The Inter Processor Interrupt Block provides the ability for any processing unit to interrupt another processing unit by performing a register write.
There are 11 IPI channels (GEN_IPI_0 through GEN_IPI_10), out of which four channels (Channel 3, 4, 5, 6) are dedicated to PMU. The rest of the channels can be assigned to APU, RPU, and PL. With this Master assignment to each IPI channel protects corresponding channel using XPPU from unmapped masters.
Each IPI channel provides the registers to trigger the interrupts to any destination. The XPPU only allows the master that is associated with channel to access those registers. In addition to the registers, IPI channels are provided with the payload buffers.
XPPU only allows the master that is associated with buffers to access those buffers.