CentOS virt - Jan 2019 - xen and libvirt

Hi

Does someone know how it is possible these parameters:

e820_host
max_grant_frames

to set with libvirt xml config?

I use them with xl config but I want to change to libvirt config/tools.
(with libvirt 4.10 it is possible to start pvh domains)

-- 
------
Greetz