Re: [Qemu-devel] Re: POLL: Why do you use kqemu?

[Andreas Färber]

Am 06.06.2009 um 19:32 schrieb Jan Kiszka:

> Blue Swirl wrote:
> > On 6/6/09, Jan Kiszka <address@hidden> wrote:
> > > Blue Swirl wrote:
> > > > Maybe the backwards compatibility features should be ported to  
> > > > QEMU?
> > > > For example, is there a workaround for
> > > > #error Missing KVM capability KVM_CAP_DESTROY_MEMORY_REGION_WORKS
> > > > ?
> > >
> > > Given that we have always-up-to-date kvm-kmod packages with  
> > > support down
> > > to reasonable kernel versions, I would prefer to keep upstream clean
> > > from old workarounds. They should only be needed for issues found  
> > > very
> > > recently (KVM_CAP_JOIN_MEMORY_REGIONS_WORKS) or that might be  
> > > found in
> > > the future.
> >
> > But then I (and from Andreas' message I gather that many others)  
> > can't
> > test KVM support on QEMU without building, installing and maintaining
> > (updating, rebuilding, reinstalling etc) my own kernel instead of the
> > distro build.
>
> You don't have to, it builds against the distro kernel's devel package
> (I'm doing most KVM development on boring distro kernels). No black
> magic involved. Really.

Consider me Joe User in that aspect: I have a fairly recent amd64  
Linux machine, with all the latest security, bugfix and enhancement  
updates installed.

$ uname -a
Linux redhead 2.6.27.24-170.2.68.fc10.x86_64 #1 SMP Wed May 20  
22:47:23 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
$ ./configure
[...]
#error Missing KVM capability KVM_CAP_DESTROY_MEMORY_REGION_WORKS

A package search for kvm results in kvm-74-10.fc10 being installed  
(plus another one with ROMs). There is no additional kvm-kmod package  
offered that I could install. What should I do?

I could try qemu-kvm.git, yes, but for one thing Anthony has been  
insistant that patches be made against upstream qemu.git and for  
another it makes me dependent on someone merging KVM-unrelated commits  
(like sparc) into qemu-kvm.git, so it doesn't sound like a longterm  
solution.

This is not about me, it's about the average user that might or might  
not use kqemu and wants to use KVM on Linux. qemu.git's configure just  
blocks them. Not just now, where Fedora 11 is four days away, it's  
been similar on Fedora 9 and throughout Fedora 10, as indicated earlier.

There are at least two solutions:

i) Make configure hint users what to do. (README just references qemu- 
doc.html, which is not yet built and doesn't contain anything helpful  
here anyway.) Other options are even less verbose though (e.g.  
Documentation). Building a new kernel or kernel module is not always  
an option.

ii) Merge the apparently existant workarounds upstream. I thought this  
was the overall plan anyway? Has this changed, like the original plan  
of Glauber's kqemu-friendly qemu-accel abstraction?

Sourceforge (the KVM download link) appears to be down currently btw.  
Savannah is not the only one with problems, it seems.

Andreas