From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754300AbYJASGl (ORCPT ); Wed, 1 Oct 2008 14:06:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753364AbYJASGb (ORCPT ); Wed, 1 Oct 2008 14:06:31 -0400 Received: from gw.goop.org ([64.81.55.164]:45285 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753383AbYJASGa (ORCPT ); Wed, 1 Oct 2008 14:06:30 -0400 Message-ID: <48E3BC21.4080803@goop.org> Date: Wed, 01 Oct 2008 11:06:25 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.16 (X11/20080919) MIME-Version: 1.0 To: akataria@vmware.com CC: "H. Peter Anvin" , "avi@redhat.com" , Rusty Russell , Gerd Hoffmann , Ingo Molnar , the arch/x86 maintainers , LKML , "Nakajima, Jun" , Daniel Hecht , Zach Amsden , "virtualization@lists.linux-foundation.org" , "kvm@vger.kernel.org" Subject: Re: [RFC] CPUID usage for interaction between Hypervisors and Linux. References: <1222881242.9381.17.camel@alok-dev1> <48E3B19D.6060905@zytor.com> <1222882431.9381.23.camel@alok-dev1> In-Reply-To: <1222882431.9381.23.camel@alok-dev1> X-Enigmail-Version: 0.95.6 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 Alok Kataria wrote: > Its not a user who has to do anything special here. > There are *intelligent* VM developers out there who can export a > different CPUid interface depending on the guest OS type. And this is > what most of the hypervisors do (not necessarily for CPUID, but for > other things right now). > No, that's always a terrible idea. Sure, its necessary to deal with some backward-compatibility issues, but we should even consider a new interface which assumes this kind of thing. We want properly enumerable interfaces. J