[libvirt] live-migration is not working with libvirt-0.6.2 on RHEL5.3

[Gerrit Slomma]

So i still do not get live migration up and running with libvirt-0.6.2 
on RHEL5.3
My setup is as following:
Host#1 rr016: RHEL5.3 2.6.18-128.el5.x86_64; 4 GB RAM; C2D T8300
Host#2 rr017: RHEL5.3 2.6.18-128.el5.x86_64; 3 GB RAM; C2D E6550

on both hosts:
kvm-85 compiled rpms from sourceforge.org (current release)
qemu-0.10.0 (from kvm-85)
qemu-img 0.9.1-11 from EPEL
libvirt-0.6.2 compiled rpms from libvirt.org (current release) + applied 
RHEL5-build-patch

Network: bridged network-if eth0 on bridge sw0 via 
/etc/sysconfig/network-scripts/ifcfg-eth0 and 
/etc/sysconfig/network-scripts/ifcfg-sw0, nothing in 
/etc/libvirt/qemu/networks besides the (untouched) default.xml.
iptables: disabled to avoid side-effects
Images: exported from a third host via iscsi and accessible from both 
involved hosts

if i bring up a VM on host#2 that is not defined on host#1 this VM comes 
up fine and i could ssh into it.

[root at rr017 ~]# virsh dominfo rr019v3
Id:             5
Name:           rr019v3
UUID:           ff1ba599-5801-fca9-ab33-8962c2dfa46c
OS Typ:         hvm
Status:         laufend
CPU(s):         2
CPU-Zeit:       26,9s
Max Speicher:   1572864 kB
Verwendeter Speicher: 1572864 kB
Automatischer Start: deaktiviert

if i try to migrate it without URI specified the migration fails with an 
"unknown failure" whereas the failure is obvious to me: wrong port

[root at rr017 ~]# virsh migrate rr019v3 qemu+tcp://192.168.1.119:16509/system
Please enter your authentication name:root
Please enter your password:
Fehler: Unknown failure

[root at rr017 ~]# tail -f /var/log/libvirt/qemu/rr019v3.log
info balloon
Using KVM without synchronous MMU, ballooning disabled
stop
migrate "tcp:rr016:49152"
migration failed
cont

[root at rr016 ~]# tail -f /var/log/libvirt/qemu/rr019v3.log
LC_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin HOME=/root USER=root 
LOGNAME=root /usr/bin/kvm -S -M pc -m 1536 -smp 2 -name rr019v3 -uuid 
ff1ba599-5801-fca9-ab33-8962c2dfa46c -monitor pty -pidfile 
/var/run/libvirt/qemu//rr019v3.pid -boot c -drive 
file=/dev/disk/by-path/ip-192.168.1.1:3260-iscsi-rr010:01-lun-6,if=ide,index=0 
-net nic,macaddr=00:16:3e:69:94:05,vlan=0 -net 
tap,fd=17,script=,vlan=0,ifname=vnet0 -serial none -parallel none -usb 
-vnc 127.0.0.1:0 -k de -incoming tcp:0.0.0.0:49152
char device redirected to /dev/pts/3
info cpus
* CPU #0: pc=0x00000000000ffff0 thread_id=8550
  CPU #1: pc=0x00000000000ffff0 thread_id=8551
balloon 1536

trying --live as a parameter the same applies:

[root at rr017 ~]# virsh migrate --live rr019v3 
qemu+tcp://192.168.1.119:16509/system
Please enter your authentication name:root
Please enter your password:
Fehler: Unknown failure

[root at rr017 ~]# tail -f /var/log/libvirt/qemu/rr019v3.log
info balloon
Using KVM without synchronous MMU, ballooning disabled
migrate "tcp:rr016:49153"
migration failed

[root at rr016 ~]# tail -f /var/log/libvirt/qemu/rr019v3.log
C_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin HOME=/root USER=root 
LOGNAME=root /usr/bin/kvm -S -M pc -m 1536 -smp 2 -name rr019v3 -uuid 
ff1ba599-5801-fca9-ab33-8962c2dfa46c -monitor pty -pidfile 
/var/run/libvirt/qemu//rr019v3.pid -boot c -drive 
file=/dev/disk/by-path/ip-192.168.1.1:3260-iscsi-rr010:01-lun-6,if=ide,index=0 
-net nic,macaddr=00:16:3e:69:94:05,vlan=0 -net 
tap,fd=17,script=,vlan=0,ifname=vnet0 -serial none -parallel none -usb 
-vnc 127.0.0.1:0 -k de -incoming tcp:0.0.0.0:49153
char device redirected to /dev/pts/3
info cpus
* CPU #0: pc=0x00000000000ffff0 thread_id=8641
  CPU #1: pc=0x00000000000ffff0 thread_id=8642
balloon 1536

Specifying the URI migration works, and the VM appears on the target-host

[root at rr017 ~]# virsh migrate rr019v3 
qemu+tcp://192.168.1.119:16509/system tcp:192.168.1.119:16509
Please enter your authentication name:root
Please enter your password:

[root at rr016 ~]# virsh list
 Id Name                 Status
----------------------------------
  3 rr019v3              laufend

But the status is laufend - that means "running" in english - whereas i 
have to suspend and resume the VM to get it up, then it is running on 
the target-host.
Backmigration is not possible and hangs endless, the libvirtd must be 
restarted on both hosts to get them back up.

Specifying --live as a parameter for the migration does have the same 
effect on the VM as omitting the parameter.
When doing the same on the commandline everything works fine, i even 
start the VM via ssh from the source-host on the target-host and migrate 
over the net with minimal downtime.
Why doesn't this work? Has anybody got a working setup with RHEL5 up and 
running?