Message-ID: <6a97d0ab100e596c3f4c26c64aaf945018d82a5e.camel@redhat.com>
Subject: Re: [PATCH v2 1/3] KVM: SVM: Refactor AVIC hardware setup logic
 into helper function
From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org
Cc:     pbonzini@redhat.com, joro@8bytes.org, seanjc@google.com,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        peterz@infradead.org, hpa@zytor.com, thomas.lendacky@amd.com,
        jon.grimm@amd.com
Date:   Fri, 03 Dec 2021 09:39:40 +0200
In-Reply-To: <20211202235825.12562-2-suravee.suthikulpanit@amd.com>
References: <20211202235825.12562-1-suravee.suthikulpanit@amd.com>
         <20211202235825.12562-2-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 Thu, 2021-12-02 at 17:58 -0600, Suravee Suthikulpanit wrote:
> To prepare for upcoming AVIC changes. There is no functional change.
> 
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
>  arch/x86/kvm/svm/avic.c | 10 ++++++++++
>  arch/x86/kvm/svm/svm.c  |  8 +-------
>  arch/x86/kvm/svm/svm.h  |  1 +
>  3 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> index 8052d92069e0..6aca1682f4b7 100644
> --- a/arch/x86/kvm/svm/avic.c
> +++ b/arch/x86/kvm/svm/avic.c
> @@ -1011,3 +1011,13 @@ void svm_vcpu_unblocking(struct kvm_vcpu *vcpu)
>  		kvm_vcpu_update_apicv(vcpu);
>  	avic_set_running(vcpu, true);
>  }
> +
> +bool avic_hardware_setup(bool avic, bool npt)
> +{
> +	if (!avic || !npt || !boot_cpu_has(X86_FEATURE_AVIC))
> +		return false;
Nitpick: Why to pass these as local variables? npt_enabled for example is
used in many places directly.

> +
> +	pr_info("AVIC enabled\n");
> +	amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);
> +	return true;
> +}
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 989685098b3e..d23bc7a7c48e 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -1031,13 +1031,7 @@ static __init int svm_hardware_setup(void)
>  			nrips = false;
>  	}
>  
> -	enable_apicv = avic = avic && npt_enabled && boot_cpu_has(X86_FEATURE_AVIC);
> -
> -	if (enable_apicv) {
> -		pr_info("AVIC enabled\n");
> -
> -		amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);
> -	}
> +	enable_apicv = avic = avic_hardware_setup(avic, npt_enabled);
>  
>  	if (vls) {
>  		if (!npt_enabled ||
> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
> index 5d30db599e10..1d2d72e56dd1 100644
> --- a/arch/x86/kvm/svm/svm.h
> +++ b/arch/x86/kvm/svm/svm.h
> @@ -515,6 +515,7 @@ static inline bool avic_vcpu_is_running(struct kvm_vcpu *vcpu)
>  	return (READ_ONCE(*entry) & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK);
>  }
>  
> +bool avic_hardware_setup(bool avic, bool npt);
>  int avic_ga_log_notifier(u32 ga_tag);
>  void avic_vm_destroy(struct kvm *kvm);
>  int avic_vm_init(struct kvm *kvm);

Best regards,
	Maxim Levitsky