The XilPM client library supports the Arm Secure Monitor Call (SMC) interface as an alternative to the Inter-Processor Interrupt (IPI) mailbox for issuing Platform Management (PM) requests to the Platform Loader and Manager (PLM). The SMC transport is intended for applications that execute at AArch64 Non-secure Exception Level 1 (EL1 NS), where the Arm Trusted Firmware-A (TF-A) at EL3 forwards PM requests to the PLM and routes asynchronous PM notifications back to the Non-secure world.
When the SMC transport is built into the XilPM client, the same public XilPM APIs are used by the application; only the underlying transport changes.