linux-kernel - Re: [PATCH v3 3/3] KVM: SVM: Fix disable pause loop exit/pause filtering capability on SVM

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Message-ID: <CANRm+CzgB2G5TqcBYikq3JserkbBkNr5a9Q8Fw8E6s49TtrmvA@mail.gmail.com>
Date:   Fri, 31 Jul 2020 17:44:45 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, kvm <kvm@...r.kernel.org>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>
Subject: Re: [PATCH v3 3/3] KVM: SVM: Fix disable pause loop exit/pause
 filtering capability on SVM

On Fri, 31 Jul 2020 at 15:21, Paolo Bonzini <pbonzini@...hat.com> wrote:
>
> On 31/07/20 05:12, Wanpeng Li wrote:
> > From: Wanpeng Li <wanpengli@...cent.com>
> >
> > 'Commit 8566ac8b8e7c ("KVM: SVM: Implement pause loop exit logic in SVM")'
> > drops disable pause loop exit/pause filtering capability completely, I
> > guess it is a merge fault by Radim since disable vmexits capabilities and
> > pause loop exit for SVM patchsets are merged at the same time. This patch
> > reintroduces the disable pause loop exit/pause filtering capability support.
> >
> > Reported-by: Haiwei Li <lihaiwei@...cent.com>
> > Tested-by: Haiwei Li <lihaiwei@...cent.com>
> > Fixes: 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM)
> > Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
> > ---
> > v2 -> v3:
> >  * simplify the condition in init_vmcb()
> >
> >  arch/x86/kvm/svm/svm.c | 9 ++++++---
> >  1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> > index c0da4dd..bf77f90 100644
> > --- a/arch/x86/kvm/svm/svm.c
> > +++ b/arch/x86/kvm/svm/svm.c
> > @@ -1090,7 +1090,7 @@ static void init_vmcb(struct vcpu_svm *svm)
> >       svm->nested.vmcb = 0;
> >       svm->vcpu.arch.hflags = 0;
> >
> > -     if (pause_filter_count) {
> > +     if (!kvm_pause_in_guest(svm->vcpu.kvm)) {
> >               control->pause_filter_count = pause_filter_count;
> >               if (pause_filter_thresh)
> >                       control->pause_filter_thresh = pause_filter_thresh;
> > @@ -2693,7 +2693,7 @@ static int pause_interception(struct vcpu_svm *svm)
> >       struct kvm_vcpu *vcpu = &svm->vcpu;
> >       bool in_kernel = (svm_get_cpl(vcpu) == 0);
> >
> > -     if (pause_filter_thresh)
> > +     if (!kvm_pause_in_guest(vcpu->kvm))
> >               grow_ple_window(vcpu);
> >
> >       kvm_vcpu_on_spin(vcpu, in_kernel);
> > @@ -3780,7 +3780,7 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu)
> >
> >  static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
> >  {
> > -     if (pause_filter_thresh)
> > +     if (!kvm_pause_in_guest(vcpu->kvm))
> >               shrink_ple_window(vcpu);
> >  }
> >
> > @@ -3958,6 +3958,9 @@ static void svm_vm_destroy(struct kvm *kvm)
> >
> >  static int svm_vm_init(struct kvm *kvm)
> >  {
> > +     if (!pause_filter_count || !pause_filter_thresh)
> > +             kvm->arch.pause_in_guest = true;
> > +
> >       if (avic) {
> >               int ret = avic_vm_init(kvm);
> >               if (ret)
> >
>
> Queued all three, thanks.  Please do send a testcase for patch 1
> however, I only queued it in order to have it in 5.8.

Thanks, will do in the next week, today is too busy. :)

    Wanpeng