Hello, Since commit 97527e9c4fd37140 on main branch FreeBSD should be able to boot and work as a Xen dom0 from UEFI.
Booting from UEFI also requires the usage of xen-kernel 4.14.1_1, previous versions of xen-kernel won't boot correctly under UEFI. The way to setup the system is exactly the same as when using BIOS, xen_kernel and xen_cmdline options should be set in loader.conf, see: https://docs.freebsd.org/en_US.ISO8859-1/books/handbook/virtualization-host-xen.html I don't have plans to backport for 13.0, but will consider backporting to stable/13 at a later point if there are no issues, so the functionality could be used in 13.1. This has been tested on a single Intel box with UEFI, some wider testing would be appreciated. Thanks to tsoome, imp and kib for the reviews. Roger.