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



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5024 c046a42c-6fe2-441c-8c8c-71466251a162

hw/apic.c

@@ -566,6 +566,8 @@ static void apic_timer_update(APICState *s, int64_t current_time)
         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)