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Groups > linux.kernel > #1677506
| From | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay |
| Date | 2017-06-29 10:00 +0200 |
| Message-ID | <tXCwP-4ON-29@gated-at.bofh.it> (permalink) |
| References | <tX9XP-bC-3@gated-at.bofh.it> <tXk6S-6H0-5@gated-at.bofh.it> <tXm8F-7TU-1@gated-at.bofh.it> <tXmim-7Xs-19@gated-at.bofh.it> <tXyCR-2nE-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 29/06/2017 05:42, Wanpeng Li wrote:
> So how about something like this?
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index d24c874..900ce86 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1504,21 +1504,26 @@ static void cancel_hv_timer(struct kvm_lapic *apic)
> static bool start_hv_timer(struct kvm_lapic *apic)
> {
> u64 tscdeadline = apic->lapic_timer.tscdeadline;
> + bool need_cancel = apic->lapic_timer.hv_timer_in_use;
> + if (!atomic_read(&apic->lapic_timer.pending) || apic_lvtt_period(apic)) {
> + int r = kvm_x86_ops->set_hv_timer(apic->vcpu, tscdeadline);
> + if (r >= 0) {
> + need_cancel = false;
> + apic->lapic_timer.hv_timer_in_use = true;
> + hrtimer_cancel(&apic->lapic_timer.timer);
> +
> + /* In case the sw timer triggered in the window */
> + if (atomic_read(&apic->lapic_timer.pending) &&
> + !apic_lvtt_period(apic))
> + need_cancel = true;
> + else if (r && (apic_lvtt_oneshot(apic) ||
> apic_lvtt_tscdeadline(apic)))
> + apic_timer_expired(apic);
> + }
> + }
>
> - if ((atomic_read(&apic->lapic_timer.pending) &&
> - !apic_lvtt_period(apic)) ||
> - kvm_x86_ops->set_hv_timer(apic->vcpu, tscdeadline)) {
> - if (apic->lapic_timer.hv_timer_in_use)
> - cancel_hv_timer(apic);
> - } else {
> - apic->lapic_timer.hv_timer_in_use = true;
> - hrtimer_cancel(&apic->lapic_timer.timer);
> + if (need_cancel)
> + cancel_hv_timer(apic);
>
> - /* In case the sw timer triggered in the window */
> - if (atomic_read(&apic->lapic_timer.pending) &&
> - !apic_lvtt_period(apic))
> - cancel_hv_timer(apic);
> - }
> trace_kvm_hv_timer_state(apic->vcpu->vcpu_id,
> apic->lapic_timer.hv_timer_in_use);
> return apic->lapic_timer.hv_timer_in_use;
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 4f616db..0a0e696 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -11125,6 +11125,9 @@ static int vmx_set_hv_timer(struct kvm_vcpu
> *vcpu, u64 guest_deadline_tsc)
> u64 guest_tscl = kvm_read_l1_tsc(vcpu, tscl);
> u64 delta_tsc = max(guest_deadline_tsc, guest_tscl) - guest_tscl;
>
> + if (delta_tsc == 0)
> + return 1;
You still need to enable the preemption timer even if you return 1, so
in lapic.c it becomes
if (!apic_lvtt_period(apic)) {
if (r)
apic_timer_expired(apic);
if (atomic_read(&apic->lapic_timer.pending))
need_cancel = true;
}
Otherwise it looks good. Thanks for your persistence. :)
Paolo
> /* Convert to host delta tsc if tsc scaling is enabled */
> if (vcpu->arch.tsc_scaling_ratio != kvm_default_tsc_scaling_ratio &&
> u64_shl_div_u64(delta_tsc,
>
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[PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-28 03:30 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-06-28 14:20 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-28 16:00 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-06-28 16:10 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-28 16:10 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-28 16:30 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-06-28 16:40 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-29 05:50 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-06-29 10:00 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-29 10:20 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-29 10:50 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-06-29 13:50 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-29 14:00 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-06-29 14:10 +0200
Re: [PATCH v3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-06-29 14:20 +0200
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