linux-kernel - Re: [PATCH v2 5/10] KVM MMU: split kvm_sync

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Message-ID: <4BD41063.9010704@redhat.com>
Date:	Sun, 25 Apr 2010 12:50:27 +0300
From:	Avi Kivity <avi@...hat.com>
To:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	KVM list <kvm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 5/10] KVM MMU: split kvm_sync_page() function

On 04/25/2010 10:00 AM, Xiao Guangrong wrote:
> Split kvm_sync_page() into kvm_sync_page() and kvm_sync_page_transient()
> to clarify the code address Avi's suggestion
>
> kvm_sync_page_transient() function only update shadow page but not mark
> it sync and not write protect sp->gfn. it will be used by later patch
>
> Signed-off-by: Xiao Guangrong<xiaoguangrong@...fujitsu.com>
> ---
>   arch/x86/kvm/mmu.c |   17 +++++++++++++++++
>   1 files changed, 17 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index abf8bd4..60a91c6 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1196,6 +1196,23 @@ static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
>
>   static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
>
> +static int kvm_sync_page_transient(struct kvm_vcpu *vcpu,
> +				   struct kvm_mmu_page *sp)
> +{
> +	if (sp->role.cr4_pae != !!is_pae(vcpu)) {
> +		kvm_mmu_zap_page(vcpu->kvm, sp);
> +		return 1;
> +	}
> +
> +	if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
> +		kvm_mmu_zap_page(vcpu->kvm, sp);
> +		return 1;
> +	}
> +
> +	kvm_mmu_flush_tlb(vcpu);
> +	return 0;
> +}
> +
>    

This isn't a split; it duplicates the code.

Since there are some parts in the middle of kvm_sync_page() you don't 
want in sync_page_transient(), you can put them into helpers so that 
sync_page and sync_page_transient only call helpers.

-- 
error compiling committee.c: too many arguments to function

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