From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758759AbZEKT20 (ORCPT ); Mon, 11 May 2009 15:28:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755948AbZEKT2E (ORCPT ); Mon, 11 May 2009 15:28:04 -0400 Received: from terminus.zytor.com ([198.137.202.10]:42027 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756986AbZEKT2D (ORCPT ); Mon, 11 May 2009 15:28:03 -0400 Message-ID: <4A087BF8.9010709@zytor.com> Date: Mon, 11 May 2009 12:26:48 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Robert Richter CC: Jaswinder Singh Rajput , Ingo Molnar , "H. Peter Anvin" , x86 maintainers , LKML Subject: Re: [git-pull -tip] x86: Addition of cpufeatures to friendly access miscellaneous MSRs References: <1242058494.5139.7.camel@ht.satnam> <4A086B58.30607@zytor.com> <20090511184727.GF10722@erda.amd.com> In-Reply-To: <20090511184727.GF10722@erda.amd.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Robert Richter wrote: > > Anyway, I think this was already decided. So, maybe for debugging we > should simply read the msrs with rdmsr_safe() and use the exception > handler to check if the msr is implemented. This would avoid most of > the otherwise unused cpufeature flags above. > For that use, it's probably the right thing to do. (FWIW, I agree that dumping MSRs in userspace is the right thing to do. This is being heavily discussed on the util-linux-ng list, as far as I can tell.) -hpa