diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index b48047f50c..34a9736b5e 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -32,6 +32,7 @@
 #include "hw/i386/pc.h"
 #include "hw/i386/apic.h"
 #include "hw/pci-host/i440fx.h"
+#include "hw/rtc/mc146818rtc.h"
 #include "hw/southbridge/piix.h"
 #include "hw/display/ramfb.h"
 #include "hw/firmware/smbios.h"
@@ -40,16 +41,16 @@
 #include "hw/usb.h"
 #include "net/net.h"
 #include "hw/ide/pci.h"
-#include "hw/ide/piix.h"
 #include "hw/irq.h"
 #include "sysemu/kvm.h"
 #include "hw/kvm/clock.h"
 #include "hw/sysbus.h"
+#include "hw/i2c/i2c.h"
 #include "hw/i2c/smbus_eeprom.h"
 #include "hw/xen/xen-x86.h"
+#include "hw/xen/xen.h"
 #include "exec/memory.h"
 #include "hw/acpi/acpi.h"
-#include "hw/acpi/piix4.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "sysemu/xen.h"
@@ -66,6 +67,7 @@
 #include "kvm/kvm-cpu.h"
 
 #define MAX_IDE_BUS 2
+#define XEN_IOAPIC_NUM_PIRQS 128ULL
 
 #ifdef CONFIG_IDE_ISA
 static const int ide_iobase[MAX_IDE_BUS] = { 0x1f0, 0x170 };
@@ -73,6 +75,32 @@ static const int ide_iobase2[MAX_IDE_BUS] = { 0x3f6, 0x376 };
 static const int ide_irq[MAX_IDE_BUS] = { 14, 15 };
 #endif
 
+/*
+ * Return the global irq number corresponding to a given device irq
+ * pin. We could also use the bus number to have a more precise mapping.
+ */
+static int pci_slot_get_pirq(PCIDevice *pci_dev, int pci_intx)
+{
+    int slot_addend;
+    slot_addend = PCI_SLOT(pci_dev->devfn) - 1;
+    return (pci_intx + slot_addend) & 3;
+}
+
+static void piix_intx_routing_notifier_xen(PCIDevice *dev)
+{
+    int i;
+
+    /* Scan for updates to PCI link routes (0x60-0x63). */
+    for (i = 0; i < PIIX_NUM_PIRQS; i++) {
+        uint8_t v = dev->config_read(dev, PIIX_PIRQCA + i, 1);
+        if (v & 0x80) {
+            v = 0;
+        }
+        v &= 0xf;
+        xen_set_pci_link_route(i, v);
+    }
+}
+
 /* PC hardware initialisation */
 static void pc_init1(MachineState *machine,
                      const char *host_type, const char *pci_type)
@@ -84,7 +112,7 @@ static void pc_init1(MachineState *machine,
     MemoryRegion *system_io = get_system_io();
     PCIBus *pci_bus;
     ISABus *isa_bus;
-    int piix3_devfn = -1;
+    Object *piix4_pm;
     qemu_irq smi_irq;
     GSIState *gsi_state;
     BusState *idebus[MAX_IDE_BUS];
@@ -205,10 +233,9 @@ static void pc_init1(MachineState *machine,
     gsi_state = pc_gsi_create(&x86ms->gsi, pcmc->pci_enabled);
 
     if (pcmc->pci_enabled) {
-        PIIX3State *piix3;
+        DeviceState *dev;
         PCIDevice *pci_dev;
-        const char *type = xen_enabled() ? TYPE_PIIX3_XEN_DEVICE
-                                         : TYPE_PIIX3_DEVICE;
+        int i;
 
         pci_bus = i440fx_init(pci_type,
                               i440fx_host,
@@ -216,21 +243,65 @@ static void pc_init1(MachineState *machine,
                               x86ms->below_4g_mem_size,
                               x86ms->above_4g_mem_size,
                               pci_memory, ram_memory);
+        pci_bus_map_irqs(pci_bus,
+                         xen_enabled() ? xen_pci_slot_get_pirq
+                                       : pci_slot_get_pirq);
         pcms->bus = pci_bus;
 
-        pci_dev = pci_create_simple_multifunction(pci_bus, -1, true, type);
-        piix3 = PIIX3_PCI_DEVICE(pci_dev);
-        piix3->pic = x86ms->gsi;
-        piix3_devfn = piix3->dev.devfn;
-        isa_bus = ISA_BUS(qdev_get_child_bus(DEVICE(piix3), "isa.0"));
+        pci_dev = pci_new_multifunction(-1, true, TYPE_PIIX3_DEVICE);
+        object_property_set_bool(OBJECT(pci_dev), "has-usb",
+                                 machine_usb(machine), &error_abort);
+        object_property_set_bool(OBJECT(pci_dev), "has-acpi",
+                                 x86_machine_is_acpi_enabled(x86ms),
+                                 &error_abort);
+        qdev_prop_set_uint32(DEVICE(pci_dev), "smb_io_base", 0xb100);
+        object_property_set_bool(OBJECT(pci_dev), "smm-enabled",
+                                 x86_machine_is_smm_enabled(x86ms),
+                                 &error_abort);
+        pci_realize_and_unref(pci_dev, pci_bus, &error_fatal);
+
+        if (xen_enabled()) {
+            pci_device_set_intx_routing_notifier(
+                        pci_dev, piix_intx_routing_notifier_xen);
+
+            /*
+             * Xen supports additional interrupt routes from the PCI devices to
+             * the IOAPIC: the four pins of each PCI device on the bus are also
+             * connected to the IOAPIC directly.
+             * These additional routes can be discovered through ACPI.
+             */
+            pci_bus_irqs(pci_bus, xen_intx_set_irq, pci_dev,
+                         XEN_IOAPIC_NUM_PIRQS);
+        }
+
+        dev = DEVICE(object_resolve_path_component(OBJECT(pci_dev), "pic"));
+        for (i = 0; i < ISA_NUM_IRQS; i++) {
+            qdev_connect_gpio_out(dev, i, x86ms->gsi[i]);
+        }
+        isa_bus = ISA_BUS(qdev_get_child_bus(DEVICE(pci_dev), "isa.0"));
+        rtc_state = ISA_DEVICE(object_resolve_path_component(OBJECT(pci_dev),
+                                                             "rtc"));
+        piix4_pm = object_resolve_path_component(OBJECT(pci_dev), "pm");
+        dev = DEVICE(object_resolve_path_component(OBJECT(pci_dev), "ide"));
+        pci_ide_create_devs(PCI_DEVICE(dev));
+        idebus[0] = qdev_get_child_bus(dev, "ide.0");
+        idebus[1] = qdev_get_child_bus(dev, "ide.1");
     } else {
         pci_bus = NULL;
+        piix4_pm = NULL;
         isa_bus = isa_bus_new(NULL, get_system_memory(), system_io,
                               &error_abort);
+        isa_bus_irqs(isa_bus, x86ms->gsi);
+
+        rtc_state = isa_new(TYPE_MC146818_RTC);
+        qdev_prop_set_int32(DEVICE(rtc_state), "base_year", 2000);
+        isa_realize_and_unref(rtc_state, isa_bus, &error_fatal);
+
         i8257_dma_init(isa_bus, 0);
         pcms->hpet_enabled = false;
+        idebus[0] = NULL;
+        idebus[1] = NULL;
     }
-    isa_bus_irqs(isa_bus, x86ms->gsi);
 
     if (x86ms->pic == ON_OFF_AUTO_ON || x86ms->pic == ON_OFF_AUTO_AUTO) {
         pc_i8259_create(isa_bus, gsi_state->i8259_irq);
@@ -252,18 +323,12 @@ static void pc_init1(MachineState *machine,
     }
 
     /* init basic PC hardware */
-    pc_basic_device_init(pcms, isa_bus, x86ms->gsi, &rtc_state, true,
+    pc_basic_device_init(pcms, isa_bus, x86ms->gsi, rtc_state, true,
                          0x4);
 
     pc_nic_init(pcmc, isa_bus, pci_bus);
 
     if (pcmc->pci_enabled) {
-        PCIDevice *dev;
-
-        dev = pci_create_simple(pci_bus, piix3_devfn + 1, TYPE_PIIX3_IDE);
-        pci_ide_create_devs(dev);
-        idebus[0] = qdev_get_child_bus(&dev->qdev, "ide.0");
-        idebus[1] = qdev_get_child_bus(&dev->qdev, "ide.1");
         pc_cmos_init(pcms, idebus[0], idebus[1], rtc_state);
     }
 #ifdef CONFIG_IDE_ISA
@@ -289,21 +354,9 @@ static void pc_init1(MachineState *machine,
     }
 #endif
 
-    if (pcmc->pci_enabled && machine_usb(machine)) {
-        pci_create_simple(pci_bus, piix3_devfn + 2, "piix3-usb-uhci");
-    }
-
-    if (pcmc->pci_enabled && x86_machine_is_acpi_enabled(X86_MACHINE(pcms))) {
-        PCIDevice *piix4_pm;
-
+    if (piix4_pm) {
         smi_irq = qemu_allocate_irq(pc_acpi_smi_interrupt, first_cpu, 0);
-        piix4_pm = pci_new(piix3_devfn + 3, TYPE_PIIX4_PM);
-        qdev_prop_set_uint32(DEVICE(piix4_pm), "smb_io_base", 0xb100);
-        qdev_prop_set_bit(DEVICE(piix4_pm), "smm-enabled",
-                          x86_machine_is_smm_enabled(x86ms));
-        pci_realize_and_unref(piix4_pm, pci_bus, &error_fatal);
 
-        qdev_connect_gpio_out(DEVICE(piix4_pm), 0, x86ms->gsi[9]);
         qdev_connect_gpio_out_named(DEVICE(piix4_pm), "smi-irq", 0, smi_irq);
         pcms->smbus = I2C_BUS(qdev_get_child_bus(DEVICE(piix4_pm), "i2c"));
         /* TODO: Populate SPD eeprom data.  */
@@ -315,7 +368,7 @@ static void pc_init1(MachineState *machine,
                                  object_property_allow_set_link,
                                  OBJ_PROP_LINK_STRONG);
         object_property_set_link(OBJECT(machine), PC_MACHINE_ACPI_DEVICE_PROP,
-                                 OBJECT(piix4_pm), &error_abort);
+                                 piix4_pm, &error_abort);
     }
 
     if (machine->nvdimms_state->is_enabled) {
@@ -405,6 +458,9 @@ static void pc_xen_hvm_init(MachineState *machine)
     }
 
     pc_xen_hvm_init_pci(machine);
+    if (xen_igd_gfx_pt_enabled()) {
+        xen_igd_reserve_slot(pcms->bus);
+    }
     pci_create_simple(pcms->bus, -1, "xen-platform");
 }
 #endif
@@ -441,6 +497,11 @@ static void pc_i440fx_8_0_machine_options(MachineClass *m)
     pc_i440fx_machine_options(m);
     m->alias = "pc";
     m->is_default = true;
+#ifdef CONFIG_MICROVM_DEFAULT
+    m->is_default = false;
+#else
+    m->is_default = true;
+#endif
 }
 
 DEFINE_I440FX_MACHINE(v8_0, "pc-i440fx-8.0", NULL,
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index 0ec7e52183..eff38155ef 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -780,15 +780,6 @@ static void xen_pt_realize(PCIDevice *d, Error **errp)
                s->hostaddr.bus, s->hostaddr.slot, s->hostaddr.function,
                s->dev.devfn);
 
-    xen_host_pci_device_get(&s->real_device,
-                            s->hostaddr.domain, s->hostaddr.bus,
-                            s->hostaddr.slot, s->hostaddr.function,
-                            errp);
-    if (*errp) {
-        error_append_hint(errp, "Failed to \"open\" the real pci device");
-        return;
-    }
-
     s->is_virtfn = s->real_device.is_virtfn;
     if (s->is_virtfn) {
         XEN_PT_LOG(d, "%04x:%02x:%02x.%d is a SR-IOV Virtual Function\n",
@@ -950,11 +941,50 @@ static void xen_pci_passthrough_instance_init(Object *obj)
     PCI_DEVICE(obj)->cap_present |= QEMU_PCI_CAP_EXPRESS;
 }
 
+void xen_igd_reserve_slot(PCIBus *pci_bus)
+{
+    XEN_PT_LOG(0, "Reserving PCI slot 2 for IGD\n");
+    pci_bus->slot_reserved_mask |= XEN_PCI_IGD_SLOT_MASK;
+}
+
+static void xen_igd_clear_slot(DeviceState *qdev, Error **errp)
+{
+    ERRP_GUARD();
+    PCIDevice *pci_dev = (PCIDevice *)qdev;
+    XenPCIPassthroughState *s = XEN_PT_DEVICE(pci_dev);
+    XenPTDeviceClass *xpdc = XEN_PT_DEVICE_GET_CLASS(s);
+    PCIBus *pci_bus = pci_get_bus(pci_dev);
+
+    if (!(pci_bus->slot_reserved_mask & XEN_PCI_IGD_SLOT_MASK))
+        return;
+
+    xen_host_pci_device_get(&s->real_device,
+                            s->hostaddr.domain, s->hostaddr.bus,
+                            s->hostaddr.slot, s->hostaddr.function,
+                            errp);
+    if (*errp) {
+        error_append_hint(errp, "Failed to \"open\" the real pci device");
+        return;
+    }
+
+    if (is_igd_vga_passthrough(&s->real_device) &&
+        s->real_device.domain == 0 && s->real_device.bus == 0 &&
+        s->real_device.dev == 2 && s->real_device.func == 0 &&
+        s->real_device.vendor_id == PCI_VENDOR_ID_INTEL) {
+        pci_bus->slot_reserved_mask &= ~XEN_PCI_IGD_SLOT_MASK;
+        XEN_PT_LOG(pci_dev, "Intel IGD found, using slot 2\n");
+    }
+    xpdc->pci_qdev_realize(qdev, errp);
+}
+
 static void xen_pci_passthrough_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
 
+    XenPTDeviceClass *xpdc = XEN_PT_DEVICE_CLASS(klass);
+    xpdc->pci_qdev_realize = dc->realize;
+    dc->realize = xen_igd_clear_slot;
     k->realize = xen_pt_realize;
     k->exit = xen_pt_unregister_device;
     k->config_read = xen_pt_pci_read_config;
@@ -977,6 +1007,7 @@ static const TypeInfo xen_pci_passthrough_info = {
     .instance_size = sizeof(XenPCIPassthroughState),
     .instance_finalize = xen_pci_passthrough_finalize,
     .class_init = xen_pci_passthrough_class_init,
+    .class_size = sizeof(XenPTDeviceClass),
     .instance_init = xen_pci_passthrough_instance_init,
     .interfaces = (InterfaceInfo[]) {
         { INTERFACE_CONVENTIONAL_PCI_DEVICE },
diff --git a/hw/xen/xen_pt.h b/hw/xen/xen_pt.h
index cf10fc7bbf..8c25932b4b 100644
--- a/hw/xen/xen_pt.h
+++ b/hw/xen/xen_pt.h
@@ -2,6 +2,7 @@
 #define XEN_PT_H
 
 #include "hw/xen/xen_common.h"
+#include "hw/pci/pci_bus.h"
 #include "xen-host-pci-device.h"
 #include "qom/object.h"
 
@@ -40,7 +41,20 @@ typedef struct XenPTReg XenPTReg;
 #define TYPE_XEN_PT_DEVICE "xen-pci-passthrough"
 OBJECT_DECLARE_SIMPLE_TYPE(XenPCIPassthroughState, XEN_PT_DEVICE)
 
+#define XEN_PT_DEVICE_CLASS(klass) \
+    OBJECT_CLASS_CHECK(XenPTDeviceClass, klass, TYPE_XEN_PT_DEVICE)
+#define XEN_PT_DEVICE_GET_CLASS(obj) \
+    OBJECT_GET_CLASS(XenPTDeviceClass, obj, TYPE_XEN_PT_DEVICE)
+
+typedef void (*XenPTQdevRealize)(DeviceState *qdev, Error **errp);
+
+typedef struct XenPTDeviceClass {
+    PCIDeviceClass parent_class;
+    XenPTQdevRealize pci_qdev_realize;
+} XenPTDeviceClass;
+
 uint32_t igd_read_opregion(XenPCIPassthroughState *s);
+void xen_igd_reserve_slot(PCIBus *pci_bus);
 void igd_write_opregion(XenPCIPassthroughState *s, uint32_t val);
 void xen_igd_passthrough_isa_bridge_create(XenPCIPassthroughState *s,
                                            XenHostPCIDevice *dev);
@@ -75,6 +89,8 @@ typedef int (*xen_pt_conf_byte_read)
 
 #define XEN_PCI_INTEL_OPREGION 0xfc
 
+#define XEN_PCI_IGD_SLOT_MASK 0x4UL /* Intel IGD slot_reserved_mask */
+
 typedef enum {
     XEN_PT_GRP_TYPE_HARDWIRED = 0,  /* 0 Hardwired reg group */
     XEN_PT_GRP_TYPE_EMU,            /* emul reg group */
diff --git a/hw/xen/xen_pt_stub.c b/hw/xen/xen_pt_stub.c
index 2d8cac8d54..5c108446a8 100644
--- a/hw/xen/xen_pt_stub.c
+++ b/hw/xen/xen_pt_stub.c
@@ -20,3 +20,7 @@ void xen_igd_gfx_pt_set(bool value, Error **errp)
         error_setg(errp, "Xen PCI passthrough support not built in");
     }
 }
+
+void xen_igd_reserve_slot(PCIBus *pci_bus)
+{
+}
