Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <ff67344c0efe06d1422aa84e56738a0812c69bfc.camel@redhat.com>
Subject: Re: [PATCH v3 08/14] KVM: SVM: Update AVIC settings when changing
 APIC mode
From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc:     pbonzini@redhat.com, seanjc@google.com, joro@8bytes.org,
        jon.grimm@amd.com, wei.huang2@amd.com, terry.bowman@amd.com
Date:   Wed, 04 May 2022 15:19:30 +0300
In-Reply-To: <20220504073128.12031-9-suravee.suthikulpanit@amd.com>
References: <20220504073128.12031-1-suravee.suthikulpanit@amd.com>
         <20220504073128.12031-9-suravee.suthikulpanit@amd.com>
Content-Type: text/plain; charset="UTF-8"
User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) 
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Wed, 2022-05-04 at 02:31 -0500, Suravee Suthikulpanit wrote:
> Update and refresh AVIC settings when guest APIC mode is updated
> (e.g. changing between disabled, xAPIC, or x2APIC).
> 
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
>  arch/x86/kvm/svm/avic.c | 16 ++++++++++++++++
>  arch/x86/kvm/svm/svm.c  |  1 +
>  2 files changed, 17 insertions(+)
> 
> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> index 3ebeea19b487..d185dd8ddf17 100644
> --- a/arch/x86/kvm/svm/avic.c
> +++ b/arch/x86/kvm/svm/avic.c
> @@ -691,6 +691,22 @@ void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu)
>  	avic_handle_ldr_update(vcpu);
>  }
>  
> +void avic_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
> +{
> +	struct vcpu_svm *svm = to_svm(vcpu);
> +
> +	if (!lapic_in_kernel(vcpu) || (avic_mode == AVIC_MODE_NONE))
> +		return;
> +
> +	if (kvm_get_apic_mode(vcpu) == LAPIC_MODE_INVALID) {
> +		WARN_ONCE(true, "Invalid local APIC state (vcpu_id=%d)", vcpu->vcpu_id);
> +		return;
> +	}
> +
> +	kvm_vcpu_update_apicv(&svm->vcpu);

Why to have this call? I think that all that is needed is only to call the
avic_refresh_apicv_exec_ctrl.

Best regards,
	Maxim Levitsky


> +	avic_refresh_apicv_exec_ctrl(&svm->vcpu);
> +}
> +
>  static int avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
>  {
>  	int ret = 0;
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 314628b6bff4..9066568fd19d 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -4692,6 +4692,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
>  	.enable_nmi_window = svm_enable_nmi_window,
>  	.enable_irq_window = svm_enable_irq_window,
>  	.update_cr8_intercept = svm_update_cr8_intercept,
> +	.set_virtual_apic_mode = avic_set_virtual_apic_mode,
>  	.refresh_apicv_exec_ctrl = avic_refresh_apicv_exec_ctrl,
>  	.check_apicv_inhibit_reasons = avic_check_apicv_inhibit_reasons,
>  	.apicv_post_state_restore = avic_apicv_post_state_restore,