From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753687AbXDCVp7 (ORCPT ); Tue, 3 Apr 2007 17:45:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753686AbXDCVp7 (ORCPT ); Tue, 3 Apr 2007 17:45:59 -0400 Received: from terminus.zytor.com ([192.83.249.54]:33794 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751955AbXDCVp6 (ORCPT ); Tue, 3 Apr 2007 17:45:58 -0400 Message-ID: <4612CAF4.908@zytor.com> Date: Tue, 03 Apr 2007 14:45:24 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 1.5.0.9 (X11/20070212) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Arnd Bergmann , Cornelia Huck , Andi Kleen , Christian Borntraeger , virtualization@lists.linux-foundation.org, Virtualization Mailing List , Linux Kernel Mailing List , mathiasen@gmail.com Subject: Re: A set of "standard" virtual devices? References: <4611652F.700@zytor.com> <200704031951.00544.arnd@arndb.de> <4612A5F0.2080609@goop.org> <200704032142.51976.arnd@arndb.de> <4612B123.2040105@goop.org> <4612B303.5000109@zytor.com> <4612C077.60502@goop.org> In-Reply-To: <4612C077.60502@goop.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: > > So, what you're saying is: > > 1. assuming there's going to be a vast number of miscellaneous devices > 2. it would be best if there were one per device rather than one per > hypervisor per device > 3. so we'd have one linux device driver > > But this implies that the work is just pushed off into all the > hypervisors to support this new device over the generic interface; > there's no overall reduction of code or complexity, other than making > "wc" on the kernel source smaller. > Sure there is, assuming you deal about heterogenous clients. I'm not sure Xen is (although that is, as far as I understand, being remedied), which might explain your different perspective. Consider that this may not even be about Linux -- having these standard devices would enable, say, 'doze device drivers to be written and shared. > That said, something like USB is probably the best bet for this kind of > low-performance device. I think. Not that I really know anything about > USB. USB is evil in the extreme for this kind of stuff. Although in theory you can have any HCI you want, in practice the ones that are implemented requires a very complex framework for full compatiblity. -hpa