diff --git a/hw/xen_platform.c b/hw/xen_platform.c
index fb6be6a..0b89075 100644
--- a/hw/xen_platform.c
+++ b/hw/xen_platform.c
@@ -32,8 +32,8 @@
 #include "xen_common.h"
 #include "net.h"
 #include "xen_backend.h"
-#include "rwhandler.h"
 #include "trace.h"
+#include "exec-memory.h"
 
 #include <xenguest.h>
 
@@ -51,6 +51,9 @@
 
 typedef struct PCIXenPlatformState {
     PCIDevice  pci_dev;
+    MemoryRegion fixed_io;
+    MemoryRegion bar;
+    MemoryRegion mmio_bar;
     uint8_t flags; /* used only for version_id == 2 */
     int drivers_blacklisted;
     uint16_t driver_product_version;
@@ -221,21 +224,32 @@ static void platform_fixed_ioport_reset(void *opaque)
     platform_fixed_ioport_writeb(s, XEN_PLATFORM_IOPORT, 0);
 }
 
+const MemoryRegionPortio xen_platform_ioport[] = {
+    { 0, 16, 4, .write = platform_fixed_ioport_writel, },
+    { 0, 16, 2, .write = platform_fixed_ioport_writew, },
+    { 0, 16, 1, .write = platform_fixed_ioport_writeb, },
+    { 0, 16, 2, .read = platform_fixed_ioport_readw, },
+    { 0, 16, 1, .read = platform_fixed_ioport_readb, },
+    PORTIO_END_OF_LIST()
+};
+
+static const MemoryRegionOps platform_fixed_io_ops = {
+    .old_portio = xen_platform_ioport,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
 static void platform_fixed_ioport_init(PCIXenPlatformState* s)
 {
-    register_ioport_write(XEN_PLATFORM_IOPORT, 16, 4, platform_fixed_ioport_writel, s);
-    register_ioport_write(XEN_PLATFORM_IOPORT, 16, 2, platform_fixed_ioport_writew, s);
-    register_ioport_write(XEN_PLATFORM_IOPORT, 16, 1, platform_fixed_ioport_writeb, s);
-    register_ioport_read(XEN_PLATFORM_IOPORT, 16, 2, platform_fixed_ioport_readw, s);
-    register_ioport_read(XEN_PLATFORM_IOPORT, 16, 1, platform_fixed_ioport_readb, s);
+    memory_region_init_io(&s->fixed_io, &platform_fixed_io_ops, s,
+                          "xen-fixed", 16);
+    memory_region_add_subregion(get_system_io(), XEN_PLATFORM_IOPORT,
+                                &s->fixed_io);
 }
 
 /* Xen Platform PCI Device */
 
 static uint32_t xen_platform_ioport_readb(void *opaque, uint32_t addr)
 {
-    addr &= 0xff;
-
     if (addr == 0) {
         return platform_fixed_ioport_readb(opaque, XEN_PLATFORM_IOPORT);
     } else {
@@ -247,9 +261,6 @@ static void xen_platform_ioport_writeb(void *opaque, uint32_t addr, uint32_t val
 {
     PCIXenPlatformState *s = opaque;
 
-    addr &= 0xff;
-    val  &= 0xff;
-
     switch (addr) {
     case 0: /* Platform flags */
         platform_fixed_ioport_writeb(opaque, XEN_PLATFORM_IOPORT, val);
@@ -262,15 +273,23 @@ static void xen_platform_ioport_writeb(void *opaque, uint32_t addr, uint32_t val
     }
 }
 
-static void platform_ioport_map(PCIDevice *pci_dev, int region_num, pcibus_t addr, pcibus_t size, int type)
-{
-    PCIXenPlatformState *d = DO_UPCAST(PCIXenPlatformState, pci_dev, pci_dev);
+static MemoryRegionPortio xen_pci_portio[] = {
+    { 0, 0x100, 1, .read = xen_platform_ioport_readb, },
+    { 0, 0x100, 1, .write = xen_platform_ioport_writeb, },
+    PORTIO_END_OF_LIST()
+};
+
+static const MemoryRegionOps xen_pci_io_ops = {
+    .old_portio = xen_pci_portio,
+};
 
-    register_ioport_write(addr, size, 1, xen_platform_ioport_writeb, d);
-    register_ioport_read(addr, size, 1, xen_platform_ioport_readb, d);
+static void platform_ioport_bar_setup(PCIXenPlatformState *d)
+{
+    memory_region_init_io(&d->bar, &xen_pci_io_ops, d, "xen-pci", 0x100);
 }
 
-static uint32_t platform_mmio_read(ReadWriteHandler *handler, pcibus_t addr, int len)
+static uint64_t platform_mmio_read(void *opaque, target_phys_addr_t addr,
+                                   unsigned size)
 {
     DPRINTF("Warning: attempted read from physical address "
             "0x" TARGET_FMT_plx " in xen platform mmio space\n", addr);
@@ -278,28 +297,24 @@ static uint32_t platform_mmio_read(ReadWriteHandler *handler, pcibus_t addr, int
     return 0;
 }
 
-static void platform_mmio_write(ReadWriteHandler *handler, pcibus_t addr,
-                                uint32_t val, int len)
+static void platform_mmio_write(void *opaque, target_phys_addr_t addr,
+                                uint64_t val, unsigned size)
 {
-    DPRINTF("Warning: attempted write of 0x%x to physical "
+    DPRINTF("Warning: attempted write of 0x%"PRIx64" to physical "
             "address 0x" TARGET_FMT_plx " in xen platform mmio space\n",
             val, addr);
 }
 
-static ReadWriteHandler platform_mmio_handler = {
+static const MemoryRegionOps platform_mmio_handler = {
     .read = &platform_mmio_read,
     .write = &platform_mmio_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static void platform_mmio_map(PCIDevice *d, int region_num,
-                              pcibus_t addr, pcibus_t size, int type)
+static void platform_mmio_setup(PCIXenPlatformState *d)
 {
-    int mmio_io_addr;
-
-    mmio_io_addr = cpu_register_io_memory_simple(&platform_mmio_handler,
-                                                 DEVICE_NATIVE_ENDIAN);
-
-    cpu_register_physical_memory(addr, size, mmio_io_addr);
+    memory_region_init_io(&d->mmio_bar, &platform_mmio_handler, d,
+                          "xen-mmio", 0x1000000);
 }
 
 static int xen_platform_post_load(void *opaque, int version_id)
@@ -337,12 +352,14 @@ static int xen_platform_initfn(PCIDevice *dev)
 
     pci_conf[PCI_INTERRUPT_PIN] = 1;
 
-    pci_register_bar(&d->pci_dev, 0, 0x100,
-            PCI_BASE_ADDRESS_SPACE_IO, platform_ioport_map);
+    platform_ioport_bar_setup(d);
+    pci_register_bar_region(&d->pci_dev, 0,
+                            PCI_BASE_ADDRESS_SPACE_IO, &d->bar);
 
     /* reserve 16MB mmio address for share memory*/
-    pci_register_bar(&d->pci_dev, 1, 0x1000000,
-            PCI_BASE_ADDRESS_MEM_PREFETCH, platform_mmio_map);
+    platform_mmio_setup(d);
+    pci_register_bar_region(&d->pci_dev, 1,
+                            PCI_BASE_ADDRESS_MEM_PREFETCH, &d->mmio_bar);
 
     platform_fixed_ioport_init(d);
 
