From: Volodymyr Babchuk <vlad.babchuk@xxxxxxxxx>
This patch series enables dynamic shared memory support in the TEE
subsystem as a whole and in OP-TEE in particular.
Global Platform TEE specification  allows client applications
to register part of own memory as a shared buffer between
application and TEE. This allows fast zero-copy communication between
TEE and REE. But current implementation of TEE in Linux does not support
Also, current implementation of OP-TEE transport uses fixed size
pre-shared buffer for all communications with OP-TEE OS. This is okay
in the most use cases. But this prevents use of OP-TEE in virtualized
a) We can't share the same buffer between different virtual machines
b) Physically contiguous memory as seen by VM can be non-contiguous
in reality (and as seen by OP-TEE OS) due to second stage of
c) Size of this pre-shared buffer is limited.
So, first part of this patch series adds generic register/unregister
interface to tee subsystem. Next patches add necessary features
into OP-TEE driver, so it can use not only static pre-shared buffer,
but whole RAM to communicate with OP-TEE OS.