@beshleman exactly that is the final goal
getting DRTM for guests and Measured Boot for the host
My plan was to get the following
1- Measured Boot for the host
2- full disk encryption for the guests using vTPM (Storing the keys in the TPM module)
3- DRTM for the guests
based on your answer I see the first 2 goals are achievable, Measured boot for the host is fully supported by xenserver so it is just a matter of getting the source code of Supplemental pack and compile it and we can even add it as an option to xcp-ng
for vTPM i know the xen project emulate it but they keep the seed in the physical TPM device in the host (https://fossies.org/linux/xen/docs/man/xen-vtpmmgr.7.pod)
So if i can get the first 2 goals that would be great start for me