Red Hat ENTERPRISE LINUX 5 - VIRTUALIZATION GUIDE Manual page 170

Chapter 11. Xen Para-virtualized Drivers
Important
The host system requires Red Hat Enterprise Linux 5.1 or newer.
Finding which kernel you are using
Write the output of the command below down or remember it. This is the value that
determines which packages and modules you need to download.
# rpm -q --queryformat '%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH}\n'
kernel
Your output should appear similar to this:
kernel-PAE-2.6.18-53.1.4.el5.i686
The name of the kernel is PAE (an abbreviation of Physical Address Extensions), kernel
version is 2.6.18, the release is 53.1.4.el5 and the architecture is i686. The kernel rpm
should always be in the format kernel-name-version-release.arch.rpm.
Important Restrictions
Para-virtualized device drivers can be installed after successfully installing a guest operating system.
You will need a functioning host and guest before you can install these drivers.
Para-virtualized block devices and GRUB
GRUB can not presently, access para-virtualized block devices. Therefore, a guest
can not be booted from a device that uses the para-virtualized block device drivers.
Specifically, the disk that contains the Master Boot Record(MBR), a disk containing a boot
loader (GRUB), or a disk that contains the kernel initrd images. That is, any disk which
contains the /boot directory or partition can not use the para-virtualized block device
drivers.
Red Hat Enterprise Linux 3 kernel variant architecture dependencies
For Red Hat Enterprise Linux 3 based guest operating systems you must use the processor specific
kernel and para-virtualized driver RPMs as seen in the tables below. If you fail to install the matching
para-virtualized driver package loading of the xen-pci-platform module will fail.
The table below shows which host kernel is required to run a Red Hat Enterprise Linux 3 guest on if
the guest was compiled for an Intel processor.
Guest kernel type
ia32e (UP and SMP)
i686
i686-SMP
156
Required host kernel type
x86_64
i686
i686