Hi,

the complete message is:

[ 3411.029025] Uhhuh. NMI received for unknown reason 30 on CPU 0.
[ 3411.029028] Do you have a strange power saving mode enabled?
[ 3411.029028] Dazed and confused, but trying to continue
[ 3441.028990] Uhhuh. NMI received for unknown reason 20 on CPU 0.
[ 3441.028996] Do you have a strange power saving mode enabled?
[ 3441.028996] Dazed and confused, but trying to continue

When it happens, it seems to happen very often (every 30 seconds) and
the guest typically locks up totally after 1-2 days.

Host and guest are both SLES12SP2 with kernel-4.4.21-84/88. There is no
problem when the guest is freshly started (virsh start guest), but as
soon as I issue a 'reboot' within the guest, the messages start after a
few seconds.

Anyone seen this and knows a workaround?

Franz.