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

[Markus Armbruster]

Anthony Liguori <address@hidden> writes:

> Markus Armbruster wrote:
>> Dor Laor <address@hidden> 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.