linux-kernel - Re: [PATCH 2/4] KVM: SVM: Fixes setting V

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Message-ID: <a963a336-4096-b53a-276b-6509f5cb9402@redhat.com>
Date:   Wed, 6 May 2020 18:29:49 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     joro@...tes.org, jon.grimm@....com, mlevitsk@...hat.com
Subject: Re: [PATCH 2/4] KVM: SVM: Fixes setting V_IRQ while AVIC is still
 enabled

On 06/05/20 15:17, Suravee Suthikulpanit wrote:
>   */
> -void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit)
> +void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit,
> +			      struct kvm_vcpu *except)
>  {
>  	unsigned long old, new, expected;
>  
> @@ -8110,7 +8111,16 @@ void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit)
>  	trace_kvm_apicv_update_request(activate, bit);
>  	if (kvm_x86_ops.pre_update_apicv_exec_ctrl)
>  		kvm_x86_ops.pre_update_apicv_exec_ctrl(kvm, activate);
> -	kvm_make_all_cpus_request(kvm, KVM_REQ_APICV_UPDATE);
> +
> +	/*
> +	 * Sending request to update APICV for all other vcpus,
> +	 * while update the calling vcpu immediately instead of
> +	 * waiting for another #VMEXIT to handle the request.
> +	 */
> +	kvm_make_all_cpus_request_except(kvm, KVM_REQ_APICV_UPDATE,
> +					 except);
> +	if (except)
> +		kvm_vcpu_update_apicv(except);

Can you use kvm_get_running_vcpu() instead of touching all callers?
Also a slightly better subject would be "KVM: SVM: Disable AVIC before
setting V_IRQ".

Paolo