RE: [PATCH 1/2] x86/efi: Unmap efi boot services code/data regions from efi_pgd

[Prakhya, Sai Praneeth]

> > The one bit that is odd is the cpa->pfn field - for unmapped pages
> > that's totally uninteresting and I'm wondering whether setting it to 0
> > wouldn't be better.
> >
> > Does the CPU _ever_ look look at the PFN if the page is
> > !_PAGE_PRESENT, for example speculatively? If yes then what is the
> > recommended value for the pfn - zero perhaps?
> >
> 
> This is L1TF, right?  Isn't all ones the recommended value?
> 
> I would love to see EFI start treating its mm just like any other mm at some
> point, though.  That is, it should not modify any mappings in the kernel range,
> and it could use the regular mm modification APIs for the user range.  But maybe
> this is a pipe dream.

Sounds good to me. I have some more fixes for EFI code and as soon as they are done, 
I will start looking into this.

Regards,
Sai