From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:46323) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tclby-0000SV-Kp for qemu-devel@nongnu.org; Sun, 25 Nov 2012 18:27:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Tclbx-0005a0-9C for qemu-devel@nongnu.org; Sun, 25 Nov 2012 18:27:42 -0500 Date: Mon, 26 Nov 2012 10:24:30 +1100 From: David Gibson Message-ID: <20121125232430.GF4071@truffula.fritz.box> References: <50ACD6AC.6030001@suse.de> <20121121152737.GC5730@redhat.com> <20121122022718.GY18362@truffula.fritz.box> <20121122072303.GA23260@redhat.com> <20121123041307.GD5588@truffula.fritz.box> <20121123105323.GB7051@redhat.com> <20121123125951.GC4071@truffula.fritz.box> <20121123134414.GA9153@redhat.com> <003DB287-169A-4A79-BE7D-5507DB1BEC92@suse.de> <20121123140158.GB9153@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121123140158.GB9153@redhat.com> Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH 12/12] pseries: Generate unique LIOBNs for PCI host bridges List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: "qemu-ppc@nongnu.org List" , Alexander Graf , qemu-devel qemu-devel On Fri, Nov 23, 2012 at 04:01:58PM +0200, Michael S. Tsirkin wrote: > On Fri, Nov 23, 2012 at 02:44:15PM +0100, Alexander Graf wrote: > > > > On 23.11.2012, at 14:44, Michael S. Tsirkin wrote: > > > > > On Fri, Nov 23, 2012 at 11:59:51PM +1100, David Gibson wrote: > > >>> Look, even if solution using a required property is less elegant for CLI > > >>> use, it will work, won't it? > > >>> So how about we merge it so that things work, and then we can discuss a > > >>> patch on top that auto-generates this property? > > >> > > >> Well, there you have a point. And actually I've realised there are > > >> other things we need to assign uniquely for each PHB and don't yet (IO > > >> window addresses). So I need to look at a wider rework of this, which > > >> I'll start on next week. > > > > > > Fine. Basically my point is it's typically a mistake to > > > make some userspace visible parameter depend on order > > > of initialization of devices in qemu. I don't insist > > > on making users fully specify such parameters but it > > > is one way to do this. > > > > I think it's reasonable to require to be able to specify it. If you > > don't, it's fine to base on device order IMHO. > > Let me clarify why it's not fine. My understanding is these addresses > do not change across reboots on real hardware. Well, the BUID would be expected to remain the same. The others probably remain stable across reboots in practice, but I don't think there's any reason they need to - the kernel will get the LIOBN and window addresses from the device tree afresh on every boot. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson