[CentOS] VirtIO drivers and CentOS 5.4(Final)

Hi All

My guest is a CentOS 5.4 VM:

[root at localhost ~]# uname -a
Linux localhost 2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 2009 x86_64 
x86_64 x86_64 GNU/Linux
[root at localhost ~]# cat /etc/*release
CentOS release 5.4 (Final)

I wanted to know if the virtio drivers on this guest are stable.

The reason for asking this question is that i found this link:

http://wiki.libvirt.org/page/Virtio

which states that in order to use the virtio drivers i need to be using 
the kernel >=2.6.25 , but i am using the kernel version 2.6.18 in my 
guest VM. I am actually able to use the virtio drivers in my VM even 
with this kernel version and hence i wanted to know if they are stable 
to be used.

Did red hat backport these drivers to CentOS 5.4 ? If yes , Can you 
please point me to any bug to track this backport activity or any 
announcement of this backport task ?  I need that to show to my team so 
that we can release note this information as part of releasing our product.

Appreciate your help in this regard.

Thanks
Jatin