Re: [PATCH] KVM: MMU: Segregate mmu pages created with different cr4.pge settings

[Avi Kivity <avi@redhat.com>]

Marcelo Tosatti wrote:
> On Wed, Jan 07, 2009 at 01:32:41PM +0200, Avi Kivity wrote:
>   
>> Marcelo Tosatti wrote:
>>     
>>> Let me shoot at one direction: a shadow page with PGE bit in either
>>> state is created. Later that shadow page is nuked (via mmu notifiers,
>>> for example). 
>>>       
>> I doubt that mmu notifiers were invoked in this case (the bug would be  
>> very rare); in any case we flush the tlb.
>>     
>
> There are other events that zap shadow pages. Anyway, someone else
> should figure why NPT dislikes duplicate shadow page tables for 
> the same address space. How about this, untested:
>
> KVM: MMU: zero base_role on TDP mmu context initialization
>
> A recent change which propagates CR4.PGE to shadow page roles broke NPT,
> perhaps due to the allocation of duplicate shadow trees for the same
> address space (actual details unknown).
>
> In the meantime, since guest CR4.PGE is controlled by HW with
> NPT, and the relevant role information for TDP is passed directly to
> kvm_mmu_get_page, zero base_role on TDP mmu context init.
>
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 10bdb2a..44ffcf6 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2231,6 +2231,8 @@ static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
>  		context->root_level = PT32_ROOT_LEVEL;
>  	}
>  
> +	vcpu->arch.mmu.base_role = 0;
> +
>  	return 0;
>  }
>  
>   

Won't even compile, will it?

-- 
error compiling committee.c: too many arguments to function