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SubjectRe: [PATCH v5 6/9] KVM: MMU: introduce pte_prefetch_topup_memory_cache()


Avi Kivity wrote:
> On 07/13/2010 08:48 AM, Xiao Guangrong wrote:
>>
>>> Right. We should fix those too.
>>>
>>> Prefetch is much more worrying though, especially with ept. If a guest
>>> is using just 1/8 of the pages, it can look to migration as if it's
>>> using 100% of the pages. The impact can be pretty large.
>>>
>> We disabled prefetch if ept is enabled since it can break access bit
>> tracking.
>>
>
> Oh yes.
>
>> I'll fix the dirty bit tracking before post the new version of this
>> patchset.
>>
>
> Should be simple - disable prefetch for slots that have dirty tracking
> enabled.

Agree.

>
> What about the Linux accessed and dirty bits? Need to instantiate the
> speculative sptes with accessed and dirty bits clear (and later examine
> them when we release the page).
>

I see, will do :-)


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