Re: Optimized clocksource with AMD AVIC enabled for Windows guest

[Vitaly Kuznetsov]

Vitaly Kuznetsov <vkuznets@redhat.com> writes:

> +
> +     auto_eoi_new = bitmap_weight(synic->auto_eoi_bitmap, 256);
> +
> +     /* Hyper-V SynIC auto EOI SINT's are not compatible with APICV */
> +     if (!auto_eoi_old && auto_eoi_new) {
> +             if (atomic_inc_return(&hv->synic_auto_eoi_used) == 1)
> +                     kvm_request_apicv_update(vcpu->kvm, false,
> +                                              APICV_INHIBIT_REASON_HYPERV);
> +     } else if (!auto_eoi_old && auto_eoi_new) {

Sigh, this 'else' should be 

} else if (!auto_eoi_new && auto_eoi_old) {

...

> +             if (atomic_dec_return(&hv->synic_auto_eoi_used) == 0)
> +                     kvm_request_apicv_update(vcpu->kvm, true,
> +                                              APICV_INHIBIT_REASON_HYPERV);
> +     }
>  }
>  
>  static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint,
> @@ -903,12 +923,6 @@ int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool 
> dont_zero_synic_pages)
>  {
>       struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
>  
> -     /*
> -      * Hyper-V SynIC auto EOI SINT's are
> -      * not compatible with APICV, so request
> -      * to deactivate APICV permanently.
> -      */
> -     kvm_request_apicv_update(vcpu->kvm, false, APICV_INHIBIT_REASON_HYPERV);
>       synic->active = true;
>       synic->dont_zero_synic_pages = dont_zero_synic_pages;
>       synic->control = HV_SYNIC_CONTROL_ENABLE;

-- 
Vitaly