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

[René Rebe]

Hi,

Steve Fosdick wrote:
> On Thu, 2009-02-05 at 13:03 -0600, Anthony Liguori wrote:
>
>   
> > Personally, I'd prefer that it lived outside of the QEMU tree.  It is 
> > never going to go into upstream Linux and it's not something that I 
> > think is worth supporting.
> >     
>
> Does anyone here have any stats on what people are using QEMU for?
>
> I ask this because I suspect a significant use case is running an x86
> guest on an x86 host and, at the moment, the only way to get reasonable
> performance on a non virtualisation-enhanced CPU seems to be to use
> kqmeu.
>
> Now, I can understand the developers of kvm only supporting the
> virtualisation-enhanced CPUs because, looking to the future they will be
> common.  I suspect at the moment though there are plenty of people
> running VMs on older hardware.
>
> I can also see that if it would take major refactoring to get kqemu into
> the main kernal tree it is probably not worth the efforts as, by the
> time that work is complete the ratio virtualisation-enhanced CPUs to
> older, non virtualisation-enhanced CPUs would be higher.
>
> To my mind mind, what would be good right now is if someone (or some
> people) understands kqemu well enough that, if kernel changes break it,
> it can be fixed, not forever but until more people have
> virtualisation-enhanced CPUs and can use KVM instead.
>   
Indeed. Though I used KVM for the past months to do Linux development
and system testing / integration I had a use case for kqemu (non-VT CPU)
just this week and was surprised to find quite "old" kqemu release just 
build
and work for booth 2.6.26 and 2.6.28. And so far there was no problem with
it.

While I have no problem having it long time ported to the KVM interface,
just declaring some quite useful and functional piece of open source work
obsolete and unsupported quite drastic. This work should be not be lost
so easily.

When kqemu is supposed to be gotten upstream the question remains what
to do with the freebsd, windows, solaris, etc. glue code.

If I would know more of the internals of kqemu I would even volunteer to
maintain it - however, I just took the first look at it yesterday which does
not really qualify to maintain it just yet. Though I would work on getting
it adapted on future kernel changes, and/or even hunt a bug if it starts
crashing in one or another scenario for me (but right now I have to hunt
some crashing with 32bit host KVM for a start).

Yours,

--
 René Rebe - ExactCODE GmbH - Europe, Germany, Berlin
 http://exactcode.de | http://t2-project.org | http://rene.rebe.name