Re: [PATCHv5 08/19] x86/mm: Introduce variables to store number, shift and mask of KeyIDs

From: Kirill A. Shutemov
Date: Fri Jul 20 2018 - 08:35:01 EST


On Thu, Jul 19, 2018 at 07:23:27AM -0700, Dave Hansen wrote:
> On 07/19/2018 03:21 AM, Kirill A. Shutemov wrote:
> > On Wed, Jul 18, 2018 at 04:19:10PM -0700, Dave Hansen wrote:
> >> On 07/17/2018 04:20 AM, Kirill A. Shutemov wrote:
> >>> mktme_nr_keyids holds number of KeyIDs available for MKTME, excluding
> >>> KeyID zero which used by TME. MKTME KeyIDs start from 1.
> >>>
> >>> mktme_keyid_shift holds shift of KeyID within physical address.
> >> I know what all these words mean, but the combination of them makes no
> >> sense to me. I still don't know what the variable does after reading this.
> >>
> >> Is this the lowest bit in the physical address which is used for the
> >> KeyID? How many bits you must shift up a KeyID to get to the location
> >> at which it can be masked into the physical address?
> > Right.
> >
> > I'm not sure what is not clear from the description. It look fine to me.
>
> Well, OK, I guess I can write a better one for you.
>
> "Position in the PTE of the lowest bit of the KeyID"
>
> It's also a name that could use some love (now that I know what it
> does). mktme_keyid_pte_shift would be much better. Or
> mktme_keyid_low_pte_bit.

Okay, thanks.

--
Kirill A. Shutemov