Query about cpuidle

[Andrew Cooper <andrew.cooper3@citrix.com>]

Hello,

We have recently had a support escalation about Xen-4.1.1 being unable
to boot on HP BL460c G7 blades.  The problem turned out to be a null
function pointer deference (ns_to_tick in cpu_idle.c) during early boot
of dom0, in the set_cx_pminfo function.

I applied your patch, changeset 23662:2faba14bac13, about initializing
default C state information, and this appears to have fixed the problem.

However, I see in the patch that setting up the function pointers
(ns_to_tick, tick_to_ns etc) is predicated on the hypercall coming in on
CPU0.  What guarantees are in place to ensure that these function
pointers get set up?  I cant see anything obvious from the code, but
have to admit that the null pointer deference appears to have gone away.

Thanks in advance,

-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com