There was some discussion about the lack of visibility of the Xen4CentOS development process.
The Xen spec files and supporting patches are kept in a git tree. I've pushed copies of these trees here:
https://github.com/gwd/sig-virt-xen
xen-44 is the branch for Xen 4.4 development, and xen-46 is the branch for Xen 4.6 development.
As is normal, these repos do not contain many of the binary tarballs required to build. The best way to get these is to download a recent srpm (from http://cbs.centos.org/repos/virt7-xen-46-testing/source/SRPMS/ -- replacing virt6 with virt7 or 44 with 46 as appropriate).
The patches to the xen hypervisor are in a rather unusual format: a git "am". This makes it *much* easier to rebase and manipulate the queue if you're familiar with git; but it does add a bit to get familiar with.
To manipulate the am patchqueue (using 4.4.3 as an example):
1. Check out a git repo and make a branch based on the baseline version
$ git checkout -b centos/pq/4.4.3 RELEASE-4.4.3
2. Import SOURCES/xen-queue.am
$ git am ${path-to-package-repo}/SOURCES/xen-queue.am
OR using stackgit:
$ stg init $ stg import -M ${path-to-package-repo}/SOURCES/xen-queue.am
3. Manipulate the patchqueue using normal git (or stackgit) commands
4. Export the queue again:
git format-patch --stdout -N RELEASE-4.4.3 > ${path-to-package-repo}/SOURCES/xen-queue.am
-George