From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754608AbZHYGpc (ORCPT ); Tue, 25 Aug 2009 02:45:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754273AbZHYGpb (ORCPT ); Tue, 25 Aug 2009 02:45:31 -0400 Received: from terminus.zytor.com ([198.137.202.10]:38583 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754551AbZHYGpa (ORCPT ); Tue, 25 Aug 2009 02:45:30 -0400 Message-ID: <4A93884E.3000403@zytor.com> Date: Mon, 24 Aug 2009 23:44:30 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Borislav Petkov , Ingo Molnar , mingo@redhat.com, linux-kernel@vger.kernel.org, kjwinchester@gmail.com, tglx@linutronix.de, borislav.petkov@amd.com, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/urgent] x86, AMD: Disable wrongly set X86_FEATURE_LAHF_LM CPUID bit References: <1250251594-8348-2-git-send-email-borislav.petkov@amd.com> <20090816064132.GA16278@elte.hu> <20090816214934.GB7765@liondog.tnic> <4A8EDC02.8000508@zytor.com> <20090822163750.GA31631@liondog.tnic> <4A92F93F.8000502@zytor.com> <20090825055215.GA22595@liondog.tnic> In-Reply-To: <20090825055215.GA22595@liondog.tnic> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/24/2009 10:52 PM, Borislav Petkov wrote: > On Mon, Aug 24, 2009 at 01:34:07PM -0700, H. Peter Anvin wrote: >> Looks reasonable... although part of me wonders if having a pointer to >> an array containing the entire register file in and out is even better, >> of if I'm just overengineering at this point. > > Hmm, let's have necessity determine that. I can only think of %edi being > used as an input reg to rd/wrmsr beside %ecx but it could be very well > that some other x86 hardware uses other regs too. Do we actually need > all regs or a two should suffice? > Hard to know. In theory we shouldn't need ESI and EDI either! As I said, I wouldn't have worried about it at all if it wasn't for paravirt_ops turning these things into ABIs. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.