From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36412) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c9wvn-0007k0-UU for qemu-devel@nongnu.org; Thu, 24 Nov 2016 11:31:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c9wvk-0002jR-0D for qemu-devel@nongnu.org; Thu, 24 Nov 2016 11:31:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58194) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c9wvj-0002io-Q8 for qemu-devel@nongnu.org; Thu, 24 Nov 2016 11:31:23 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D1973C05B1DE for ; Thu, 24 Nov 2016 16:31:22 +0000 (UTC) References: <1479777133-23567-1-git-send-email-ehabkost@redhat.com> <47c2fb2a-7785-b7b9-bf7d-5743cbc5f4be@redhat.com> <20161123173515.GB27297@thinpad.lan.raisama.net> <871sy1f1de.fsf@dusky.pond.sub.org> <878ts8ans3.fsf@dusky.pond.sub.org> From: Marcel Apfelbaum Message-ID: <120cce2b-742c-bdaf-8b6d-3df3bc652a89@redhat.com> Date: Thu, 24 Nov 2016 18:31:19 +0200 MIME-Version: 1.0 In-Reply-To: <878ts8ans3.fsf@dusky.pond.sub.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC 00/15] qmp: Report supported device types on 'query-machines' List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Eduardo Habkost , libvir-list@redhat.com, qemu-devel@nongnu.org, Laine Stump , "Michael S. Tsirkin" On 11/24/2016 05:41 PM, Markus Armbruster wrote: > Marcel Apfelbaum writes: > >> On 11/24/2016 03:34 PM, Markus Armbruster wrote: >>> Eduardo Habkost writes: >>> >>>> On Wed, Nov 23, 2016 at 06:43:16PM +0200, Marcel Apfelbaum wrote: >>>>> On 11/22/2016 03:11 AM, Eduardo Habkost wrote: >>>>>> The Problem >>>> >> >> [...] >> >>> Our decision to have hybrid PCI/PCIe devices and buses breeds >>> considerable complexity. I wish we had avoided them, but I believe it's >>> too late to change now. >>> >>>>> This still does not solve the problem that some devices makes >>>>> sense only on a specific arch. >>> >> >> Hi Markus, >> >>> Examples? >>> >> >> One quick example would be that we don't want to see >> Intel's IOH 3420 PCIe Root Port in an ARM machine, >> or a pxb on a Q35 machine (in this case we want pxb-pcie) > > Such a device would be weird. But would it be wrong? Define wrong :) Wrong enough for > QEMU to reject it? QEMU accepts them and they even function correctly as far as I know. Unless QEMU rejects it, there's no reason not to > list it as pluggable. > This is the gray area I can't argue. I do think that Eduardo's work may present an opportunity to change QEMU's mantra: "everything goes as long as it works" to "here is what this configuration supports". Thanks, Marcel >> I do believe there are other examples, I'll try to think of more. >> >> Thanks, >> Marcel >> >> [...]