linux-kernel - Re: [PATCH v5 3/6] x86/sev: Split off startup code from core code

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Message-ID: <CAMj1kXGDyM-W1umDsBGO17+UqczhODBcb73StPELfOAQN2_V2A@mail.gmail.com>
Date: Wed, 23 Apr 2025 17:50:00 +0200
From: Ard Biesheuvel <ardb@...nel.org>
To: Tom Lendacky <thomas.lendacky@....com>
Cc: Ard Biesheuvel <ardb+git@...gle.com>, linux-kernel@...r.kernel.org, 
	linux-efi@...r.kernel.org, x86@...nel.org, mingo@...nel.org, 
	Dionna Amalie Glaze <dionnaglaze@...gle.com>, Kevin Loughlin <kevinloughlin@...gle.com>
Subject: Re: [PATCH v5 3/6] x86/sev: Split off startup code from core code

On Wed, 23 Apr 2025 at 17:22, Tom Lendacky <thomas.lendacky@....com> wrote:
>
> On 4/18/25 09:12, Ard Biesheuvel wrote:
> > From: Ard Biesheuvel <ardb@...nel.org>
> >
> > Disentangle the SEV core code and the SEV code that is called during
> > early boot. The latter piece will be moved into startup/ in a subsequent
> > patch.
> >
> > Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
>
> This patch breaks SNP guests. The SNP guest boots, but no longer has
> access to the VMPCK keys needed to communicate with the ASP, which is
> used, for example, to obtain an attestation report.
>
> It looks like the secrets_pa is defined as static in both startup.c and
> core.c. It is set by a function in startup.c and so when used in core.c
> its value will be 0.
>
> The following fixed the issue for me. Let me know if it can be squashed
> in or a full patch is needed. Although, it likely should be named
> sev_secrets_pa since it is no longer static.
>

Thanks for the fix, and apologies for using you as a guinea pig - I've
been struggling to get access to SEV-SNP capable hardware, although a
suitable EPYC based machine should be arriving in a month or 2.

I'd assume a proper patch is better, and renaming it to sev_secrets_pa
doesn't seem that intrusive. But it is ultimately Ingo's call.