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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Sun, 6 Aug 2023 00:19:46 +0200
Message-ID: <CAMj1kXE+jgLztL1mQ6VDkJWfAjSJnxapoUAsvqaSQmfi=kr=hg@mail.gmail.com>
Subject: Re: [PATCH v8 00/23] efi/x86: Avoid bare metal decompressor during
 EFI boot
To:     Borislav Petkov <bp@alien8.de>
Cc:     linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Evgeniy Baskov <baskov@ispras.ru>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Alexey Khoroshilov <khoroshilov@ispras.ru>,
        Peter Jones <pjones@redhat.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Dave Young <dyoung@redhat.com>,
        Mario Limonciello <mario.limonciello@amd.com>,
        Kees Cook <keescook@chromium.org>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Joerg Roedel <jroedel@suse.de>
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On Sat, 5 Aug 2023 at 23:07, Borislav Petkov <bp@alien8.de> wrote:
>
> On Sat, Aug 05, 2023 at 07:37:17PM +0200, Ard Biesheuvel wrote:
> > So this is the host booting, right?
>
> Yes.
>
> > So is the position of the C bit perhaps getting detect incorrectly?
>
> I don't know yet. But the evildoer is someone else:
>
> 02d47ce2ae02 ("x86/head_64: Store boot_params pointer in callee save register")
>
> after bisection. More staring later as to why...
>

How bizarre.

But that was a bonus patch anyway, so we could just drop it for now.