From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60101) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YzQ58-0004yp-PB for qemu-devel@nongnu.org; Mon, 01 Jun 2015 09:48:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YzQ55-0001Et-HE for qemu-devel@nongnu.org; Mon, 01 Jun 2015 09:48:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41193) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YzQ55-0001EH-9j for qemu-devel@nongnu.org; Mon, 01 Jun 2015 09:48:43 -0400 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 9010439CA7D for ; Mon, 1 Jun 2015 13:48:42 +0000 (UTC) Message-ID: <556C62B7.5080305@redhat.com> Date: Mon, 01 Jun 2015 16:48:39 +0300 From: Marcel Apfelbaum MIME-Version: 1.0 References: <1432568042-19553-1-git-send-email-marcel@redhat.com> <1432568042-19553-24-git-send-email-marcel@redhat.com> <20150531181221.GJ5268@redhat.com> <556C2985.9000909@redhat.com> <1433158819.19671.23.camel@nilsson.home.kraxel.org> <20150601141532-mutt-send-email-mst@redhat.com> <556C4E3F.7050102@redhat.com> <20150601142731-mutt-send-email-mst@redhat.com> <556C5881.8070605@redhat.com> <556C5E14.6090503@redhat.com> In-Reply-To: <556C5E14.6090503@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH V7 23/24] apci: fix PXB behaviour if used with unsupported BIOS List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Laszlo Ersek , "Michael S. Tsirkin" Cc: pbonzini@redhat.com, Gerd Hoffmann , qemu-devel@nongnu.org On 06/01/2015 04:28 PM, Laszlo Ersek wrote: > On 06/01/15 15:05, Marcel Apfelbaum wrote: >> On 06/01/2015 03:27 PM, Michael S. Tsirkin wrote: >>> On Mon, Jun 01, 2015 at 03:21:19PM +0300, Marcel Apfelbaum wrote: >>>> On 06/01/2015 03:17 PM, Michael S. Tsirkin wrote: >>>>> On Mon, Jun 01, 2015 at 01:40:19PM +0200, Gerd Hoffmann wrote: >>>>>> On Mo, 2015-06-01 at 12:44 +0300, Marcel Apfelbaum wrote: >>>>>>> On 05/31/2015 09:12 PM, Michael S. Tsirkin wrote: >>>>>>>> On Mon, May 25, 2015 at 06:34:01PM +0300, Marcel Apfelbaum wrote: >>>>>>>>> PXB does not work with unsupported bioses, but should >>>>>>>>> not interfere with normal OS operation. >>>>>>>>> We don't ship them anymore, but it's reasonable >>>>>>>>> to keep the work-around until we update the bios in qemu. >>>>>>>> >>>>>>>> We already did, did we not? >>>>>>> Yes, we did, but Gerd preferred to keep this patch around. >>>>>>> Adding him to thread. >>>>>> >>>>>> seabios bundled with qemu isn't the only possible firmware. >>>>>> >>>>>> We have ovmf, coreboot, qboot. >>>>> >>>>> ovmf is especially interesting. Marcel, did you look at what >>>>> happens with pxb and ovmf? >>>> No, I talked to Laszlo about it, he said ovmf is not there yet. >>>> OVMF will not query the extra buses, so the devices on the extra bus >>>> will not be visible. >>>> Adding him to the thread. >>>> >>>> Thanks, >>>> Marcel >>> >>> But does OVMF need this specific patch? >> I don't think so because more than likely it doesn't scan for the extra >> buses, >> so it will not try to configure these devices. >> Laszlo, am I right? > > Well, I don't know. :) > > First, I'm not seeing the specific patch in question (can you pls send > me a URL into the web archive, or a Message-Id?) Well, there are a few patches, all this series, You can look for patches: 13/24 hw/acpi: add support for i440fx 'snooping' root busses -> acpi declarations 18/24 hw/pci: introduce PCI Expander Bridge (PXB) 19/24 hw/pci: inform bios if the system has extra pci root buses Basically we add the pxb resources to ACPI tables and then inform BIOS using etc/extra-pci-roots fw_config file that he has extra roots to scan. If the OVMF only looks for bus 0 and does not scan all possible buses it will not see PXB's root bus Thanks, Marcel > Second, recently I tested OVMF on Q35, but not just with a simple / > usual command line invocation -- I tested it on a Q35 machine configured > by libvirt. That's a very different animal. > > While it exposed a problem in OVMF's own boot order processing: > > https://github.com/tianocore/edk2/commit/feca17fa4b > > I was surprised to see that the PCI bus driver enumerated devices behind > two bridges no less without any problems. So, bridges off the one root > bridge should work, but several root bridges probably won't. (Exposing > root bridges is the responsibility of another driver, and they are not > enumerable in the usual way.) > > Thanks > Laszlo >