Re: [PATCH v2 1/3] KVM: x86: Allow CPU to force vendor-specific TDP level

Yu Zhang
2021-08-10T14:37:50Z

On Tue, Aug 10, 2021 at 02:47:27PM +0200, Paolo Bonzini wrote:
> On 10/08/21 13:00, Yu Zhang wrote:
> > I guess it's because, unlike EPT which are with either 4 or 5 levels, NPT's
> > level can range from 2 to 5, depending on the host paging mode...
>
> Yes, on Linux that will be one of 3/4/5 based on host paging mode, and it
> will apply to all N_CR3...
>
> > But shadow EPT does not have such annoyance. Is above understanding correct?
>
> ... Right, because shadow EPT cannot have less than 4 levels, and it can
> always use 4 levels if that's what L1 uses.

Interesting. :) Thanks a lot for the explanation!

B.R.
Yu