[Qemu-devel] [5024] APIC: Do not start zero-period timers (Jan Kiszka)

[Qemu-devel] [5024] APIC: Do not start zero-period timers (Jan Kiszka)

[Anthony Liguori]

Revision: 5024
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5024
Author:   aliguori
Date:     2008-08-18 14:19:42 +0000 (Mon, 18 Aug 2008)

Log Message:
-----------
APIC: Do not start zero-period timers (Jan Kiszka)

The APIC timer must not start when the initial count is (still) zero.

This caused occasional stalls when booting secondary CPUs of Linux SMP
guests.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

Modified Paths:
--------------
    trunk/hw/apic.c

Modified: trunk/hw/apic.c
===================================================================
--- trunk/hw/apic.c	2008-08-18 14:00:20 UTC (rev 5023)
+++ trunk/hw/apic.c	2008-08-18 14:19:42 UTC (rev 5024)
@@ -566,6 +566,8 @@
         d = (current_time - s->initial_count_load_time) >>
             s->count_shift;
         if (s->lvt[APIC_LVT_TIMER] & APIC_LVT_TIMER_PERIODIC) {
+            if (!s->initial_count)
+                goto no_timer;
             d = ((d / ((uint64_t)s->initial_count + 1)) + 1) * ((uint64_t)s->initial_count + 1);
         } else {
             if (d >= s->initial_count)