From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=43017 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OdQ0B-0002WM-Eh for qemu-devel@nongnu.org; Mon, 26 Jul 2010 11:54:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OdQ08-0006GC-4e for qemu-devel@nongnu.org; Mon, 26 Jul 2010 11:54:03 -0400 Received: from mail-gy0-f173.google.com ([209.85.160.173]:54971) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OdQ08-0006Fv-0A for qemu-devel@nongnu.org; Mon, 26 Jul 2010 11:54:00 -0400 Received: by gyd10 with SMTP id 10so1023758gyd.4 for ; Mon, 26 Jul 2010 08:53:59 -0700 (PDT) Message-ID: <4C4DAF94.1040300@codemonkey.ws> Date: Mon, 26 Jul 2010 10:53:56 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH] move 'unsafe' to end of caching modes in help References: <4C4704FC020000480009AB6E@sinclair.provo.novell.com> <4C475EC0.2000805@codemonkey.ws> <20100721213238.GB28871@redhat.com> <4C476A8A.6000707@codemonkey.ws> <20100721215833.GC28871@redhat.com> <4C478534.2020106@codemonkey.ws> <20100722084225.GA1524@redhat.com> <4C485383.8020904@codemonkey.ws> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: qemu-devel@nongnu.org, Bruce Rogers On 07/23/2010 03:00 AM, Markus Armbruster wrote: > Anthony Liguori writes: > > >> On 07/22/2010 03:42 AM, Daniel P. Berrange wrote: >> >>> On Wed, Jul 21, 2010 at 06:39:32PM -0500, Anthony Liguori wrote: >>> > [...] > >>>> If a distro backports a feature, it should change the QEMU version >>>> string. If it doesn't, that's a distro problem. >>>> >>>> >>> This puts you in the position of having to maintain an ever changing >>> giant compatability table between version numbers and features, which >>> just results in madness. >>> >>> >> Or working with QEMU to have a better solution. >> >> We've been complaining for a long time about parsing help output and >> we've made changes as "temporary" stop gaps for libvirt too many times >> in the past. >> >> This problem needs to get fixed properly. >> > You almost sound like Dan refused to consider anything but parsing help > output, like it were Dan's fault that QEMU still doesn't provide a > usable interface for querying its capabilities, and like the way to get > it was to put more pressure on Dan. > I'm not blaming anyone. As I see it, we have a supported interface for determining which interfaces are supported by a given version of QEMU--the version number. If the version number is not reliable because downstreams backport features in an undetectable way, that is not our (upstream) problem. I'm a practical guy, and I don't see that it's a huge burden for libvirt to detect downstreams and build a feature matrix based on versions. If someone demonstrates that it's infeasible, I'll happily reconsider. > That would be unfair. Dan posted patches to fix this problem properly, > which puts the ball squarely in our court. The patches are a good step, but they don't solve the problem. There will always be older versions of libvirt and older versions of QEMU so what's libvirt going to do with those? > Could we please refrain from > gratuitously fscking up libvirt just a bit longer, until we finish > improving and merging Dan's patches? > Even without doing version based feature detection, libvirt could just do a better job of parsing the help output. The help output is *not* a supported interface. There are very simple changes libvirt can and should make. The fix to this "problem" belongs in libvirt, no QEMU. Regards, Anthony Liguori > [...] >