replay: don't process events at virtual clock checkpoint

As QEMU becomes more multi-threaded and non-synchronized, checkpoints
move from thread to thread. And the event queue that processed at checkpoints
should belong to the same thread in both record and replay executions.
This patch disables asynchronous event processing at virtual clock
checkpoint, because it may be invoked in different threads at record and
replay. This patch is temporary fix until the checkpoints are completely
refactored.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Message-Id: <20181018063345.7433.11678.stgit@pasha-VirtualBox>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/replay/replay-events.c b/replay/replay-events.c
index 0964a8283887697c09bae508364dffa6dca148c4..d9a2d495b92e0386644fc71b98b782bbd0b368c7 100644 (file)
--- a/replay/replay-events.c
+++ b/replay/replay-events.c
@@ -190,6 +190,7 @@ void replay_save_events(int checkpoint)
 {
     g_assert(replay_mutex_locked());
     g_assert(checkpoint != CHECKPOINT_CLOCK_WARP_START);
+    g_assert(checkpoint != CHECKPOINT_CLOCK_VIRTUAL);
     while (!QTAILQ_EMPTY(&events_list)) {
         Event *event = QTAILQ_FIRST(&events_list);
         replay_save_event(event, checkpoint);

diff --git a/replay/replay.c b/replay/replay.c
index 379b51ab46f13e354e3d1479c7bed471b3a8ae4f..8b172b2d1bee57a0ae533b4fcc856b471655fb9d 100644 (file)
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -214,7 +214,14 @@ bool replay_checkpoint(ReplayCheckpoint checkpoint)
         /* This checkpoint belongs to several threads.
            Processing events from different threads is
            non-deterministic */
-        if (checkpoint != CHECKPOINT_CLOCK_WARP_START) {
+        if (checkpoint != CHECKPOINT_CLOCK_WARP_START
+            /* FIXME: this is temporary fix, other checkpoints
+                      may also be invoked from the different threads someday.
+                      Asynchronous event processing should be refactored
+                      to create additional replay event kind which is
+                      nailed to the one of the threads and which processes
+                      the event queue. */
+            && checkpoint != CHECKPOINT_CLOCK_VIRTUAL) {
             replay_save_events(checkpoint);
         }
         res = true;