Hello!

I've tried kdb on Xen 4.1 to debug hypervisor&Dom0 online and I should
say it works well.
Took kdb from http://xenbits.xen.org/ext/debuggers.hg/

It seems there are still one issue I run into.

 GET_PROCESSOR_ID macros defined in arch/x86/x86_64/entry.S is
out-of-date and should be updated for Xen-4.1. I mean that one uses
fixed offset to get processor_id field.

        orq  $(STACK_SIZE-16),reg;    \


That offset has been changed in cpu_info structure in new Xen.

I attached  the patch how it should be fixed on my vision. Please,
review the one.

Sergey.