KVM: Avoid infinite-frequency local apic timer

If the local apic initial count is zero, don't start a an hrtimer with infinite
frequency, locking up the host.

Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2cbee94..68a6b15 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -647,6 +647,10 @@ static void start_apic_timer(struct kvm_lapic *apic)
        apic->timer.period = apic_get_reg(apic, APIC_TMICT) *
                    APIC_BUS_CYCLE_NS * apic->timer.divide_count;
        atomic_set(&apic->timer.pending, 0);
+
+       if (!apic->timer.period)
+               return;
+
        hrtimer_start(&apic->timer.dev,
                      ktime_add_ns(now, apic->timer.period),
                      HRTIMER_MODE_ABS);