From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.7 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id E2A867D2F0 for ; Fri, 16 Aug 2019 14:43:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727326AbfHPOnf (ORCPT ); Fri, 16 Aug 2019 10:43:35 -0400 Received: from charlotte.tuxdriver.com ([70.61.120.58]:42833 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727245AbfHPOnf (ORCPT ); Fri, 16 Aug 2019 10:43:35 -0400 Received: from cpe-2606-a000-1405-226e-0-0-0-cbf.dyn6.twc.com ([2606:a000:1405:226e::cbf] helo=localhost) by smtp.tuxdriver.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.63) (envelope-from ) id 1hydRo-0001vH-GH; Fri, 16 Aug 2019 10:43:26 -0400 Date: Fri, 16 Aug 2019 10:42:45 -0400 From: Neil Horman To: "Theodore Y. Ts'o" , Pavel Machek , "Lendacky, Thomas" , "linux-kernel@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-pm@vger.kernel.org" , "x86@kernel.org" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "Rafael J . Wysocki" , Chen Yu , Jonathan Corbet Subject: Re: Non-random RDRAND Re: [PATCH] x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h Message-ID: <20190816144245.GA25489@localhost.localdomain> References: <776cb5c2d33e7fd0d2893904724c0e52b394f24a.1565817448.git.thomas.lendacky@amd.com> <20190814232434.GA31769@amd> <20190815151224.GB18727@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190815151224.GB18727@mit.edu> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, Aug 15, 2019 at 11:12:24AM -0400, Theodore Y. Ts'o wrote: > On Thu, Aug 15, 2019 at 01:24:35AM +0200, Pavel Machek wrote: > > Burn it with fire! > > > > I mean... people were afraid RDRAND would be backdoored, and you now > > confirm ... it indeed _is_ backdoored? /., here's news for you! > > To be fair to AMD, I wouldn't call it a backdoor. Hanlon's razor is > applicable here: > > "Never attribute to malice that which can be adequately > explained by neglect." > > (Sometimes other words are used instead of neglect, but i'm trying to > be nice.) > Is it worth setting up a quirk for the Excavator era cpus, that triggers a call to rdseed on resume? Working under the assumption that calling rdseed would kick the rdrand instruction back into gear. Neil > > - Ted > > P.S. Also applicable: > > https://www.youtube.com/watch?v=XZxzJGgox_E >