
     vram_base += size;
 
-    io_memory = cpu_register_io_memory(0, tcx_dac_read, tcx_dac_write, s);
+    io_memory = cpu_register_io_memory(tcx_dac_read, tcx_dac_write, s);
     cpu_register_physical_memory(addr + 0x00200000ULL, TCX_DAC_NREGS,
                                  io_memory);
 
-    dummy_memory = cpu_register_io_memory(0, tcx_dummy_read, tcx_dummy_write,
+    dummy_memory = cpu_register_io_memory(tcx_dummy_read, tcx_dummy_write,
                                           s);
     cpu_register_physical_memory(addr + 0x00700000ULL, TCX_TEC_NREGS,
                                  dummy_memory);
diff --git a/hw/tusb6010.c b/hw/tusb6010.c
index f3aa7b1..622de81 100644
--- a/hw/tusb6010.c
+++ b/hw/tusb6010.c
@@ -742,7 +742,7 @@
     s->mask = 0xffffffff;
     s->intr = 0x00000000;
     s->otg_timer_val = 0;
-    s->iomemtype[1] = cpu_register_io_memory(0, tusb_async_readfn,
+    s->iomemtype[1] = cpu_register_io_memory(tusb_async_readfn,
                     tusb_async_writefn, s);
     s->irq = intr;
     s->otg_timer = qemu_new_timer(vm_clock, tusb_otg_tick, s);
diff --git a/hw/unin_pci.c b/hw/unin_pci.c
index a9ef217..b2ebc31 100644
--- a/hw/unin_pci.c
+++ b/hw/unin_pci.c
@@ -179,9 +179,9 @@
                               pci_unin_set_irq, pci_unin_map_irq,
                               pic, 11 << 3, 4);
 
-    pci_mem_config = cpu_register_io_memory(0, pci_unin_main_config_read,
+    pci_mem_config = cpu_register_io_memory(pci_unin_main_config_read,
                                             pci_unin_main_config_write, s);
-    pci_mem_data = cpu_register_io_memory(0, pci_unin_main_read,
+    pci_mem_data = cpu_register_io_memory(pci_unin_main_read,
                                           pci_unin_main_write, s);
     cpu_register_physical_memory(0xf2800000, 0x1000, pci_mem_config);
     cpu_register_physical_memory(0xf2c00000, 0x1000, pci_mem_data);
@@ -226,9 +226,9 @@
 #endif
 
     /* Uninorth AGP bus */
-    pci_mem_config = cpu_register_io_memory(0, pci_unin_config_read,
+    pci_mem_config = cpu_register_io_memory(pci_unin_config_read,
                                             pci_unin_config_write, s);
-    pci_mem_data = cpu_register_io_memory(0, pci_unin_main_read,
+    pci_mem_data = cpu_register_io_memory(pci_unin_main_read,
                                           pci_unin_main_write, s);
     cpu_register_physical_memory(0xf0800000, 0x1000, pci_mem_config);
     cpu_register_physical_memory(0xf0c00000, 0x1000, pci_mem_data);
@@ -247,9 +247,9 @@
 #if 0 // XXX: not needed for now
     /* Uninorth internal bus */
     s = &pci_bridge[2];
-    pci_mem_config = cpu_register_io_memory(0, pci_unin_config_read,
+    pci_mem_config = cpu_register_io_memory(pci_unin_config_read,
                                             pci_unin_config_write, s);
-    pci_mem_data = cpu_register_io_memory(0, pci_unin_read,
+    pci_mem_data = cpu_register_io_memory(pci_unin_read,
                                           pci_unin_write, s);
     cpu_register_physical_memory(0xf4800000, 0x1000, pci_mem_config);
     cpu_register_physical_memory(0xf4c00000, 0x1000, pci_mem_data);
diff --git a/hw/usb-ohci.c b/hw/usb-ohci.c
index 1cc1b62..b921875 100644
--- a/hw/usb-ohci.c
+++ b/hw/usb-ohci.c
@@ -1682,7 +1682,7 @@
                 usb_frame_time, usb_bit_time);
     }
 
-    ohci->mem = cpu_register_io_memory(0, ohci_readfn, ohci_writefn, ohci);
+    ohci->mem = cpu_register_io_memory(ohci_readfn, ohci_writefn, ohci);
     ohci->localmem_base = localmem_base;
     ohci->name = name;
 
diff --git a/hw/versatile_pci.c b/hw/versatile_pci.c
index e454d49..e89add1 100644
--- a/hw/versatile_pci.c
+++ b/hw/versatile_pci.c
@@ -124,7 +124,7 @@
 
     /* ??? Register memory space.  */
 
-    s->mem_config = cpu_register_io_memory(0, pci_vpb_config_read,
+    s->mem_config = cpu_register_io_memory(pci_vpb_config_read,
                                            pci_vpb_config_write, bus);
     sysbus_init_mmio_cb(dev, 0x04000000, pci_vpb_map);
 
diff --git a/hw/versatilepb.c b/hw/versatilepb.c
index 03cf4d8..1f1b1bc 100644
--- a/hw/versatilepb.c
+++ b/hw/versatilepb.c
@@ -140,7 +140,7 @@
         sysbus_init_irq(dev, &s->parent[i]);
     }
     s->irq = 31;
-    iomemtype = cpu_register_io_memory(0, vpb_sic_readfn,
+    iomemtype = cpu_register_io_memory(vpb_sic_readfn,
                                        vpb_sic_writefn, s);
     sysbus_init_mmio(dev, 0x1000, iomemtype);
     /* ??? Save/restore.  */
diff --git a/hw/vga.c b/hw/vga.c
index 013ff10..c07c4da 100644
--- a/hw/vga.c
+++ b/hw/vga.c
@@ -2347,7 +2347,7 @@
 #endif
 #endif /* CONFIG_BOCHS_VBE */
 
-    vga_io_memory = cpu_register_io_memory(0, vga_mem_read, vga_mem_write, s);
+    vga_io_memory = cpu_register_io_memory(vga_mem_read, vga_mem_write, s);
     cpu_register_physical_memory(isa_mem_base + 0x000a0000, 0x20000,
                                  vga_io_memory);
     qemu_register_coalesced_mmio(isa_mem_base + 0x000a0000, 0x20000);
@@ -2417,8 +2417,8 @@
     int s_ioport_ctrl, vga_io_memory;
 
     s->it_shift = it_shift;
-    s_ioport_ctrl = cpu_register_io_memory(0, vga_mm_read_ctrl, vga_mm_write_ctrl, s);
-    vga_io_memory = cpu_register_io_memory(0, vga_mem_read, vga_mem_write, s);
+    s_ioport_ctrl = cpu_register_io_memory(vga_mm_read_ctrl, vga_mm_write_ctrl, s);
+    vga_io_memory = cpu_register_io_memory(vga_mem_read, vga_mem_write, s);
 
     register_savevm("vga", 0, 2, vga_save, vga_load, s);
 
diff --git a/hw/vmware_vga.c b/hw/vmware_vga.c
index 79da1ff..5c2e524 100644
--- a/hw/vmware_vga.c
+++ b/hw/vmware_vga.c
@@ -1201,7 +1201,7 @@
 
     s->vram_base = addr;
 #ifdef DIRECT_VRAM
-    iomemtype = cpu_register_io_memory(0, vmsvga_vram_read,
+    iomemtype = cpu_register_io_memory(vmsvga_vram_read,
                     vmsvga_vram_write, s);
 #else
     iomemtype = s->vga.vram_offset | IO_MEM_RAM;
diff --git a/hw/wdt_i6300esb.c b/hw/wdt_i6300esb.c
index f7ddea2..986a89f 100644
--- a/hw/wdt_i6300esb.c
+++ b/hw/wdt_i6300esb.c
@@ -368,7 +368,7 @@
 
     i6300esb_debug("addr = %x, size = %x, type = %d\n", addr, size, type);
 
-    io_mem = cpu_register_io_memory (0, mem_read, mem_write, d);
+    io_mem = cpu_register_io_memory(mem_read, mem_write, d);
     cpu_register_physical_memory (addr, 0x10, io_mem);
     /* qemu_register_coalesced_mmio (addr, 0x10); ? */
 }
diff --git a/hw/xilinx_ethlite.c b/hw/xilinx_ethlite.c
index 77cd6fb..2e1909f 100644
--- a/hw/xilinx_ethlite.c
+++ b/hw/xilinx_ethlite.c
@@ -218,7 +218,7 @@
     s->c_rx_pingpong = qdev_get_prop_int(&dev->qdev, "rxpingpong", 1);
     s->rxbuf = 0;
 
-    regs = cpu_register_io_memory(0, eth_read, eth_write, s);
+    regs = cpu_register_io_memory(eth_read, eth_write, s);
     sysbus_init_mmio(dev, R_MAX * 4, regs);
 
     qdev_get_macaddr(&dev->qdev, s->macaddr);
diff --git a/hw/xilinx_intc.c b/hw/xilinx_intc.c
index 0b17fae..0540f52 100644
--- a/hw/xilinx_intc.c
+++ b/hw/xilinx_intc.c
@@ -154,7 +154,7 @@
     qdev_init_gpio_in(&dev->qdev, irq_handler, 32);
     sysbus_init_irq(dev, &p->parent_irq);
 
-    pic_regs = cpu_register_io_memory(0, pic_read, pic_write, p);
+    pic_regs = cpu_register_io_memory(pic_read, pic_write, p);
     sysbus_init_mmio(dev, R_MAX * 4, pic_regs);
 }
 
diff --git a/hw/xilinx_timer.c b/hw/xilinx_timer.c
index d0e8f18..a64ad2d 100644
--- a/hw/xilinx_timer.c
+++ b/hw/xilinx_timer.c
@@ -211,7 +211,7 @@
         ptimer_set_freq(xt->ptimer, freq_hz);
     }
 
-    timer_regs = cpu_register_io_memory(0, timer_read, timer_write, t);
+    timer_regs = cpu_register_io_memory(timer_read, timer_write, t);
     sysbus_init_mmio(dev, R_MAX * 4 * t->nr_timers, timer_regs);
 }
 
diff --git a/hw/xilinx_uartlite.c b/hw/xilinx_uartlite.c
index 5cfb36c..9bf2e91 100644
--- a/hw/xilinx_uartlite.c
+++ b/hw/xilinx_uartlite.c
@@ -201,7 +201,7 @@
     sysbus_init_irq(dev, &s->irq);
 
     uart_update_status(s);
-    uart_regs = cpu_register_io_memory(0, uart_read, uart_write, s);
+    uart_regs = cpu_register_io_memory(uart_read, uart_write, s);
     sysbus_init_mmio(dev, R_MAX * 4, uart_regs);
 
     s->chr = qdev_init_chardev(&dev->qdev);
diff --git a/hw/zaurus.c b/hw/zaurus.c
index 7cf47b9..53191ef 100644
--- a/hw/zaurus.c
+++ b/hw/zaurus.c
@@ -228,7 +228,7 @@
 
     s->status = 0x02;
     s->in = qemu_allocate_irqs(scoop_gpio_set, s, 16);
-    iomemtype = cpu_register_io_memory(0, scoop_readfn,
+    iomemtype = cpu_register_io_memory(scoop_readfn,
                     scoop_writefn, s);
     cpu_register_physical_memory(target_base, 0x1000, iomemtype);
     register_savevm("scoop", instance, 1, scoop_save, scoop_load, s);
diff --git a/kqemu.c b/kqemu.c
index 1718498..c27c6ae 100644
--- a/kqemu.c
+++ b/kqemu.c
@@ -990,7 +990,7 @@
 static void qpi_init(void)
 {
     kqemu_comm_base = 0xff000000 | 1;
-    qpi_io_memory = cpu_register_io_memory(0, 
+    qpi_io_memory = cpu_register_io_memory(
                                            qpi_mem_read, 
                                            qpi_mem_write, NULL);
     cpu_register_physical_memory(kqemu_comm_base & ~0xfff,