linux-kernel - Re: [PATCH] KVM: SVM: use __GFP_ZERO instead of clear

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Message-ID: <24eaf0bbbc64da013b724adf1d6b2e0d53a6ed99.camel@redhat.com>
Date:   Thu, 17 Sep 2020 12:45:48 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     lihaiwei.kernel@...il.com, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, x86@...nel.org
Cc:     pbonzini@...hat.com, sean.j.christopherson@...el.com,
        vkuznets@...hat.com, wanpengli@...cent.com, jmattson@...gle.com,
        joro@...tes.org, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, hpa@...or.com, Haiwei Li <lihaiwei@...cent.com>
Subject: Re: [PATCH] KVM: SVM: use __GFP_ZERO instead of clear_page()

On Wed, 2020-09-16 at 16:36 +0800, lihaiwei.kernel@...il.com wrote:
> From: Haiwei Li <lihaiwei@...cent.com>
> 
> Use __GFP_ZERO while alloc_page().
> 
> Signed-off-by: Haiwei Li <lihaiwei@...cent.com>
> ---
>  arch/x86/kvm/svm/avic.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> index ac830cd50830..f73f84d56452 100644
> --- a/arch/x86/kvm/svm/avic.c
> +++ b/arch/x86/kvm/svm/avic.c
> @@ -153,20 +153,18 @@ int avic_vm_init(struct kvm *kvm)
>  		return 0;
>  
>  	/* Allocating physical APIC ID table (4KB) */
> -	p_page = alloc_page(GFP_KERNEL_ACCOUNT);
> +	p_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
>  	if (!p_page)
>  		goto free_avic;
>  
>  	kvm_svm->avic_physical_id_table_page = p_page;
> -	clear_page(page_address(p_page));
>  
>  	/* Allocating logical APIC ID table (4KB) */
> -	l_page = alloc_page(GFP_KERNEL_ACCOUNT);
> +	l_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
>  	if (!l_page)
>  		goto free_avic;
>  
>  	kvm_svm->avic_logical_id_table_page = l_page;
> -	clear_page(page_address(l_page));
>  
>  	spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
>   again:
Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>

Best regards,
	Maxim Levitsky