I mean, it's not uniformly literally technically identical, but yes, an Android phone running its OS in ring 0 while other OSs run in other VMs on top of the EL

I mean, it's not uniformly literally technically identical, but yes, an Android phone running its OS in ring 0 while other OSs run in other VMs on top of the EL2 (ring -1) hypervisor under the supervision of the Secure Monitor in L3 (ring -2) is very much in the same boat. Suggested reading: * https://www.maven-silicon.com/blog/privilege-levels-in-arm-architecture/ https://www.maven-silicon.com/blog/privilege-levels-in-arm-a... * https://projectzero.google/2017/02/lifting-hyper-visor-bypassing-samsungs.html https://projectzero.google/2017/02/lifting-hyper-visor-bypas... * https://en.wikipedia.org/wiki/ARM_architecture_family#Security_extensions https://en.wikipedia.org/wiki/ARM_architecture_family#Securi... * https://docs.samsungknox.com/admin/fundamentals/whitepaper/samsung-knox-mobile-security/system-security/real-time-kernel-protection/ https://docs.samsungknox.com/admin/fundamentals/whitepaper/s... (in which Samsung uses firmware running under the kernel to protect against kernel exploits)