From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=40684 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Obit1-0001OT-85 for qemu-devel@nongnu.org; Wed, 21 Jul 2010 19:39:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Obit0-0001E4-00 for qemu-devel@nongnu.org; Wed, 21 Jul 2010 19:39:39 -0400 Received: from mail-iw0-f173.google.com ([209.85.214.173]:35805) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Obisz-0001E0-NL for qemu-devel@nongnu.org; Wed, 21 Jul 2010 19:39:37 -0400 Received: by iwn6 with SMTP id 6so764296iwn.4 for ; Wed, 21 Jul 2010 16:39:36 -0700 (PDT) Message-ID: <4C478534.2020106@codemonkey.ws> Date: Wed, 21 Jul 2010 18:39:32 -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> In-Reply-To: <20100721215833.GC28871@redhat.com> 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: "Daniel P. Berrange" Cc: qemu-devel@nongnu.org, Bruce Rogers On 07/21/2010 04:58 PM, Daniel P. Berrange wrote: >> Yes there is. Use the version number. >> > The version number is not suitable, because features can be removed at > compile time and/or I don't see any features that libvirt would need to know about that are disabled at compile time that aren't disabled by platform features (i.e. being on a Linux vs. Windows host). > added via patch backports. If a distro backports a feature, it should change the QEMU version string. If it doesn't, that's a distro problem. > The only reliable way is > to query the QEMU binary to ask it what it actually supports. > And you do that by asking QEMU what it's version number is. If the version number isn't reliable because a distro backported features without changing it, then the distro is broken. It's no different than if we had a capabilities system and a distro added a feature without adjusting the advertises capabilities. Regards, Anthony Liguori > Regards, > Daniel >