The kernel-xen package is compiled with PAE support. This means that machines
such as my Pentium-M laptop can not run Xen.
There is a very tricky situation with Xen on i386 & PAE. You basically have to
have a matched stack, either all PAE, or all non-PAE - you can't mix & match.
Since PAE is needed for machines with > 4 GB ram, and all current CPUs do now
have PAE (even current laptop targetted CPUs), in FC6 the decision was made to
go for PAE kernels. Unfortunately this excludes some older laptops without PAE.
Does matched stack mean that you need to compile all xen-relevant packages
compiled with or without PAE support? If that's the case, then I understand the
decision, but if it's not, then it would be better to have kernel-xen and
kernel-xenPAE instead of what we currently have.
No, it's only the kernel-xen package that matters (that package includes both
the kernel and the hypervisor, which are the only two components that care about
PAE status.) But the PAE choice in paravirtualised guests MUST match that in
the dom0 host.