From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: Configuration vs. compat hints [was Re: [Qemu-devel] [PATCHv3 03/13] qemu: add routines to manage PCI capabilities] Date: Fri, 12 Jun 2009 11:12:55 -0500 Message-ID: <4A327E87.6080005@codemonkey.ws> References: <20090610145540.GI19375@poweredge.glommer> <20090610150129.GC28601@redhat.com> <200906101624.30659.paul@codesourcery.com> <20090610174301.GC7416@shareable.org> <20090610182227.GN28601@redhat.com> <20090610192702.GH7416@shareable.org> <1244796209.16425.20.camel@blaa> <4A326C7E.3020309@codemonkey.ws> <1244822007.30522.68.camel@blaa> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jamie Lokier , "Michael S. Tsirkin" , Carsten Otte , kvm@vger.kernel.org, Glauber Costa , Rusty Russell , qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, Blue Swirl , Christian Borntraeger , Paul Brook , Avi Kivity To: Mark McLoughlin Return-path: Received: from qw-out-2122.google.com ([74.125.92.25]:53730 "EHLO qw-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753497AbZFLQM4 (ORCPT ); Fri, 12 Jun 2009 12:12:56 -0400 Received: by qw-out-2122.google.com with SMTP id 5so1493564qwd.37 for ; Fri, 12 Jun 2009 09:12:59 -0700 (PDT) In-Reply-To: <1244822007.30522.68.camel@blaa> Sender: kvm-owner@vger.kernel.org List-ID: Mark McLoughlin wrote: > On Fri, 2009-06-12 at 09:55 -0500, Anthony Liguori wrote: > >> Mark McLoughlin wrote: >> >>> On Wed, 2009-06-10 at 20:27 +0100, Jamie Lokier wrote: >>> >>> = Solution - Separate configuration from compat hints = >>> >>> As I suggested before: >>> >>> - Allow the VM manager to dump compat hints; this would be an opaque >>> file format, more like the savevm format than a config file >>> >>> >> How is compat hints different from a device tree? >> >> In my mind, that's what compat hints is. I don't see another sane way >> to implement it. >> > > A device tree with a different purpose than a config file. > > In its simplest form it could be a device tree with a version number for > each device[1]. > I think the point is that you don't need version numbers if you have a proper device tree. NB the device tree contains no host configuration information. Regards, Anthony Liguori > The other obvious piece to add to it would be PCI addresses, so that > even if you remove a device, the addresses assigned to existing devices > don't change. > > Cheers, > Mark. > > [1] - Adding such a per-device version number to the config file would > solve problem (2) > >