From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59559) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1biJrp-0003Nk-IX for qemu-devel@nongnu.org; Fri, 09 Sep 2016 07:21:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1biJrl-0003kB-74 for qemu-devel@nongnu.org; Fri, 09 Sep 2016 07:21:08 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:56157) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1biJrk-0003jw-Ue for qemu-devel@nongnu.org; Fri, 09 Sep 2016 07:21:05 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u89BHvNr033569 for ; Fri, 9 Sep 2016 07:21:04 -0400 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0a-001b2d01.pphosted.com with ESMTP id 25bc2sefvk-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 09 Sep 2016 07:21:04 -0400 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 9 Sep 2016 12:21:01 +0100 Date: Fri, 9 Sep 2016 13:20:56 +0200 From: Cornelia Huck In-Reply-To: References: <1473416072-7063-1-git-send-email-maxime.coquelin@redhat.com> <1473416072-7063-3-git-send-email-maxime.coquelin@redhat.com> <20160909124038.10fb8181.cornelia.huck@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-Id: <20160909132056.736715d2.cornelia.huck@de.ibm.com> Subject: Re: [Qemu-devel] [PATCH 2/2] virtio-pci: Disable modern interface if backend without VIRTIO_F_VERSION_1 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcel Apfelbaum Cc: Maxime Coquelin , mst@redhat.com, qemu-devel@nongnu.org, vkaplans@redhat.com, qemu-stable@nongnu.org On Fri, 9 Sep 2016 14:04:55 +0300 Marcel Apfelbaum wrote: > On 09/09/2016 01:40 PM, Cornelia Huck wrote: > > On Fri, 9 Sep 2016 12:14:32 +0200 > > Maxime Coquelin wrote: > > > >> This patch makes pci devices plugging more robust, by not confusing > >> guest with modern interface when the backend doesn't support > >> VIRTIO_F_VERSION_1. > >> > >> Cc: Marcel Apfelbaum > >> Cc: Michael S. Tsirkin > >> Cc: qemu-stable@nongnu.org > >> Signed-off-by: Maxime Coquelin > >> --- > >> hw/virtio/virtio-pci.c | 15 +++++++++++++++ > >> hw/virtio/virtio-pci.h | 5 +++++ > >> 2 files changed, 20 insertions(+) > > > > Note that 11380b361 ("virtio: handle non-virtio-1-capable backend for > > ccw") fixes this issue for ccw via the introduction of a > > ->post_plugged() callback. Unfortunately, we did not find a good way to > > make it work for pci back then. > > It seems that for ccw is enough to rewind dev->rev_max, > sadly for pci we need to rewind a lot of settings/resources. Yes, that what I meant with 'more flexibility for ccw'. > > Thanks, > Marcel > > > > > Two comments: > > - ->post_plugged() handles the dependencies (as noticed for your first > > patch) - and this is due to it being called after the plugging is > > already done. > > - I don't really like pci and ccw being too different. We have probably > > more flexibility with the handling for ccw, so I could probably convert > > ccw to the same mechanism that pci uses. Maybe there are other uses for > > ->post_plugged()? > > >