28 days of usage without freezing's! and again the settings\configuration that i understand is the reason for success:
fedora 21 i686 xfce4 host with lxdm , (updates & upgrades done on host and guests) , parcellite clipboard manager on host and guests (the default clipboard managers are killed and disabled for autostart,) some times failed for autostart the parcellite on kde's but that is not problem , can just start it and is ready on seconds.
- xml is edited for clipboard sharing right by the directions on whonix-kvm documentation.
not touch any other settings on virt-manager \xml's
*I am sorry , i use ver, 11. not 12, so my posts here are for whonix ver. 11.
I am stop the posts here , (28 days without freezings). At curent level , the download option for whonix images is ver. 12, if they have freezings to , can aply the workaround in that post.