linux-kernel - Re: [PATCH v2 2/2] x86/sev: Add callback to apply RMP table fixups for kexec.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5d515e4e-5db8-4840-a200-a67e7df8043b@amd.com>
Date: Fri, 26 Apr 2024 09:56:25 -0500
From: "Kalra, Ashish" <ashish.kalra@....com>
To: Borislav Petkov <bp@...en8.de>
Cc: thomas.lendacky@....com, michael.roth@....com, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] x86/sev: Add callback to apply RMP table fixups
 for kexec.

On 4/26/2024 7:58 AM, Borislav Petkov wrote:

> On Wed, Apr 24, 2024 at 06:48:08PM -0500, Kalra, Ashish wrote:
>> This callback needs to be invoked as part of setup_arch() as it needs e820
>> table to be setup in e820__memory_setup() before the callback is invoked and
>> snp_init() is called from sme_enable() in kernel/head_64.S (startup_64),
>> which is much before start_kernel() -> setup_arch() is invoked.
> So?
>
> snp_init() still runs before e820__memory_setup(). So what's stopping
> you?

As i have already explained above, snp_init() runs before 
e820__memory_setup() so we can't invoke this callback in snp_init() as 
e820 tables have still not been setup. Again to summarize, the e820 
tables are setup in e820__memory_setup() which runs after snp_init().

Additionally, RMP table also get probed after snp_init(). So this 
callback cannot be invoked in snp_init().

I have added this comment to v3 of this patch series which i posted 
yesterday, so please look at those.

Thanks, Ashish