diff --git a/hw/xen/xen_pt.h b/hw/xen/xen_pt.h
index 4d3a18d..507165c 100644
--- a/hw/xen/xen_pt.h
+++ b/hw/xen/xen_pt.h
@@ -302,5 +302,9 @@ extern int xen_has_gfx_passthru;
 int xen_pt_register_vga_regions(XenHostPCIDevice *dev);
 int xen_pt_unregister_vga_regions(XenHostPCIDevice *dev);
 int xen_pt_setup_vga(XenHostPCIDevice *dev);
+int pci_create_pch(PCIBus *bus);
+void igd_pci_write(PCIDevice *pci_dev, uint32_t config_addr,
+                   uint32_t val, int len);
+uint32_t igd_pci_read(PCIDevice *pci_dev, uint32_t config_addr, int len);
 
 #endif /* !XEN_PT_H */
diff --git a/hw/xen/xen_pt_graphics.c b/hw/xen/xen_pt_graphics.c
index 51b174f..72e30ac 100644
--- a/hw/xen/xen_pt_graphics.c
+++ b/hw/xen/xen_pt_graphics.c
@@ -4,6 +4,7 @@
 #include "xen_pt.h"
 #include "xen-host-pci-device.h"
 #include "hw/xen/xen_backend.h"
+#include "hw/pci/pci_bus.h"
 
 static int is_vga_passthrough(XenHostPCIDevice *dev)
 {
@@ -293,3 +294,161 @@ static int create_pch_isa_bridge(PCIBus *bus, XenHostPCIDevice *hdev)
     XEN_PT_LOG(dev, "Intel PCH ISA bridge created.\n");
     return 0;
 }
+
+int pci_create_pch(PCIBus *bus)
+{
+    XenHostPCIDevice hdev;
+    int r = 0;
+
+    if (!xen_has_gfx_passthru) {
+        return -1;
+    }
+
+    r = xen_host_pci_device_get(&hdev, 0, 0, 0x1f, 0);
+    if (r) {
+        XEN_PT_ERR(NULL, "Failed to find Intel PCH on host\n");
+        goto err;
+    }
+
+    if (hdev.vendor_id == PCI_VENDOR_ID_INTEL) {
+        r = create_pch_isa_bridge(bus, &hdev);
+        if (r) {
+            XEN_PT_ERR(NULL, "Failed to create PCH ISA bridge.\n");
+            goto err;
+        }
+    }
+
+    xen_host_pci_device_put(&hdev);
+
+err:
+    return r;
+}
+
+/*
+ * Currently we just pass this physical host bridge for IGD, 00:02.0.
+ */
+static int is_igd_passthrough(PCIDevice *pci_dev)
+{
+    PCIDevice *f = pci_dev->bus->devices[PCI_DEVFN(2, 0)];
+    if (pci_dev->bus->devices[PCI_DEVFN(2, 0)]) {
+        XenPCIPassthroughState *s = DO_UPCAST(XenPCIPassthroughState, dev, f);
+        return (is_vga_passthrough(&s->real_device)
+                    && (s->real_device.vendor_id == PCI_VENDOR_ID_INTEL));
+    } else {
+        return 0;
+    }
+}
+
+void igd_pci_write(PCIDevice *pci_dev, uint32_t config_addr,
+                   uint32_t val, int len)
+{
+    XenHostPCIDevice dev;
+    int r;
+
+    /* IGD read/write is through the host bridge.
+     * ISA bridge is only for detect purpose. In i915 driver it will
+     * probe ISA bridge to discover the IGD, see comment in i915_drv.c:
+     * intel_detect_pch():
+     * The reason to probe ISA bridge instead of Dev31:Fun0 is to
+     * make graphics device passthrough work easy for VMM, that only
+     * need to expose ISA bridge to let driver know the real hardware
+     * underneath. This is a requirement from virtualization team.
+     */
+
+    assert(pci_dev->devfn == 0x00);
+
+    if (!is_igd_passthrough(pci_dev)) {
+        goto write_default;
+    }
+
+    switch (config_addr) {
+    case 0x58:      /* PAVPC Offset */
+        break;
+    default:
+        /* Just sets the emulated values. */
+        goto write_default;
+    }
+
+    /* Host write */
+    r = xen_host_pci_device_get(&dev, 0, 0, 0, 0);
+    if (r) {
+        XEN_PT_ERR(pci_dev, "Can't get pci_dev_host_bridge\n");
+        abort();
+    }
+
+    r = xen_host_pci_set_block(&dev, config_addr, (uint8_t *)&val, len);
+    if (r) {
+        XEN_PT_ERR(pci_dev, "Can't get pci_dev_host_bridge\n");
+        abort();
+    }
+
+    xen_host_pci_device_put(&dev);
+
+    return;
+
+write_default:
+    pci_default_write_config(pci_dev, config_addr, val, len);
+}
+
+uint32_t igd_pci_read(PCIDevice *pci_dev, uint32_t config_addr, int len)
+{
+    XenHostPCIDevice dev;
+    uint32_t val;
+    int r;
+
+    /* IGD read/write is through the host bridge.
+     * ISA bridge is only for detect purpose. In i915 driver it will
+     * probe ISA bridge to discover the IGD, see comment in i915_drv.c:
+     * intel_detect_pch():
+     * The reason to probe ISA bridge instead of Dev31:Fun0 is to
+     * make graphics device passthrough work easy for VMM, that only
+     * need to expose ISA bridge to let driver know the real hardware
+     * underneath. This is a requirement from virtualization team.
+     */
+    assert(pci_dev->devfn == 0x00);
+
+    if (!is_igd_passthrough(pci_dev)) {
+        goto read_default;
+    }
+
+    switch (config_addr) {
+    case 0x00:        /* vendor id */
+    case 0x02:        /* device id */
+    case 0x08:        /* revision id */
+    case 0x2c:        /* sybsystem vendor id */
+    case 0x2e:        /* sybsystem id */
+    case 0x50:        /* SNB: processor graphics control register */
+    case 0x52:        /* processor graphics control register */
+    case 0xa0:        /* top of memory */
+    case 0xb0:        /* ILK: BSM: should read from dev 2 offset 0x5c */
+    case 0x58:        /* SNB: PAVPC Offset */
+    case 0xa4:        /* SNB: graphics base of stolen memory */
+    case 0xa8:        /* SNB: base of GTT stolen memory */
+        break;
+    default:
+        /* Just gets the emulated values. */
+        goto read_default;
+    }
+
+    /* Host read */
+    r = xen_host_pci_device_get(&dev, 0, 0, 0, 0);
+    if (r) {
+        goto err_out;
+    }
+
+    r = xen_host_pci_get_block(&dev, config_addr, (uint8_t *)&val, len);
+    if (r) {
+        goto err_out;
+    }
+
+    xen_host_pci_device_put(&dev);
+
+    return val;
+
+read_default:
+    return pci_default_read_config(pci_dev, config_addr, len);
+
+err_out:
+    XEN_PT_ERR(pci_dev, "Can't get pci_dev_host_bridge\n");
+    return -1;
+}
