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    SubjectRe: [RFC PATCH v2 38/69] KVM: x86: Add option to force LAPIC expiration wait
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    On 03/07/21 00:04, 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.
    >
    > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
    > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>

    Is there a better (existing after the previous patches) flag to test, or
    possibly can it use vm_type following the suggestion I gave for patch 28?

    Paolo

    > ---
    > 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 977a704e3ff1..3cfc0485a46e 100644
    > --- a/arch/x86/kvm/lapic.c
    > +++ b/arch/x86/kvm/lapic.c
    > @@ -1622,12 +1622,12 @@ 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 997c45a5963a..2bd32d86ad6f 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 bcc3fc4872a3..b12bfdbc394b 100644
    > --- a/arch/x86/kvm/svm/svm.c
    > +++ b/arch/x86/kvm/svm/svm.c
    > @@ -3774,7 +3774,7 @@ 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 36756a356704..7ce15a2c3490 100644
    > --- a/arch/x86/kvm/vmx/vmx.c
    > +++ b/arch/x86/kvm/vmx/vmx.c
    > @@ -6727,7 +6727,7 @@ static 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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