Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH v2 3/3] KVM: SVM: Fix disable pause loop exit/pause filtering capability on SVM | Date | Wed, 29 Jul 2020 14:20:54 +0200 |
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Wanpeng Li <kernellwp@gmail.com> writes:
> From: Wanpeng Li <wanpengli@tencent.com> > > Commit 8566ac8b (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. > > We can observe 2.9% hackbench improvement for a 92 vCPUs guest on AMD > Rome Server. > > Reported-by: Haiwei Li <lihaiwei@tencent.com> > Tested-by: Haiwei Li <lihaiwei@tencent.com> > Fixes: 8566ac8b (KVM: SVM: Implement pause loop exit logic in SVM) > Signed-off-by: Wanpeng Li <wanpengli@tencent.com> > --- > 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..c20f127 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 (pause_filter_count && !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_thresh) > + kvm->arch.pause_in_guest = true;
Would it make sense to do
if (!pause_filter_count || !pause_filter_thresh) kvm->arch.pause_in_guest = true;
here and simplify the condition in init_vmcb()?
> + > if (avic) { > int ret = avic_vm_init(kvm); > if (ret)
-- Vitaly
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