Hi Okash, Varun,
Sorry I've not had a chance to properly read this email thread yet so apologies if my comment is irrelevant. I just wanted to point out that TF-A Tests provide some tests for MEM_PROTECT [1] and MEM_PROTECT_CHECK [2] SMC interfaces, in case that helps clarifying their intended usage.
Cheers, Sandrine
[1] https://git.trustedfirmware.org/TF-A/tf-a-tests.git/tree/tftf/tests/runtime_...
[2] https://git.trustedfirmware.org/TF-A/tf-a-tests.git/tree/tftf/tests/runtime_...