diff mbox

[v2,01/22] KVM: MMU: fix walking shadow page table

Message ID 4E01FBF4.9070004@cn.fujitsu.com (mailing list archive)
State New, archived
Headers show

Commit Message

Xiao Guangrong June 22, 2011, 2:28 p.m. UTC
Properly check the last mapping, and do not walk to the next level if last spte
is met

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 arch/x86/kvm/mmu.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

Comments

Marcelo Tosatti June 22, 2011, 5:13 p.m. UTC | #1
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@cn.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.

> -		if (is_large_pte(*iterator->sptep))
> -			return false;
> -
>  	iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
>  	iterator->sptep	= ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
>  	return true;
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Xiao Guangrong June 23, 2011, 2:05 a.m. UTC | #2
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@cn.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.
> 

OK, will fix, thanks!
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Xiao Guangrong June 27, 2011, 6:35 a.m. UTC | #3
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@cn.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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diff mbox

Patch

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)
-		if (is_large_pte(*iterator->sptep))
-			return false;
-
 	iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
 	iterator->sptep	= ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
 	return true;
@@ -1528,6 +1524,11 @@  static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
 
 static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
 {
+	if (is_last_spte(*iterator->sptep, iterator->level)) {
+		iterator->level = 0;
+		return;
+	}
+
 	iterator->shadow_addr = *iterator->sptep & PT64_BASE_ADDR_MASK;
 	--iterator->level;
 }