From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41566) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z5ILS-0001jO-VP for qemu-devel@nongnu.org; Wed, 17 Jun 2015 14:45:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z5ILQ-0002Aq-3a for qemu-devel@nongnu.org; Wed, 17 Jun 2015 14:45:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57826) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z5ILP-0002Ag-OH for qemu-devel@nongnu.org; Wed, 17 Jun 2015 14:45:52 -0400 Date: Wed, 17 Jun 2015 20:45:47 +0200 From: "Michael S. Tsirkin" Message-ID: <20150617204535-mutt-send-email-mst@redhat.com> References: <1434117956-4929-1-git-send-email-dslutz@verizon.com> <20150617160826-mutt-send-email-mst@redhat.com> <558180A0.8040708@redhat.com> <20150617161716-mutt-send-email-mst@redhat.com> <558183C1.3010402@redhat.com> <20150617162836-mutt-send-email-mst@redhat.com> <55819D8F.3000003@redhat.com> <20150617182322-mutt-send-email-mst@redhat.com> <5581A844.9090203@Gmail.com> <5581AAF0.3000307@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5581AAF0.3000307@redhat.com> Subject: Re: [Qemu-devel] [PATCH v7 0/9] Add limited support of VMware's hyper-call rpc List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Markus Armbruster , qemu-devel@nongnu.org, Don Slutz , Luiz Capitulino , Don Slutz , Anthony Liguori , Andreas =?iso-8859-1?Q?F=E4rber?= , Richard Henderson On Wed, Jun 17, 2015 at 07:14:24PM +0200, Paolo Bonzini wrote: > > > On 17/06/2015 19:03, Don Slutz wrote: > > On 06/17/15 12:29, Michael S. Tsirkin wrote: > >> On Wed, Jun 17, 2015 at 06:17:19PM +0200, Paolo Bonzini wrote: > >>> > >>> > >>> On 17/06/2015 16:29, Michael S. Tsirkin wrote: > >>>> On Wed, Jun 17, 2015 at 04:27:13PM +0200, Paolo Bonzini wrote: > >>>>> > >>>>> > >>>>> On 17/06/2015 16:18, Michael S. Tsirkin wrote: > >>>>>>>> Yes, that's what was done for parallel and pcspk as well. There's no > >>>>>>>> infrastructure to avoid it. > >>>>>>>> > >>>>>>>> Paolo > >>>>>> How do you mean? We have multiple ways to keep devices > >>>>>> compatible with old versions. > >>>>>> Set a new property to skip the extra stuff. > >>>>> > >>>>> Not if the device didn't have a vmstate at all, unfortunately. > >>>> > >>>> Skip creating the device completely for old machine types. > >>> > >>> Which device? The vmstate is tied to the same device that has always > >>> been created. > >> > >> Just disable the new functionality. Make it behave in > >> a compatible way. > >> > >>> we enable this thing by default (why do we?) > >> > >> Sigh. There is a very simple way to add a device in qemu: let user > >> request it with -device. If one does this, one gets to maintain the > >> resulting mess without bothering with pc maintainers in any way. > >> > >> But of course, everyone implementing a new feature feels it's such a > >> great thing, and completel zero risk, it must be part of the default > >> machine. Guess what, one then gets to bother with versioning from day 0. > >> > >>>>>> this seems like a big deal ... > >>>>> > >>>>> The PC speaker device is also enabled by default. > >>>> > >>>> This is historical, isn't it? > >>> > >>> Yes, but it has broken 2.3->2.2 migration. > >>> > >>> Let's just stop fighting windmills. > >>> > >>> Paolo > >> > >> I don't see what you are saying. Suddenly guest visible > >> changes within a machine type are ok? > >> > >> So we have a bug, need to fix it, preferably before piling up > >> more features. The best way imho is for 2.4 to avoid > >> this device unless requested explicitly. > >> > > > > My take on this is that Michael would like me to have a vmport_rpc=on > > option, just like vmport=on (which already exists). With a default of off. > > It wouldn't be enough, because dc->vmsd would be non-NULL anyway. For which device class? > (But yes, that option would be a good thing anyway). > > Paolo