linux-kernel - Re: [PATCH v4 2/2] x86/devmem: Drop /dev/mem access for confidential guests

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: <9a4b347f-9a18-4578-9031-0d1bc98e668d@intel.com>
Date: Mon, 28 Apr 2025 08:53:47 -0700
From: Dave Hansen <dave.hansen@...el.com>
To: Dan Williams <dan.j.williams@...el.com>, dave.hansen@...ux.intel.com
Cc: x86@...nel.org, Kees Cook <kees@...nel.org>,
 Ingo Molnar <mingo@...nel.org>, Naveen N Rao <naveen@...nel.org>,
 Vishal Annapurve <vannapurve@...gle.com>,
 Kirill Shutemov <kirill.shutemov@...ux.intel.com>,
 Nikolay Borisov <nik.borisov@...e.com>, stable@...r.kernel.org,
 linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/2] x86/devmem: Drop /dev/mem access for confidential
 guests

On 4/18/25 13:04, Dan Williams wrote:
> Nikolay reports [1] that accessing BIOS data (first 1MB of the physical
> address space) via /dev/mem results in an SEPT violation.

Would most developers reading this know what an "SEPT violation" is or
what its implications are?

This results in an immediate exit from and termination of the TDX guest,
right?