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);
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
