Re: [Qemu-devel] Re: [PATCH v2 3/9] provide in-kernel ioapic

[Anthony Liguori <aliguori@us.ibm.com>]

Jamie Lokier wrote:
> Avi Kivity wrote:
>   
>> On 10/08/2009 03:49 PM, Anthony Liguori wrote:
>>     
>>> Glauber Costa wrote:
>>>       
>>>> This patch provides kvm with an in-kernel ioapic. We are currently 
>>>> not enabling it.
>>>> The code is heavily based on what's in qemu-kvm.git.
>>>>         
>>> It really ought to be it's own file and own device model.  Having the 
>>> code mixed in with ioapic.c is confusing because it's unclear what 
>>> code is in use when the in-kernel model is used.
>>>       
>> I disagree.  It's the same device with the same guest-visible interface 
>> and the same host-visible interface (save/restore, 'info ioapic' if we 
>> write one).  Splitting it into two files will only result in code 
>> duplication.
>>
>> Think of it as an ioapic accelerator.
>>     
>
> Haven't we already confirmed that it *isn't* just an ioapic accelerator
> because you can't migrate between in-kernel iopic and qemu's ioapic?
>
> Imho, if they cannot be swapped transparently, they are different
> device emulations.
>
> OF course there's nothing wrong with sharing lots of code.
>   

If you avoid having a common save format, you get an overall reduction 
in code size and there's virtually no code to share.

-- 
Regards,

Anthony Liguori