| Date | Tue, 5 Apr 2022 17:33:51 +0200 | Subject | Re: [RFC PATCH v5 076/104] KVM: x86: Add option to force LAPIC expiration wait | From | Paolo Bonzini <> |
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On 3/4/22 20:49, isaku.yamahata@intel.com wrote: > From: Sean Christopherson <sean.j.christopherson@intel.com> > > Add an option to skip the IRR check-in kvm_wait_lapic_expire(). This > will be used by TDX to wait if there is an outstanding notification for > a TD, i.e. a virtual interrupt is being triggered via posted interrupt > processing. KVM TDX doesn't emulate PI processing, i.e. there will > never be a bit set in IRR/ISR, so the default behavior for APICv of > querying the IRR doesn't work as intended.
Would be better to explain "doesn't work as intended" more verbosely. Otherwise,
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > arch/x86/kvm/lapic.c | 4 ++-- > arch/x86/kvm/lapic.h | 2 +- > arch/x86/kvm/svm/svm.c | 2 +- > arch/x86/kvm/vmx/vmx.c | 2 +- > 4 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 9322e6340a74..d49f029ef0e3 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -1620,12 +1620,12 @@ static void __kvm_wait_lapic_expire(struct kvm_vcpu *vcpu) > __wait_lapic_expire(vcpu, tsc_deadline - guest_tsc); > } > > -void kvm_wait_lapic_expire(struct kvm_vcpu *vcpu) > +void kvm_wait_lapic_expire(struct kvm_vcpu *vcpu, bool force_wait) > { > if (lapic_in_kernel(vcpu) && > vcpu->arch.apic->lapic_timer.expired_tscdeadline && > vcpu->arch.apic->lapic_timer.timer_advance_ns && > - lapic_timer_int_injected(vcpu)) > + (force_wait || lapic_timer_int_injected(vcpu))) > __kvm_wait_lapic_expire(vcpu); > } > EXPORT_SYMBOL_GPL(kvm_wait_lapic_expire); > diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h > index 2b44e533fc8d..2a0119ef9e96 100644 > --- a/arch/x86/kvm/lapic.h > +++ b/arch/x86/kvm/lapic.h > @@ -233,7 +233,7 @@ static inline int kvm_lapic_latched_init(struct kvm_vcpu *vcpu) > > bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector); > > -void kvm_wait_lapic_expire(struct kvm_vcpu *vcpu); > +void kvm_wait_lapic_expire(struct kvm_vcpu *vcpu, bool force_wait); > > void kvm_bitmap_or_dest_vcpus(struct kvm *kvm, struct kvm_lapic_irq *irq, > unsigned long *vcpu_bitmap); > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index c7eec23e9ebe..a46415845f48 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -3766,7 +3766,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) > clgi(); > kvm_load_guest_xsave_state(vcpu); > > - kvm_wait_lapic_expire(vcpu); > + kvm_wait_lapic_expire(vcpu, false); > > /* > * If this vCPU has touched SPEC_CTRL, restore the guest's value if > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 00f88aa25047..9b7bd52d19a9 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6838,7 +6838,7 @@ fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) > if (enable_preemption_timer) > vmx_update_hv_timer(vcpu); > > - kvm_wait_lapic_expire(vcpu); > + kvm_wait_lapic_expire(vcpu, false); > > /* > * If this vCPU has touched SPEC_CTRL, restore the guest's value if
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