diff --git a/Makefile.target b/Makefile.target
index 651500e..5098299 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -222,6 +222,9 @@ obj-$(CONFIG_NO_XEN) += xen-stub.o
 
 obj-i386-$(CONFIG_XEN) += xen_platform.o
 
+# Xen PCI Passthrough
+obj-i386-$(CONFIG_XEN_PCI_PASSTHROUGH) += host-pci-device.o
+
 # Inter-VM PCI shared memory
 CONFIG_IVSHMEM =
 ifeq ($(CONFIG_KVM), y)
diff --git a/hw/host-pci-device.c b/hw/host-pci-device.c
new file mode 100644
index 0000000..3dacb30
--- /dev/null
+++ b/hw/host-pci-device.c
@@ -0,0 +1,278 @@
+/*
+ * Copyright (C) 2011       Citrix Ltd.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "host-pci-device.h"
+
+#define PCI_MAX_EXT_CAP \
+    ((PCIE_CONFIG_SPACE_SIZE - PCI_CONFIG_SPACE_SIZE) / (PCI_CAP_SIZEOF + 4))
+
+enum error_code {
+    ERROR_SYNTAX = 1,
+};
+
+static int path_to(const HostPCIDevice *d,
+                   const char *name, char *buf, ssize_t size)
+{
+    return snprintf(buf, size, "/sys/bus/pci/devices/%04x:%02x:%02x.%x/%s",
+                    d->domain, d->bus, d->dev, d->func, name);
+}
+
+static int get_resource(HostPCIDevice *d)
+{
+    int i, rc = 0;
+    FILE *f;
+    char path[PATH_MAX];
+    unsigned long long start, end, flags, size;
+
+    path_to(d, "resource", path, sizeof (path));
+    f = fopen(path, "r");
+    if (!f) {
+        fprintf(stderr, "Error: Can't open %s: %s\n", path, strerror(errno));
+        return -errno;
+    }
+
+    for (i = 0; i < PCI_NUM_REGIONS; i++) {
+        if (fscanf(f, "%llx %llx %llx", &start, &end, &flags) != 3) {
+            fprintf(stderr, "Error: Syntax error in %s\n", path);
+            rc = ERROR_SYNTAX;
+            break;
+        }
+        if (start) {
+            size = end - start + 1;
+        } else {
+            size = 0;
+        }
+
+        if (i < PCI_ROM_SLOT) {
+            d->io_regions[i].base_addr = start;
+            d->io_regions[i].size = size;
+            d->io_regions[i].flags = flags;
+        } else {
+            d->rom.base_addr = start;
+            d->rom.size = size;
+            d->rom.flags = flags;
+        }
+    }
+
+    fclose(f);
+    return rc;
+}
+
+static int get_hex_value(HostPCIDevice *d, const char *name,
+                         unsigned long *pvalue)
+{
+    char path[PATH_MAX];
+    FILE *f;
+    unsigned long value;
+
+    path_to(d, name, path, sizeof (path));
+    f = fopen(path, "r");
+    if (!f) {
+        fprintf(stderr, "Error: Can't open %s: %s\n", path, strerror(errno));
+        return -errno;
+    }
+    if (fscanf(f, "%lx\n", &value) != 1) {
+        fprintf(stderr, "Error: Syntax error in %s\n", path);
+        fclose(f);
+        return ERROR_SYNTAX;
+    }
+    fclose(f);
+    *pvalue = value;
+    return 0;
+}
+
+static bool pci_dev_is_virtfn(HostPCIDevice *d)
+{
+    char path[PATH_MAX];
+    struct stat buf;
+
+    path_to(d, "physfn", path, sizeof (path));
+    return !stat(path, &buf);
+}
+
+static int host_pci_config_fd(HostPCIDevice *d)
+{
+    char path[PATH_MAX];
+
+    if (d->config_fd < 0) {
+        path_to(d, "config", path, sizeof (path));
+        d->config_fd = open(path, O_RDWR);
+        if (d->config_fd < 0) {
+            fprintf(stderr, "HostPCIDevice: Can not open '%s': %s\n",
+                    path, strerror(errno));
+        }
+    }
+    return d->config_fd;
+}
+static int host_pci_config_read(HostPCIDevice *d, int pos, void *buf, int len)
+{
+    int fd = host_pci_config_fd(d);
+    int res = 0;
+
+again:
+    res = pread(fd, buf, len, pos);
+    if (res != len) {
+        if (res < 0 && (errno == EINTR || errno == EAGAIN)) {
+            goto again;
+        }
+        fprintf(stderr, "%s: read failed: %s (fd: %i)\n",
+                __func__, strerror(errno), fd);
+        return -errno;
+    }
+    return 0;
+}
+static int host_pci_config_write(HostPCIDevice *d,
+                                 int pos, const void *buf, int len)
+{
+    int fd = host_pci_config_fd(d);
+    int res = 0;
+
+again:
+    res = pwrite(fd, buf, len, pos);
+    if (res != len) {
+        if (res < 0 && (errno == EINTR || errno == EAGAIN)) {
+            goto again;
+        }
+        fprintf(stderr, "%s: write failed: %s\n",
+                __func__, strerror(errno));
+        return -errno;
+    }
+    return 0;
+}
+
+int host_pci_get_byte(HostPCIDevice *d, int pos, uint8_t *p)
+{
+    uint8_t buf;
+    int rc = host_pci_config_read(d, pos, &buf, 1);
+    if (rc == 0) {
+        *p = buf;
+    }
+    return rc;
+}
+int host_pci_get_word(HostPCIDevice *d, int pos, uint16_t *p)
+{
+    uint16_t buf;
+    int rc = host_pci_config_read(d, pos, &buf, 2);
+    if (rc == 0) {
+        *p = le16_to_cpu(buf);
+    }
+    return rc;
+}
+int host_pci_get_long(HostPCIDevice *d, int pos, uint32_t *p)
+{
+    uint32_t buf;
+    int rc = host_pci_config_read(d, pos, &buf, 4);
+    if (rc == 0) {
+        *p = le32_to_cpu(buf);
+    }
+    return rc;
+}
+int host_pci_get_block(HostPCIDevice *d, int pos, uint8_t *buf, int len)
+{
+    return host_pci_config_read(d, pos, buf, len);
+}
+
+int host_pci_set_byte(HostPCIDevice *d, int pos, uint8_t data)
+{
+    return host_pci_config_write(d, pos, &data, 1);
+}
+int host_pci_set_word(HostPCIDevice *d, int pos, uint16_t data)
+{
+    data = cpu_to_le16(data);
+    return host_pci_config_write(d, pos, &data, 2);
+}
+int host_pci_set_long(HostPCIDevice *d, int pos, uint32_t data)
+{
+    data = cpu_to_le32(data);
+    return host_pci_config_write(d, pos, &data, 4);
+}
+int host_pci_set_block(HostPCIDevice *d, int pos, uint8_t *buf, int len)
+{
+    return host_pci_config_write(d, pos, buf, len);
+}
+
+uint32_t host_pci_find_ext_cap_offset(HostPCIDevice *d, uint32_t cap)
+{
+    uint32_t header = 0;
+    int max_cap = PCI_MAX_EXT_CAP;
+    int pos = PCI_CONFIG_SPACE_SIZE;
+
+    do {
+        if (host_pci_get_long(d, pos, &header)) {
+            break;
+        }
+        /*
+         * If we have no capabilities, this is indicated by cap ID,
+         * cap version and next pointer all being 0.
+         */
+        if (header == 0) {
+            break;
+        }
+
+        if (PCI_EXT_CAP_ID(header) == cap) {
+            return pos;
+        }
+
+        pos = PCI_EXT_CAP_NEXT(header);
+        if (pos < PCI_CONFIG_SPACE_SIZE) {
+            break;
+        }
+
+        max_cap--;
+    } while (max_cap > 0);
+
+    return 0;
+}
+
+HostPCIDevice *host_pci_device_get(uint8_t bus, uint8_t dev, uint8_t func)
+{
+    HostPCIDevice *d = NULL;
+    unsigned long v = 0;
+
+    d = g_new0(HostPCIDevice, 1);
+
+    d->config_fd = -1;
+    d->domain = 0;
+    d->bus = bus;
+    d->dev = dev;
+    d->func = func;
+
+    if (host_pci_config_fd(d) == -1) {
+        goto error;
+    }
+    if (get_resource(d) != 0) {
+        goto error;
+    }
+
+    if (get_hex_value(d, "vendor", &v)) {
+        goto error;
+    }
+    d->vendor_id = v;
+    if (get_hex_value(d, "device", &v)) {
+        goto error;
+    }
+    d->device_id = v;
+    d->is_virtfn = pci_dev_is_virtfn(d);
+
+    return d;
+error:
+    if (d->config_fd >= 0) {
+        close(d->config_fd);
+    }
+    g_free(d);
+    return NULL;
+}
+
+void host_pci_device_put(HostPCIDevice *d)
+{
+    if (d->config_fd >= 0) {
+        close(d->config_fd);
+    }
+    g_free(d);
+}
diff --git a/hw/host-pci-device.h b/hw/host-pci-device.h
new file mode 100644
index 0000000..c8880eb
--- /dev/null
+++ b/hw/host-pci-device.h
@@ -0,0 +1,75 @@
+#ifndef HW_HOST_PCI_DEVICE
+#  define HW_HOST_PCI_DEVICE
+
+#include "pci.h"
+
+/*
+ * from linux/ioport.h
+ * IO resources have these defined flags.
+ */
+#define IORESOURCE_BITS         0x000000ff      /* Bus-specific bits */
+
+#define IORESOURCE_TYPE_BITS    0x00000f00      /* Resource type */
+#define IORESOURCE_IO           0x00000100
+#define IORESOURCE_MEM          0x00000200
+#define IORESOURCE_IRQ          0x00000400
+#define IORESOURCE_DMA          0x00000800
+
+#define IORESOURCE_PREFETCH     0x00001000      /* No side effects */
+#define IORESOURCE_READONLY     0x00002000
+#define IORESOURCE_CACHEABLE    0x00004000
+#define IORESOURCE_RANGELENGTH  0x00008000
+#define IORESOURCE_SHADOWABLE   0x00010000
+
+#define IORESOURCE_SIZEALIGN    0x00020000      /* size indicates alignment */
+#define IORESOURCE_STARTALIGN   0x00040000      /* start field is alignment */
+
+#define IORESOURCE_MEM_64       0x00100000
+
+    /* Userland may not map this resource */
+#define IORESOURCE_EXCLUSIVE    0x08000000
+#define IORESOURCE_DISABLED     0x10000000
+#define IORESOURCE_UNSET        0x20000000
+#define IORESOURCE_AUTO         0x40000000
+    /* Driver has marked this resource busy */
+#define IORESOURCE_BUSY         0x80000000
+
+
+typedef struct HostPCIIORegion {
+    unsigned long flags;
+    pcibus_t base_addr;
+    pcibus_t size;
+} HostPCIIORegion;
+
+typedef struct HostPCIDevice {
+    uint16_t domain;
+    uint8_t bus;
+    uint8_t dev;
+    uint8_t func;
+
+    uint16_t vendor_id;
+    uint16_t device_id;
+
+    HostPCIIORegion io_regions[PCI_NUM_REGIONS - 1];
+    HostPCIIORegion rom;
+
+    bool is_virtfn;
+
+    int config_fd;
+} HostPCIDevice;
+
+HostPCIDevice *host_pci_device_get(uint8_t bus, uint8_t dev, uint8_t func);
+void host_pci_device_put(HostPCIDevice *pci_dev);
+
+int host_pci_get_byte(HostPCIDevice *d, int pos, uint8_t *p);
+int host_pci_get_word(HostPCIDevice *d, int pos, uint16_t *p);
+int host_pci_get_long(HostPCIDevice *d, int pos, uint32_t *p);
+int host_pci_get_block(HostPCIDevice *d, int pos, uint8_t *buf, int len);
+int host_pci_set_byte(HostPCIDevice *d, int pos, uint8_t data);
+int host_pci_set_word(HostPCIDevice *d, int pos, uint16_t data);
+int host_pci_set_long(HostPCIDevice *d, int pos, uint32_t data);
+int host_pci_set_block(HostPCIDevice *d, int pos, uint8_t *buf, int len);
+
+uint32_t host_pci_find_ext_cap_offset(HostPCIDevice *s, uint32_t cap);
+
+#endif /* !HW_HOST_PCI_DEVICE */
