| Message ID | 1588055009-12677-3-git-send-email-wanpengli@tencent.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: VMX: Tscdeadline timer emulation fastpath | expand |
Wanpeng Li <kernellwp@gmail.com> writes: > From: Wanpeng Li <wanpengli@tencent.com> > > We can't observe benefit from single target IPI fastpath when APICv is > disabled, let's just enable IPI and Timer fastpath when APICv is enabled > for now. > > Tested-by: Haiwei Li <lihaiwei@tencent.com> > Cc: Haiwei Li <lihaiwei@tencent.com> > Signed-off-by: Wanpeng Li <wanpengli@tencent.com> > --- > arch/x86/kvm/svm/svm.c | 2 +- > arch/x86/kvm/vmx/vmx.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 8f8fc65..1e7220e 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -3344,7 +3344,7 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu) > > static enum exit_fastpath_completion svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu) > { > - if (!is_guest_mode(vcpu) && > + if (!is_guest_mode(vcpu) && vcpu->arch.apicv_active && > to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR && > to_svm(vcpu)->vmcb->control.exit_info_1) > return handle_fastpath_set_msr_irqoff(vcpu); > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 9b5adb4..f207004 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6585,7 +6585,7 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) > > static enum exit_fastpath_completion vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) > { > - if (!is_guest_mode(vcpu)) { > + if (!is_guest_mode(vcpu) && vcpu->arch.apicv_active) { > switch (to_vmx(vcpu)->exit_reason) { > case EXIT_REASON_MSR_WRITE: > return handle_fastpath_set_msr_irqoff(vcpu); I think that apicv_active checks are specific to APIC MSRs but handle_fastpath_set_msr_irqoff() can handle any other MSR as well. I'd suggest to move the check inside handle_fastpath_set_msr_irqoff(). Also, enabling Hyper-V SynIC leads to disabling apicv. It it still pointless to keep fastpath enabled?
On 30/04/20 15:34, Vitaly Kuznetsov wrote: >> static enum exit_fastpath_completion vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) >> { >> - if (!is_guest_mode(vcpu)) { >> + if (!is_guest_mode(vcpu) && vcpu->arch.apicv_active) { >> switch (to_vmx(vcpu)->exit_reason) { >> case EXIT_REASON_MSR_WRITE: >> return handle_fastpath_set_msr_irqoff(vcpu); > I think that apicv_active checks are specific to APIC MSRs but > handle_fastpath_set_msr_irqoff() can handle any other MSR as well. I'd > suggest to move the check inside handle_fastpath_set_msr_irqoff(). > > Also, enabling Hyper-V SynIC leads to disabling apicv. It it still > pointless to keep fastpath enabled? Indeed, only fast paths that only apply to apicv should be disabled (and ideally there should be a WARN_ON in the code that doesn't support !apicv). Paolo
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 8f8fc65..1e7220e 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3344,7 +3344,7 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu) static enum exit_fastpath_completion svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu) { - if (!is_guest_mode(vcpu) && + if (!is_guest_mode(vcpu) && vcpu->arch.apicv_active && to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR && to_svm(vcpu)->vmcb->control.exit_info_1) return handle_fastpath_set_msr_irqoff(vcpu); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 9b5adb4..f207004 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6585,7 +6585,7 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) static enum exit_fastpath_completion vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) { - if (!is_guest_mode(vcpu)) { + if (!is_guest_mode(vcpu) && vcpu->arch.apicv_active) { switch (to_vmx(vcpu)->exit_reason) { case EXIT_REASON_MSR_WRITE: return handle_fastpath_set_msr_irqoff(vcpu);