Hi
No 1st hand experience, just passing the information...
If some of you are hosting NetBSD on Xenserver, that might impact: http://mail-index.netbsd.org/port-xen/2017/10/23/msg009097.html
and the work around listed in http://mail-index.netbsd.org/port-xen/2017/10/23/msg009098.html
"I guess this is the patch from XSA-240, you need to boot with pv-linear-pt=true on the Xen command line"
Cheers
Tru