Re: [PATCH 4/9] Implement hsave v5

[Anthony Liguori <anthony@codemonkey.ws>]

Alexander Graf wrote:
>
> On 30.10.2008, at 19:04, Anthony Liguori wrote:
>
>
>>>
>>>     kmem_cache_free(kvm_vcpu_cache, svm);
>>> }
>>> @@ -1376,6 +1383,9 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, 
>>> unsigned ecx, u64 *data)
>>>     case MSR_IA32_LASTINTTOIP:
>>>         *data = svm->vmcb->save.last_excp_to;
>>>         break;
>>> +    case MSR_VM_HSAVE_PA:
>>> +        *data = 0;
>>> +        break;
>>>
>>
>> I'm confused as to why you aren't allowing userspace to set/get this 
>> MSR?  Wouldn't it be needed for save/restore?
>
> I don't see any benefit from actually exporting that MSR atm. KVM does 
> never read it and it'd just add additional overhead on every userspace 
> transition, as it'd need to be synced every time.

Save and restore?

Regards,

Anthony Liguori

> Alex
>