[Qemu-devel] Re: [PATCH, RFC] qemu-timer: fix alarm_timer pending

[Paolo Bonzini <pbonzini@redhat.com>]

On 03/19/2010 06:24 AM, TeLeMan wrote:
> I fetched the lastest qemu-timer codes and found qemu would have no
> response when the guest os was WinXP and the timer was "dynticks" on
> the win32 host.  After qemu froze, it seemed the win32_rearm_timer()
> would never be called and alarm_timer->pending was always 0.
> I could not find the more deeper reason and just referred to the
> previous implement to make this patch.

Interesting, it ran fine for me under Wine.

I can see why the patch you have works, but I don't think it's 100% 
correct.  alarm_timer->pending should remain 1 until qemu_run_all_timers 
runs.  Can you test this one instead:

diff --git a/qemu-timer.c b/qemu-timer.c
index 329d3a4..49eac86 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -706,14 +706,14 @@ void configure_icount(const char *option)

  void qemu_run_all_timers(void)
  {
+    alarm_timer->pending = 0;
+
      /* rearm timer, if not periodic */
      if (alarm_timer->expired) {
          alarm_timer->expired = 0;
          qemu_rearm_alarm_timer(alarm_timer);
      }

-    alarm_timer->pending = 0;
-
      /* vm time timers */
      if (vm_running) {
          qemu_run_timers(vm_clock);


If it doesn't work, I'm fine with TeLeMan's patch.

Paolo