diff --git a/hw/acpi/core.c b/hw/acpi/core.c
index 7206e9c69..b07fedac5 100644
--- a/hw/acpi/core.c
+++ b/hw/acpi/core.c
@@ -419,7 +419,8 @@ void acpi_pm1_evt_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
                        MemoryRegion *parent)
 {
     ar->pm1.evt.update_sci = update_sci;
-    memory_region_init_io(&ar->pm1.evt.io, NULL, &acpi_pm_evt_ops, ar, "acpi-evt", 4);
+    memory_region_init_io(&ar->pm1.evt.io, memory_region_owner(parent),
+                          &acpi_pm_evt_ops, ar, "acpi-evt", 4);
     memory_region_add_subregion(parent, 0, &ar->pm1.evt.io);
 }
 
@@ -481,7 +482,8 @@ void acpi_pm_tmr_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
 {
     ar->tmr.update_sci = update_sci;
     ar->tmr.timer = qemu_new_timer_ns(vm_clock, acpi_pm_tmr_timer, ar);
-    memory_region_init_io(&ar->tmr.io, NULL, &acpi_pm_tmr_ops, ar, "acpi-tmr", 4);
+    memory_region_init_io(&ar->tmr.io, memory_region_owner(parent),
+                          &acpi_pm_tmr_ops, ar, "acpi-tmr", 4);
     memory_region_add_subregion(parent, 8, &ar->tmr.io);
 }
 
@@ -552,7 +554,8 @@ void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent, uint8_t s4_val)
     ar->pm1.cnt.s4_val = s4_val;
     ar->wakeup.notify = acpi_notify_wakeup;
     qemu_register_wakeup_notifier(&ar->wakeup);
-    memory_region_init_io(&ar->pm1.cnt.io, NULL, &acpi_pm_cnt_ops, ar, "acpi-cnt", 2);
+    memory_region_init_io(&ar->pm1.cnt.io, memory_region_owner(parent),
+                          &acpi_pm_cnt_ops, ar, "acpi-cnt", 2);
     memory_region_add_subregion(parent, 4, &ar->pm1.cnt.io);
 }
 
diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 8ce52e78c..3fb443d06 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -205,7 +205,7 @@ static void pm_powerdown_req(Notifier *n, void *opaque)
 void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm,
                   qemu_irq sci_irq)
 {
-    memory_region_init(&pm->io, NULL, "ich9-pm", ICH9_PMIO_SIZE);
+    memory_region_init(&pm->io, OBJECT(lpc_pci), "ich9-pm", ICH9_PMIO_SIZE);
     memory_region_set_enabled(&pm->io, false);
     memory_region_add_subregion(pci_address_space_io(lpc_pci),
                                 0, &pm->io);
@@ -215,12 +215,12 @@ void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs *pm,
     acpi_pm1_cnt_init(&pm->acpi_regs, &pm->io, 2);
 
     acpi_gpe_init(&pm->acpi_regs, ICH9_PMIO_GPE0_LEN);
-    memory_region_init_io(&pm->io_gpe, NULL, &ich9_gpe_ops, pm, "apci-gpe0",
-                          ICH9_PMIO_GPE0_LEN);
+    memory_region_init_io(&pm->io_gpe, OBJECT(lpc_pci), &ich9_gpe_ops, pm,
+                          "apci-gpe0", ICH9_PMIO_GPE0_LEN);
     memory_region_add_subregion(&pm->io, ICH9_PMIO_GPE0_STS, &pm->io_gpe);
 
-    memory_region_init_io(&pm->io_smi, NULL, &ich9_smi_ops, pm, "apci-smi",
-                          8);
+    memory_region_init_io(&pm->io_smi, OBJECT(lpc_pci), &ich9_smi_ops, pm,
+                          "apci-smi", 8);
     memory_region_add_subregion(&pm->io, ICH9_PMIO_SMI_EN, &pm->io_smi);
 
     pm->irq = sci_irq;
diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 10fc92501..948ea8795 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -424,7 +424,7 @@ static int piix4_pm_initfn(PCIDevice *dev)
     memory_region_add_subregion(pci_address_space_io(dev),
                                 s->smb_io_base, &s->smb.io);
 
-    memory_region_init(&s->io, NULL, "piix4-pm", 64);
+    memory_region_init(&s->io, OBJECT(s), "piix4-pm", 64);
     memory_region_set_enabled(&s->io, false);
     memory_region_add_subregion(pci_address_space_io(dev),
                                 0, &s->io);
@@ -671,19 +671,19 @@ static int piix4_device_hotplug(DeviceState *qdev, PCIDevice *dev,
 static void piix4_acpi_system_hot_add_init(MemoryRegion *parent,
                                            PCIBus *bus, PIIX4PMState *s)
 {
-    memory_region_init_io(&s->io_gpe, NULL, &piix4_gpe_ops, s, "apci-gpe0",
-                          GPE_LEN);
+    memory_region_init_io(&s->io_gpe, OBJECT(s), &piix4_gpe_ops, s,
+                          "acpi-gpe0", GPE_LEN);
     memory_region_add_subregion(parent, GPE_BASE, &s->io_gpe);
 
-    memory_region_init_io(&s->io_pci, NULL, &piix4_pci_ops, s, "apci-pci-hotplug",
-                          PCI_HOTPLUG_SIZE);
+    memory_region_init_io(&s->io_pci, OBJECT(s), &piix4_pci_ops, s,
+                          "acpi-pci-hotplug", PCI_HOTPLUG_SIZE);
     memory_region_add_subregion(parent, PCI_HOTPLUG_ADDR,
                                 &s->io_pci);
     pci_bus_hotplug(bus, piix4_device_hotplug, &s->dev.qdev);
 
     qemu_for_each_cpu(piix4_init_cpu_status, &s->gpe_cpu);
-    memory_region_init_io(&s->io_cpu, NULL, &cpu_hotplug_ops, s, "apci-cpu-hotplug",
-                          PIIX4_PROC_LEN);
+    memory_region_init_io(&s->io_cpu, OBJECT(s), &cpu_hotplug_ops, s,
+                          "acpi-cpu-hotplug", PIIX4_PROC_LEN);
     memory_region_add_subregion(parent, PIIX4_PROC_BASE, &s->io_cpu);
     s->cpu_added_notifier.notify = piix4_cpu_added_req;
     qemu_register_cpu_added_notifier(&s->cpu_added_notifier);
diff --git a/hw/alpha/typhoon.c b/hw/alpha/typhoon.c
index 99427e82d..63cc2cbe1 100644
--- a/hw/alpha/typhoon.c
+++ b/hw/alpha/typhoon.c
@@ -741,7 +741,7 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
 
     /* Main memory region, 0x00.0000.0000.  Real hardware supports 32GB,
        but the address space hole reserved at this point is 8TB.  */
-    memory_region_init_ram(&s->ram_region, NULL, "ram", ram_size);
+    memory_region_init_ram(&s->ram_region, OBJECT(s), "ram", ram_size);
     vmstate_register_ram_global(&s->ram_region);
     memory_region_add_subregion(addr_space, 0, &s->ram_region);
 
@@ -750,22 +750,25 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
        the flash ROM.  I'm not sure that we need to implement it at all.  */
 
     /* Pchip0 CSRs, 0x801.8000.0000, 256MB.  */
-    memory_region_init_io(&s->pchip.region, NULL, &pchip_ops, s, "pchip0", 256*MB);
+    memory_region_init_io(&s->pchip.region, OBJECT(s), &pchip_ops, s, "pchip0",
+                          256*MB);
     memory_region_add_subregion(addr_space, 0x80180000000ULL,
                                 &s->pchip.region);
 
     /* Cchip CSRs, 0x801.A000.0000, 256MB.  */
-    memory_region_init_io(&s->cchip.region, NULL, &cchip_ops, s, "cchip0", 256*MB);
+    memory_region_init_io(&s->cchip.region, OBJECT(s), &cchip_ops, s, "cchip0",
+                          256*MB);
     memory_region_add_subregion(addr_space, 0x801a0000000ULL,
                                 &s->cchip.region);
 
     /* Dchip CSRs, 0x801.B000.0000, 256MB.  */
-    memory_region_init_io(&s->dchip_region, NULL, &dchip_ops, s, "dchip0", 256*MB);
+    memory_region_init_io(&s->dchip_region, OBJECT(s), &dchip_ops, s, "dchip0",
+                          256*MB);
     memory_region_add_subregion(addr_space, 0x801b0000000ULL,
                                 &s->dchip_region);
 
     /* Pchip0 PCI memory, 0x800.0000.0000, 4GB.  */
-    memory_region_init(&s->pchip.reg_mem, NULL, "pci0-mem", 4*GB);
+    memory_region_init(&s->pchip.reg_mem, OBJECT(s), "pci0-mem", 4*GB);
     memory_region_add_subregion(addr_space, 0x80000000000ULL,
                                 &s->pchip.reg_mem);
 
@@ -773,8 +776,8 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
     /* ??? Ideally we drop the "system" i/o space on the floor and give the
        PCI subsystem the full address space reserved by the chipset.
        We can't do that until the MEM and IO paths in memory.c are unified.  */
-    memory_region_init_io(&s->pchip.reg_io, NULL, &alpha_pci_bw_io_ops, NULL,
-                          "pci0-io", 32*MB);
+    memory_region_init_io(&s->pchip.reg_io, OBJECT(s), &alpha_pci_bw_io_ops,
+                          NULL, "pci0-io", 32*MB);
     memory_region_add_subregion(addr_space, 0x801fc000000ULL,
                                 &s->pchip.reg_io);
 
@@ -784,13 +787,13 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
     phb->bus = b;
 
     /* Pchip0 PCI special/interrupt acknowledge, 0x801.F800.0000, 64MB.  */
-    memory_region_init_io(&s->pchip.reg_iack, NULL, &alpha_pci_iack_ops, b,
+    memory_region_init_io(&s->pchip.reg_iack, OBJECT(s), &alpha_pci_iack_ops, b,
                           "pci0-iack", 64*MB);
     memory_region_add_subregion(addr_space, 0x801f8000000ULL,
                                 &s->pchip.reg_iack);
 
     /* Pchip0 PCI configuration, 0x801.FE00.0000, 16MB.  */
-    memory_region_init_io(&s->pchip.reg_conf, NULL, &alpha_pci_conf1_ops, b,
+    memory_region_init_io(&s->pchip.reg_conf, OBJECT(s), &alpha_pci_conf1_ops, b,
                           "pci0-conf", 16*MB);
     memory_region_add_subregion(addr_space, 0x801fe000000ULL,
                                 &s->pchip.reg_conf);
diff --git a/hw/arm/armv7m.c b/hw/arm/armv7m.c
index 4b82bbaf9..5b22e847a 100644
--- a/hw/arm/armv7m.c
+++ b/hw/arm/armv7m.c
@@ -124,8 +124,8 @@ static int bitband_init(SysBusDevice *dev)
 {
     BitBandState *s = FROM_SYSBUS(BitBandState, dev);
 
-    memory_region_init_io(&s->iomem, NULL, &bitband_ops, &s->base, "bitband",
-                          0x02000000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &bitband_ops, &s->base,
+                          "bitband", 0x02000000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
 }
diff --git a/hw/arm/highbank.c b/hw/arm/highbank.c
index c02afceb5..de6c98a68 100644
--- a/hw/arm/highbank.c
+++ b/hw/arm/highbank.c
@@ -149,8 +149,8 @@ static int highbank_regs_init(SysBusDevice *dev)
     HighbankRegsState *s = FROM_SYSBUS(HighbankRegsState, dev);
 
     s->iomem = g_new(MemoryRegion, 1);
-    memory_region_init_io(s->iomem, NULL, &hb_mem_ops, s->regs, "highbank_regs",
-                          0x1000);
+    memory_region_init_io(s->iomem, OBJECT(s), &hb_mem_ops, s->regs,
+                          "highbank_regs", 0x1000);
     sysbus_init_mmio(dev, s->iomem);
 
     return 0;
diff --git a/hw/arm/integratorcp.c b/hw/arm/integratorcp.c
index 436d89b30..249a43025 100644
--- a/hw/arm/integratorcp.c
+++ b/hw/arm/integratorcp.c
@@ -249,10 +249,10 @@ static int integratorcm_init(SysBusDevice *dev)
     }
     memcpy(integrator_spd + 73, "QEMU-MEMORY", 11);
     s->cm_init = 0x00000112;
-    memory_region_init_ram(&s->flash, NULL, "integrator.flash", 0x100000);
+    memory_region_init_ram(&s->flash, OBJECT(s), "integrator.flash", 0x100000);
     vmstate_register_ram_global(&s->flash);
 
-    memory_region_init_io(&s->iomem, NULL, &integratorcm_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &integratorcm_ops, s,
                           "integratorcm", 0x00800000);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -374,7 +374,8 @@ static int icp_pic_init(SysBusDevice *dev)
     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);
-    memory_region_init_io(&s->iomem, NULL, &icp_pic_ops, s, "icp-pic", 0x00800000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &icp_pic_ops, s,
+                          "icp-pic", 0x00800000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
 }
diff --git a/hw/arm/musicpal.c b/hw/arm/musicpal.c
index bca8fdf06..b06d4426e 100644
--- a/hw/arm/musicpal.c
+++ b/hw/arm/musicpal.c
@@ -389,8 +389,8 @@ static int mv88w8618_eth_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq);
     s->nic = qemu_new_nic(&net_mv88w8618_info, &s->conf,
                           object_get_typename(OBJECT(dev)), dev->qdev.id, s);
-    memory_region_init_io(&s->iomem, NULL, &mv88w8618_eth_ops, s, "mv88w8618-eth",
-                          MP_ETH_SIZE);
+    memory_region_init_io(&s->iomem, OBJECT(s), &mv88w8618_eth_ops, s,
+                          "mv88w8618-eth", MP_ETH_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
 }
@@ -612,7 +612,7 @@ static int musicpal_lcd_init(SysBusDevice *dev)
 
     s->brightness = 7;
 
-    memory_region_init_io(&s->iomem, NULL, &musicpal_lcd_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &musicpal_lcd_ops, s,
                           "musicpal-lcd", MP_LCD_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -740,7 +740,7 @@ static int mv88w8618_pic_init(SysBusDevice *dev)
 
     qdev_init_gpio_in(&dev->qdev, mv88w8618_pic_set_irq, 32);
     sysbus_init_irq(dev, &s->parent_irq);
-    memory_region_init_io(&s->iomem, NULL, &mv88w8618_pic_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &mv88w8618_pic_ops, s,
                           "musicpal-pic", MP_PIC_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -905,7 +905,7 @@ static int mv88w8618_pit_init(SysBusDevice *dev)
         mv88w8618_timer_init(dev, &s->timer[i], 1000000);
     }
 
-    memory_region_init_io(&s->iomem, NULL, &mv88w8618_pit_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &mv88w8618_pit_ops, s,
                           "musicpal-pit", MP_PIT_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -999,7 +999,7 @@ static int mv88w8618_flashcfg_init(SysBusDevice *dev)
     mv88w8618_flashcfg_state *s = FROM_SYSBUS(mv88w8618_flashcfg_state, dev);
 
     s->cfgr0 = 0xfffe4285; /* Default as set by U-Boot for 8 MB flash */
-    memory_region_init_io(&s->iomem, NULL, &mv88w8618_flashcfg_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &mv88w8618_flashcfg_ops, s,
                           "musicpal-flashcfg", MP_FLASHCFG_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
@@ -1074,7 +1074,7 @@ static void musicpal_misc_init(Object *obj)
     SysBusDevice *sd = SYS_BUS_DEVICE(obj);
     MusicPalMiscState *s = MUSICPAL_MISC(obj);
 
-    memory_region_init_io(&s->iomem, NULL, &musicpal_misc_ops, NULL,
+    memory_region_init_io(&s->iomem, OBJECT(s), &musicpal_misc_ops, NULL,
                           "musicpal-misc", MP_MISC_SIZE);
     sysbus_init_mmio(sd, &s->iomem);
 }
@@ -1121,7 +1121,7 @@ static int mv88w8618_wlan_init(SysBusDevice *dev)
 {
     MemoryRegion *iomem = g_new(MemoryRegion, 1);
 
-    memory_region_init_io(iomem, NULL, &mv88w8618_wlan_ops, NULL,
+    memory_region_init_io(iomem, OBJECT(dev), &mv88w8618_wlan_ops, NULL,
                           "musicpal-wlan", MP_WLAN_SIZE);
     sysbus_init_mmio(dev, iomem);
     return 0;
@@ -1327,7 +1327,7 @@ static int musicpal_gpio_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->iomem, NULL, &musicpal_gpio_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &musicpal_gpio_ops, s,
                           "musicpal-gpio", MP_GPIO_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -1484,7 +1484,7 @@ static int musicpal_key_init(SysBusDevice *dev)
 {
     musicpal_key_state *s = FROM_SYSBUS(musicpal_key_state, dev);
 
-    memory_region_init(&s->iomem, NULL, "dummy", 0);
+    memory_region_init(&s->iomem, OBJECT(s), "dummy", 0);
     sysbus_init_mmio(dev, &s->iomem);
 
     s->kbd_extended = 0;
diff --git a/hw/arm/pxa2xx.c b/hw/arm/pxa2xx.c
index d046edc16..5a226544f 100644
--- a/hw/arm/pxa2xx.c
+++ b/hw/arm/pxa2xx.c
@@ -764,7 +764,8 @@ static int pxa2xx_ssp_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->iomem, NULL, &pxa2xx_ssp_ops, s, "pxa2xx-ssp", 0x1000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &pxa2xx_ssp_ops, s,
+                          "pxa2xx-ssp", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     register_savevm(&dev->qdev, "pxa2xx_ssp", -1, 0,
                     pxa2xx_ssp_save, pxa2xx_ssp_load, s);
@@ -1131,7 +1132,8 @@ static int pxa2xx_rtc_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->rtc_irq);
 
-    memory_region_init_io(&s->iomem, NULL, &pxa2xx_rtc_ops, s, "pxa2xx-rtc", 0x10000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &pxa2xx_rtc_ops, s,
+                          "pxa2xx-rtc", 0x10000);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
@@ -1481,8 +1483,8 @@ static int pxa2xx_i2c_initfn(SysBusDevice *dev)
 
     s->bus = i2c_init_bus(&dev->qdev, "i2c");
 
-    memory_region_init_io(&s->iomem, NULL, &pxa2xx_i2c_ops, s,
-                          "pxa2xx-i2x", s->region_size);
+    memory_region_init_io(&s->iomem, OBJECT(s), &pxa2xx_i2c_ops, s,
+                          "pxa2xx-i2c", s->region_size);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
 
diff --git a/hw/arm/pxa2xx_gpio.c b/hw/arm/pxa2xx_gpio.c
index abf41dc8d..f8c3ee073 100644
--- a/hw/arm/pxa2xx_gpio.c
+++ b/hw/arm/pxa2xx_gpio.c
@@ -283,7 +283,7 @@ static int pxa2xx_gpio_initfn(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, pxa2xx_gpio_set, s->lines);
     qdev_init_gpio_out(&dev->qdev, s->handler, s->lines);
 
-    memory_region_init_io(&s->iomem, NULL, &pxa_gpio_ops, s, "pxa2xx-gpio", 0x1000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &pxa_gpio_ops, s, "pxa2xx-gpio", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq0);
     sysbus_init_irq(dev, &s->irq1);
diff --git a/hw/arm/pxa2xx_pic.c b/hw/arm/pxa2xx_pic.c
index 042d4222c..8929b6db4 100644
--- a/hw/arm/pxa2xx_pic.c
+++ b/hw/arm/pxa2xx_pic.c
@@ -278,7 +278,7 @@ DeviceState *pxa2xx_pic_init(hwaddr base, ARMCPU *cpu)
     qdev_init_gpio_in(dev, pxa2xx_pic_set_irq, PXA2XX_PIC_SRCS);
 
     /* Enable IC memory-mapped registers access.  */
-    memory_region_init_io(&s->iomem, NULL, &pxa2xx_pic_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &pxa2xx_pic_ops, s,
                           "pxa2xx-pic", 0x00100000);
     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, base);
diff --git a/hw/arm/spitz.c b/hw/arm/spitz.c
index 60ad30da5..593b75e55 100644
--- a/hw/arm/spitz.c
+++ b/hw/arm/spitz.c
@@ -169,7 +169,7 @@ static int sl_nand_init(SysBusDevice *dev) {
     nand = drive_get(IF_MTD, 0, 0);
     s->nand = nand_init(nand ? nand->bdrv : NULL, s->manf_id, s->chip_id);
 
-    memory_region_init_io(&s->iomem, NULL, &sl_ops, s, "sl", 0x40);
+    memory_region_init_io(&s->iomem, OBJECT(s), &sl_ops, s, "sl", 0x40);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
diff --git a/hw/arm/stellaris.c b/hw/arm/stellaris.c
index 30e7b7659..a2b6b1724 100644
--- a/hw/arm/stellaris.c
+++ b/hw/arm/stellaris.c
@@ -307,7 +307,7 @@ static int stellaris_gptm_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->irq);
     qdev_init_gpio_out(&dev->qdev, &s->trigger, 1);
 
-    memory_region_init_io(&s->iomem, NULL, &gptm_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &gptm_ops, s,
                           "gptm", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -862,7 +862,7 @@ static int stellaris_i2c_init(SysBusDevice * dev)
     bus = i2c_init_bus(&dev->qdev, "i2c");
     s->bus = bus;
 
-    memory_region_init_io(&s->iomem, NULL, &stellaris_i2c_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &stellaris_i2c_ops, s,
                           "i2c", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     /* ??? For now we only implement the master interface.  */
@@ -1145,7 +1145,7 @@ static int stellaris_adc_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->irq[n]);
     }
 
-    memory_region_init_io(&s->iomem, NULL, &stellaris_adc_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &stellaris_adc_ops, s,
                           "adc", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     stellaris_adc_reset(s);
diff --git a/hw/arm/strongarm.c b/hw/arm/strongarm.c
index 0f5a54556..feaaf4508 100644
--- a/hw/arm/strongarm.c
+++ b/hw/arm/strongarm.c
@@ -173,7 +173,8 @@ static int strongarm_pic_initfn(SysBusDevice *dev)
     StrongARMPICState *s = FROM_SYSBUS(StrongARMPICState, dev);
 
     qdev_init_gpio_in(&dev->qdev, strongarm_pic_set_irq, SA_PIC_SRCS);
-    memory_region_init_io(&s->iomem, NULL, &strongarm_pic_ops, s, "pic", 0x1000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &strongarm_pic_ops, s,
+                          "pic", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
     sysbus_init_irq(dev, &s->fiq);
@@ -383,7 +384,8 @@ static int strongarm_rtc_init(SysBusDevice *dev)
     sysbus_init_irq(dev, &s->rtc_irq);
     sysbus_init_irq(dev, &s->rtc_hz_irq);
 
-    memory_region_init_io(&s->iomem, NULL, &strongarm_rtc_ops, s, "rtc", 0x10000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &strongarm_rtc_ops, s,
+                          "rtc", 0x10000);
     sysbus_init_mmio(dev, &s->iomem);
 
     return 0;
@@ -637,7 +639,8 @@ static int strongarm_gpio_initfn(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, strongarm_gpio_set, 28);
     qdev_init_gpio_out(&dev->qdev, s->handler, 28);
 
-    memory_region_init_io(&s->iomem, NULL, &strongarm_gpio_ops, s, "gpio", 0x1000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &strongarm_gpio_ops, s,
+                          "gpio", 0x1000);
 
     sysbus_init_mmio(dev, &s->iomem);
     for (i = 0; i < 11; i++) {
@@ -808,7 +811,8 @@ static int strongarm_ppc_init(SysBusDevice *dev)
     qdev_init_gpio_in(&dev->qdev, strongarm_ppc_set, 22);
     qdev_init_gpio_out(&dev->qdev, s->handler, 22);
 
-    memory_region_init_io(&s->iomem, NULL, &strongarm_ppc_ops, s, "ppc", 0x1000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &strongarm_ppc_ops, s,
+                          "ppc", 0x1000);
 
     sysbus_init_mmio(dev, &s->iomem);
 
@@ -1204,7 +1208,8 @@ static int strongarm_uart_init(SysBusDevice *dev)
 {
     StrongARMUARTState *s = FROM_SYSBUS(StrongARMUARTState, dev);
 
-    memory_region_init_io(&s->iomem, NULL, &strongarm_uart_ops, s, "uart", 0x10000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &strongarm_uart_ops, s,
+                          "uart", 0x10000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
 
@@ -1496,7 +1501,8 @@ static int strongarm_ssp_init(SysBusDevice *dev)
 
     sysbus_init_irq(dev, &s->irq);
 
-    memory_region_init_io(&s->iomem, NULL, &strongarm_ssp_ops, s, "ssp", 0x1000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &strongarm_ssp_ops, s,
+                          "ssp", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
 
     s->bus = ssi_create_bus(&dev->qdev, "ssi");
diff --git a/hw/arm/versatilepb.c b/hw/arm/versatilepb.c
index cc0616574..08878b9c4 100644
--- a/hw/arm/versatilepb.c
+++ b/hw/arm/versatilepb.c
@@ -154,7 +154,8 @@ static int vpb_sic_init(SysBusDevice *dev)
         sysbus_init_irq(dev, &s->parent[i]);
     }
     s->irq = 31;
-    memory_region_init_io(&s->iomem, NULL, &vpb_sic_ops, s, "vpb-sic", 0x1000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &vpb_sic_ops, s,
+                          "vpb-sic", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     return 0;
 }
diff --git a/hw/audio/ac97.c b/hw/audio/ac97.c
index 47e6f1977..365b2f186 100644
--- a/hw/audio/ac97.c
+++ b/hw/audio/ac97.c
@@ -1378,8 +1378,10 @@ static int ac97_initfn (PCIDevice *dev)
     c[PCI_INTERRUPT_LINE] = 0x00;      /* intr_ln interrupt line rw */
     c[PCI_INTERRUPT_PIN] = 0x01;      /* intr_pn interrupt pin ro */
 
-    memory_region_init_io (&s->io_nam, NULL, &ac97_io_nam_ops, s, "ac97-nam", 1024);
-    memory_region_init_io (&s->io_nabm, NULL, &ac97_io_nabm_ops, s, "ac97-nabm", 256);
+    memory_region_init_io (&s->io_nam, OBJECT(s), &ac97_io_nam_ops, s,
+                           "ac97-nam", 1024);
+    memory_region_init_io (&s->io_nabm, OBJECT(s), &ac97_io_nabm_ops, s,
+                           "ac97-nabm", 256);
     pci_register_bar (&s->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io_nam);
     pci_register_bar (&s->dev, 1, PCI_BASE_ADDRESS_SPACE_IO, &s->io_nabm);
     qemu_register_reset (ac97_on_reset, s);
diff --git a/hw/audio/cs4231.c b/hw/audio/cs4231.c
index fb9b70070..fabe9e64a 100644
--- a/hw/audio/cs4231.c
+++ b/hw/audio/cs4231.c
@@ -144,7 +144,8 @@ static int cs4231_init1(SysBusDevice *dev)
 {
     CSState *s = FROM_SYSBUS(CSState, dev);
 
-    memory_region_init_io(&s->iomem, NULL, &cs_mem_ops, s, "cs4321", CS_SIZE);
+    memory_region_init_io(&s->iomem, OBJECT(s), &cs_mem_ops, s, "cs4321",
+                          CS_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);
 
diff --git a/hw/audio/cs4231a.c b/hw/audio/cs4231a.c
index c31da2ea1..7365c3c1d 100644
--- a/hw/audio/cs4231a.c
+++ b/hw/audio/cs4231a.c
@@ -648,7 +648,8 @@ static void cs4231a_initfn (Object *obj)
 {
     CSState *s = CS4231A (obj);
 
-    memory_region_init_io (&s->ioports, NULL, &cs_ioport_ops, s, "cs4231a", 4);
+    memory_region_init_io (&s->ioports, OBJECT(s), &cs_ioport_ops, s,
+                           "cs4231a", 4);
 }
 
 static void cs4231a_realizefn (DeviceState *dev, Error **errp)
diff --git a/hw/audio/es1370.c b/hw/audio/es1370.c
index b953df2d4..f2c40daec 100644
--- a/hw/audio/es1370.c
+++ b/hw/audio/es1370.c
@@ -1035,7 +1035,7 @@ static int es1370_initfn (PCIDevice *dev)
     c[PCI_MIN_GNT] = 0x0c;
     c[PCI_MAX_LAT] = 0x80;
 
-    memory_region_init_io (&s->io, NULL, &es1370_io_ops, s, "es1370", 256);
+    memory_region_init_io (&s->io, OBJECT(s), &es1370_io_ops, s, "es1370", 256);
     pci_register_bar (&s->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io);
     qemu_register_reset (es1370_on_reset, s);
 
diff --git a/hw/audio/intel-hda.c b/hw/audio/intel-hda.c
index e94602f59..58984dc73 100644
--- a/hw/audio/intel-hda.c
+++ b/hw/audio/intel-hda.c
@@ -1135,7 +1135,7 @@ static int intel_hda_init(PCIDevice *pci)
     /* HDCTL off 0x40 bit 0 selects signaling mode (1-HDA, 0 - Ac97) 18.1.19 */
     conf[0x40] = 0x01;
 
-    memory_region_init_io(&d->mmio, NULL, &intel_hda_mmio_ops, d,
+    memory_region_init_io(&d->mmio, OBJECT(d), &intel_hda_mmio_ops, d,
                           "intel-hda", 0x4000);
     pci_register_bar(&d->pci, 0, 0, &d->mmio);
     if (d->msi) {
diff --git a/hw/audio/marvell_88w8618.c b/hw/audio/marvell_88w8618.c
index e04e9325f..b40ea43c6 100644
--- a/hw/audio/marvell_88w8618.c
+++ b/hw/audio/marvell_88w8618.c
@@ -244,7 +244,7 @@ static int mv88w8618_audio_init(SysBusDevice *dev)
 
     wm8750_data_req_set(s->wm, mv88w8618_audio_callback, s);
 
-    memory_region_init_io(&s->iomem, NULL, &mv88w8618_audio_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &mv88w8618_audio_ops, s,
                           "audio", MP_AUDIO_SIZE);
     sysbus_init_mmio(dev, &s->iomem);
 
diff --git a/hw/audio/milkymist-ac97.c b/hw/audio/milkymist-ac97.c
index 79a00fd0d..133de4e74 100644
--- a/hw/audio/milkymist-ac97.c
+++ b/hw/audio/milkymist-ac97.c
@@ -300,7 +300,7 @@ static int milkymist_ac97_init(SysBusDevice *dev)
     s->voice_out = AUD_open_out(&s->card, s->voice_out,
             "mm_ac97.out", s, ac97_out_cb, &as);
 
-    memory_region_init_io(&s->regs_region, NULL, &ac97_mmio_ops, s,
+    memory_region_init_io(&s->regs_region, OBJECT(s), &ac97_mmio_ops, s,
             "milkymist-ac97", R_MAX * 4);
     sysbus_init_mmio(dev, &s->regs_region);
 
diff --git a/hw/audio/pcspk.c b/hw/audio/pcspk.c
index 123793b3e..7ad59a13e 100644
--- a/hw/audio/pcspk.c
+++ b/hw/audio/pcspk.c
@@ -167,7 +167,7 @@ static void pcspk_initfn(Object *obj)
 {
     PCSpkState *s = PC_SPEAKER(obj);
 
-    memory_region_init_io(&s->ioport, NULL, &pcspk_io_ops, s, "elcr", 1);
+    memory_region_init_io(&s->ioport, OBJECT(s), &pcspk_io_ops, s, "elcr", 1);
 }
 
 static void pcspk_realizefn(DeviceState *dev, Error **errp)
diff --git a/hw/audio/pl041.c b/hw/audio/pl041.c
index 5dd18c7d9..7d331b957 100644
--- a/hw/audio/pl041.c
+++ b/hw/audio/pl041.c
@@ -543,7 +543,7 @@ static int pl041_init(SysBusDevice *dev)
     }
 
     /* Connect the device to the sysbus */
-    memory_region_init_io(&s->iomem, NULL, &pl041_ops, s, "pl041", 0x1000);
+    memory_region_init_io(&s->iomem, OBJECT(s), &pl041_ops, s, "pl041", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);
     sysbus_init_irq(dev, &s->irq);