On Wed, Mar 21, 2012 at 06:25:16PM +0200, Avi Kivity wrote: > On 03/21/2012 06:18 PM, Corey Minyard wrote: > > > >> Look at drivers/char/ipmi/ipmi_msghandler.c. It has code to send panic > >> event over IMPI. The code is pretty complex. Of course if we a going to > >> implement something more complex than simple hypercall for panic > >> notification we better do something more interesting with it than just > >> saying "panic happened", like sending stack traces on all cpus for > >> instance. > > > > I doubt that's the best example, unfortunately. The IPMI event log > > has limited space and it has to be send a little piece at a time since > > each log entry is 14 bytes. It just prints the panic string, nothing > > else. Not that it isn't useful, it has saved my butt before. > > > > You have lots of interesting options with paravirtualization. You > > could, for instance, create a console driver that delivered all > > console output efficiently through a hypercall. That would be really > > easy. Or, as you mention, a custom way to deliver panic information. > > Collecting information like stack traces would be harder to > > accomplish, as I don't think there is currently a way to get it except > > by sending it to printk. > > That already exists; virtio-console (or serial console emulation) can do > the job. > > In fact the feature can be implemented 100% host side by searching for a > panic string signature in the console logs. You can even go one better and search for the panic string in the guest memory directly, which is what virt-dmesg does :-) http://people.redhat.com/~rjones/virt-dmesg/ Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
