diff --git a/hw/apb_pci.c b/hw/apb_pci.c
index 71c5e75..cbc11ab 100644
--- a/hw/apb_pci.c
+++ b/hw/apb_pci.c
@@ -191,7 +191,6 @@ static void apb_pci_config_write(ReadWriteHandler
*h, pcibus_t addr,
 {
     APBState *s = container_of(h, APBState, pci_config_handler);

-    val = qemu_bswap_len(val, size);
     APB_DPRINTF("%s: addr " TARGET_FMT_lx " val %x\n", __func__, addr, val);
     pci_data_write(s->bus, addr, val, size);
 }
@@ -203,7 +202,6 @@ static uint32_t
apb_pci_config_read(ReadWriteHandler *h, pcibus_t addr,
     APBState *s = container_of(h, APBState, pci_config_handler);

     ret = pci_data_read(s->bus, addr, size);
-    ret = qemu_bswap_len(ret, size);
     APB_DPRINTF("%s: addr " TARGET_FMT_lx " -> %x\n", __func__, addr, ret);
     return ret;
 }
@@ -217,13 +215,13 @@ static void pci_apb_iowriteb (void *opaque,
target_phys_addr_t addr,
 static void pci_apb_iowritew (void *opaque, target_phys_addr_t addr,
                                   uint32_t val)
 {
-    cpu_outw(addr & IOPORTS_MASK, bswap16(val));
+    cpu_outw(addr & IOPORTS_MASK, val);
 }

 static void pci_apb_iowritel (void *opaque, target_phys_addr_t addr,
                                 uint32_t val)
 {
-    cpu_outl(addr & IOPORTS_MASK, bswap32(val));
+    cpu_outl(addr & IOPORTS_MASK, val);
 }

 static uint32_t pci_apb_ioreadb (void *opaque, target_phys_addr_t addr)
@@ -238,7 +236,7 @@ static uint32_t pci_apb_ioreadw (void *opaque,
target_phys_addr_t addr)
 {
     uint32_t val;

-    val = bswap16(cpu_inw(addr & IOPORTS_MASK));
+    val = cpu_inw(addr & IOPORTS_MASK);
     return val;
 }

@@ -246,7 +244,7 @@ static uint32_t pci_apb_ioreadl (void *opaque,
target_phys_addr_t addr)
 {
     uint32_t val;

-    val = bswap32(cpu_inl(addr & IOPORTS_MASK));
+    val = cpu_inl(addr & IOPORTS_MASK);
     return val;
 }

@@ -425,12 +423,14 @@ static int pci_pbm_init_device(SysBusDevice *dev)
     s->pci_config_handler.write = apb_pci_config_write;
     pci_config = cpu_register_io_memory_simple(&s->pci_config_handler);
     assert(pci_config >= 0);
+    pci_config = cpu_physical_memory_toggle_bswap(pci_config);
     /* at region 1 */
     sysbus_init_mmio(dev, 0x1000000ULL, pci_config);

     /* pci_ioport */
     pci_ioport = cpu_register_io_memory(pci_apb_ioread,
                                         pci_apb_iowrite, s);
+    pci_ioport = cpu_physical_memory_toggle_bswap(pci_ioport);
     /* at region 2 */
     sysbus_init_mmio(dev, 0x10000ULL, pci_ioport);

diff --git a/hw/dec_pci.c b/hw/dec_pci.c
index ee49d5a..f6b5a0c 100644
--- a/hw/dec_pci.c
+++ b/hw/dec_pci.c
@@ -69,8 +69,10 @@ static int pci_dec_21154_init_device(SysBusDevice *dev)

     s = FROM_SYSBUS(DECState, dev);

-    pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 1);
-    pci_mem_data = pci_host_data_register_mmio(&s->host_state, 1);
+    pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 0);
+    pci_mem_data = pci_host_data_register_mmio(&s->host_state, 0);
+    pci_mem_config = cpu_physical_memory_toggle_bswap(pci_mem_config);
+    pci_mem_data = cpu_physical_memory_toggle_bswap(pci_mem_data);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
     return 0;
diff --git a/hw/grackle_pci.c b/hw/grackle_pci.c
index 91c755f..ae69c21 100644
--- a/hw/grackle_pci.c
+++ b/hw/grackle_pci.c
@@ -108,8 +108,10 @@ static int pci_grackle_init_device(SysBusDevice *dev)

     s = FROM_SYSBUS(GrackleState, dev);

-    pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 1);
-    pci_mem_data = pci_host_data_register_mmio(&s->host_state, 1);
+    pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 0);
+    pci_mem_config = cpu_physical_memory_toggle_bswap(pci_mem_config);
+    pci_mem_data = pci_host_data_register_mmio(&s->host_state, 0);
+    pci_mem_data = cpu_physical_memory_toggle_bswap(pci_mem_data);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);

diff --git a/hw/ppc4xx_pci.c b/hw/ppc4xx_pci.c
index 6e437e7..f7335b7 100644
--- a/hw/ppc4xx_pci.c
+++ b/hw/ppc4xx_pci.c
@@ -102,10 +102,6 @@ static void pci4xx_cfgaddr_writel(void *opaque,
target_phys_addr_t addr,
 {
     PPC4xxPCIState *ppc4xx_pci = opaque;

-#ifdef TARGET_WORDS_BIGENDIAN
-    value = bswap32(value);
-#endif
-
     ppc4xx_pci->pci_state.config_reg = value & ~0x3;
 }

@@ -120,10 +116,6 @@ static void ppc4xx_pci_reg_write4(void *opaque,
target_phys_addr_t offset,
 {
     struct PPC4xxPCIState *pci = opaque;

-#ifdef TARGET_WORDS_BIGENDIAN
-    value = bswap32(value);
-#endif
-
     /* We ignore all target attempts at PCI configuration, effectively
      * assuming a bidirectional 1:1 mapping of PLB and PCI space. */

@@ -251,10 +243,6 @@ static uint32_t ppc4xx_pci_reg_read4(void
*opaque, target_phys_addr_t offset)
         value = 0;
     }

-#ifdef TARGET_WORDS_BIGENDIAN
-    value = bswap32(value);
-#endif
-
     return value;
 }

@@ -375,18 +363,25 @@ PCIBus *ppc4xx_pci_init(CPUState *env, qemu_irq
pci_irqs[4],
                                    pci4xx_cfgaddr_write, controller);
     if (index < 0)
         goto free;
+#ifdef TARGET_WORDS_BIGENDIAN
+    index = cpu_physical_memory_toggle_bswap(index);
+#endif
     cpu_register_physical_memory(config_space + PCIC0_CFGADDR, 4, index);

     /* CFGDATA */
-    index = pci_host_data_register_mmio(&controller->pci_state, 1);
+    index = pci_host_data_register_mmio(&controller->pci_state, 0);
     if (index < 0)
         goto free;
+    index = cpu_physical_memory_toggle_bswap(index);
     cpu_register_physical_memory(config_space + PCIC0_CFGDATA, 4, index);

     /* Internal registers */
     index = cpu_register_io_memory(pci_reg_read, pci_reg_write, controller);
     if (index < 0)
         goto free;
+#ifdef TARGET_WORDS_BIGENDIAN
+    index = cpu_physical_memory_toggle_bswap(index);
+#endif
     cpu_register_physical_memory(registers, PCI_REG_SIZE, index);

     qemu_register_reset(ppc4xx_pci_reset, controller);
diff --git a/hw/prep_pci.c b/hw/prep_pci.c
index 0c2afe9..16c677c 100644
--- a/hw/prep_pci.c
+++ b/hw/prep_pci.c
@@ -49,14 +49,12 @@ static void PPC_PCIIO_writeb (void *opaque,
target_phys_addr_t addr, uint32_t va
 static void PPC_PCIIO_writew (void *opaque, target_phys_addr_t addr,
uint32_t val)
 {
     PREPPCIState *s = opaque;
-    val = bswap16(val);
     pci_data_write(s->bus, PPC_PCIIO_config(addr), val, 2);
 }

 static void PPC_PCIIO_writel (void *opaque, target_phys_addr_t addr,
uint32_t val)
 {
     PREPPCIState *s = opaque;
-    val = bswap32(val);
     pci_data_write(s->bus, PPC_PCIIO_config(addr), val, 4);
 }

@@ -73,7 +71,6 @@ static uint32_t PPC_PCIIO_readw (void *opaque,
target_phys_addr_t addr)
     PREPPCIState *s = opaque;
     uint32_t val;
     val = pci_data_read(s->bus, PPC_PCIIO_config(addr), 2);
-    val = bswap16(val);
     return val;
 }

@@ -82,7 +79,6 @@ static uint32_t PPC_PCIIO_readl (void *opaque,
target_phys_addr_t addr)
     PREPPCIState *s = opaque;
     uint32_t val;
     val = pci_data_read(s->bus, PPC_PCIIO_config(addr), 4);
-    val = bswap32(val);
     return val;
 }

@@ -126,6 +122,7 @@ PCIBus *pci_prep_init(qemu_irq *pic)

     PPC_io_memory = cpu_register_io_memory(PPC_PCIIO_read,
                                            PPC_PCIIO_write, s);
+    PPC_io_memory = cpu_physical_memory_toggle_bswap(PPC_io_memory);
     cpu_register_physical_memory(0x80800000, 0x00400000, PPC_io_memory);

     /* PCI host bridge */
diff --git a/hw/unin_pci.c b/hw/unin_pci.c
index 1310211..6694a00 100644
--- a/hw/unin_pci.c
+++ b/hw/unin_pci.c
@@ -121,7 +121,7 @@ static void unin_data_write(ReadWriteHandler *handler,
                             pcibus_t addr, uint32_t val, int len)
 {
     UNINState *s = container_of(handler, UNINState, data_handler);
-    val = qemu_bswap_len(val, len);
+
     UNIN_DPRINTF("write addr %" FMT_PCIBUS " len %d val %x\n", addr, len, val);
     pci_data_write(s->host_state.bus,
                    unin_get_config_reg(s->host_state.config_reg, addr),
@@ -138,7 +138,6 @@ static uint32_t unin_data_read(ReadWriteHandler *handler,
                         unin_get_config_reg(s->host_state.config_reg, addr),
                         len);
     UNIN_DPRINTF("read addr %" FMT_PCIBUS " len %d val %x\n", addr, len, val);
-    val = qemu_bswap_len(val, len);
     return val;
 }

@@ -151,10 +150,12 @@ static int pci_unin_main_init_device(SysBusDevice *dev)
     /* Uninorth main bus */
     s = FROM_SYSBUS(UNINState, dev);

-    pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 1);
+    pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 0);
+    pci_mem_config = cpu_physical_memory_toggle_bswap(pci_mem_config);
     s->data_handler.read = unin_data_read;
     s->data_handler.write = unin_data_write;
     pci_mem_data = cpu_register_io_memory_simple(&s->data_handler);
+    pci_mem_data = cpu_physical_memory_toggle_bswap(pci_mem_data);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);

@@ -172,10 +173,12 @@ static int pci_u3_agp_init_device(SysBusDevice *dev)
     /* Uninorth U3 AGP bus */
     s = FROM_SYSBUS(UNINState, dev);

-    pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 1);
+    pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 0);
+    pci_mem_config = cpu_physical_memory_toggle_bswap(pci_mem_config);
     s->data_handler.read = unin_data_read;
     s->data_handler.write = unin_data_write;
     pci_mem_data = cpu_register_io_memory_simple(&s->data_handler);
+    pci_mem_data = cpu_physical_memory_toggle_bswap(pci_mem_data);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);

@@ -195,7 +198,9 @@ static int pci_unin_agp_init_device(SysBusDevice *dev)
     s = FROM_SYSBUS(UNINState, dev);

     pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 0);
-    pci_mem_data = pci_host_data_register_mmio(&s->host_state, 1);
+    pci_mem_config = cpu_physical_memory_toggle_bswap(pci_mem_config);
+    pci_mem_data = pci_host_data_register_mmio(&s->host_state, 0);
+    pci_mem_data = cpu_physical_memory_toggle_bswap(pci_mem_data);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
     return 0;
@@ -210,7 +215,8 @@ static int pci_unin_internal_init_device(SysBusDevice *dev)
     s = FROM_SYSBUS(UNINState, dev);

     pci_mem_config = pci_host_conf_register_mmio(&s->host_state, 0);
-    pci_mem_data = pci_host_data_register_mmio(&s->host_state, 1);
+    pci_mem_data = pci_host_data_register_mmio(&s->host_state, 0);
+    pci_mem_data = cpu_physical_memory_toggle_bswap(pci_mem_data);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
     return 0;
