XSM dummy policy blocking event channel creation

[Ross Philipson <ross.philipson@citrix.com>]

I am working on the next set of V4V patches to post to the list. I have 
pulled the very latest staging branch of Xen and I quickly ran into a 
new problem. We are basically trying to create an event channel during 
the creation of dom0. We have split up the evtchn_alloc_unbound() 
function into two functions but the basic problem is the same. The call 
to xsm_evtchn_unbound() is returning -EPERM from the new code in 
xsm/dummy.h. This patch set added this functionality:

http://lists.xen.org/archives/html/xen-devel/2012-11/msg01920.html

Specifically we are failing this part of the test return -EPERM:

static always_inline int xsm_default_action(
     xsm_default_t action, struct domain *src, struct domain *target)
{
     ...
     case XSM_TARGET:
         if ( src != target && !IS_PRIV_FOR(src, target) )
             return -EPERM;

The src domain is the current->domain which is idle_domain and target is 
dom0 which is in the process of being created. Neither of them is 
privileged (dom0 is not set to privileged yet). And I have not gotten 
past dom0 creation yet so I don't know what will happen when V4V tries 
to initialize for domU's.

I need some advice on how to proceed here. I am not terribly conversant 
in the working of XSM and do not have a clear idea how to proceed.

Thanks,
Ross Philipson