Hello!
Xen and related packages (libvirt, virt-install, virt-manager etc) in Upcoming CentOS 5.3 support running and installing Fedora 10 (and Fedora 11) paravirtual domU guest virtual machines.
These upstream fixes (new features) make it possible:
"RHEL5.3 xen: include support for booting Fedora 10 DomU (i.e. bzImage support)" https://bugzilla.redhat.com/show_bug.cgi?id=457199
"update virtinst to install f10 xen guests" https://bugzilla.redhat.com/show_bug.cgi?id=460585
But beware there's a bug in 32bit x86 Fedora 10 installer (anaconda). It installs wrong kernel to the domU (it should install kernel-PAE but it installs normal kernel), and that will prevent the domU from starting after installation. Xen only supports PAE kernels for 32bit PV guests.
It's this bug: "anaconda installs the wrong kernel for i686 xen guests" https://bugzilla.redhat.com/show_bug.cgi?id=470905
It can be "fixed" by using a kickstart file for installation, which forces installation of kernel-PAE instead of normal kernel.
Example of such kickstart: http://pasik.reaktio.net/fedora/f10-xen-domu-ks.cfg
Fedora 11 (current rawhide of 2009-03-24) does not have that bug anymore, so paravirtual F11 Xen PV domU installation should work out-of-the-box.
I've tested and verified all the above works. Hopefully that helps someone :)
-- Pasi