linux-kernel - Re: [PATCH v2 3/5] x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path

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] [day] [month] [year] [list]

Message-ID: <20201021124946.GA30514@8bytes.org>
Date:   Wed, 21 Oct 2020 14:49:46 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     Joerg Roedel <jroedel@...e.de>, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Kees Cook <keescook@...omium.org>,
        Martin Radev <martin.b.radev@...il.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/5] x86/boot/compressed/64: Check SEV encryption in
 64-bit boot-path

On Tue, Oct 20, 2020 at 12:04:28PM -0400, Arvind Sankar wrote:
> This is called from both assembly and C, but anyway, you're already
> assuming r10 and r11 can be clobbered safely, and you just took out the
> save/restores in set_sev_encryption_mask, which is actually called only
> from assembly.

Alright, maybe I was a bit too caucious. I changed the CR4 handling to
use %r8 and %r9 instead, which are also clobbered.

Regards,

	Joerg