RE: [RFC PATCH v6 5/6] KVM: x86: add vCPU scoped toggling for disabled exits

Kechen Lu
2023-01-30T20:57:55Z

Hi Chao,

> -----Original Message-----
> From: Chao Gao <chao.gao@intel.com>
> Sent: Sunday, January 29, 2023 10:42 PM
> To: Kechen Lu <kechenl@nvidia.com>
> Cc: kvm@vger.kernel.org; seanjc@google.com; pbonzini@redhat.com;
> zhi.wang.linux@gmail.com; shaoqin.huang@intel.com;
> vkuznets@redhat.com; linux-kernel@vger.kernel.org
> Subject: Re: [RFC PATCH v6 5/6] KVM: x86: add vCPU scoped toggling for
> disabled exits
>
> External email: Use caution opening links or attachments
>
>
> On Sat, Jan 21, 2023 at 02:07:37AM +0000, Kechen Lu wrote:
> >+static void svm_update_disabled_exits(struct kvm_vcpu *vcpu)
>
> Is it possible to call this function on vCPU creation, i.e., consolidate
> initialization and runtime toggling?
>

Chao, can you elaborate on this? If I understand correctly,
you mean replacing the current redundant code on vCPU creation
for checking the xxx_in_guest and set intercept, while instead, calling this
svm/vmx_update_disabled_exits()? Yeah, I think this makes sense to
me.

BR,
Kechen

> >+{
> >+ struct vcpu_svm *svm = to_svm(vcpu);
> >+ struct vmcb_control_area *control = &svm->vmcb->control;
> >+
> >+ if (kvm_hlt_in_guest(vcpu))
> >+ svm_clr_intercept(svm, INTERCEPT_HLT);
> >+ else
> >+ svm_set_intercept(svm, INTERCEPT_HLT);
> >+
> >+ if (kvm_mwait_in_guest(vcpu)) {
> >+ svm_clr_intercept(svm, INTERCEPT_MONITOR);
> >+ svm_clr_intercept(svm, INTERCEPT_MWAIT);
> >+ } else {
> >+ svm_set_intercept(svm, INTERCEPT_MONITOR);
> >+ svm_set_intercept(svm, INTERCEPT_MWAIT);
> >+ }
> >+
> >+ if (kvm_pause_in_guest(vcpu)) {
> >+ svm_clr_intercept(svm, INTERCEPT_PAUSE);
> >+ } else {
> >+ control->pause_filter_count = pause_filter_count;
> >+ if (pause_filter_thresh)
> >+ control->pause_filter_thresh = pause_filter_thresh;
> >+ }
> >+}
> >+
> > static void svm_vm_destroy(struct kvm *kvm) {
> > avic_vm_destroy(kvm);
> >@@ -4825,7 +4852,10 @@ static struct kvm_x86_ops svm_x86_ops
> __initdata = {
> > .complete_emulated_msr = svm_complete_emulated_msr,
> >
> > .vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector,
> >+
> > .vcpu_get_apicv_inhibit_reasons =
> > avic_vcpu_get_apicv_inhibit_reasons,
> >+
> >+ .update_disabled_exits = svm_update_disabled_exits,
> > };
> >
> > /*
> >diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index
> >019a20029878..f5137afdd424 100644
> >--- a/arch/x86/kvm/vmx/vmx.c
> >+++ b/arch/x86/kvm/vmx/vmx.c
> >@@ -8070,6 +8070,41 @@ static void vmx_vm_destroy(struct kvm *kvm)
> > free_pages((unsigned long)kvm_vmx->pid_table,
> >vmx_get_pid_table_order(kvm)); }
> >
> >+static void vmx_update_disabled_exits(struct kvm_vcpu *vcpu)
>
> ditto.