diff --git a/hw/pci.c b/hw/pci.c
index c656bd047c8831d92a96f24367348ae25071ddb4..dc14ead55886ef4d09f55df396fc15e6ee2a26f2 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -98,24 +98,47 @@ static void pci_bus_reset(void *opaque)
     }
 }
 
-PCIBus *pci_register_bus(DeviceState *parent, const char *name,
-                         pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
-                         void *irq_opaque, int devfn_min, int nirq)
+void pci_bus_new_inplace(PCIBus *bus, DeviceState *parent,
+                         const char *name, int devfn_min)
 {
-    PCIBus *bus;
     static int nbus = 0;
 
-    bus = FROM_QBUS(PCIBus, qbus_create(&pci_bus_info, parent, name));
-    bus->set_irq = set_irq;
-    bus->map_irq = map_irq;
-    bus->irq_opaque = irq_opaque;
+    qbus_create_inplace(&bus->qbus, &pci_bus_info, parent, name);
     bus->devfn_min = devfn_min;
-    bus->nirq = nirq;
-    bus->irq_count = qemu_mallocz(nirq * sizeof(bus->irq_count[0]));
     bus->next = first_bus;
     first_bus = bus;
     vmstate_register(nbus++, &vmstate_pcibus, bus);
     qemu_register_reset(pci_bus_reset, bus);
+}
+
+PCIBus *pci_bus_new(DeviceState *parent, const char *name, int devfn_min)
+{
+    PCIBus *bus;
+
+    bus = qemu_mallocz(sizeof(*bus));
+    bus->qbus.qdev_allocated = 1;
+    pci_bus_new_inplace(bus, parent, name, devfn_min);
+    return bus;
+}
+
+void pci_bus_irqs(PCIBus *bus, pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
+                  void *irq_opaque, int nirq)
+{
+    bus->set_irq = set_irq;
+    bus->map_irq = map_irq;
+    bus->irq_opaque = irq_opaque;
+    bus->nirq = nirq;
+    bus->irq_count = qemu_mallocz(nirq * sizeof(bus->irq_count[0]));
+}
+
+PCIBus *pci_register_bus(DeviceState *parent, const char *name,
+                         pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
+                         void *irq_opaque, int devfn_min, int nirq)
+{
+    PCIBus *bus;
+
+    bus = pci_bus_new(parent, name, devfn_min);
+    pci_bus_irqs(bus, set_irq, map_irq, irq_opaque, nirq);
     return bus;
 }
 
diff --git a/hw/pci.h b/hw/pci.h
index ba748ff9cda2166b65767d0607313099a9e4a82c..c5c8c570d707edafbd76b4ebe64758cd49879a6f 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -248,6 +248,11 @@ int pci_device_load(PCIDevice *s, QEMUFile *f);
 
 typedef void (*pci_set_irq_fn)(void *opaque, int irq_num, int level);
 typedef int (*pci_map_irq_fn)(PCIDevice *pci_dev, int irq_num);
+void pci_bus_new_inplace(PCIBus *bus, DeviceState *parent,
+                         const char *name, int devfn_min);
+PCIBus *pci_bus_new(DeviceState *parent, const char *name, int devfn_min);
+void pci_bus_irqs(PCIBus *bus, pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
+                  void *irq_opaque, int nirq);
 PCIBus *pci_register_bus(DeviceState *parent, const char *name,
                          pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
                          void *irq_opaque, int devfn_min, int nirq);