From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39730) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z5H5r-0003Sp-5z for qemu-devel@nongnu.org; Wed, 17 Jun 2015 13:25:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z5H5j-00044a-G6 for qemu-devel@nongnu.org; Wed, 17 Jun 2015 13:25:43 -0400 Received: from mail-wg0-x22a.google.com ([2a00:1450:400c:c00::22a]:36424) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z5H5j-00044U-97 for qemu-devel@nongnu.org; Wed, 17 Jun 2015 13:25:35 -0400 Received: by wgzl5 with SMTP id l5so42801078wgz.3 for ; Wed, 17 Jun 2015 10:25:34 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <5581AD8C.40202@redhat.com> Date: Wed, 17 Jun 2015 19:25:32 +0200 From: Paolo Bonzini MIME-Version: 1.0 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> In-Reply-To: <5581AAF0.3000307@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit 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: Don Slutz , "Michael S. Tsirkin" Cc: Markus Armbruster , qemu-devel@nongnu.org, Don Slutz , Luiz Capitulino , Anthony Liguori , =?windows-1252?Q?Andreas_F=E4rber?= , Richard Henderson On 17/06/2015 19:14, 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. > > (But yes, that option would be a good thing anyway). Even better would be to have a "-global vmport.rpc=no" option. It would be simpler to disable it in existing machine types. Paolo