Create devices behind the Armv8-A Base Platform FVP's SMMU

I want to do something similar to https://community.arm.com/support-forums/f/soc-design-and-simulation-forum/46584/which-devices-are-behind-the-armv8-a-base-platform-fvp-s-smmu and was wondering if it...
What is the difference between AEMv8-A Base Platform FVP and Armv8 Foundation Model FVP ?

I wish to run OPTEE + Android. Which of these two options are suitable for it ? What are the differences ? Which option allows modification to the secure monitor code ?
What is the difference between AEMv8-A Base Platform FVP and Armv8 Foundation Model FVP ?

I wish to run OPTEE + Android. Which of these two options are suitable for it ? What are the differences ? Which option allows modification to the secure monitor code ?
Reason Behind EL2 in non-secured state ARMv8

Hi Experts, What is the reason behind allowing EL2 only in non-secured state in ARMv8 ? Regards, Techguyz
Reason Behind EL2 in non-secured state ARMv8

Hi Experts, What is the reason behind allowing EL2 only in non-secured state in ARMv8 ? Regards, Techguyz