Re: [Qemu-devel] [PATCH] net: Inform the user about deprecated -net options

[Paolo Bonzini]

On 15/12/2015 18:50, Thomas Huth wrote:
> On 15/12/15 18:31, Paolo Bonzini wrote:
>>
>> On 15/12/2015 18:15, Thomas Huth wrote:
>>> On 15/12/15 17:21, Paolo Bonzini wrote:
> [...]
>>>> For example you could print all DEVICE_CATEGORY_NETWORK devices that
>>>> support device_add.
>>>
>>> I think that would not work since spapr-vlan is not hot-pluggable.
>>
>> cannot_instantiate_with_device_add_yet which actually refers to -device,
>> not really device_add, so it would work.
> 
> I just tried:
> 
> (qemu) device_add spapr-vlan
> Bus 'spapr-vio' does not support hotplugging
> 
> ... did I miss something?

When I said "support device_add" I really meant "does not have
cannot_instantiate_with_device_add_yet", but spapr-vlan should pass that
test.

>>>> The thing is, people are still running QEMU from the command line.
>>>>
>>>> "-net nic -net bridge,br=virbr0" is still much less of a mouthful than
>>>> "-netdev bridge,br=virbr0,id=br -device rtl8139,netdev=br" if all I want
>>>> is something I can ssh into.
>>>>
>>>> It's easy to deprecate things.  It's hard to convince users that it's
>>>> worth, and you haven't convinced this user. :)
>>>
>>> Ok, if you want to maintain that legacy stuff forever - fine.
>>
>> I don't want to, but I think we have to.  It would be a good idea to get
>> rid of it, but unfortunately it's not a feasible idea IMHO.
> 
> If the code gets unmaintainable because there is too much legacy cruft
> in it, that's IMHO even worse. At one point in time, you just have to
> get rid of such stuff ... but well, maybe the time for the "-net" option
> just has not come yet.

Yes, indeed.  I don't think it's unmaintainable.  It used to be much
worse, and it could be improved.

Paolo