diff --git a/exec.c b/exec.c
index a18f833..0b0118b 100644
--- a/exec.c
+++ b/exec.c
@@ -1827,13 +1827,11 @@ static void memory_map_init(void)
 {
     system_memory = g_malloc(sizeof(*system_memory));
     memory_region_init(system_memory, "system", INT64_MAX);
-    address_space_init(&address_space_memory, system_memory);
-    address_space_memory.name = "memory";
+    address_space_init(&address_space_memory, system_memory, "memory");
 
     system_io = g_malloc(sizeof(*system_io));
     memory_region_init(system_io, "io", 65536);
-    address_space_init(&address_space_io, system_io);
-    address_space_io.name = "I/O";
+    address_space_init(&address_space_io, system_io, "I/O");
 
     memory_listener_register(&core_memory_listener, &address_space_memory);
     memory_listener_register(&io_memory_listener, &address_space_io);
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 104fe71..61b681a 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -814,7 +814,8 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     memory_region_init_alias(&pci_dev->bus_master_enable_region, "bus master",
                              dma_as->root, 0, memory_region_size(dma_as->root));
     memory_region_set_enabled(&pci_dev->bus_master_enable_region, false);
-    address_space_init(&pci_dev->bus_master_as, &pci_dev->bus_master_enable_region);
+    address_space_init(&pci_dev->bus_master_as, &pci_dev->bus_master_enable_region,
+                       name);
 
     pci_dev->devfn = devfn;
     pstrcpy(pci_dev->name, sizeof(pci_dev->name), name);
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 459398c..04e8362 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -650,7 +650,9 @@ static int spapr_phb_init(SysBusDevice *s)
         fprintf(stderr, "Unable to create TCE table for %s\n", sphb->dtbusname);
         return -1;
     }
-    address_space_init(&sphb->iommu_as, spapr_tce_get_iommu(sphb->tcet));
+    address_space_init(&sphb->iommu_as, spapr_tce_get_iommu(sphb->tcet),
+                       sphb->dtbusname);
+
     pci_setup_iommu(bus, spapr_pci_dma_iommu, sphb);
 
     QLIST_INSERT_HEAD(&spapr->phbs, sphb, list);
diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c
index 459c9f2..3c5a655 100644
--- a/hw/ppc/spapr_vio.c
+++ b/hw/ppc/spapr_vio.c
@@ -454,7 +454,7 @@ static int spapr_vio_busdev_init(DeviceState *qdev)
     if (pc->rtce_window_size) {
         uint32_t liobn = SPAPR_VIO_BASE_LIOBN | dev->reg;
         dev->tcet = spapr_tce_new_table(liobn, pc->rtce_window_size);
-        address_space_init(&dev->as, spapr_tce_get_iommu(dev->tcet));
+        address_space_init(&dev->as, spapr_tce_get_iommu(dev->tcet), qdev->id);
     }
 
     return pc->init(dev);
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 75fa2b6..3598c4f 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -192,7 +192,7 @@ struct MemoryRegionPortio {
  */
 struct AddressSpace {
     /* All fields are private. */
-    const char *name;
+    char *name;
     MemoryRegion *root;
     struct FlatView *current_map;
     int ioeventfd_nb;
@@ -892,8 +892,10 @@ void mtree_info(fprintf_function mon_printf, void *f);
  *
  * @as: an uninitialized #AddressSpace
  * @root: a #MemoryRegion that routes addesses for the address space
+ * @name: an address space name.  The name is only used for debugging
+ *        output.
  */
-void address_space_init(AddressSpace *as, MemoryRegion *root);
+void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name);
 
 
 /**
diff --git a/memory.c b/memory.c
index 2a94d7d..8e99b8a 100644
--- a/memory.c
+++ b/memory.c
@@ -1657,7 +1657,7 @@ void memory_listener_unregister(MemoryListener *listener)
     QTAILQ_REMOVE(&memory_listeners, listener, link);
 }
 
-void address_space_init(AddressSpace *as, MemoryRegion *root)
+void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name)
 {
     memory_region_transaction_begin();
     as->root = root;
@@ -1666,7 +1666,7 @@ void address_space_init(AddressSpace *as, MemoryRegion *root)
     as->ioeventfd_nb = 0;
     as->ioeventfds = NULL;
     QTAILQ_INSERT_TAIL(&address_spaces, as, address_spaces_link);
-    as->name = NULL;
+    as->name = g_strdup(name ? name : "anonymous");
     address_space_init_dispatch(as);
     memory_region_update_pending |= root->enabled;
     memory_region_transaction_commit();
@@ -1681,6 +1681,7 @@ void address_space_destroy(AddressSpace *as)
     QTAILQ_REMOVE(&address_spaces, as, address_spaces_link);
     address_space_destroy_dispatch(as);
     flatview_destroy(as->current_map);
+    g_free(as->name);
     g_free(as->current_map);
     g_free(as->ioeventfds);
 }
@@ -1807,9 +1808,6 @@ void mtree_info(fprintf_function mon_printf, void *f)
     QTAILQ_INIT(&ml_head);
 
     QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
-        if (!as->name) {
-            continue;
-        }
         mon_printf(f, "%s\n", as->name);
         mtree_print_mr(mon_printf, f, as->root, 0, 0, &ml_head);
     }
