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Implement FFA_RXTX_UNMAP_32 interface
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Description

FFA_RXTX_UNMAP_32 is the mandatory interface and must be implemented by the SPM.

Event Timeline

The possible envisioned scenario is related to booting TF-A+UEFI and support for authenticated variables.

  1. TF-A boots, including the SPM and SPs.
  2. UEFI boots, registers RX/TX with SPM, performs a mem share operation for a comm. buffer with a SP (e.g. St MM like), unmaps RX/TX
  3. OS boots, registers RX/TX with SPM, and can later invoke UEFI run-time services (e.g. query UEFI variable). UEFI uses the established comm. buffer but no longer needs RX/TX buffers.

Without FFA_RXTX_UNMAP it's not possible that both UEFI and OS invoke FFA_RXTX_MAP

FWIW, agree with Olivier's analysis.

odeprez closed this task as Resolved.Wed, Sep 15, 10:15 AM