[TF-M] Mailbox agent redesign

Hi,

Reading https://tf-m-user-guide.trustedfirmware.org/technical_references/design_docs... it mentions the plan to move ns_agent_mailbox to have "a positive valued Partition ID in the manifest" and it also states that "A standard Secure Partition gets errors when calling the Extended API".

Given that it will not possible to use the PID to identify the ns_agent_mailbox, how will the Extended API functions know whether the caller is a standard Secure Partition or not?

There was a patch https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/15142 that introduced a flag to identify the ns_agent_tz partition - would this be similar?

Also, is there a plan for which release this functionality is expected to appear?

Thanks,

Chris Brand