memory: support stateless memory listeners

Current memory listeners are incremental; that is, they are expected to
maintain their own state, and receive callbacks for changes to that state.

This patch adds support for stateless listeners; these work by receiving
a ->begin() callback (which tells them that new state is coming), a
sequence of ->region_add() and ->region_nop() callbacks, and then a
->commit() callback which signifies the end of the new state.  They should
ignore ->region_del() callbacks.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/memory.c b/memory.c
index 35e1483..6565e2e 100644
--- a/memory.c
+++ b/memory.c
@@ -676,6 +676,7 @@ static void address_space_update_topology_pass(AddressSpace *as,
             /* In both (logging may have changed) */
 
             if (adding) {
+                MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, region_nop);
                 if (frold->dirty_log_mask && !frnew->dirty_log_mask) {
                     MEMORY_LISTENER_UPDATE_REGION(frnew, as, Reverse, log_stop);
                 } else if (frnew->dirty_log_mask && !frold->dirty_log_mask) {
@@ -722,6 +723,8 @@ static void memory_region_update_topology(MemoryRegion *mr)
         return;
     }
 
+    MEMORY_LISTENER_CALL_GLOBAL(begin, Forward);
+
     if (address_space_memory.root) {
         address_space_update_topology(&address_space_memory);
     }
@@ -729,6 +732,8 @@ static void memory_region_update_topology(MemoryRegion *mr)
         address_space_update_topology(&address_space_io);
     }
 
+    MEMORY_LISTENER_CALL_GLOBAL(commit, Forward);
+
     memory_region_update_pending = false;
 }