I don't know about Android, but AMD CPUs support encrypting regions of physical memory with different keys which are accessible only to one particular VM runnin

I don't know about Android, but AMD CPUs support encrypting regions of physical memory with different keys which are accessible only to one particular VM running, but also not accessible to the host: AMD Secure Encrypted Virtualization (SEV) https://www.amd.com/en/developer/sev.html https://www.amd.com/en/developer/sev.html