[Pkg-xen-devel] Bug#770456: Bug#770456: Please start a qemu process in domain 0.

[Ian Campbell]

On Thu, 2014-11-27 at 11:02 +0100, Stefan Bader wrote:
> On 21.11.2014 13:50, Ian Campbell wrote:
> > Package: xen-utils-common
> > Version: 4.4.0-1
> > Severity: important
> > Tags: patch
> > 
> > Under some circumstances the xl toolstack needs to create a loopback
> > mount of a guest disk in dom0 (e.g. in order to run pygrub). Depending
> > on the nature of the guest disk (e.g. qcow2 or raw file image based)
> > this can require a qemu instance in dom0.
> > 
> > The upstream xencommons starts such a qemu on boot. The following patch
> > adds this to the Debian packages init script as well.
> > 
> > Once I have a bug number for this I will add it to debian/changelog and
> > push the result to feature/bugNNNN as usual.
> > 
> > Thanks,
> > Ian.
> > 
> > commit 26cce2a65c77f731e23a1395f1fe4a5da47287a4
> > Author: Ian Campbell <ijc at debian.org>
> > Date:   Fri Nov 21 11:27:45 2014 +0000
> > 
> >     Start a qemu process in dom0 to service the toolstacks loopback disk attaches.
> >     
> >     This is used to e.g. run pygrub on a VM with a qcow2 disk image.
> >     
> >     Also, remove correct pidfile when stopping xenconsoled.
> > 
> > diff --git a/debian/changelog b/debian/changelog
> > index 484583f..ff48d6a 100644
> > --- a/debian/changelog
> > +++ b/debian/changelog
> > @@ -1,3 +1,12 @@
> > +xen (4.4.1-4) UNRELEASED; urgency=medium
> > +
> > +  [ Ian Campbell ]
> > +  * Start a qemu process in dom0 to service the toolstacks loopback disk
> > +    attaches.
> > +  * Remove correct pidfile when stopping xenconsoled.
> > +
> > + -- Ian Campbell <ijc at debian.org>  Fri, 21 Nov 2014 11:26:40 +0000
> > +
> >  xen (4.4.1-3) unstable; urgency=medium
> >  
> >    [ Bastian Blank ]
> > diff --git a/debian/xen-utils-common.xen.init b/debian/xen-utils-common.xen.init
> ...
> > +
> > +qemu_start_real()
> > +{
> > +	start-stop-daemon --start --quiet --pidfile "$QEMU_PIDFILE" --exec "$QEMU" --test > /dev/null \
> > +		|| return 1
> > +	start-stop-daemon --start --quiet --pidfile "$QEMU_PIDFILE" --exec "$QEMU" -- \
> > +		$QEMU_ARGS -pidfile "$QEMU_PIDFILE" \
> > +		|| return 2
> > +}
> > +
> > +qemu_stop_real()
> > +{
> > +	start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile "$QEMU_PIDFILE" --name xenconsoled
> > +	RETVAL="$?"
> > +	[ "$RETVAL" = 2 ] && return 2
> > +	start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec "$QEMU"
> > +	[ "$?" = 2 ] && return 2
> > +	rm -f $QEMU_PIDFILE
> > +	return "$RETVAL"
> > +}
> > +
> > +
> 
> Not sure this already was handled but the --name argument of qemu_stop_real
> seems a copy-and-paste bug.

Yes it is, whoops!

>  Playing with it right now, --exec instead of --name
> also works out better since qemu-system-i386 is just about too long.

So it is, so this is probably a good idea.

Will you send an updated patch once you've finished testing?

Ian.