This is just a summary of my notes on how I got xen integration with Freenas. There wasn't much I could find on google regarding how to do this so I thought someone else might be interested. I will start by assuming a working build environment capable of successfully building 9.1.1-RELEASE.
In nanobsd/FREENAS.amd64 I added:
options NO_ADAPTIVE_MUTEXES
options NO_ADAPTIVE_RWLOCKS
options NO_ADAPTIVE_SX
# Xen HVM support
options XENHVM
device...
How I got a XenHVM kernal and xen-tools working in FreeNAS
In nanobsd/FREENAS.amd64 I added:
options NO_ADAPTIVE_MUTEXES
options NO_ADAPTIVE_RWLOCKS
options NO_ADAPTIVE_SX
# Xen HVM support
options XENHVM
device...
How I got a XenHVM kernal and xen-tools working in FreeNAS