Message-ID: <4C19EADE.6090408@cn.fujitsu.com>
Date: Thu, 17 Jun 2010 17:29:02 +0800
From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
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To: Avi Kivity <avi@redhat.com>
CC: Marcelo Tosatti <mtosatti@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
       KVM list <kvm@vger.kernel.org>
Subject: Re: [PATCH 5/6] KVM: MMU: prefetch ptes when intercepted guest #PF
References: <4C16E6ED.7020009@cn.fujitsu.com> <4C16E75F.6020003@cn.fujitsu.com> <4C16E7AD.1060101@cn.fujitsu.com> <4C16E7F4.5060801@cn.fujitsu.com> <4C16E82E.5010306@cn.fujitsu.com> <4C16E9A8.10409@cn.fujitsu.com> <4C1766D6.3040000@redhat.com> <4C19CDCC.4060404@cn.fujitsu.com> <4C19D7B1.6060908@redhat.com> <4C19E532.4070708@cn.fujitsu.com> <4C19E8E9.4060602@redhat.com>
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Avi Kivity wrote:
> On 06/17/2010 12:04 PM, Xiao Guangrong wrote:
>>
>>
>>> So we can change the fault path to always fault 16 ptes, aligned on 16
>>> pte boundary, with the needed pte called with specualtive=false.
>>>      
>> Avi, i not understand it clearly, Could you please explain it? :-(
>>    
> 
> Right now if the fault is in spte i, you prefetch ptes
> (i+1)..(i+MAX_PREFETCH-1).  I'd like to prefetch ptes (i &
> ~(MAX_PREFETCH-1))..(i | (MAX_PREFETCH - 1)).  Read all those gptes, and
> map them one by one with speculative = false only for spte i.
> 

Thanks for your explanation, i see.
 
> Perhaps we need to integrate it into walk_addr, there's  no reason to
> read the gptes twice.
> 

OK, will do it.
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