Re: [Qemu-devel] vhost_net.c broken by --kerneldir

[Arnd Bergmann]

On Wednesday 25 August 2010, Hollis Blanchard wrote:
> > We only recently fixed the kernel to have this warning in types.h, which
> > triggers more often than kernel.h, where it used to be before. In 2.6.35
> > and before, you consequently would not have noticed the problem.
> >    
> 
> Thanks Arnd, that explains it.
> 
> It looks like the --kerneldir option needs to be re-thought.

Yes. I believe that we should just kill that option, since there is
no reason for building with set of headers from a different kernel
than the one your glibc normally uses.

You obviously need copies of some headers to match qemu code, e.g.
the kvm headers, but for those we have run-time compatibility code
in qemu. Building with a newer kernel header is pointless because
qemu would not use any of the features that were added after the
release of the qemu tree you are trying to build. Building with
an older kernel header is equally pointless because all it would
do is to require #ifdef magic in qemu that ends up preventing you
from using all features of new kernels.

        Arnd