From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [Qemu-devel] [PATCHv2 4/8] Store IDE bus id in IDEBus structure for easy access. Date: Fri, 5 Nov 2010 20:44:56 +0200 Message-ID: <20101105184456.GD9617@redhat.com> References: <20101103164308.GJ7881@redhat.com> <20101104080730.GA6018@redhat.com> <20101104092348.GB6018@redhat.com> <20101104152631.GA14910@redhat.com> <20101105155427.GB9617@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: blauwirbel@gmail.com, alex.williamson@redhat.com, qemu-devel@nongnu.org, kvm@vger.kernel.org To: Markus Armbruster Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42134 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753293Ab0KESo7 (ORCPT ); Fri, 5 Nov 2010 14:44:59 -0400 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Fri, Nov 05, 2010 at 05:31:38PM +0100, Markus Armbruster wrote: > Gleb Natapov writes: > > > On Fri, Nov 05, 2010 at 03:04:05PM +0100, Markus Armbruster wrote: > [...] > >> >> >> There has been quite some discussion on "canonical path" on the list, > >> >> >> but no consensus. Ironically, one of the places where we got stuck was > >> >> >> ISA. You cut right through that, so that's progress. Maybe people > >> >> >> aren't looking ;) > >> >> > That is funny since the problem was already solved looong time ago. Just > >> >> > look at Open Firmware device path. They are capable of addressing all > >> >> > devices just fine, ISA devices included. What specific problem you had > >> >> > with ISA bus? > >> >> > >> >> Lack of consensus. I was in favour of using I/O base, just like you do. > >> >> There were worries about ISA devices not using any I/O ports. > >> > There is a solution for that problem for almost 15 years and we are > >> > still looking for consensus on qemu list?! Here is ISA device binding > >> > spec for Open Firmware: http://playground.sun.com/1275/bindings/isa/isa0_4d.ps > >> > If ISA device have no IO ports MMIO is used. > >> > >> Precedence should promote consensus, but it can't replace it. If you > >> can push the list to consensus, more power to you. > > I do not see disagreement right now :) You are saying you agree. Blue > > Swirl asked me to use Open Firmware so I assume he agrees to. So who is > > against and what are his arguments? > > Start here: > > http://lists.nongnu.org/archive/html/qemu-devel/2010-06/msg01618.html I saw this in fact. The wouldn't agree with this device path proposal too. It mixes qemu internal names (which is a big no-no for my purpose) and bus addresses. Paul made sensible points there and if you look closely what he proposes is what I implemented here. Regarding ISA ("busses that don't have a consistent addressing scheme" he called it) he himself proposed to use address of the first IO port/memory region as an ID. This is what is already implemented by my patch. -- Gleb.