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    Subject[RFC PATCH v5 076/104] KVM: x86: Add option to force LAPIC expiration wait
    Date
    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>
    ---
    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
    --
    2.25.1
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