Re: Automatic loading of xen-evtchn module in Xen 4.0.0?

[Jeremy Fitzhardinge <jeremy@goop.org>]

On 03/27/2010 10:32 AM, Pasi Kärkkäinen wrote:
> Hello,
>
> xend automatically mounts /proc/xen, but it doesn't try loading evtchn or xen-evtchn modules.
> Should we add automatic loading of these modules?
>
> xend doesn't start if xen event channel functionality is missing.
>
> Fedora Xen rpms do load modules automatically, like this:
>
> # cat /etc/sysconfig/modules/xen.modules
> #!/bin/sh
>
> test -d /proc/xen                               || exit 0
> test -f /proc/xen/capabilities                  || mount -t xenfs xen /proc/xen
> test -f /proc/xen/capabilities                  || exit 0
> grep -q "control_d" /proc/xen/capabilities      || exit 0
>
> for module in xen-evtchn evtchn blkbk netbk; do
>          modprobe ${module}>/dev/null 2>&1
> done
>    

We should be able to make these mount automatically with udev rules, I 
think, but I'm not sure whether you can do udev rules to mount misc 
devices (which is what /dev/xen/evtchn is).

I think the front/back xenbus and device drivers are still a bit of a 
mess with regard to modules; I have to admit I tend to just compile them 
all in.  It would be nice to get all that properly sorted out so they 
can be sensibly modularized and auto-loaded as required.  (A good first 
step would be to systematically work out what compile combinations 
actually work or fail, hint, hint ;)

     J