[Qemu-devel] Re: [PATCH] Revive -version 'QEMU PC Emulator...'

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 05/13/2010 08:07 AM, Jes Sorensen wrote:
> On 05/13/10 15:04, Cole Robinson wrote:
>    
>> On 05/13/2010 04:35 AM, Jes Sorensen wrote:
>>      
>>> On 05/12/10 22:48, Cole Robinson wrote:
>>> I think rather than 1, it would be better to add a patch to libvirt to
>>> catch both formats. I know Chris Lalancette already cooked up a patch
>>> for this. Combined with the 2) patch I just posted, and 3) I think that
>>> should take care of the problems.
>>>        
>> It doesn't solve the problem for existing libvirt installations. It's
>> not uncommon for users to track just the latest kvm releases without
>> upgrading libvirt: any future qemu or kvm release will break every
>> version of libvirt that exists today. Given that unfortunate case, I
>> still recommend reverting the 'PC' change at least for long enough for a
>> few fixed libvirt releases to make it into the wild.
>>      
> But that is no different from what we have today. Users who update their
> qemu and see issues with libvirt can also be asked to update libvirt. I
> have already had several cases where I needed to do that anyway.
>
> I don't like reverting a change like this, just to schedule it to be
> reapplied again later.
>    

The problem is, we've been down this road many times before.  Every 
time, the libvirt folks say they just need this one change for 
compatibility and keep on using the help output.  I understand that 
that's the easiest thing to do so we need to make it easier for them to 
do the right thing (which probably means making it harder to do the 
wrong thing :-)).

So I'm willing to apply this patch but only as part of a larger series 
that eliminates the need for libvirt to parse help output.  The 
important question is then, what information is libvirt getting from the 
help output today.

Regards,

Anthony Liguori

> Cheers,
> Jes
>
>