Description of problem:
After upgrade to F9 of my DomU guest there is only one virtual processor found in this machine. I can't increase number of CPUs.

Version-Release number of selected component (if applicable):
Dom0:
kernel-xen-2.6.21.7-5.fc8
xen-3.1.2-2.fc8
Domu:
kernel-xen-2.6.25.3-2.fc9.x86_64

How reproducible:
Always.

Steps to Reproduce:
1. boot F9 with latest updates and set "cpus = 2" or more
2. see output of: xm list

Actual results:
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0  2145     8     r-----    181.6
builder                                      7  2048     1     r-----     81.3

Expected results:
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0  2145     8     r-----    181.6
builder                                      7  2048     8     r-----     81.3
                                                      ^^^^ - 8 here is OK

Additional info:
With kernel from F8 (2.6.21.7-3.fc8xen) all CPUs are OK.

You also can try to increase number of CPUs by running:
    xm vcpu-set builder 8
without effect, no error is raised, but nothing is changed.

And also output of /proc/cpuinfo on guest contains only one processor.