linux-kernel - Re: [PATCH v4 1/5] KVM: MMU: fix release noslot pfn

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Date:	Fri, 12 Oct 2012 17:49:30 +0800
From:	Xiao Guangrong <xiaoguangrong.eric@...il.com>
To:	Marcelo Tosatti <mtosatti@...hat.com>
CC:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>,
	Avi Kivity <avi@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: Re: [PATCH v4 1/5] KVM: MMU: fix release noslot pfn

On 10/11/2012 10:31 PM, Marcelo Tosatti wrote:
> On Thu, Oct 11, 2012 at 09:06:12PM +0800, Xiao Guangrong wrote:
>> On 10/10/2012 11:11 PM, Marcelo Tosatti wrote:
>>
>>>
>>> Why does is_error_pfn() return true for mmio spte? Its not an "error",
>>> after all. 
>>>
>>> Please kill is_invalid_pfn and use
>>>
>>> -> is_error_pfn for checking for errors (mmio spte is not an error pfn,
>>> its a special pfn)
>>>
>>> -> add explicit is_noslot_pfn checks where necessary in the code
>>> (say to avoid interpreting a noslot_pfn's pfn "address" bits).
>>>
>>> (should have noticed this earlier, sorry).
>>
>> Never mind, your comments are always appreciated! ;)
>>
>> Marcelo, is it good to you?
>> (will post it after your check and full test)
> 
> Yes, this works (please check the validity of each case in addition to
> testing, haven't done it).
> 
> Also add a oneline comment on top of each
> is_error_pfn,is_noslot_pfn,is_error_noslot_pfn
> 
> /* is_noslot_pfn: userspace translation valid but no memory slot */
> /* is_error_pfn: ... */
> 
> etc.
> 

Marcelo, i think this fix should be backport and your idea can be a
separate patchset. Yes?
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