Re: [PATCH] KVM: LAPIC: Also cancel preemption timer when disarm LAPIC timer

[Wanpeng Li]

On Tue, 24 Mar 2020 at 23:24, Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> wrote:
>
> Wanpeng Li <kernellwp@xxxxxxxxx> writes:
>
> > From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> >
> > The timer is disarmed when switching between TSC deadline and other modes,
> > we should set everything to disarmed state, however, LAPIC timer can be
> > emulated by preemption timer, it still works if vmx->hv_deadline_timer is
> > not -1. This patch also cancels preemption timer when disarm LAPIC timer.
> >
> > Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> > ---
> >  arch/x86/kvm/lapic.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> > index 338de38..a38f1a8 100644
> > --- a/arch/x86/kvm/lapic.c
> > +++ b/arch/x86/kvm/lapic.c
> > @@ -1445,6 +1445,8 @@ static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
> >       }
> >  }
> >
> > +static void cancel_hv_timer(struct kvm_lapic *apic);
> > +
>
> Nitpick: cancel_hv_timer() is only 4 lines long so I'd suggest we move
> it instead of adding a forward declaration.

There are other preemption timer operations like start_hv_timer etc
around cancel_hv_timer, so it is not that suitable to move directly.

    Wanpeng