linux-kernel - Re: [PATCH v5 02/13] x86/sev: Check for the presence of an SVSM in the SNP Secrets page

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Message-ID: <952085da-d209-5144-19ef-26c5e7b03cfb@amd.com>
Date: Wed, 5 Jun 2024 16:17:07 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: Borislav Petkov <bp@...en8.de>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org, linux-coco@...ts.linux.dev,
 svsm-devel@...onut-svsm.dev, Thomas Gleixner <tglx@...utronix.de>,
 Ingo Molnar <mingo@...hat.com>, Dave Hansen <dave.hansen@...ux.intel.com>,
 "H. Peter Anvin" <hpa@...or.com>, Andy Lutomirski <luto@...nel.org>,
 Peter Zijlstra <peterz@...radead.org>,
 Dan Williams <dan.j.williams@...el.com>, Michael Roth
 <michael.roth@....com>, Ashish Kalra <ashish.kalra@....com>
Subject: Re: [PATCH v5 02/13] x86/sev: Check for the presence of an SVSM in
 the SNP Secrets page

On 6/5/24 14:38, Borislav Petkov wrote:
> On Wed, Jun 05, 2024 at 10:18:45AM -0500, Tom Lendacky wrote:
>> During early boot phases, check for the presence of an SVSM when running
>> as an SEV-SNP guest.
>>
>> An SVSM is present if not running at VMPL0 and the 64-bit value at offset
>> 0x148 into the secrets page is non-zero. If an SVSM is present, save the
>> SVSM Calling Area address (CAA), located at offset 0x150 into the secrets
>> page, and set the VMPL level of the guest, which should be non-zero, to
>> indicate the presence of an SVSM.
>>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
>> ---
>>   .../arch/x86/amd-memory-encryption.rst        | 23 ++++++
>>   arch/x86/boot/compressed/sev.c                | 21 +++---
>>   arch/x86/include/asm/sev-common.h             |  4 ++
>>   arch/x86/include/asm/sev.h                    | 34 ++++++++-
>>   arch/x86/kernel/sev-shared.c                  | 71 +++++++++++++++++++
>>   arch/x86/kernel/sev.c                         |  7 ++
>>   6 files changed, 151 insertions(+), 9 deletions(-)
> 
> I did some touch-ups ontop:

Works for me, thanks!

Tom

>