I am currently trying to get Xen to boot on my Lenovo T430 laptop with
BIOS 2.68 and using master results in no output to the screen and the
machine being completely hung (must pull the power cable). I've gone
ahead and bisected it and the resultant commit is:

commit 4824bdfdabebd4042277461cb3cbefa61c624804
Author: Chao Peng <chao.p.peng@linux.intel.com>
Date: Tue Jul 7 15:42:49 2015 +0200

x86: add socket_cpumask

Maintain socket_cpumask which contains all the HT and core siblings
in the same socket.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

Since I'm not getting any output I'm at a loss how to debug this problem

further. I do have Intel AMT setup with Serial Over LAN working so if its

at all possible to get more info over serial I will do that. I am already booting

Xen with console=vga,com1 com1=115200,amt loglvl=all so not sure what

else to add.