RHEV Guests high availability

Can someone explain  how does RHEV-M  detects that a guest has gone offline  and as a result  has to follow HA  policy ?

As far as I understood   the RHEV  treats every guest as a process - if  it crashes  then a guest should be restarted .

If I  simulate   guest  kernel panic event  ( echo c> /proc/sysrq-trigger)  - nothing happens .But it should be since guest  stops to respond . What is the scope/kinds  of  guest's  events RHEV reacts to ?

Please clarify .

Vladimir Berezovski .