From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754231AbYJAUIY (ORCPT ); Wed, 1 Oct 2008 16:08:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751660AbYJAUIP (ORCPT ); Wed, 1 Oct 2008 16:08:15 -0400 Received: from gw.goop.org ([64.81.55.164]:36375 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751484AbYJAUIO (ORCPT ); Wed, 1 Oct 2008 16:08:14 -0400 Message-ID: <48E3D8A8.604@goop.org> Date: Wed, 01 Oct 2008 13:08:08 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.16 (X11/20080919) MIME-Version: 1.0 To: Anthony Liguori CC: akataria@vmware.com, kvm@vger.kernel.org, the arch/x86 maintainers , Dan Hecht , LKML , virtualization@lists.linux-foundation.org, "avi@redhat.com" , "H. Peter Anvin" , Ingo Molnar Subject: Re: [RFC] CPUID usage for interaction between Hypervisors and Linux. References: <1222881242.9381.17.camel@alok-dev1> <48E3BBC1.2050607__35819.6151479662$1222884502$gmane$org@goop.org> <48E3D7A0.3000403@codemonkey.ws> In-Reply-To: <48E3D7A0.3000403@codemonkey.ws> X-Enigmail-Version: 0.95.6 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 Anthony Liguori wrote: > Mmm, cpuid bikeshedding :-) My shade of blue is better. >> The space 0x40000000-0x400000ff is reserved for hypervisor usage. >> >> This region is divided into 16 16-leaf blocks. Each block has the >> structure: >> >> 0x400000x0: >> eax: max used leaf within the leaf block (max 0x400000xf) > > Why even bother with this? It doesn't seem necessary in your proposal. It allows someone to incrementally add things to their block in a fairly orderly way. But more importantly, its the prevailing idiom, and the existing and proposed cpuid schemes already do this, so they'd fit in as-is. J