diff --git a/hw/pci.c b/hw/pci.c
index b88ed3527bd4502193b0fbafcf119c360c1b9565..5f97afad69faea437141e7170d1127d9c17d9121 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -196,6 +196,48 @@ PCIDevice *pci_register_device(PCIBus *bus, const char *name,
     return pci_dev;
 }
 
+static target_phys_addr_t pci_to_cpu_addr(target_phys_addr_t addr)
+{
+    return addr + pci_mem_base;
+}
+
+static void pci_unregister_io_regions(PCIDevice *pci_dev)
+{
+    PCIIORegion *r;
+    int i;
+
+    for(i = 0; i < PCI_NUM_REGIONS; i++) {
+        r = &pci_dev->io_regions[i];
+        if (!r->size || r->addr == -1)
+            continue;
+        if (r->type == PCI_ADDRESS_SPACE_IO) {
+            isa_unassign_ioport(r->addr, r->size);
+        } else {
+            cpu_register_physical_memory(pci_to_cpu_addr(r->addr),
+                                                     r->size,
+                                                     IO_MEM_UNASSIGNED);
+        }
+    }
+}
+
+int pci_unregister_device(PCIDevice *pci_dev)
+{
+    int ret = 0;
+
+    if (pci_dev->unregister)
+        ret = pci_dev->unregister(pci_dev);
+    if (ret)
+        return ret;
+
+    pci_unregister_io_regions(pci_dev);
+
+    qemu_free_irqs(pci_dev->irq);
+    pci_irq_index--;
+    pci_dev->bus->devices[pci_dev->devfn] = NULL;
+    qemu_free(pci_dev);
+    return 0;
+}
+
 void pci_register_io_region(PCIDevice *pci_dev, int region_num,
                             uint32_t size, int type,
                             PCIMapIORegionFunc *map_func)
@@ -218,11 +260,6 @@ void pci_register_io_region(PCIDevice *pci_dev, int region_num,
     *(uint32_t *)(pci_dev->config + addr) = cpu_to_le32(type);
 }
 
-static target_phys_addr_t pci_to_cpu_addr(target_phys_addr_t addr)
-{
-    return addr + pci_mem_base;
-}
-
 static void pci_update_mappings(PCIDevice *d)
 {
     PCIIORegion *r;
diff --git a/hw/pci.h b/hw/pci.h
index d827d1253c9827f6b3bf3379337e295e16289022..b4341bbc8c303036c483263f00f3df4e0eca073b 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -125,6 +125,7 @@ typedef uint32_t PCIConfigReadFunc(PCIDevice *pci_dev,
                                    uint32_t address, int len);
 typedef void PCIMapIORegionFunc(PCIDevice *pci_dev, int region_num,
                                 uint32_t addr, uint32_t size, int type);
+typedef int PCIUnregisterFunc(PCIDevice *pci_dev);
 
 #define PCI_ADDRESS_SPACE_MEM		0x00
 #define PCI_ADDRESS_SPACE_IO		0x01
@@ -189,6 +190,7 @@ struct PCIDevice {
     /* do not access the following fields */
     PCIConfigReadFunc *config_read;
     PCIConfigWriteFunc *config_write;
+    PCIUnregisterFunc *unregister;
     /* ??? This is a PC-specific hack, and should be removed.  */
     int irq_index;
 
@@ -203,6 +205,7 @@ PCIDevice *pci_register_device(PCIBus *bus, const char *name,
                                int instance_size, int devfn,
                                PCIConfigReadFunc *config_read,
                                PCIConfigWriteFunc *config_write);
+int pci_unregister_device(PCIDevice *pci_dev);
 
 void pci_register_io_region(PCIDevice *pci_dev, int region_num,
                             uint32_t size, int type,