From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59644) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WYaa2-0000zV-Vr for qemu-devel@nongnu.org; Fri, 11 Apr 2014 08:29:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WYaZx-0005yj-15 for qemu-devel@nongnu.org; Fri, 11 Apr 2014 08:29:14 -0400 Message-ID: <5347E011.9080308@suse.de> Date: Fri, 11 Apr 2014 14:29:05 +0200 From: Alexander Graf MIME-Version: 1.0 References: <49b80c368134449bb2b9093204aef6b6@BL2PR03MB210.namprd03.prod.outlook.com> <53170DFB.5050005@ozlabs.ru> <53172815.50806@redhat.com> <20140305134011.GH1993@redhat.com> <531730D8.6010607@redhat.com> <20140305142134.GI1993@redhat.com> <531735C3.3010203@redhat.com> <20140410092437.GA7746@redhat.com> <5347D4A8.3040708@ozlabs.ru> <5347DFB9.1070401@redhat.com> In-Reply-To: <5347DFB9.1070401@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] QEMU: PCI bus name on PowerPC platforms List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake , Alexey Kardashevskiy , "Daniel P. Berrange" , Paolo Bonzini Cc: Li Zhang , "qemu-ppc@nongnu.org" , "qemu-devel@nongnu.org" , "Hong-Hua.Yin@freescale.com" , "david@gibson.dropbear.id.au" On 11.04.14 14:27, Eric Blake wrote: > On 04/11/2014 05:40 AM, Alexey Kardashevskiy wrote: > >>> but AFAICT nothing got merged to change this for all the other boards as >>> discussed here :-( This is painful for libvirt since we have todo even >>> more hacks triggered off machine names now, instead of being able to >>> rely on pci.0 naming as we hoped. >> Sorry, I am missing the point. >> How could making a platform similar to many others force you to do more >> hacks, not less? > As mentioned in the thread here: > https://lists.gnu.org/archive/html/qemu-devel/2014-04/threads.html#01565 > > If there is a way to query via QMP to see which naming scheme is in > effect, there are no hacks involved - we just ask and get it right. > > If ALL platforms behave identically as of a certain release, we have a > minimal hack - catering to releases older than that, where a downstream > backport may have to tweak how we detect older releases, but it is only > a single place to be hacked. > > But with just this patch, you have caused the situation where it is > neither introspectible, nor consistent across qemu versions. The only > way to code that up in libvirt is to do MULTIPLE version checks and > correlate it with architecture checks - and that's the hack we don't > want to have to support. Every single version check done in lieu of > proper feature introspection is yet one more pain point when features > get backported across version numbers downstream. So how do you support -M ppce500 which also uses pci.0 and runs on (booke) ppc64? Alex