From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754008AbZH3UCx (ORCPT ); Sun, 30 Aug 2009 16:02:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753975AbZH3UCx (ORCPT ); Sun, 30 Aug 2009 16:02:53 -0400 Received: from terminus.zytor.com ([198.137.202.10]:35387 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753962AbZH3UCw (ORCPT ); Sun, 30 Aug 2009 16:02:52 -0400 Message-ID: <4A9ADAC3.3020004@zytor.com> Date: Sun, 30 Aug 2009 13:02:11 -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 , 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: [PATCH 3/3] x86, AMD: Disable wrongly set X86_FEATURE_LAHF_LM CPUID bit References: <1251633031-2244-1-git-send-email-petkovbb@gmail.com> <1251633031-2244-3-git-send-email-petkovbb@gmail.com> <4A9AD17A.6060507@zytor.com> <20090830193039.GB22234@liondog.tnic> In-Reply-To: <20090830193039.GB22234@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 08/30/2009 12:30 PM, Borislav Petkov wrote: > On Sun, Aug 30, 2009 at 12:22:34PM -0700, H. Peter Anvin wrote: >> On 08/30/2009 04:50 AM, Borislav Petkov wrote: >>> clear_cpu_cap(c, X86_FEATURE_LAHF_LM); >>> + if (!rdmsrl_amd_safe(0xc001100d, &val)) { >>> + val &= ~(1ULL << 32); >>> + wrmsr_amd_safe(0xc001100d, (u32) val, >>> + (u32)(val >> 32)); >>> + } >>> + } >> We presumably want/need wrmsrl_amd_safe() here! > > Actually, it is wrmsr_amd_safe() because we need the magic value in > %edi. wrmsr_amd_safe() calls the _regs variant with the array argument. > And we don't have a wrmsrl_amd_safe-one which gets a 64bit msr value as > an argument similar to the rdmsrl one. > That's exactly the point. We shouldn't have rdmsrl_amd_safe() on one hand and wrmsr_asm_safe() on the other. I have already fixed this up in my tree, but this kind of asymmetry should have been a big red flashing light. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.