linux-kernel - Re: [PATCH 8/9] KVM: do not release the error pfn

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Date:	Thu, 2 Aug 2012 10:14:01 -0300
From:	Marcelo Tosatti <mtosatti@...hat.com>
To:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
Cc:	Avi Kivity <avi@...hat.com>, LKML <linux-kernel@...r.kernel.org>,
	KVM <kvm@...r.kernel.org>
Subject: Re: [PATCH 8/9] KVM: do not release the error pfn

On Sun, Jul 29, 2012 at 04:18:58PM +0800, Xiao Guangrong wrote:
> After commit a2766325cf9f9, the error pfn is replaced by the
> error code, it need not be released anymore
> 
> [ The patch is compiling tested for powerpc ]
> 
> Signed-off-by: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
> ---
>  arch/powerpc/kvm/e500_tlb.c |    1 -
>  arch/x86/kvm/mmu.c          |    6 +++---
>  arch/x86/kvm/mmu_audit.c    |    4 +---
>  arch/x86/kvm/paging_tmpl.h  |    8 ++------
>  virt/kvm/iommu.c            |    1 -
>  virt/kvm/kvm_main.c         |   14 ++++++++------
>  6 files changed, 14 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/powerpc/kvm/e500_tlb.c b/arch/powerpc/kvm/e500_tlb.c
> index c8f6c58..09ce5ac 100644
> --- a/arch/powerpc/kvm/e500_tlb.c
> +++ b/arch/powerpc/kvm/e500_tlb.c
> @@ -524,7 +524,6 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
>  		if (is_error_pfn(pfn)) {
>  			printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
>  					(long)gfn);
> -			kvm_release_pfn_clean(pfn);
>  			return;
>  		}
> 
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 320a781..949a5b8 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2498,7 +2498,9 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
>  				rmap_recycle(vcpu, sptep, gfn);
>  		}
>  	}
> -	kvm_release_pfn_clean(pfn);
> +
> +	if (!is_error_pfn(pfn))
> +		kvm_release_pfn_clean(pfn);
>  }

Can it ever be error_pfn? Seems a problem if so.


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