From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45583) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZxAYp-0004S1-EK for qemu-devel@nongnu.org; Fri, 13 Nov 2015 04:22:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZxAYm-0004Zi-C7 for qemu-devel@nongnu.org; Fri, 13 Nov 2015 04:22:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:40129) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZxAYm-0004Zb-5z for qemu-devel@nongnu.org; Fri, 13 Nov 2015 04:22:20 -0500 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id A0DAEC0032ED for ; Fri, 13 Nov 2015 09:22:19 +0000 (UTC) References: <1447341076-11573-1-git-send-email-marcel@redhat.com> <1447341076-11573-2-git-send-email-marcel@redhat.com> <1447406002.1400.94.camel@redhat.com> From: Marcel Apfelbaum Message-ID: <5645ABC8.9040902@redhat.com> Date: Fri, 13 Nov 2015 11:22:16 +0200 MIME-Version: 1.0 In-Reply-To: <1447406002.1400.94.camel@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/4] hw/pxb: remove the built-in pci bridge List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: rth@twiddle.ne, ehabkost@redhat.com, mst@redhat.com, qemu-devel@nongnu.org, imammedo@redhat.com, pbonzini@redhat.com On 11/13/2015 11:13 AM, Gerd Hoffmann wrote: > On Do, 2015-11-12 at 17:11 +0200, Marcel Apfelbaum wrote: >> As part of porting the pxb device to Q35 remove the internal pci-2-pci >> bridge. The only way to hot-pug devices on the extra PCI root buses >> is by adding a pci-2-pci to the pxb before the firmware assign the >> IO/mem resources. > > I think this breaks live migration and is guest-visible too. So not > going to fly without backward-compatibility mode for old machine > types ... > > Possibly it is easier to just have have pci and pcie pxb devices look > differenty rather than adding all the compatibility fluff. > Hi Gerd, Thank you for the review. Yes, you are right about migration, but I prefer to add a compat-prop rather than different devices because I do want to remove the internal pci-bridge even for pxb PCI. The reason is the feedback I got from libvirt that "composed" device are not recommended. In conclusion, since I am going to get rid of the pci-bridge, the devices will be exactly the same (except for the internal bus). I want to use the same concept as virtio-pci devices that get to be "express" on PCIe, but remain PCI on PCI buses. Thanks, Marcel > cheers, > Gerd > >