Re: [PATCH v2 1/2] KVM: LAPIC: Disarm LAPIC timer includes pending timer around TSC deadline switch

From: Wanpeng Li
Date: Thu May 19 2022 - 04:51:31 EST


ping,
On Wed, 11 May 2022 at 10:39, Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
>
> From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
>
> The timer is disarmed when switching between TSC deadline and other modes,
> however, the pending timer is still in-flight, so let's accurately set
> everything to a disarmed state, this patch does it by clearing pending
> when canceling the timer.
>
> Fixes: 4427593258 (KVM: x86: thoroughly disarm LAPIC timer around TSC deadline switch)
> Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> ---
> v1 -> v2:
> * clear pending in cancel_apic_timer
>
> arch/x86/kvm/lapic.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 66b0eb0bda94..6268880c8eed 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1548,6 +1548,7 @@ static void cancel_apic_timer(struct kvm_lapic *apic)
> if (apic->lapic_timer.hv_timer_in_use)
> cancel_hv_timer(apic);
> preempt_enable();
> + atomic_set(&apic->lapic_timer.pending, 0);
> }
>
> static void apic_update_lvtt(struct kvm_lapic *apic)
> --
> 2.25.1
>