Re: [PATCH 5/6] Nested SVM: Implement INVLPGA

[Avi Kivity <avi@redhat.com>]

Joerg Roedel wrote:
> On Fri, May 15, 2009 at 10:22:19AM +0200, Alexander Graf wrote:
>   
>> SVM adds another way to do INVLPG by ASID which Hyper-V makes use of,
>> so let's implement it!
>>
>> For now we just do the same thing invlpg does, as asid switching
>> means we flush the mmu anyways. That might change one day though.
>>
>>  
>> +static int invlpga_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
>> +{
>> +	struct kvm_vcpu *vcpu = &svm->vcpu;
>> +	nsvm_printk("INVLPGA\n");
>> +	svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
>> +	skip_emulated_instruction(&svm->vcpu);
>> +
>> +	kvm_mmu_reset_context(vcpu);
>> +	kvm_mmu_load(vcpu);
>> +	return 1;
>> +}
>> +
>>     
>
> Hmm, since we flush the TLB on every nested-guest entry I think we can
> make this function a nop.
>   

I think, unless it specified ASID 0?  In that case you need a local tlb 
flush.

(the kvm_mmu_reset_context() and kvm_mmu_load() are total overkills in 
any case).

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.