From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
According to the SDM 10.5.4.1:
A write of 0 to the initial-count register effectively stops the local
APIC timer, in both one-shot and periodic mode.
However, the lapic timer oneshot/periodic mode which is emulated by vmx-preemption
timer doesn't stop by writing 0 to TMICT since vmx->hv_deadline_tsc is still
programmed and the guest will receive the spurious timer interrupt later. This
patch fixes it by also cancelling the vmx-preemption timer when writing 0 to
the initial-count register.
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
---
v1 -> v2:
* rename to cancel_apic_timer
* update patch description
arch/x86/kvm/lapic.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 8120e86..6d72d8f 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1494,6 +1494,15 @@ static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
static void cancel_hv_timer(struct kvm_lapic *apic);
+static void cancel_apic_timer(struct kvm_lapic *apic)
+{
+ hrtimer_cancel(&apic->lapic_timer.timer);
+ preempt_disable();
+ if (apic->lapic_timer.hv_timer_in_use)
+ cancel_hv_timer(apic);
+ preempt_enable();
+}
+
static void apic_update_lvtt(struct kvm_lapic *apic)
{
u32 timer_mode = kvm_lapic_get_reg(apic, APIC_LVTT) &
@@ -1502,11 +1511,7 @@ static void apic_update_lvtt(struct kvm_lapic *apic)
if (apic->lapic_timer.timer_mode != timer_mode) {
if (apic_lvtt_tscdeadline(apic) != (timer_mode ==
APIC_LVT_TIMER_TSCDEADLINE)) {
- hrtimer_cancel(&apic->lapic_timer.timer);
- preempt_disable();
- if (apic->lapic_timer.hv_timer_in_use)
- cancel_hv_timer(apic);
- preempt_enable();
+ cancel_apic_timer(apic);
kvm_lapic_set_reg(apic, APIC_TMICT, 0);
apic->lapic_timer.period = 0;
apic->lapic_timer.tscdeadline = 0;
@@ -2092,7 +2097,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
if (apic_lvtt_tscdeadline(apic))
break;
- hrtimer_cancel(&apic->lapic_timer.timer);
+ cancel_apic_timer(apic);
kvm_lapic_set_reg(apic, APIC_TMICT, val);
start_apic_timer(apic);
break;
--
2.7.4
