linux-kernel - Re: [PATCH 02/15] KVM: MMU: do not update slot bitmap if spte is nonpresent

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Date:	Mon, 20 Jun 2011 13:28:06 -0300
From:	Marcelo Tosatti <mtosatti@...hat.com>
To:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
Cc:	Avi Kivity <avi@...hat.com>, LKML <linux-kernel@...r.kernel.org>,
	KVM <kvm@...r.kernel.org>
Subject: Re: [PATCH 02/15] KVM: MMU: do not update slot bitmap if spte is
 nonpresent

On Tue, Jun 07, 2011 at 08:59:25PM +0800, Xiao Guangrong wrote:
> Set slot bitmap only if the spte is present
> 
> Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
> ---
>  arch/x86/kvm/mmu.c |   15 +++++++--------
>  1 files changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index cda666a..125f78d 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -743,9 +743,6 @@ static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
>  	struct kvm_mmu_page *sp;
>  	unsigned long *rmapp;
>  
> -	if (!is_rmap_spte(*spte))
> -		return 0;
> -

Not sure if this is safe, what if the spte is set as nonpresent but
rmap not removed?

BTW i don't see what patch 1 and this have to do with the goal
of the series.

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