memory: Introduce replay_discarded callback for RamDiscardManager

Introduce replay_discarded callback similar to our existing
replay_populated callback, to be used my migration code to never migrate
discarded memory.

Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 04280450c9..20f1b27377 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -550,6 +550,7 @@ static inline void ram_discard_listener_init(RamDiscardListener *rdl,
 }
 
 typedef int (*ReplayRamPopulate)(MemoryRegionSection *section, void *opaque);
+typedef void (*ReplayRamDiscard)(MemoryRegionSection *section, void *opaque);
 
 /*
  * RamDiscardManagerClass:
@@ -639,6 +640,21 @@ struct RamDiscardManagerClass {
                             ReplayRamPopulate replay_fn, void *opaque);
 
     /**
+     * @replay_discarded:
+     *
+     * Call the #ReplayRamDiscard callback for all discarded parts within the
+     * #MemoryRegionSection via the #RamDiscardManager.
+     *
+     * @rdm: the #RamDiscardManager
+     * @section: the #MemoryRegionSection
+     * @replay_fn: the #ReplayRamDiscard callback
+     * @opaque: pointer to forward to the callback
+     */
+    void (*replay_discarded)(const RamDiscardManager *rdm,
+                             MemoryRegionSection *section,
+                             ReplayRamDiscard replay_fn, void *opaque);
+
+    /**
      * @register_listener:
      *
      * Register a #RamDiscardListener for the given #MemoryRegionSection and
@@ -682,6 +698,11 @@ int ram_discard_manager_replay_populated(const RamDiscardManager *rdm,
                                          ReplayRamPopulate replay_fn,
                                          void *opaque);
 
+void ram_discard_manager_replay_discarded(const RamDiscardManager *rdm,
+                                          MemoryRegionSection *section,
+                                          ReplayRamDiscard replay_fn,
+                                          void *opaque);
+
 void ram_discard_manager_register_listener(RamDiscardManager *rdm,
                                            RamDiscardListener *rdl,
                                            MemoryRegionSection *section);