Re: [PATCH 1/2] KVM: LAPIC: write 0 to TMICT should also cancel vmx-preemption timer

From: Wanpeng Li
Date: Thu Jun 03 2021 - 20:37:49 EST


On Thu, 3 Jun 2021 at 23:20, Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
>
> On Thu, Jun 03, 2021, Wanpeng Li wrote:
> > 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.
> >
> > The lapic timer oneshot/periodic mode which is emulated by vmx-preemption
> > timer doesn't stop since vmx->hv_deadline_tsc is still set.
>
> But the VMX preemption timer is only used for deadline, never for oneshot or
> periodic. Am I missing something?

Yes, it is upstream.
https://lore.kernel.org/kvm/1477304593-3453-1-git-send-email-wanpeng.li@xxxxxxxxxxx/

Wanpeng