Messages in this thread | | | Subject | Re: [PATCH 6/6] KVM: VMX: enable IPI virtualization | From | Zeng Guang <> | Date | Tue, 20 Jul 2021 09:07:22 +0800 |
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On 7/19/2021 9:58 PM, Paolo Bonzini wrote: > On 19/07/21 14:38, Zeng Guang wrote: >>> Understood, but in practice all uses of vmx->ipiv_active are >>> guarded by kvm_vcpu_apicv_active so they are always reached with >>> vmx->ipiv_active == enable_ipiv. >>> >>> The one above instead seems wrong and should just use enable_ipiv. >> enable_ipiv associate with "IPI virtualization" setting in tertiary >> exec controls and enable_apicv which depends on cpu_has_vmx_apicv(). >> kvm_vcpu_apicv_active still can be false even if enable_ipiv is true, >> e.g. in case irqchip not emulated in kernel. > Right, kvm_vcpu_apicv_active *is* set in init_vmcs. But there's an > "if (kvm_vcpu_apicv_active(&vmx->vcpu))" above. You can just stick > > if (enable_ipicv) > install_pid(vmx); Ok, got your point now. I will revise to remove vmx->ipiv_active. Thanks. > inside there. As to the other occurrences of vmx->ipiv_active, look here: > >> + if (!kvm_vcpu_apicv_active(vcpu)) >> + return; >> + >> + if ((!kvm_arch_has_assigned_device(vcpu->kvm) || >> + !irq_remapping_cap(IRQ_POSTING_CAP)) && >> + !to_vmx(vcpu)->ipiv_active) >> return; >> > This one can be enable_ipiv because APICv must be active. > >> + if (!kvm_vcpu_apicv_active(vcpu)) >> + return 0; >> + >> + /* Put vCPU into a list and set NV to wakeup vector if it is >> + * one of the following cases: >> + * 1. any assigned device is in use. >> + * 2. IPI virtualization is enabled. >> + */ >> + if ((!kvm_arch_has_assigned_device(vcpu->kvm) || >> + !irq_remapping_cap(IRQ_POSTING_CAP)) && !to_vmx(vcpu)->ipiv_active) >> return 0; > This one can be !enable_ipiv because APICv must be active. > >> @@ -3870,6 +3877,8 @@ static void vmx_update_msr_bitmap_x2apic(struct kvm_vcpu *vcpu, u8 mode) >> vmx_enable_intercept_for_msr(vcpu, X2APIC_MSR(APIC_TMCCT), MSR_TYPE_RW); >> vmx_disable_intercept_for_msr(vcpu, X2APIC_MSR(APIC_EOI), MSR_TYPE_W); >> vmx_disable_intercept_for_msr(vcpu, X2APIC_MSR(APIC_SELF_IPI), MSR_TYPE_W); >> + vmx_set_intercept_for_msr(vcpu, X2APIC_MSR(APIC_ICR), >> + MSR_TYPE_RW, !to_vmx(vcpu)->ipiv_active); >> } >> } > Is inside "if (mode & MSR_BITMAP_MODE_X2APIC_APICV)" so APICv must be > activ; so it can be enable_ipiv as well. > > In conclusion, you do not need vmx->ipiv_active. > > Paolo >
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