HVM virtualization?

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

One of my hosting providers is converting VPSes from PV to HVM 
virtualization due to security issue
https://xenbits.xen.org/xsa/advisory-286.html

They say NetBSD does not work under HVM mode and can choose a different 
BSD (or Linux).

Can someone tell me about this? I did look briefly at 
http://wiki.netbsd.org/ports/xen/howto/ but don't understand the context 
of the wiki saying it is supported but the hosting provider saying it 
does not work.

Thanks!