On 03/06/2011 12:48 AM, Marcelo Tosatti wrote:
> On Fri, Mar 04, 2011 at 06:57:27PM +0800, Xiao Guangrong wrote:
>> Don not walk to the next level if spte is mapping to the large page
>>
>> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
>> ---
>> arch/x86/kvm/mmu.c | 3 ++-
>> 1 files changed, 2 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>> index b9bf016..10e0982 100644
>> --- a/arch/x86/kvm/mmu.c
>> +++ b/arch/x86/kvm/mmu.c
>> @@ -3819,7 +3819,8 @@ int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
>> for_each_shadow_entry(vcpu, addr, iterator) {
>> sptes[iterator.level-1] = *iterator.sptep;
>> nr_sptes++;
>> - if (!is_shadow_present_pte(*iterator.sptep))
>> + if (!is_shadow_present_pte(*iterator.sptep) ||
>> + is_last_spte(*iterator.sptep, iterator.level))
>> break;
>> }
>> spin_unlock(&vcpu->kvm->mmu_lock);
>
> shadow_walk_okay covers that case.
>
We can get the large mapping pte in the loop:
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)
if (is_large_pte(*iterator->sptep))
return false;
......
}
if level > 1 and pte.pse is set, it will return true.
And, i think this judgment is useless:
if (iterator->level == PT_PAGE_TABLE_LEVEL)
if (is_large_pte(*iterator->sptep))
return false;
since if level = 1, the pte bit7 is PAT.
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