[CentOS-virt] custom Xen on custom kernel on CentOS 7

Tue Feb 27 17:46:00 UTC 2018
John Vetter <john.vetter at mail.com>

Sorry reseding in text format.

I'm trying to run an arbitrary Xen version (4.7.x) on a recent kernel (say, 4.13.x) on CentOS 7.
What is the recommended way for doing this? (I am new to Xen and virtualization).
I tried the following:
1. installed xen4centos.
2. built linux kernel 4.13.x and installed it (using make install)
3. built xen 4.7.x and installed it (using make install).
grub2-mkconfig and grub-bootxen.sh don't seem to be picking up the combination of new kernel and new xen and making an entry in the grub.cfg file.
It did make an entry for the new Xen with the kernel installed with xen4centos.
I looked at the grub-bootxen.sh script but was unable to figure a way out. How do I get the installation scripts to make an entry for my new kernel and new Xen?