Re: [Qemu-devel] Re: Cutting a new QEMU release

[Anthony Liguori <anthony@codemonkey.ws>]

Jamie Lokier wrote:
> Anthony Liguori wrote:
>   
> Yes, it's unfortunate how its history worked out.  On the face of it,
> it looks like Fabrice was hoping for someone to pay for it.  Maybe
> they did.  I remember a vague murmur of an attempt to make an open
> source replacement for kqemu when it was still binary-only; that
> didn't go anywhere as far as I remember.
>
> Anthony: If one or more maintainers were to step up, perhaps even
> begin adapting the kqemu interface to kvm's, would you be interested
> in folding it in the main qemu/kvm project as an official feature?
>   

Actions speak louder than words.  All it takes is for someone to setup a 
tree somewhere with kqemu in it, and start working on it and merging 
patches.  Once that happens, we can discuss the long term future wrt KVM 
and QEMU.  Otherwise, it's just pontificating here.  Merging into Linux 
proper is going to be a lot of work.

I strongly suspect you won't see anyone step up.  From a developer 
perspective, it's a case of diminishing returns.  The more work you put 
into it, the less useful it is to people.  Every day that goes buy, the 
potential audience grows smaller.  Furthermore, the barrier to entry for 
someone to get a better solution is (i.e. KVM) is rather small.  Just 
buy a new CPU.

I think the only way it would prove useful to maintain is if some 
developer either has a deep desire to mess around with this kind of 
stuff or has a large customer base with pre-VT/SVM hardware that they 
wish to support.  So far, no such developer has proven to exist.  
Recall, even when kqemu was the only solution (but closed source), there 
wasn't really anyone interested/willing to maintain qvm86.

N.B. KVM and kqemu are not equal solutions.  Even at it's best, kqemu is 
going to be significantly slower than KVM in most cases.  When dealing 
with more modern CPUs (Barcelonas and Core i7s), the difference is going 
to be extremely high.

Regards,

Anthony Liguori

> Straw poll: who here's interested in maintaining kqemu?
>
> I have very little time, but plenty of x86 intimate knowledge and
> kernel knowledge, and have used kqemu occasionally.  I can offer my
> hand as "interested a bit, not by myself".
>
> (Also, perhaps some of the Windows / other kqemu bits might be useful
> in porting kvm to Windows.  Now that we have nested kvm, those of us
> who never run a native Windows host can think about testing such a thing ;-)
>
> -- Jamie
>
>
>