Commit 89e46eb4 authored Feb 27, 2018 by Pavel Dovgalyuk Committed by Paolo Bonzini Mar 12, 2018

replay: don't process async events when warping the clock



Virtual clock is warped from iothread and vcpu thread. When the hardware
events associated with warp checkpoint, then interrupt delivering may be
non-deterministic if checkpoint is processed in different threads in record
and replay.
This patch disables event processing for clock warp checkpoint and leaves
all hardware events to other checkpoints (e.g., virtual clock).

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20180227095316.1060.4134.stgit@pasha-VirtualBox>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>

parent 821c1130

replay/replay-events.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -205,6 +205,7 @@ static void replay_save_event(Event *event, int checkpoint)
		void replay_save_events(int checkpoint)
		{
		g_assert(replay_mutex_locked());
		g_assert(checkpoint != CHECKPOINT_CLOCK_WARP_START);
		while (!QTAILQ_EMPTY(&events_list)) {
		Event *event = QTAILQ_FIRST(&events_list);
		replay_save_event(event, checkpoint);

replay/replay.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -211,7 +211,12 @@ bool replay_checkpoint(ReplayCheckpoint checkpoint)
		} else if (replay_mode == REPLAY_MODE_RECORD) {
		g_assert(replay_mutex_locked());
		replay_put_event(EVENT_CHECKPOINT + checkpoint);
		/* This checkpoint belongs to several threads.
		Processing events from different threads is
		non-deterministic */
		if (checkpoint != CHECKPOINT_CLOCK_WARP_START) {
		replay_save_events(checkpoint);
		}
		res = true;
		}
		out: