From owner-cvs-all@FreeBSD.ORG Sun Nov 11 02:26:47 2007 Return-Path: Delivered-To: cvs-all@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C8A5D16A41A for ; Sun, 11 Nov 2007 02:26:47 +0000 (UTC) (envelope-from cperciva@freebsd.org) Received: from pd2mo1so.prod.shaw.ca (idcmail-mo1so.shaw.ca [24.71.223.10]) by mx1.freebsd.org (Postfix) with ESMTP id 9A25813C48D for ; Sun, 11 Nov 2007 02:26:47 +0000 (UTC) (envelope-from cperciva@freebsd.org) Received: from pd3mr3so.prod.shaw.ca (pd3mr3so-qfe3.prod.shaw.ca [10.0.141.179]) by l-daemon (Sun ONE Messaging Server 6.0 HotFix 1.01 (built Mar 15 2004)) with ESMTP id <0JRB00F46LGAJ220@l-daemon> for cvs-all@FreeBSD.org; Sat, 10 Nov 2007 19:26:34 -0700 (MST) Received: from pn2ml10so.prod.shaw.ca ([10.0.121.80]) by pd3mr3so.prod.shaw.ca (Sun Java System Messaging Server 6.2-7.05 (built Sep 5 2006)) with ESMTP id <0JRB0055MLGAV600@pd3mr3so.prod.shaw.ca> for cvs-all@FreeBSD.org; Sat, 10 Nov 2007 19:26:35 -0700 (MST) Received: from hexahedron.daemonology.net ([24.82.201.197]) by l-daemon (Sun ONE Messaging Server 6.0 HotFix 1.01 (built Mar 15 2004)) with SMTP id <0JRB00L0DLG9MY50@l-daemon> for cvs-all@FreeBSD.org; Sat, 10 Nov 2007 19:26:34 -0700 (MST) Received: (qmail 1388 invoked from network); Sun, 11 Nov 2007 02:26:32 +0000 Received: from unknown (HELO hexahedron.daemonology.net) (127.0.0.1) by localhost with SMTP; Sun, 11 Nov 2007 02:26:32 +0000 Date: Sat, 10 Nov 2007 18:26:31 -0800 From: Colin Percival In-reply-to: <47349F8D.5040509@FreeBSD.org> To: Kris Kennaway Message-id: <47366857.7050802@freebsd.org> MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit X-Enigmail-Version: 0.95.0 References: <200711081945.lA8JjKcW080540@repoman.freebsd.org> <47337724.9040108@FreeBSD.org> <47340B7F.6040505@freebsd.org> <47349F8D.5040509@FreeBSD.org> User-Agent: Thunderbird 2.0.0.6 (X11/20071102) Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/amd64/amd64 mp_machdep.c src/sys/i386/i386 mp_machdep.c X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Nov 2007 02:26:47 -0000 Kris Kennaway wrote: > Colin Percival wrote: >> To quote core@, whom I agree with on this point: >> We think this decision should be revisited once at least one of the >> following occur: new crypto code is made available by crypto vendors to >> address cache-related attacks, or sufficient work is performed on >> scheduling and protection mechanisms to prevent the attack from being >> exploited. >> >> When I have time, I'm working on a cryptographic library ... > > Sounds possibly infeasible and at the very least a long way off. Is it > appropriate to continue to leave hyperthreading disabled for the > indefinite future pending the completion of a library you hope to one > day write? You seem to be ignoring the second half of core's criteria for revisiting this decision: "or sufficient work is performed on scheduling and protection mechanisms to prevent the attack from being exploited". This certainly seems to be the route which involves less work -- but since my expertise is in cryptography rather than schedulers, I can only work on the cryptographic option. Colin Percival