Just a heads-up: A Xen package with XSAs through 163 is on its way through the build system. I'll send an announcement when I've tagged it as ready to be propagated to the mirrors.
As with the last XSA update, it will depend on having manually updated to the new Virt SIG repository layout. If you haven't already please run the following in preparation:
yum install http://buildlogs.centos.org/centos/6/virt/x86_64/xen/centos-release-xen-7-11...
(And note that this package depends on a package from centos-extras, so if you have that repo disabled by default you'll need to enable it to perform the above command.)
-George