Re: [Qemu-devel] State of KVM bits in linux-headers

[Alexander Graf]

On 11.01.2012, at 21:16, Anthony Liguori wrote:

> On 01/11/2012 02:05 PM, Alexander Graf wrote:
>> 
>> On 11.01.2012, at 20:59, Anthony Liguori wrote:
>> 
>>> On 01/11/2012 01:53 PM, Alexander Graf wrote:
>>>> 
>>>> On 11.01.2012, at 20:52, Anthony Liguori wrote:
>>>> 
>>>>>> IIRC, we never had this problem with qemu-kvm - as the merges were
>>>>>> coordinated with the kernel (subsystem) tree.
>>>>> 
>>>>> Are you suggesting that kvm header updates go through uq/master?  That 
>>>>> seems reasonable to me and is certainly the least amount of change.
>>>> 
>>>> So how about code that actually leverages the new headers?
>>> 
>>> Shared KVM infrastructure should go through uq/master.  So changes to 
>>> kvm-all.c, linux-headers/* should go through uq/master.
>>> 
>>> Target specific kvm changes should go through the appropriate 
>>> submaintainers tree.
>> 
>> So then if I add some target specific stuff to KVM,
> 
> That requires a header update?

Almost all of the time, yes. The target is still rather incomplete. And even in 
places where it is, hardware evolves and we just get new information we need to 
pass back and forth.

> 
>> I have to
>> 
>>   * send pullreq to KVM
>>   * wait for that to be applied
>>   * post a patch to uq/master to update headers
> 
> Strictly from a QEMU perspective, we can't depend on APIs that aren't 
> committed upstream yet.

The question again is: When do we consider something upstream?

> 
>>   * wait for that to merge back to qemu.git
>>   * send a pull request to qemu.git
> 
> Maybe we need to bring a stripped down version of Linux into qemu.git to make 
> it easier to simultaneously update both trees... ;-)

Nice one ;)

> 
>> 
>> right? And then after about 3 months we'll have the feature available ;).
> 
> You can always just get Acked-by's from the appropriate maintainers.  That's 
> just as good as going through the tree.

So every time we change headers, I just require Avi's ack and then he can't 
complain on those patches later? Good idea! :)


Alex