Re: [Qemu-devel] Re: [PATCH] Add -no-virtio-balloon command-line option

[Anthony Liguori <anthony@codemonkey.ws>]

Markus Armbruster wrote:
> Anthony Liguori <anthony@codemonkey.ws> writes:
>
>   
>> Markus Armbruster wrote:
>>     
>>> Dor Laor <dlaor@redhat.com> writes:
>>>
>>>   
>>>       
>>>> Gerd Hoffmann wrote:
>>>>     
>>>>         
>>>>>> This new option may be used to disable the virtio-balloon device.
>>>>>>
>>>>>>         
>>>>>>             
>>>>> ACK, looks good.
>>>>>
>>>>> And I can drop my lazy patch which just comments out virtio-balloon
>>>>> in the code ;)
>>>>>       
>>>>>           
>>>> Actually, I rather have the balloon disabled by default. It's like any
>>>> other pci device which needs
>>>> explicit command line specification. Why consume a pci slot if not
>>>> implicitly required?
>>>>     
>>>>         
>>> I agree.  The command line is plenty magic without implicitly added
>>> PCI devices.
>>>
>>> Besides, negative options -no-virtio-balloon lead to ugly
>>> double-negatives like if (!no_virtio_balloon).
>>>   
>>>       
>> It does no harm to add the device by default so why force the user to
>> explicitly enable it?
>>
>> Regards,
>>
>> Anthony Liguori
>>     
>
> I don't care whether it's on or off by default.  I just object to the
> ugly -no-virtio-balloon.
>
> We need to do (at least) two things to the virtio-balloon device:
> suppress it, and control its PCI address.  We can do both with one
> option, but it better not be called -no-virtio-balloon then.
>
> Options controlling devices should always be extensible to accept
> arbitrary name=value arguments.
>   
It's not in a released version of QEMU so we can remove the option and 
change it's syntax.

-balloon none
-balloon virtio
-balloon virtio,addr=00:01.3

Could be a reasonable approach.

Regards,

Anthony Liguori