Re: [tip:efi/core] x86/efi: Unmap EFI boot services code/data regions from efi_pgd

[Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>]

On Sat, 22 Dec, at 12:07:48PM, Ard Biesheuvel wrote:
> On Fri, 21 Dec 2018 at 20:29, Borislav Petkov <bp@xxxxxxxxx> wrote:
> >
> > On Fri, Dec 21, 2018 at 06:26:23PM +0100, Ard Biesheuvel wrote:
> > > On Fri, 21 Dec 2018 at 18:13, Borislav Petkov <bp@xxxxxxxxx> wrote:
> > > >
> > > > On Fri, Dec 21, 2018 at 06:02:29PM +0100, Ard Biesheuvel wrote:
> > > > > As far as I can tell, the SGI x86 UV platforms still rely on this, so
> > > > > we're stuck with it for the foreseeable future.
> > > >
> > > > What happened with the old apple laptops which couldn't handle high
> > > > virtual mappings and needed 1:1? We don't care anymore?
> > > >
> > >
> > > If that is the case (I wouldn't know) then yes, there is a second
> > > reason why we need to keep this code.
> >
> > Fleming knows details and he's on CC, lemme "pull" him up into To: :-)
> >
> 
> IIUC the 1:1 mapping and the 'old' mapping are two different things,
> and the new mapping also contains a 1:1 mapping of the boot services
> regions, at least until SetVirtualAddressMap() returns.

Yep, they're different. And yes the 1:1 mapping should stick around
with the new scheme IIRC (it's been a while).