diff --git a/hw/apb_pci.c b/hw/apb_pci.c
index 8c38d41..db18f45 100644
--- a/hw/apb_pci.c
+++ b/hw/apb_pci.c
@@ -45,46 +45,6 @@ typedef struct APBState {
     PCIHostState host_state;
 } APBState;
 
-static void pci_apb_config_writel (void *opaque, target_phys_addr_t addr,
-                                         uint32_t val)
-{
-    APBState *s = opaque;
-
-#ifdef TARGET_WORDS_BIGENDIAN
-    val = bswap32(val);
-#endif
-    APB_DPRINTF("config_writel addr " TARGET_FMT_plx " val %x\n", addr,
-                val);
-    s->host_state.config_reg = val;
-}
-
-static uint32_t pci_apb_config_readl (void *opaque,
-                                            target_phys_addr_t addr)
-{
-    APBState *s = opaque;
-    uint32_t val;
-
-    val = s->host_state.config_reg;
-#ifdef TARGET_WORDS_BIGENDIAN
-    val = bswap32(val);
-#endif
-    APB_DPRINTF("config_readl addr " TARGET_FMT_plx " val %x\n", addr,
-                val);
-    return val;
-}
-
-static CPUWriteMemoryFunc * const pci_apb_config_write[] = {
-    &pci_apb_config_writel,
-    &pci_apb_config_writel,
-    &pci_apb_config_writel,
-};
-
-static CPUReadMemoryFunc * const pci_apb_config_read[] = {
-    &pci_apb_config_readl,
-    &pci_apb_config_readl,
-    &pci_apb_config_readl,
-};
-
 static void apb_config_writel (void *opaque, target_phys_addr_t addr,
                                uint32_t val)
 {
@@ -266,8 +226,7 @@ static int pci_pbm_init_device(SysBusDevice *dev)
                                           pci_apb_iowrite, s);
     sysbus_init_mmio(dev, 0x10000ULL, pci_ioport);
     /* mem_config  */
-    pci_mem_config = cpu_register_io_memory(pci_apb_config_read,
-                                            pci_apb_config_write, s);
+    pci_mem_config = pci_host_config_register_io_memory(&s->host_state);
     sysbus_init_mmio(dev, 0x10ULL, pci_mem_config);
     /* mem_data */
     pci_mem_data = pci_host_data_register_io_memory(&s->host_state);
diff --git a/hw/grackle_pci.c b/hw/grackle_pci.c
index 8407cd2..58dcd11 100644
--- a/hw/grackle_pci.c
+++ b/hw/grackle_pci.c
@@ -43,45 +43,6 @@ typedef struct GrackleState {
     PCIHostState host_state;
 } GrackleState;
 
-static void pci_grackle_config_writel (void *opaque, target_phys_addr_t addr,
-                                       uint32_t val)
-{
-    GrackleState *s = opaque;
-
-    GRACKLE_DPRINTF("config_writel addr " TARGET_FMT_plx " val %x\n", addr,
-                    val);
-#ifdef TARGET_WORDS_BIGENDIAN
-    val = bswap32(val);
-#endif
-    s->host_state.config_reg = val;
-}
-
-static uint32_t pci_grackle_config_readl (void *opaque, target_phys_addr_t addr)
-{
-    GrackleState *s = opaque;
-    uint32_t val;
-
-    val = s->host_state.config_reg;
-#ifdef TARGET_WORDS_BIGENDIAN
-    val = bswap32(val);
-#endif
-    GRACKLE_DPRINTF("config_readl addr " TARGET_FMT_plx " val %x\n", addr,
-                    val);
-    return val;
-}
-
-static CPUWriteMemoryFunc * const pci_grackle_config_write[] = {
-    &pci_grackle_config_writel,
-    &pci_grackle_config_writel,
-    &pci_grackle_config_writel,
-};
-
-static CPUReadMemoryFunc * const pci_grackle_config_read[] = {
-    &pci_grackle_config_readl,
-    &pci_grackle_config_readl,
-    &pci_grackle_config_readl,
-};
-
 /* Don't know if this matches real hardware, but it agrees with OHW.  */
 static int pci_grackle_map_irq(PCIDevice *pci_dev, int irq_num)
 {
@@ -147,8 +108,7 @@ static int pci_grackle_init_device(SysBusDevice *dev)
 
     s = FROM_SYSBUS(GrackleState, dev);
 
-    pci_mem_config = cpu_register_io_memory(pci_grackle_config_read,
-                                            pci_grackle_config_write, s);
+    pci_mem_config = pci_host_config_register_io_memory(&s->host_state);
     pci_mem_data = pci_host_data_register_io_memory(&s->host_state);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
@@ -167,8 +127,7 @@ static int pci_dec_21154_init_device(SysBusDevice *dev)
 
     s = FROM_SYSBUS(GrackleState, dev);
 
-    pci_mem_config = cpu_register_io_memory(pci_grackle_config_read,
-                                            pci_grackle_config_write, s);
+    pci_mem_config = pci_host_config_register_io_memory(&s->host_state);
     pci_mem_data = pci_host_data_register_io_memory(&s->host_state);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
diff --git a/hw/pci_host.c b/hw/pci_host.c
index 29d19f9..99416c8 100644
--- a/hw/pci_host.c
+++ b/hw/pci_host.c
@@ -32,6 +32,114 @@ do { printf("pci_host_data: " fmt , ## __VA_ARGS__); } while (0)
 #define PCI_DPRINTF(fmt, ...)
 #endif
 
+static void pci_host_config_writel(void *opaque, target_phys_addr_t addr,
+                                   uint32_t val)
+{
+    PCIHostState *s = opaque;
+
+#ifdef TARGET_WORDS_BIGENDIAN
+    val = bswap32(val);
+#endif
+    PCI_DPRINTF("%s addr " TARGET_FMT_plx " val %"PRIx32"\n",
+                __func__, addr, val);
+    s->config_reg = val;
+}
+
+static uint32_t pci_host_config_readl(void *opaque, target_phys_addr_t addr)
+{
+    PCIHostState *s = opaque;
+    uint32_t val = s->config_reg;
+
+#ifdef TARGET_WORDS_BIGENDIAN
+    val = bswap32(val);
+#endif
+    PCI_DPRINTF("%s addr " TARGET_FMT_plx " val %"PRIx32"\n",
+                __func__, addr, val);
+    return val;
+}
+
+static CPUWriteMemoryFunc * const pci_host_config_write[] = {
+    &pci_host_config_writel,
+    &pci_host_config_writel,
+    &pci_host_config_writel,
+};
+
+static CPUReadMemoryFunc * const pci_host_config_read[] = {
+    &pci_host_config_readl,
+    &pci_host_config_readl,
+    &pci_host_config_readl,
+};
+
+int pci_host_config_register_io_memory(PCIHostState *s)
+{
+    return cpu_register_io_memory(pci_host_config_read,
+                                  pci_host_config_write, s);
+}
+
+static void pci_host_config_writel_noswap(void *opaque,
+                                          target_phys_addr_t addr,
+                                          uint32_t val)
+{
+    PCIHostState *s = opaque;
+
+    PCI_DPRINTF("%s addr " TARGET_FMT_plx " val %"PRIx32"\n",
+                __func__, addr, val);
+    s->config_reg = val;
+}
+
+static uint32_t pci_host_config_readl_noswap(void *opaque,
+                                             target_phys_addr_t addr)
+{
+    PCIHostState *s = opaque;
+    uint32_t val = s->config_reg;
+
+    PCI_DPRINTF("%s addr " TARGET_FMT_plx " val %"PRIx32"\n",
+                __func__, addr, val);
+    return val;
+}
+
+static CPUWriteMemoryFunc * const pci_host_config_write_noswap[] = {
+    &pci_host_config_writel_noswap,
+    &pci_host_config_writel_noswap,
+    &pci_host_config_writel_noswap,
+};
+
+static CPUReadMemoryFunc * const pci_host_config_read_noswap[] = {
+    &pci_host_config_readl_noswap,
+    &pci_host_config_readl_noswap,
+    &pci_host_config_readl_noswap,
+};
+
+int pci_host_config_register_io_memory_noswap(PCIHostState *s)
+{
+    return cpu_register_io_memory(pci_host_config_read_noswap,
+                                  pci_host_config_write_noswap, s);
+}
+
+static void pci_host_config_writel_ioport(void *opaque,
+                                          uint32_t addr, uint32_t val)
+{
+    PCIHostState *s = opaque;
+
+    PCI_DPRINTF("%s addr %"PRIx32 " val %"PRIx32"\n", __func__, addr, val);
+    s->config_reg = val;
+}
+
+static uint32_t pci_host_config_readl_ioport(void *opaque, uint32_t addr)
+{
+    PCIHostState *s = opaque;
+    uint32_t val = s->config_reg;
+
+    PCI_DPRINTF("%s addr %"PRIx32" val %"PRIx32"\n", __func__, addr, val);
+    return val;
+}
+
+void pci_host_config_register_ioport(uint32_t start, PCIHostState *s)
+{
+    register_ioport_write(start, 4, 4, pci_host_config_writel_ioport, s);
+    register_ioport_read(start, 4, 4, pci_host_config_readl_ioport, s);
+}
+
 #define PCI_ADDR_T      target_phys_addr_t
 #define PCI_HOST_SUFFIX _mmio
 
diff --git a/hw/pci_host.h b/hw/pci_host.h
index 4c723ee..ae71d7f 100644
--- a/hw/pci_host.h
+++ b/hw/pci_host.h
@@ -37,9 +37,12 @@ typedef struct {
 } PCIHostState;
 
 /* for mmio */
+int pci_host_config_register_io_memory(PCIHostState *s);
+int pci_host_config_register_io_memory_noswap(PCIHostState *s);
 int pci_host_data_register_io_memory(PCIHostState *s);
 
 /* for ioio */
+void pci_host_config_register_ioport(uint32_t start, PCIHostState *s);
 void pci_host_data_register_ioport(pio_addr_t start, PCIHostState *s);
 
 #endif /* PCI_HOST_H */
diff --git a/hw/piix_pci.c b/hw/piix_pci.c
index 866348d..bf0005e 100644
--- a/hw/piix_pci.c
+++ b/hw/piix_pci.c
@@ -44,18 +44,6 @@ struct PCII440FXState {
     PIIX3State *piix3;
 };
 
-static void i440fx_addr_writel(void* opaque, uint32_t addr, uint32_t val)
-{
-    I440FXState *s = opaque;
-    s->config_reg = val;
-}
-
-static uint32_t i440fx_addr_readl(void* opaque, uint32_t addr)
-{
-    I440FXState *s = opaque;
-    return s->config_reg;
-}
-
 static void piix3_set_irq(void *opaque, int irq_num, int level);
 
 /* return the global irq number corresponding to a given device irq
@@ -192,8 +180,7 @@ static int i440fx_pcihost_initfn(SysBusDevice *dev)
 {
     I440FXState *s = FROM_SYSBUS(I440FXState, dev);
 
-    register_ioport_write(0xcf8, 4, 4, i440fx_addr_writel, s);
-    register_ioport_read(0xcf8, 4, 4, i440fx_addr_readl, s);
+    pci_host_config_register_ioport(0xcf8, s);
 
     pci_host_data_register_ioport(0xcfc, s);
     return 0;
diff --git a/hw/ppce500_pci.c b/hw/ppce500_pci.c
index 7c8cdad..223de3a 100644
--- a/hw/ppce500_pci.c
+++ b/hw/ppce500_pci.c
@@ -84,37 +84,6 @@ struct PPCE500PCIState {
 
 typedef struct PPCE500PCIState PPCE500PCIState;
 
-static uint32_t pcie500_cfgaddr_readl(void *opaque, target_phys_addr_t addr)
-{
-    PPCE500PCIState *pci = opaque;
-
-    pci_debug("%s: (addr:" TARGET_FMT_plx ") -> value:%x\n", __func__, addr,
-              pci->pci_state.config_reg);
-    return pci->pci_state.config_reg;
-}
-
-static CPUReadMemoryFunc * const pcie500_cfgaddr_read[] = {
-    &pcie500_cfgaddr_readl,
-    &pcie500_cfgaddr_readl,
-    &pcie500_cfgaddr_readl,
-};
-
-static void pcie500_cfgaddr_writel(void *opaque, target_phys_addr_t addr,
-                                  uint32_t value)
-{
-    PPCE500PCIState *controller = opaque;
-
-    pci_debug("%s: value:%x -> (addr:" TARGET_FMT_plx ")\n", __func__, value,
-              addr);
-    controller->pci_state.config_reg = value & ~0x3;
-}
-
-static CPUWriteMemoryFunc * const pcie500_cfgaddr_write[] = {
-    &pcie500_cfgaddr_writel,
-    &pcie500_cfgaddr_writel,
-    &pcie500_cfgaddr_writel,
-};
-
 static uint32_t pci_reg_read4(void *opaque, target_phys_addr_t addr)
 {
     PPCE500PCIState *pci = opaque;
@@ -324,8 +293,7 @@ PCIBus *ppce500_pci_init(qemu_irq pci_irqs[4], target_phys_addr_t registers)
     controller->pci_dev = d;
 
     /* CFGADDR */
-    index = cpu_register_io_memory(pcie500_cfgaddr_read,
-                                   pcie500_cfgaddr_write, controller);
+    index = pci_host_config_register_io_memory_noswap(&controller->pci_state);
     if (index < 0)
         goto free;
     cpu_register_physical_memory(registers + PCIE500_CFGADDR, 4, index);
diff --git a/hw/prep_pci.c b/hw/prep_pci.c
index 5a5b3da..a338f81 100644
--- a/hw/prep_pci.c
+++ b/hw/prep_pci.c
@@ -28,18 +28,6 @@
 
 typedef PCIHostState PREPPCIState;
 
-static void pci_prep_addr_writel(void* opaque, uint32_t addr, uint32_t val)
-{
-    PREPPCIState *s = opaque;
-    s->config_reg = val;
-}
-
-static uint32_t pci_prep_addr_readl(void* opaque, uint32_t addr)
-{
-    PREPPCIState *s = opaque;
-    return s->config_reg;
-}
-
 static inline uint32_t PPC_PCIIO_config(target_phys_addr_t addr)
 {
     int i;
@@ -139,8 +127,7 @@ PCIBus *pci_prep_init(qemu_irq *pic)
     s->bus = pci_register_bus(NULL, "pci",
                               prep_set_irq, prep_map_irq, pic, 0, 4);
 
-    register_ioport_write(0xcf8, 4, 4, pci_prep_addr_writel, s);
-    register_ioport_read(0xcf8, 4, 4, pci_prep_addr_readl, s);
+    pci_host_config_register_ioport(0xcf8, s);
 
     pci_host_data_register_ioport(0xcfc, s);
 
diff --git a/hw/unin_pci.c b/hw/unin_pci.c
index 6b8f98b..a9a62fd 100644
--- a/hw/unin_pci.c
+++ b/hw/unin_pci.c
@@ -41,74 +41,6 @@ typedef struct UNINState {
     PCIHostState host_state;
 } UNINState;
 
-static void pci_unin_main_config_writel (void *opaque, target_phys_addr_t addr,
-                                         uint32_t val)
-{
-    UNINState *s = opaque;
-
-    UNIN_DPRINTF("config_writel addr " TARGET_FMT_plx " val %x\n", addr, val);
-#ifdef TARGET_WORDS_BIGENDIAN
-    val = bswap32(val);
-#endif
-
-    s->host_state.config_reg = val;
-}
-
-static uint32_t pci_unin_main_config_readl (void *opaque,
-                                            target_phys_addr_t addr)
-{
-    UNINState *s = opaque;
-    uint32_t val;
-
-    val = s->host_state.config_reg;
-#ifdef TARGET_WORDS_BIGENDIAN
-    val = bswap32(val);
-#endif
-    UNIN_DPRINTF("config_readl addr " TARGET_FMT_plx " val %x\n", addr, val);
-
-    return val;
-}
-
-static CPUWriteMemoryFunc * const pci_unin_main_config_write[] = {
-    &pci_unin_main_config_writel,
-    &pci_unin_main_config_writel,
-    &pci_unin_main_config_writel,
-};
-
-static CPUReadMemoryFunc * const pci_unin_main_config_read[] = {
-    &pci_unin_main_config_readl,
-    &pci_unin_main_config_readl,
-    &pci_unin_main_config_readl,
-};
-
-static void pci_unin_config_writel (void *opaque, target_phys_addr_t addr,
-                                    uint32_t val)
-{
-    UNINState *s = opaque;
-
-    s->host_state.config_reg = val;
-}
-
-static uint32_t pci_unin_config_readl (void *opaque,
-                                       target_phys_addr_t addr)
-{
-    UNINState *s = opaque;
-
-    return s->host_state.config_reg;
-}
-
-static CPUWriteMemoryFunc * const pci_unin_config_write[] = {
-    &pci_unin_config_writel,
-    &pci_unin_config_writel,
-    &pci_unin_config_writel,
-};
-
-static CPUReadMemoryFunc * const pci_unin_config_read[] = {
-    &pci_unin_config_readl,
-    &pci_unin_config_readl,
-    &pci_unin_config_readl,
-};
-
 /* Don't know if this matches real hardware, but it agrees with OHW.  */
 static int pci_unin_map_irq(PCIDevice *pci_dev, int irq_num)
 {
@@ -152,10 +84,8 @@ static int pci_unin_main_init_device(SysBusDevice *dev)
     /* Uninorth main bus */
     s = FROM_SYSBUS(UNINState, dev);
 
-    pci_mem_config = cpu_register_io_memory(pci_unin_main_config_read,
-                                            pci_unin_main_config_write, s);
+    pci_mem_config = pci_host_config_register_io_memory(&s->host_state);
     pci_mem_data = pci_host_data_register_io_memory(&s->host_state);
-
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
 
@@ -174,8 +104,7 @@ static int pci_dec_21154_init_device(SysBusDevice *dev)
     s = FROM_SYSBUS(UNINState, dev);
 
     // XXX: s = &pci_bridge[2];
-    pci_mem_config = cpu_register_io_memory(pci_unin_config_read,
-                                            pci_unin_config_write, s);
+    pci_mem_config = pci_host_config_register_io_memory_noswap(&s->host_state);
     pci_mem_data = pci_host_data_register_io_memory(&s->host_state);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
@@ -190,8 +119,7 @@ static int pci_unin_agp_init_device(SysBusDevice *dev)
     /* Uninorth AGP bus */
     s = FROM_SYSBUS(UNINState, dev);
 
-    pci_mem_config = cpu_register_io_memory(pci_unin_config_read,
-                                            pci_unin_config_write, s);
+    pci_mem_config = pci_host_config_register_io_memory_noswap(&s->host_state);
     pci_mem_data = pci_host_data_register_io_memory(&s->host_state);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
@@ -206,8 +134,7 @@ static int pci_unin_internal_init_device(SysBusDevice *dev)
     /* Uninorth internal bus */
     s = FROM_SYSBUS(UNINState, dev);
 
-    pci_mem_config = cpu_register_io_memory(pci_unin_config_read,
-                                            pci_unin_config_write, s);
+    pci_mem_config = pci_host_config_register_io_memory_noswap(&s->host_state);
     pci_mem_data = pci_host_data_register_io_memory(&s->host_state);
     sysbus_init_mmio(dev, 0x1000, pci_mem_config);
     sysbus_init_mmio(dev, 0x1000, pci_mem_data);
