Hi Reinhard,

This is correct at current and needs SFC specification to clarification in future.

The existing PSA Firmware Framework proposes a thread based Secure Partition and the IPC manner about how the information is shared between these process. The SFC model (which is a well know model but do not have a specification yet) combines secure services as a library and makes the information-sharing mechanism complicate under isolation level 2/3, which lost the advantage of 'library' model.

/Ken

From: TF-M tf-m-bounces@lists.trustedfirmware.org On Behalf Of Reinhard Keil via TF-M Sent: Tuesday, December 17, 2019 4:10 PM To: tf-m@lists.trustedfirmware.org Subject: [TF-M] Level 2/Level 3 Isolation requires IPC?

I have heard that Level 2/Level 3 isolation with TF-M requires Inter-Process Communication (IPC) mode. It does not work with Secure Function Call (SFC) mode (aka Library mode).

Is it correct, and why does Level2/Level 3 isolation require IPC?

Reinhard

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