linux-kernel - Re: [PATCH v2 01/22] KVM: MMU: fix walking shadow page table

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Date:	Mon, 27 Jun 2011 14:35:25 +0800
From:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
To:	Marcelo Tosatti <mtosatti@...hat.com>
CC:	Avi Kivity <avi@...hat.com>, LKML <linux-kernel@...r.kernel.org>,
	KVM <kvm@...r.kernel.org>
Subject: Re: [PATCH v2 01/22] KVM: MMU: fix walking shadow page table

On 06/23/2011 01:13 AM, Marcelo Tosatti wrote:
> On Wed, Jun 22, 2011 at 10:28:04PM +0800, Xiao Guangrong wrote:
>> Properly check the last mapping, and do not walk to the next level if last spte
>> is met
>>
>> Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
>> ---
>>  arch/x86/kvm/mmu.c |    9 +++++----
>>  1 files changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>> index 9c629b5..f474e93 100644
>> --- a/arch/x86/kvm/mmu.c
>> +++ b/arch/x86/kvm/mmu.c
>> @@ -1517,10 +1517,6 @@ static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
>>  	if (iterator->level < PT_PAGE_TABLE_LEVEL)
>>  		return false;
>>  
>> -	if (iterator->level == PT_PAGE_TABLE_LEVEL)
> 
> Change to >= PT_PAGE_TABLE_LEVEL, checks should be in shadow_walk_okay.
> 

Marcelo,

Sorry, i did not remember, we can not check the last spte in shadow_walk_okay,
otherwise the last spte is skipped in the loop. :-)



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