The Life of Lou Ruppert

I’ve been playing a lot with virtualization this past year. The update to Ubuntu Karmic Koala busted the OpenVZ setup I had on one of my machines, so I have been trying to look at LXC and XEN while I wait for their developers to release a kernel modern enough to work with Ubuntu 9.10.

Over the last couple days, I’ve been going over and over the instructions here , but every time I would try to boot into it, I’d get screens and screens of various kernel panics with stuff like xen_check_events or xen_force_restore, and xen_remap_exchanged_ptes. After many hours of Googling, I discovered a note about panics taking place when the CONFIG_HIGHPTE option was set. I unset that option, and now the XEN hypervisor boots flawlessly. Finally!

So if you’re trying to play with the xen hypervisor under Karmic Koala, here’s the value you’ll need to make sure is not set:

->Processor Type and Features
-> [ ] Allocate 3rd-level pagetables from highmem

Once you build your kernel without that, it should work according to instructions. I also hardcoded the root path under kernel options, but I don’t know if that’s necessary.

Edit 12/15: I noticed that after I installed this I still couldn’t get Xen to actually load a guest without crashing the whole system, so I guess I need more than this to make peace with Xen. After a month of playing with it, I’ve given up on getting a working xen setup for now, and am focusing my energies on LXC/libvirt.