1.Initiator software writes a request message to memory.
2.Initiator writes a 1 to its Trigger register for the target processor.
3.Initiator may pole its Observation register or wait for an IPI response interrupt from the target.
4.After the target has indicated it has responded to the interrupt, the initiator can read the response message in memory. This is in a pre-defined format to a pre-defined memory location.