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memory: Do not allocate FlatView in address_space_init 

This creates a new AS object without any FlatView as
memory_region_transaction_commit() may want to reuse the empty FV.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20170921085110.25598-14-aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Alexey Kardashevskiy 2017-09-21 18:51:05 +10:00 committed by Paolo Bonzini
parent 967dc9b119
commit 67ace39b25
1 changed files with 23 additions and 6 deletions
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29
memory.c
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@ -967,22 +967,37 @@ static void flatviews_reset(void)
static void address_space_set_flatview(AddressSpace *as) 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); MemoryRegion *physmr = memory_region_get_flatview_root(as->root);
FlatView *new_view = g_hash_table_lookup(flat_views, physmr); FlatView *new_view = g_hash_table_lookup(flat_views, physmr);
assert(new_view); assert(new_view);
if (old_view == new_view) {
return;
}
if (old_view) {
flatview_ref(old_view);
}
flatview_ref(new_view); flatview_ref(new_view);
if (!QTAILQ_EMPTY(&as->listeners)) { if (!QTAILQ_EMPTY(&as->listeners)) {
address_space_update_topology_pass(as, old_view, new_view, false); FlatView tmpview = { .nr = 0 }, *old_view2 = old_view;
address_space_update_topology_pass(as, old_view, new_view, true);
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. */ /* Writes are protected by the BQL. */
atomic_rcu_set(&as->current_map, new_view); 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 /* Note that all the old MemoryRegions are still alive up to this
* point. This relieves most MemoryListeners from the need to * 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 * outside the iothread mutex, in which case precise reference
* counting is necessary. * counting is necessary.
*/ */
flatview_unref(old_view); if (old_view) {
flatview_unref(old_view);
}
} }
void memory_region_transaction_begin(void) 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->ref_count = 1;
as->root = root; as->root = root;
as->malloced = false; as->malloced = false;
as->current_map = flatview_new(root); as->current_map = NULL;
as->ioeventfd_nb = 0; as->ioeventfd_nb = 0;
as->ioeventfds = NULL; as->ioeventfds = NULL;
QTAILQ_INIT(&as->listeners); QTAILQ_INIT(&as->listeners);