diff --git a/Makefile.target b/Makefile.target
index 891ea08..acf8865 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -195,6 +195,7 @@ obj-i386-y += cirrus_vga.o apic.o ioapic.o parallel.o acpi.o piix_pci.o
 obj-i386-y += usb-uhci.o vmmouse.o vmport.o vmware_vga.o hpet.o
 obj-i386-y += device-hotplug.o pci-hotplug.o smbios.o wdt_ib700.o
 obj-i386-y += ne2000-isa.o
+obj-i386-y += pc_smbus.o
 
 # shared objects
 obj-ppc-y = ppc.o ide/core.o ide/qdev.o ide/isa.o ide/pci.o ide/macio.o
@@ -225,6 +226,7 @@ obj-mips-y += ide/core.o ide/qdev.o ide/isa.o ide/pci.o ide/piix.o
 obj-mips-y += gt64xxx.o pckbd.o fdc.o mc146818rtc.o usb-uhci.o acpi.o ds1225y.o
 obj-mips-y += piix4.o parallel.o cirrus_vga.o pcspk.o $(sound-obj-y)
 obj-mips-y += mipsnet.o ne2000-isa.o
+obj-mips-y += pc_smbus.o
 obj-mips-y += pflash_cfi01.o
 obj-mips-y += vmware_vga.o
 
diff --git a/hw/acpi.c b/hw/acpi.c
index 9a69e7d..6b030bb 100644
--- a/hw/acpi.c
+++ b/hw/acpi.c
@@ -17,6 +17,7 @@
  */
 #include "hw.h"
 #include "pc.h"
+#include "pc_smbus.h"
 #include "pci.h"
 #include "qemu-timer.h"
 #include "sysemu.h"
@@ -40,15 +41,9 @@ typedef struct PIIX4PMState {
     uint8_t apms;
     QEMUTimer *tmr_timer;
     int64_t tmr_overflow_time;
-    i2c_bus *smbus;
-    uint8_t smb_stat;
-    uint8_t smb_ctl;
-    uint8_t smb_cmd;
-    uint8_t smb_addr;
-    uint8_t smb_data0;
-    uint8_t smb_data1;
-    uint8_t smb_data[32];
-    uint8_t smb_index;
+
+    PCSMBus smb;
+
     qemu_irq irq;
 } PIIX4PMState;
 
@@ -66,14 +61,6 @@ typedef struct PIIX4PMState {
 #define ACPI_ENABLE 0xf1
 #define ACPI_DISABLE 0xf0
 
-#define SMBHSTSTS 0x00
-#define SMBHSTCNT 0x02
-#define SMBHSTCMD 0x03
-#define SMBHSTADD 0x04
-#define SMBHSTDAT0 0x05
-#define SMBHSTDAT1 0x06
-#define SMBBLKDAT 0x07
-
 static PIIX4PMState *pm_state;
 
 static uint32_t get_pmtmr(PIIX4PMState *s)
@@ -279,141 +266,6 @@ static void acpi_dbg_writel(void *opaque, uint32_t addr, uint32_t val)
 #endif
 }
 
-static void smb_transaction(PIIX4PMState *s)
-{
-    uint8_t prot = (s->smb_ctl >> 2) & 0x07;
-    uint8_t read = s->smb_addr & 0x01;
-    uint8_t cmd = s->smb_cmd;
-    uint8_t addr = s->smb_addr >> 1;
-    i2c_bus *bus = s->smbus;
-
-#ifdef DEBUG
-    printf("SMBus trans addr=0x%02x prot=0x%02x\n", addr, prot);
-#endif
-    switch(prot) {
-    case 0x0:
-        smbus_quick_command(bus, addr, read);
-        break;
-    case 0x1:
-        if (read) {
-            s->smb_data0 = smbus_receive_byte(bus, addr);
-        } else {
-            smbus_send_byte(bus, addr, cmd);
-        }
-        break;
-    case 0x2:
-        if (read) {
-            s->smb_data0 = smbus_read_byte(bus, addr, cmd);
-        } else {
-            smbus_write_byte(bus, addr, cmd, s->smb_data0);
-        }
-        break;
-    case 0x3:
-        if (read) {
-            uint16_t val;
-            val = smbus_read_word(bus, addr, cmd);
-            s->smb_data0 = val;
-            s->smb_data1 = val >> 8;
-        } else {
-            smbus_write_word(bus, addr, cmd, (s->smb_data1 << 8) | s->smb_data0);
-        }
-        break;
-    case 0x5:
-        if (read) {
-            s->smb_data0 = smbus_read_block(bus, addr, cmd, s->smb_data);
-        } else {
-            smbus_write_block(bus, addr, cmd, s->smb_data, s->smb_data0);
-        }
-        break;
-    default:
-        goto error;
-    }
-    return;
-
-  error:
-    s->smb_stat |= 0x04;
-}
-
-static void smb_ioport_writeb(void *opaque, uint32_t addr, uint32_t val)
-{
-    PIIX4PMState *s = opaque;
-    addr &= 0x3f;
-#ifdef DEBUG
-    printf("SMB writeb port=0x%04x val=0x%02x\n", addr, val);
-#endif
-    switch(addr) {
-    case SMBHSTSTS:
-        s->smb_stat = 0;
-        s->smb_index = 0;
-        break;
-    case SMBHSTCNT:
-        s->smb_ctl = val;
-        if (val & 0x40)
-            smb_transaction(s);
-        break;
-    case SMBHSTCMD:
-        s->smb_cmd = val;
-        break;
-    case SMBHSTADD:
-        s->smb_addr = val;
-        break;
-    case SMBHSTDAT0:
-        s->smb_data0 = val;
-        break;
-    case SMBHSTDAT1:
-        s->smb_data1 = val;
-        break;
-    case SMBBLKDAT:
-        s->smb_data[s->smb_index++] = val;
-        if (s->smb_index > 31)
-            s->smb_index = 0;
-        break;
-    default:
-        break;
-    }
-}
-
-static uint32_t smb_ioport_readb(void *opaque, uint32_t addr)
-{
-    PIIX4PMState *s = opaque;
-    uint32_t val;
-
-    addr &= 0x3f;
-    switch(addr) {
-    case SMBHSTSTS:
-        val = s->smb_stat;
-        break;
-    case SMBHSTCNT:
-        s->smb_index = 0;
-        val = s->smb_ctl & 0x1f;
-        break;
-    case SMBHSTCMD:
-        val = s->smb_cmd;
-        break;
-    case SMBHSTADD:
-        val = s->smb_addr;
-        break;
-    case SMBHSTDAT0:
-        val = s->smb_data0;
-        break;
-    case SMBHSTDAT1:
-        val = s->smb_data1;
-        break;
-    case SMBBLKDAT:
-        val = s->smb_data[s->smb_index++];
-        if (s->smb_index > 31)
-            s->smb_index = 0;
-        break;
-    default:
-        val = 0;
-        break;
-    }
-#ifdef DEBUG
-    printf("SMB readb port=0x%04x val=0x%02x\n", addr, val);
-#endif
-    return val;
-}
-
 static void pm_io_space_update(PIIX4PMState *s)
 {
     uint32_t pm_io_base;
@@ -542,8 +394,8 @@ i2c_bus *piix4_pm_init(PCIBus *bus, int devfn, uint32_t smb_io_base,
     pci_conf[0x90] = smb_io_base | 1;
     pci_conf[0x91] = smb_io_base >> 8;
     pci_conf[0xd2] = 0x09;
-    register_ioport_write(smb_io_base, 64, 1, smb_ioport_writeb, s);
-    register_ioport_read(smb_io_base, 64, 1, smb_ioport_readb, s);
+    register_ioport_write(smb_io_base, 64, 1, smb_ioport_writeb, &s->smb);
+    register_ioport_read(smb_io_base, 64, 1, smb_ioport_readb, &s->smb);
 
     s->tmr_timer = qemu_new_timer(vm_clock, pm_tmr_timer, s);
 
@@ -551,11 +403,11 @@ i2c_bus *piix4_pm_init(PCIBus *bus, int devfn, uint32_t smb_io_base,
 
     vmstate_register(0, &vmstate_acpi, s);
 
-    s->smbus = i2c_init_bus(NULL, "i2c");
+    pc_smbus_init(&s->smb);
     s->irq = sci_irq;
     qemu_register_reset(piix4_reset, s);
 
-    return s->smbus;
+    return s->smb.smbus;
 }
 
 #define GPE_BASE 0xafe0
diff --git a/hw/pc_smbus.c b/hw/pc_smbus.c
new file mode 100644
index 0000000..850260d
--- /dev/null
+++ b/hw/pc_smbus.c
@@ -0,0 +1,178 @@
+/*
+ * PC SMBus implementation
+ * splitted from acpi.c
+ *
+ * Copyright (c) 2006 Fabrice Bellard
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA  02110-1301 USA
+ */
+#include "hw.h"
+#include "pc.h"
+#include "pc_smbus.h"
+#include "pci.h"
+#include "qemu-timer.h"
+#include "sysemu.h"
+#include "i2c.h"
+#include "smbus.h"
+#include "kvm.h"
+
+/* no save/load? */
+
+#define SMBHSTSTS       0x00
+#define SMBHSTCNT       0x02
+#define SMBHSTCMD       0x03
+#define SMBHSTADD       0x04
+#define SMBHSTDAT0      0x05
+#define SMBHSTDAT1      0x06
+#define SMBBLKDAT       0x07
+
+static void smb_transaction(PCSMBus *s)
+{
+    uint8_t prot = (s->smb_ctl >> 2) & 0x07;
+    uint8_t read = s->smb_addr & 0x01;
+    uint8_t cmd = s->smb_cmd;
+    uint8_t addr = s->smb_addr >> 1;
+    i2c_bus *bus = s->smbus;
+
+#ifdef DEBUG
+    printf("SMBus trans addr=0x%02x prot=0x%02x\n", addr, prot);
+#endif
+    switch(prot) {
+    case 0x0:
+        smbus_quick_command(bus, addr, read);
+        break;
+    case 0x1:
+        if (read) {
+            s->smb_data0 = smbus_receive_byte(bus, addr);
+        } else {
+            smbus_send_byte(bus, addr, cmd);
+        }
+        break;
+    case 0x2:
+        if (read) {
+            s->smb_data0 = smbus_read_byte(bus, addr, cmd);
+        } else {
+            smbus_write_byte(bus, addr, cmd, s->smb_data0);
+        }
+        break;
+    case 0x3:
+        if (read) {
+            uint16_t val;
+            val = smbus_read_word(bus, addr, cmd);
+            s->smb_data0 = val;
+            s->smb_data1 = val >> 8;
+        } else {
+            smbus_write_word(bus, addr, cmd, (s->smb_data1 << 8) | s->smb_data0);
+        }
+        break;
+    case 0x5:
+        if (read) {
+            s->smb_data0 = smbus_read_block(bus, addr, cmd, s->smb_data);
+        } else {
+            smbus_write_block(bus, addr, cmd, s->smb_data, s->smb_data0);
+        }
+        break;
+    default:
+        goto error;
+    }
+    return;
+
+  error:
+    s->smb_stat |= 0x04;
+}
+
+void smb_ioport_writeb(void *opaque, uint32_t addr, uint32_t val)
+{
+    PCSMBus *s = opaque;
+    addr &= 0x3f;
+#ifdef DEBUG
+    printf("SMB writeb port=0x%04x val=0x%02x\n", addr, val);
+#endif
+    switch(addr) {
+    case SMBHSTSTS:
+        s->smb_stat = 0;
+        s->smb_index = 0;
+        break;
+    case SMBHSTCNT:
+        s->smb_ctl = val;
+        if (val & 0x40)
+            smb_transaction(s);
+        break;
+    case SMBHSTCMD:
+        s->smb_cmd = val;
+        break;
+    case SMBHSTADD:
+        s->smb_addr = val;
+        break;
+    case SMBHSTDAT0:
+        s->smb_data0 = val;
+        break;
+    case SMBHSTDAT1:
+        s->smb_data1 = val;
+        break;
+    case SMBBLKDAT:
+        s->smb_data[s->smb_index++] = val;
+        if (s->smb_index > 31)
+            s->smb_index = 0;
+        break;
+    default:
+        break;
+    }
+}
+
+uint32_t smb_ioport_readb(void *opaque, uint32_t addr)
+{
+    PCSMBus *s = opaque;
+    uint32_t val;
+
+    addr &= 0x3f;
+    switch(addr) {
+    case SMBHSTSTS:
+        val = s->smb_stat;
+        break;
+    case SMBHSTCNT:
+        s->smb_index = 0;
+        val = s->smb_ctl & 0x1f;
+        break;
+    case SMBHSTCMD:
+        val = s->smb_cmd;
+        break;
+    case SMBHSTADD:
+        val = s->smb_addr;
+        break;
+    case SMBHSTDAT0:
+        val = s->smb_data0;
+        break;
+    case SMBHSTDAT1:
+        val = s->smb_data1;
+        break;
+    case SMBBLKDAT:
+        val = s->smb_data[s->smb_index++];
+        if (s->smb_index > 31)
+            s->smb_index = 0;
+        break;
+    default:
+        val = 0;
+        break;
+    }
+#ifdef DEBUG
+    printf("SMB readb port=0x%04x val=0x%02x\n", addr, val);
+#endif
+    return val;
+}
+
+void pc_smbus_init(PCSMBus *smb)
+{
+    smb->smbus = i2c_init_bus(NULL, "i2c");
+}
diff --git a/hw/pc_smbus.h b/hw/pc_smbus.h
new file mode 100644
index 0000000..5e5a66f
--- /dev/null
+++ b/hw/pc_smbus.h
@@ -0,0 +1,43 @@
+/*
+ * QEMU PC SMBUS controller Emulation
+ *
+ *  Copyright (c) 2009 Isaku Yamahata <yamahata at valinux co jp>
+ *                     VA Linux Systems Japan K.K.
+ *
+ *  This is based on piix_pci.c, but heavily modified.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA  02110-1301 USA
+ */
+#ifndef PC_SMBUS_H
+#define PC_SMBUS_H
+
+typedef struct PCSMBus {
+    i2c_bus *smbus;
+
+    uint8_t smb_stat;
+    uint8_t smb_ctl;
+    uint8_t smb_cmd;
+    uint8_t smb_addr;
+    uint8_t smb_data0;
+    uint8_t smb_data1;
+    uint8_t smb_data[32];
+    uint8_t smb_index;
+} PCSMBus;
+
+void pc_smbus_init(PCSMBus *smb);
+void smb_ioport_writeb(void *opaque, uint32_t addr, uint32_t val);
+uint32_t smb_ioport_readb(void *opaque, uint32_t addr);
+
+#endif /* !PC_SMBUS_H */
