Comment 45 for bug 378240

@User Virtual
  I believe to be done with yours charade ;)
Reproduced your build for 4.0.1-rc2 :-

# cp xen-4.0_4.0.1rc1-0ubuntu1.diff.gz xen-4.0_4.0.1rc2-0ubuntu1.diff.gz
# ./packageXen40x.sh 4.0.1-rc2

Build succeed:-
root@ServerLDX:/usr/src/build# find . -name "*.deb" -print
./400/xen-docs-4.0_4.0.1rc1-0ubuntu1_all.deb
./400/libxen4-dev_4.0.1rc1-0ubuntu1_amd64.deb
./400/libxen4_4.0.1rc1-0ubuntu1_amd64.deb
./400/xen-hypervisor-4.0_4.0.1rc1-0ubuntu1_amd64.deb
./400/xen-utils-4.0_4.0.1rc1-0ubuntu1_amd64.deb
./400/python-xen-4.0_4.0.1rc1-0ubuntu1_amd64.deb

Actually , it matches 4.0.1-rc2 . Installed debian packages been built and loaded JF's 2.6.32.15 ( which requires rc2)
under yours Xen 4.0.1-rc2 Hypervisor

Made sure:-
root@ServerLNX:/dev/xen# ls -l
total 0
crw-rw---- 1 root root 10, 60 2010-06-17 16:15 evtchn
crw-rw---- 1 root root 10, 59 2010-06-17 16:15 gntdev

It's a fair . Udev created evtchn device required for successful xend start under pvops 2.6.32.(x)
Edited your xend , removing attempt to load xen-evtchn module, which was hard linked with 2.6.32.15

# /etc/init.d/xend start

root@ServerLNX:~# xm info
host : ServerLNX
release : 2.6.32.15
version : #8 SMP Sun Jun 13 14:34:17 MSD 2010
machine : x86_64
nr_cpus : 2
nr_nodes : 1
cores_per_socket : 2
threads_per_core : 1
cpu_mhz : 2999
hw_caps : bfebfbff:20100800:00000000:00000940:0008e3fd:00000000:00000001:00000000
virt_caps : hvm
total_memory : 8191
free_memory : 1666
node_to_cpu : node0:0-1
node_to_memory : node0:1666
node_to_dma32_mem : node0:805
max_node_id : 0
xen_major : 4
xen_minor : 0
xen_extra : .1-rc2
xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xffff800000000000
xen_changeset : unavailable
xen_commandline :
cc_compiler : gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
cc_compile_by : root
cc_compile_domain :
cc_compile_date : Thu Jun 17 15:24:31 MSD 2010
xend_config_format : 4

root@ServerLNX:~# brctl show
bridge name bridge id STP enabled interfaces
eth1 8000.00221563f99f no peth1
virbr0 8000.000000000000 yes

root@ServerLNX:~# virsh version
Compiled against library: libvir 0.8.1
Using library: libvir 0.8.1
Using API: Xen 3.0.1
Running hypervisor: Xen 4.0.0

I also believe , that it's possible to write a proper one xen-4.0_4.0.1rc2-0ubuntu1.diff.gz
to create debian packages supposed to install Xen 4.0.1-rc2 and load 2.6.32.15 pvops
for Dom0 support with xend starting with no issues.