On 06/17/15 13:25, Paolo Bonzini wrote: > > > 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. >
Either way I can avoid the device creation... Unless I hear otherwise I will go the global way. Since the default would be no, should I also make the default =yes for the 2.4 pc? -Don Slutz -Don Slutz > Paolo >