Serial ports not accessible with RHEL5 xen kernel

[Caetano, Greg]

RHEL5 system with the following kernels installed:

kernel-2.6.18-8.1.8.el5
kernel-xen-2.6.18-8.1.8.el5

If I boot the non-XEN kernel, the minicom connection works with ttyS0
and 
In dmesg and /var/log/messages the port is reported

Aug 22 10:56:35 hpmgmt kernel: serial8250: ttyS0 at I/O 0x3f8 (irq = 4)
is a 16550A
Aug 22 10:56:35 hpmgmt kernel: serial8250: ttyS1 at I/O 0x2f8 (irq = 3)
is a 16550A
Aug 22 10:56:35 hpmgmt kernel: 00:09: ttyS0 at I/O 0x3f8 (irq = 4) is a
16550A


If I boot the XEN kernel, minicom doesn't work and I loose ttyS0 to Xen
and the comm port is not available
There is no report of the serial8250 device in dmesg

Aug 22 08:10:56 hpmgmt kernel: Xen virtual console successfully
installed as ttyS0

Any suggestions??? 

Greg
=======================================
Greg Caetano
HP TSG Linux Solutions Alliances Engineering
greg.caetano at hp.com