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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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