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Date:   Mon, 7 Jan 2019 15:57:52 +0000
From:   Matt Fleming <matt@codeblueprint.co.uk>
To:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc:     Borislav Petkov <bp@alien8.de>,
        "Prakhya, Sai Praneeth" <sai.praneeth.prakhya@intel.com>,
        Ingo Molnar <mingo@kernel.org>,
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Subject: Re: [tip:efi/core] x86/efi: Unmap EFI boot services code/data
 regions from efi_pgd
Message-ID: <20190107155356.GA7578@codeblueprint.co.uk>
References: <FFF73D592F13FD46B8700F0A279B802F48604575@ORSMSX114.amr.corp.intel.com>
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 <20181221171308.GJ1325@zn.tnic>
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On Sat, 22 Dec, at 12:07:48PM, Ard Biesheuvel wrote:
> On Fri, 21 Dec 2018 at 20:29, Borislav Petkov <bp@alien8.de> 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@alien8.de> 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).