This is the core of the architecture-dependent portion of the Xen
event channel/interrupt handling. Originally implemented by Julien Grall
in 2015, but heavily updated for submission by Elliott Mitchell in 2021.
This is based on the core FreeBSD interrupt code. While the additional
functionality provided by intrng could be nice, only the core is
Submitted by: Elliott Mitchell <firstname.lastname@example.org>
Original implementation: Julien Grall <email@example.com>, 2015-10-21 07:18:56
Original implementation: Julien Grall <firstname.lastname@example.org>, 2015-11-02 04:31:56