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

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Message-ID: <96417897-8bf0-e60c-6285-7286673ecd01@amd.com>
Date:   Tue, 25 Feb 2020 12:10:53 -0600
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Ard Biesheuvel <ardb@...nel.org>
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 2/25/20 11:58 AM, Ard Biesheuvel wrote:
> 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.

I had just assumed you wanted a cleaner version and didn't realize that
rng_seed was removed from struct efi. My bad for not building.

> 
> 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.

Ok, I'll re-work the patch.

Thanks,
Tom

>