Re: [Qemu-devel] [PATCH v7 0/9] Add limited support of VMware's hyper-call rpc

[Don Slutz]

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
>