diff options
| -rw-r--r-- | include/exec/memory.h | 18 | ||||
| -rw-r--r-- | memory.c | 27 |
2 files changed, 45 insertions, 0 deletions
diff --git a/include/exec/memory.h b/include/exec/memory.h index 01f10049c1..c92734ae2b 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -241,6 +241,8 @@ struct AddressSpace { struct rcu_head rcu; char *name; MemoryRegion *root; + int ref_count; + bool malloced; /* Accessed via RCU. */ struct FlatView *current_map; @@ -1189,6 +1191,22 @@ MemTxResult memory_region_dispatch_write(MemoryRegion *mr, */ void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name); +/** + * address_space_init_shareable: return an address space for a memory region, + * creating it if it does not already exist + * + * @root: a #MemoryRegion that routes addresses for the address space + * @name: an address space name. The name is only used for debugging + * output. + * + * This function will return a pointer to an existing AddressSpace + * which was initialized with the specified MemoryRegion, or it will + * create and initialize one if it does not already exist. The ASes + * are reference-counted, so the memory will be freed automatically + * when the AddressSpace is destroyed via address_space_destroy. + */ +AddressSpace *address_space_init_shareable(MemoryRegion *root, + const char *name); /** * address_space_destroy: destroy an address space @@ -2124,7 +2124,9 @@ void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name) { memory_region_ref(root); memory_region_transaction_begin(); + as->ref_count = 1; as->root = root; + as->malloced = false; as->current_map = g_new(FlatView, 1); flatview_init(as->current_map); as->ioeventfd_nb = 0; @@ -2139,6 +2141,7 @@ void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name) static void do_address_space_destroy(AddressSpace *as) { MemoryListener *listener; + bool do_free = as->malloced; address_space_destroy_dispatch(as); @@ -2150,12 +2153,36 @@ static void do_address_space_destroy(AddressSpace *as) g_free(as->name); g_free(as->ioeventfds); memory_region_unref(as->root); + if (do_free) { + g_free(as); + } +} + +AddressSpace *address_space_init_shareable(MemoryRegion *root, const char *name) +{ + AddressSpace *as; + + QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) { + if (root == as->root && as->malloced) { + as->ref_count++; + return as; + } + } + + as = g_malloc0(sizeof *as); + address_space_init(as, root, name); + as->malloced = true; + return as; } void address_space_destroy(AddressSpace *as) { MemoryRegion *root = as->root; + as->ref_count--; + if (as->ref_count) { + return; + } /* Flush out anything from MemoryListeners listening in on this */ memory_region_transaction_begin(); as->root = NULL; |