linux-kernel - Re: [PATCH v2] x86/efi: Add additional efi tables for unencrypted mapping checks

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Message-ID: <CAKv+Gu_0LUY67DwSLU1tyijuF+0mKPpvq1j3RSMy5HBxYE-3qw@mail.gmail.com>
Date:   Tue, 25 Feb 2020 18:58:18 +0100
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Tom Lendacky <thomas.lendacky@....com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        linux-efi <linux-efi@...r.kernel.org>,
        platform-driver-x86@...r.kernel.org,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v2] x86/efi: Add additional efi tables for unencrypted
 mapping checks

On Tue, 25 Feb 2020 at 18:54, Tom Lendacky <thomas.lendacky@....com> wrote:
>
> On 2/25/20 11:45 AM, Ard Biesheuvel wrote:
> > On Tue, 25 Feb 2020 at 18:41, Tom Lendacky <thomas.lendacky@....com> wrote:
> >>
> >> When booting with SME active, EFI tables must be mapped unencrypted since
> >> they were built by UEFI in unencrypted memory. Update the list of tables
> >> to be checked during early_memremap() processing to account for new EFI
> >> tables.
> >>
> >> This fixes a bug where an EFI TPM log table has been created by UEFI, but
> >> it lives in memory that has been marked as usable rather than reserved.
> >>
> >> Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
> >>
> >> ---
> >> Changes since v1:
> >> - Re-spun against EFI tree
> >
> > Which one? Surely not the one in the link I included?
>
> I did a git clone of
>
>   git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git
>
> and checked out branch next. Not sure what I missed...
>

Weird. Do you see commit 5d288dbd88606d8f215c7138b10649115d79cadd on
that branch? It removes rng_seed from struct efi, hence my request to
rebase your patch.

IMO, best is to simply drop the 'static' from rng_seed, rename it to
efi_rng_seed, and drop an extern declaration in linux/efi.h so it is
accessible from your code. I'm reluctant to put it back in struct efi.