[PATCH] replay: synchronize on every virtual timer callback

[Pavel Dovgalyuk <Pavel.Dovgaluk@gmail.com>]

Sometimes virtual timer callbacks depend on order
of virtual timer processing and warping of virtual clock.
Therefore every callback should be logged to make replay deterministic.
This patch creates a checkpoint before every virtual timer callback.
With these checkpoints virtual timers processing and clock warping
events order is completely deterministic.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
---
 util/qemu-timer.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/util/qemu-timer.c b/util/qemu-timer.c
index d548d3c1ad..47833f338f 100644
--- a/util/qemu-timer.c
+++ b/util/qemu-timer.c
@@ -588,6 +588,11 @@ bool timerlist_run_timers(QEMUTimerList *timer_list)
         qemu_mutex_lock(&timer_list->active_timers_lock);
 
         progress = true;
+        /*
+         * Callback may insert new checkpoints, therefore add new checkpoint
+         * for the virtual timers.
+         */
+        need_replay_checkpoint = timer_list->clock->type == QEMU_CLOCK_VIRTUAL;
     }
     qemu_mutex_unlock(&timer_list->active_timers_lock);