diff --git a/hw/pci_bridge.c b/hw/pci_bridge.c
index 5c6455f..06f0082 100644
--- a/hw/pci_bridge.c
+++ b/hw/pci_bridge.c
@@ -151,10 +151,14 @@ static void pci_bridge_init_alias(PCIBridge *bridge, MemoryRegion *alias,
     memory_region_add_subregion_overlap(parent_space, base, alias, 1);
 }
 
-static void pci_bridge_cleanup_alias(MemoryRegion *alias,
-                                     MemoryRegion *parent_space)
+static void pci_bridge_remove_alias(MemoryRegion *alias,
+                                    MemoryRegion *parent_space)
 {
     memory_region_del_subregion(parent_space, alias);
+}
+
+static void pci_bridge_destroy_alias(MemoryRegion *alias)
+{
     memory_region_destroy(alias);
 }
 
@@ -187,22 +191,41 @@ static void pci_bridge_region_init(PCIBridge *br)
 static void pci_bridge_region_cleanup(PCIBridge *br)
 {
     PCIBus *parent = br->dev.bus;
-    pci_bridge_cleanup_alias(&br->alias_io,
-                             parent->address_space_io);
-    pci_bridge_cleanup_alias(&br->alias_mem,
-                             parent->address_space_mem);
-    pci_bridge_cleanup_alias(&br->alias_pref_mem,
-                             parent->address_space_mem);
+    pci_bridge_remove_alias(&br->alias_io,
+                            parent->address_space_io);
+    pci_bridge_destroy_alias(&br->alias_io);
+    pci_bridge_remove_alias(&br->alias_mem,
+                            parent->address_space_mem);
+    pci_bridge_destroy_alias(&br->alias_mem);
+    pci_bridge_remove_alias(&br->alias_pref_mem,
+                            parent->address_space_mem);
+    pci_bridge_destroy_alias(&br->alias_pref_mem);
 }
 
 static void pci_bridge_update_mappings(PCIBridge *br)
 {
+    PCIBus *parent = br->dev.bus;
+    MemoryRegion alias_io_old, alias_mem_old, alias_pref_mem_old;
+
+    alias_io_old = br->alias_io;
+    alias_mem_old = br->alias_mem;
+    alias_pref_mem_old = br->alias_pref_mem;
+
     /* Make updates atomic to: handle the case of one VCPU updating the bridge
      * while another accesses an unaffected region. */
     memory_region_transaction_begin();
-    pci_bridge_region_cleanup(br);
+    pci_bridge_remove_alias(&br->alias_io,
+                            parent->address_space_io);
+    pci_bridge_remove_alias(&br->alias_mem,
+                            parent->address_space_mem);
+    pci_bridge_remove_alias(&br->alias_pref_mem,
+                            parent->address_space_mem);
     pci_bridge_region_init(br);
     memory_region_transaction_commit();
+
+    pci_bridge_destroy_alias(&alias_io_old);
+    pci_bridge_destroy_alias(&alias_mem_old);
+    pci_bridge_destroy_alias(&alias_pref_mem_old);
 }
 
 /* default write_config function for PCI-to-PCI bridge */