From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754659AbYI2J3T (ORCPT ); Mon, 29 Sep 2008 05:29:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752566AbYI2J3F (ORCPT ); Mon, 29 Sep 2008 05:29:05 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:36992 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750912AbYI2J3E (ORCPT ); Mon, 29 Sep 2008 05:29:04 -0400 X-IronPort-AV: E=Sophos;i="4.33,330,1220241600"; d="scan'208";a="21762748" Date: Mon, 29 Sep 2008 10:28:55 +0100 From: Tim Deegan To: Jeremy Fitzhardinge Cc: akataria@vmware.com, Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , LKML , the arch/x86 maintainers , "avi@redhat.com" , Rusty Russell , Zach Amsden , Daniel Hecht , "Jun.Nakajima@Intel.Com" Subject: Re: Use CPUID to communicate with the hypervisor. Message-ID: <20080929092855.GK3776@york.uk.xensource.com> References: <1222472815.29886.43.camel@alok-dev1> <48DD860C.50809@goop.org> <1222485079.23825.13.camel@alok-dev1> <48DF0F8D.3070302@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <48DF0F8D.3070302@goop.org> User-Agent: Mutt/1.5.17 (2007-11-01) X-OriginalArrivalTime: 29 Sep 2008 09:29:01.0852 (UTC) FILETIME=[CEF3EDC0:01C92215] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At 22:01 -0700 on 27 Sep (1222552861), Jeremy Fitzhardinge wrote: > Alok Kataria wrote: >>> I think there's a move towards doing a scan for a signature, such as >>> checking every 16 leaves after 0x40000000 for "a while" looking for >>> interesting signatures, so that a hypervisor can support multiple ABIs >>> at once. Given this, it would be better to define a "Generic Hypervisor >>> ABI" signature, and put all the related leaves together. >> >> Hmm interesting, do you have any pointers to this ? > > No. I think I saw a passing reference from Tim Deegan to it, but I > couldn't find it again when I looked. I was talking about checking every 256 leaves from 0x40000000, but I can't remember where I heard it. The only relevant reference I can find is the MS hypervisor interface spec's description of leaf 0x40000001: "Hypervisor vendor-neutral interface identification. This determines the semantics of the leaves from 0x40000002 through 0x400000FF" Cheers, Tim. -- Tim Deegan Principal Software Engineer, Citrix Systems (R&D) Ltd. [Company #02300071, SL9 0DZ, UK.]