[Libvir] Conflict between libvirt 0.1.8 and Xen 3.0.3

[Philippe Berthault <Philippe Berthault Bull net>]

There is a conflit between libvirt 0.1.8 and the latest release 3.0.3 of 
Xen. With Xen 3.0.3 release, the virsh vcpuinfo command (or 
virDomainGetVcpus API) always returns the 0 as physical CPU used by any 
vCPU.

Example:
#: xm vcpu-list VM1
Name   ID VCPUs   CPU State   Time(s) CPU Affinity
VM1      4     0     0   -b-      50.3 0
VM1      4     1     0   -b-      17.3 any cpu
VM1      4     2     1   -b-      34.2 1
VM1      4     3     1   -b-      21.8 any cpu

#: virsh vcpuinfo VM1
VCPU: 0
CPU: 0
...
VCPU: 1
CPU: 0
...
VCPU: 2
CPU: 0
...
VCPU: 3
CPU: 0

The same libvirt release 0.1.8 used with an older release of Xen gives a 
correct result.

I currently investigate the problem but perhaps anyone has an idea of 
the origin of this problem.