From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:59399) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T1J35-00070r-4G for qemu-devel@nongnu.org; Tue, 14 Aug 2012 11:28:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T1J33-0005UZ-LY for qemu-devel@nongnu.org; Tue, 14 Aug 2012 11:28:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8131) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T1J33-0005UT-DJ for qemu-devel@nongnu.org; Tue, 14 Aug 2012 11:28:49 -0400 Message-ID: <502A6EAD.4080700@redhat.com> Date: Tue, 14 Aug 2012 11:28:45 -0400 From: Cole Robinson MIME-Version: 1.0 References: <20120801050241.22163.78549.stgit@bling.home> <87pq6uvs52.fsf@codemonkey.ws> <502907EA.9030606@redhat.com> <5029097B.8050706@siemens.com> <87393qmvwe.fsf@codemonkey.ws> <502A6669.90200@redhat.com> <502A68F4.1080009@siemens.com> In-Reply-To: <502A68F4.1080009@siemens.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/3] VFIO-based PCI device assignment for QEMU 1.2 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Anthony Liguori , "kvm@vger.kernel.org" , "aik@ozlabs.ru" , "qemu-devel@nongnu.org" , Alex Graf , Alex Williamson , Avi Kivity On 08/14/2012 11:04 AM, Jan Kiszka wrote: > On 2012-08-14 16:53, Cole Robinson wrote: >> On 08/13/2012 03:31 PM, Anthony Liguori wrote: >>> Jan Kiszka writes: >>> >>>> On 2012-08-13 15:58, Avi Kivity wrote: >>>>> On 08/13/2012 04:27 PM, Anthony Liguori wrote: >>>>> >>>>>> Thanks for pushing this forward! Hopefully this will finally kill off >>>>>> qemu-kvm.git for good. >>>>> >>>>> No, it won't. vfio requires a 3.6 kernel, which we cannot assume anyone >>>>> has. We'll need the original device assignment code side-by-side. >>>> >>>> ...which is on my to-do list for 1.3. >>> >>> Is there a deprecation plan for the old device assignment code? >>> >>> I'm not really against the idea of requiring a new kernel for new >>> features. >>> >>> From a Fedora/OpenSUSE point of view, would supporting old kernels be a >>> requirement to stop shipping qemu-kvm.git over qemu.git? >>> >> >> Speaking as a Fedora maintainer, compatibility with old kernels isn't that >> important to us, provided the functionality of the new way is comparable to >> the old way. >> >> As far as switching over to qemu.git, I assume there will eventually be a day >> when the fork would 'end' and qemu-kvm would stop getting its own releases, >> which is when we'd switch. Maybe that assumption is wrong or over simplifying >> the trade offs, but if merge work is ongoing I don't see a very compelling >> reason to switch. > > If you sit and wait, you may find out on that specific day that someone > forget to port over feature X and Y, and now QEMU does not fit your > needs and qemu-kvm is dead. > My head isn't entirely in the sand here, I've watched the patches go by and feel pretty confident that you and co. wouldn't drop qemu-kvm if there was something missing that left qemu.git substantially lacking, at least not without announcing it clearly. I know certain defaults will change and certain cli options will go away but that just requires user education. And qemu-kvm won't really 'die', the code isn't going to disappear. If we switch to qemu.git and discover some vital piece is missing, we can temporarily carry the relevant qemu-kvm bits and try to get the issue resolved upstream. If upstream doesn't want to change, then we are back to user education. - Cole