Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753996AbYJAVbO (ORCPT ); Wed, 1 Oct 2008 17:31:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753410AbYJAVa5 (ORCPT ); Wed, 1 Oct 2008 17:30:57 -0400 Received: from yx-out-2324.google.com ([74.125.44.29]:30277 "EHLO yx-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752349AbYJAVa4 (ORCPT ); Wed, 1 Oct 2008 17:30:56 -0400 Message-ID: <48E3EBCC.70502@codemonkey.ws> Date: Wed, 01 Oct 2008 16:29:48 -0500 From: Anthony Liguori User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: akataria@vmware.com CC: Jeremy Fitzhardinge , "avi@redhat.com" , Rusty Russell , Gerd Hoffmann , "H. Peter Anvin" , 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> <48E3BBC1.2050607@goop.org> <1222894878.9381.63.camel@alok-dev1> <48E3E6DF.8060400@codemonkey.ws> <1222896215.9381.79.camel@alok-dev1> In-Reply-To: <1222896215.9381.79.camel@alok-dev1> 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 Content-Length: 1146 Lines: 28 Alok Kataria wrote: > Your explanation below answers the question you raised, the problem > being we need to have support for each of these different hypercall > mechanisms in the kernel. > I understand that this was the correct thing to do at that moment. > But do we want to go the same way again for CPUID when we can make it > generic (flat enough) for anybody to use it in the same manner and > expose a generic interface to the kernel. > But what sort of information can be stored in cpuid that's actually useful? Right now we just it in KVM for feature bits. Most of the stuff that's interesting is stored in shared memory because a guest can read that without taking a vmexit or via a hypercall. We can all agree upon a common mechanism for doing something but if no one is using that mechanism to do anything significant, what purpose does it serve? Regards, Anthony Liguori -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/