Re: [PATCH] KVM: MMU: Fix overflow of SHADOW_PT_INDEX with EPT in 32pae

[Sheng Yang <yasker@gmail.com>]

On Mon, Sep 01, 2008 at 12:40:04PM +0300, Avi Kivity wrote:
> Yang, Sheng wrote:
>> From: Sheng Yang <sheng.yang@intel.com>
>> Date: Mon, 1 Sep 2008 17:28:59 +0800
>> Subject: [PATCH] KVM: MMU: Fix overflow of SHADOW_PT_INDEX with EPT in 32pae
>>
>> EPT is 4 level by default in 32pae (48bits), but virtual address only
>> got 32 bits. This result in SHADOW_PT_INDEX() overflow when try to
>> fetch level 4 index.
>>
>> Fix it by extend virtual address to 64bits in any condition.
>>
>>   
>
> Good catch.
>
>> Signed-off-by: Sheng Yang <sheng.yang@intel.com>
>> ---
>>  arch/x86/kvm/mmu.c |    8 +++++++-
>>  1 files changed, 7 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>> index f33c594..8ca9aad 100644
>> --- a/arch/x86/kvm/mmu.c
>> +++ b/arch/x86/kvm/mmu.c
>> @@ -943,6 +943,7 @@ static int walk_shadow(struct kvm_shadow_walk *walker,
>>  	int level;
>>  	int r;
>>  	u64 *sptep;
>> +	u64 ext_addr = addr;
>>   
>
> addr isn't really a gva_t; it is a pga_t when using direct mappings.
>
> So how about changing walk_shadow() and its callbacks to use u64 instead  
> of gva_t instead?

Yeah, that's better, would update the patch soon. :)

--
regards
Yang, Sheng
>
>
> -- 
> error compiling committee.c: too many arguments to function
>
> --
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