diff --git a/memory.c b/memory.c index 8ee3c81862..3f6dd40303 100644 --- a/memory.c +++ b/memory.c @@ -967,22 +967,37 @@ static void flatviews_reset(void) static void address_space_set_flatview(AddressSpace *as) { - FlatView *old_view = address_space_get_flatview(as); + FlatView *old_view = address_space_to_flatview(as); MemoryRegion *physmr = memory_region_get_flatview_root(as->root); FlatView *new_view = g_hash_table_lookup(flat_views, physmr); assert(new_view); + if (old_view == new_view) { + return; + } + + if (old_view) { + flatview_ref(old_view); + } + flatview_ref(new_view); if (!QTAILQ_EMPTY(&as->listeners)) { - address_space_update_topology_pass(as, old_view, new_view, false); - address_space_update_topology_pass(as, old_view, new_view, true); + FlatView tmpview = { .nr = 0 }, *old_view2 = old_view; + + if (!old_view2) { + old_view2 = &tmpview; + } + address_space_update_topology_pass(as, old_view2, new_view, false); + address_space_update_topology_pass(as, old_view2, new_view, true); } /* Writes are protected by the BQL. */ atomic_rcu_set(&as->current_map, new_view); - flatview_unref(old_view); + if (old_view) { + flatview_unref(old_view); + } /* Note that all the old MemoryRegions are still alive up to this * point. This relieves most MemoryListeners from the need to @@ -990,7 +1005,9 @@ static void address_space_set_flatview(AddressSpace *as) * outside the iothread mutex, in which case precise reference * counting is necessary. */ - flatview_unref(old_view); + if (old_view) { + flatview_unref(old_view); + } } void memory_region_transaction_begin(void) @@ -2708,7 +2725,7 @@ void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name) as->ref_count = 1; as->root = root; as->malloced = false; - as->current_map = flatview_new(root); + as->current_map = NULL; as->ioeventfd_nb = 0; as->ioeventfds = NULL; QTAILQ_INIT(&as->listeners);