[TF-A] [RFC] isolation between runtime BL33 services and OS

Hi,

I am trying to identify a mechanism to enforce a form of two-way isolation between BL33 runtime services in OS, for instance: - a pair of 2MB areas that could be RO by one entity and RW by the other - an execute only BL33 2MB area?

This is similar to hypervisor except it only deals with memory, no vCPU, no GIC virtualization...

Could EL3 or EL2 install protective mappings ? BL33 could ask either EL2 hypervisor or SecureMonitor to actually install them.

Cordially,

FF