From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: Xen & VMI? Date: Tue, 6 Mar 2007 10:10:06 +0100 Message-ID: <20070306091006.GA26073@elte.hu> References: <1173101297.26165.39.camel@localhost.localdomain> <1173142644.4644.6.camel@localhost.localdomain> <45ECBDDC.8080708@vmware.com> <45ECC076.9050209@goop.org> <45ECC91D.1020809@vmware.com> <45ECC9B6.1060209@goop.org> <20070306081909.GA9331@elte.hu> <45ED2837.3020108@suse.de> <20070306085222.GA17002@elte.hu> <45ED2E63.3070700@vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <45ED2E63.3070700@vmware.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.osdl.org Errors-To: virtualization-bounces@lists.osdl.org To: Zachary Amsden Cc: virtualization , Roland McGrath , Andrew Morton , Linus Torvalds , Jan Beulich , linux-kernel@vger.kernel.org List-Id: virtualization@lists.linuxfoundation.org * Zachary Amsden wrote: > > > reduces the QA effort. You still have 5 Hypervisors you have to = > > > test against. > > > > yes, just like we have thousands of separate PC boards to support. = > > But as long as the basic ABI is the same, the QA effort on the Linux = > > kernel side is alot more focused. (Distros still have = > > 18446744073709551616 total combinations to QA, and have to make an = > > educated guess to reduce that to a more manageable number.) > = > But hardware PC boards don't do anything as remotely complicate as = > changing the semantics required for correctness in you MMU = > implementation. [...] ugh, PC boards are actually far worse and far more diverse than any = variances between hypervisors, but i digress. anyway, my point stands: the Linux kernel is significantly more = maintainable and easier to QA if it has only a single 'external' = hypervisor ABI to worry about - and that might as well be VMI. This is a = really obvious point, i expected the discussion to center more around = the specifics of such a move ;-) Ingo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933166AbXCFJLb (ORCPT ); Tue, 6 Mar 2007 04:11:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934003AbXCFJLa (ORCPT ); Tue, 6 Mar 2007 04:11:30 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:41411 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934002AbXCFJL0 (ORCPT ); Tue, 6 Mar 2007 04:11:26 -0500 Date: Tue, 6 Mar 2007 10:10:06 +0100 From: Ingo Molnar To: Zachary Amsden Cc: Gerd Hoffmann , Jeremy Fitzhardinge , virtualization , Jan Beulich , Andrew Morton , Linus Torvalds , Roland McGrath , linux-kernel@vger.kernel.org Subject: Re: Xen & VMI? Message-ID: <20070306091006.GA26073@elte.hu> References: <1173101297.26165.39.camel@localhost.localdomain> <1173142644.4644.6.camel@localhost.localdomain> <45ECBDDC.8080708@vmware.com> <45ECC076.9050209@goop.org> <45ECC91D.1020809@vmware.com> <45ECC9B6.1060209@goop.org> <20070306081909.GA9331@elte.hu> <45ED2837.3020108@suse.de> <20070306085222.GA17002@elte.hu> <45ED2E63.3070700@vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45ED2E63.3070700@vmware.com> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Zachary Amsden wrote: > > > reduces the QA effort. You still have 5 Hypervisors you have to > > > test against. > > > > yes, just like we have thousands of separate PC boards to support. > > But as long as the basic ABI is the same, the QA effort on the Linux > > kernel side is alot more focused. (Distros still have > > 18446744073709551616 total combinations to QA, and have to make an > > educated guess to reduce that to a more manageable number.) > > But hardware PC boards don't do anything as remotely complicate as > changing the semantics required for correctness in you MMU > implementation. [...] ugh, PC boards are actually far worse and far more diverse than any variances between hypervisors, but i digress. anyway, my point stands: the Linux kernel is significantly more maintainable and easier to QA if it has only a single 'external' hypervisor ABI to worry about - and that might as well be VMI. This is a really obvious point, i expected the discussion to center more around the specifics of such a move ;-) Ingo