[Qemu-block] [PATCH 11/17] migration: add is_active_iterate handler

[Vladimir Sementsov-Ogievskiy]

Only-postcopy savevm states (dirty-bitmap) don't need live iteration, so
to disable them and stop transporting empty sections there is a new
savevm handler.

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
---
 include/migration/vmstate.h | 1 +
 migration/savevm.c          | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index da62a73..6049deb 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -47,6 +47,7 @@ typedef struct SaveVMHandlers {
     /* This runs both outside and inside the iothread lock.  */
     bool (*is_active)(void *opaque);
     bool (*has_postcopy)(void *opaque);
+    bool (*is_active_iterate)(void *opaque);
 
     /* This runs outside the iothread lock in the migration case, and
      * within the lock in the savevm case.  The callback had better only
diff --git a/migration/savevm.c b/migration/savevm.c
index d1bab59..94783e5 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1034,6 +1034,11 @@ int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy)
                 continue;
             }
         }
+        if (se->ops && se->ops->is_active_iterate) {
+            if (!se->ops->is_active_iterate(se->opaque)) {
+                continue;
+            }
+        }
         /*
          * In the postcopy phase, any device that doesn't know how to
          * do postcopy should have saved it's state in the _complete
-- 
1.8.3.1