From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758219Ab3BKRWt (ORCPT ); Mon, 11 Feb 2013 12:22:49 -0500 Received: from terminus.zytor.com ([198.137.202.10]:38317 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757879Ab3BKRWs (ORCPT ); Mon, 11 Feb 2013 12:22:48 -0500 Message-ID: <511928B2.6000302@zytor.com> Date: Mon, 11 Feb 2013 09:21:54 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Borislav Petkov , X86 ML , LKML , Borislav Petkov Subject: Re: [PATCH 3/4] x86, head_32: Remove second CPUID detection from default_entry References: <1360592538-10643-1-git-send-email-bp@alien8.de> <1360592538-10643-4-git-send-email-bp@alien8.de> <18557aed-383a-4454-8222-3d2c0f0a78be@email.android.com> <20130211171541.GD2683@pd.tnic> In-Reply-To: <20130211171541.GD2683@pd.tnic> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/11/2013 09:15 AM, Borislav Petkov wrote: > On Mon, Feb 11, 2013 at 07:49:14AM -0800, H. Peter Anvin wrote: >> What about CPUs with inconsistent cpuid levels? Yes, they can and do >> happen, as we discussed on IRC. > > Yes, this should still work. We're doing the EFLAGS.ID dance right at > the beginning of default_entry on each cpu and cache cpuld level in > new_cpu_data for the time we're in this code. > > What this particular patch removes is the yet-another EFLAGS.ID dance > which we IMHO unnecessarily did after enabling paging. > > So basically nothing changes wrt handling inconsistent cpuid levels and > MSR mis-programming - we still should be taking care of those cases. > Cool. I misread your 0/4 cover and hadn't quite dug into the details yet. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.