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=unavailable 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 0EE2A7D2F0 for ; Wed, 28 Aug 2019 22:05:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726882AbfH1WFj (ORCPT ); Wed, 28 Aug 2019 18:05:39 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:57054 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726875AbfH1WFi (ORCPT ); Wed, 28 Aug 2019 18:05:38 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 74EDA820AE; Thu, 29 Aug 2019 00:05:21 +0200 (CEST) Date: Thu, 29 Aug 2019 00:05:33 +0200 From: Pavel Machek To: Thomas Gleixner Cc: Pavel Machek , Borislav Petkov , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Tom Lendacky , Andrew Cooper , Andrew Morton , Chen Yu , "H. Peter Anvin" , Ingo Molnar , Jonathan Corbet , Josh Poimboeuf , Juergen Gross , Kees Cook , "linux-doc@vger.kernel.org" , "linux-pm@vger.kernel.org" , Nathan Chancellor , Paolo Bonzini , "Rafael J. Wysocki" , "x86@kernel.org" Subject: Re: [PATCH 4.19 72/98] x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h Message-ID: <20190828220533.GA24056@amd> References: <20190828103113.GA14677@amd> <20190828114947.GC8052@amd> <20190828120024.GF4920@zn.tnic> <20190828120935.GD8052@amd> <20190828121628.GG4920@zn.tnic> <20190828122913.GE8052@amd> <20190828124621.GI4920@zn.tnic> <20190828133713.GF8052@amd> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="r5Pyd7+fXNt84Ff3" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org --r5Pyd7+fXNt84Ff3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed 2019-08-28 16:15:06, Thomas Gleixner wrote: > On Wed, 28 Aug 2019, Pavel Machek wrote: > > On Wed 2019-08-28 14:46:21, Borislav Petkov wrote: > > > On Wed, Aug 28, 2019 at 02:29:13PM +0200, Pavel Machek wrote: > > > > This is not a way to have an inteligent conversation. > > >=20 > > > No, this *is* the way to keep the conversation sane, without veering > > > off into some absurd claims. > > >=20 > > > So, to cut to the chase: you can simply add "rdrand=3Dforce" to your > > > cmdline parameters and get back to using RDRAND. > > >=20 > > > And yet if you still feel this fix does not meet your expectations, > > > you were told already to either produce patches or who to contact. I'm > > > afraid complaining on this thread won't get you anywhere but that's y= our > > > call. > >=20 > > No, this does not meet my expectations, it violates stable kernel > > rules, and will cause regression to some users, while better solution > > is known to be available. >=20 > Your unqualified ranting does not meet my expectation either and it > violates any rule of common sense. >=20 > For the record: >=20 > Neither AMD nor we have any idea which particular machines have a fixed > BIOS and which have not. There is no technical indicator either at boot > time as the wreckage manifests itself only after resume. >=20 > So in the interest of users the only sensible decision is to disable > RDRAND for this class of CPUs. No. Obviously best solution would be microcode update to fix the problem, or to enable kernel to fix the problem. > If you have a list of machines which have a fixed BIOS, then provide it > in form of patches. If not then stop claiming that there is a better > solution available. And yes, whitelist would be already better than present solution. It is not my duty to submit fixes to your proposed patch. > Anyway, I'm done with that and further rants of yours go directly to > /dev/null. >=20 > Thanks for wasting everyones time Thanks for your profesional attitude. Pavel --=20 DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany --r5Pyd7+fXNt84Ff3 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl1m+q0ACgkQMOfwapXb+vJDbwCeJQ0WoYyf8A/jB7OEGuIzpOov WaQAn2Wcm/aEi77wq5CWOsCPWQNaLvO6 =Fjjn -----END PGP SIGNATURE----- --r5Pyd7+fXNt84Ff3--