Re: [PATCH] KVM: MMU: Disassociate direct maps from guest levels

[Joerg Roedel <joro@8bytes.org>]

On Tue, Mar 23, 2010 at 12:51:15PM +0200, Avi Kivity wrote:
> On 03/17/2010 08:16 PM, Marcelo Tosatti wrote:
>> On Sun, Mar 14, 2010 at 10:22:52AM +0200, Avi Kivity wrote:
>>    
>>> Direct maps are linear translations for a section of memory, used for
>>> real mode or with large pages.  As such, they are independent of the guest
>>> levels.
>>>
>>> Teach the mmu about this by making page->role.glevels = 0 for direct maps.
>>> This allows direct maps to be shared among real mode and the various paging
>>> modes.
>>>
>>> @@ -1328,6 +1328,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
>>>   	role = vcpu->arch.mmu.base_role;
>>>   	role.level = level;
>>>   	role.direct = direct;
>>> +	if (role.direct)
>>> +		role.glevels = 0;
>>>   	role.access = access;
>>>   	if (vcpu->arch.mmu.root_level<= PT32_ROOT_LEVEL) {
>>>   		quadrant = gaddr>>  (PAGE_SHIFT + (PT64_PT_BITS * level));
>>> -- 
>>> 1.7.0.2
>>>      
>> Isnt this what happens already, since for tdp base_role.glevels is not
>> initialized?
>>    
>
> Correct.  I was thinking about the nested npt case, which will use  
> role.glevels.  Joerg, please incorporate this into your nnpt patchset.

Yes will do. I am currently out-of-office until April 6th. Expect a
re-send of the patch-set some time after that :-)

	Joerg