[mcbridematt]

IIRC Qualcomm smartphone SoCs have always run some kind of hypervisor, I believe it's to allow partitioning of the CPU cores with the modem/DSP.

They used to (mid-late 2000s) use an L4 derivative ("REX"?), with the more recent chips (including the 'X' series for PCs) using their homegrown "Gunyah" hypervisor (https://github.com/quic/gunyah-hypervisor)

[fulafel]

Would be interesting if you know of any evidence about being an architectural hw limitation. Though of course the practical difference may be small if the DRM bootloader enforces loading the hypervisor through cryptographic checksums. But I guess if a customer asked they would allow it and the hardware could do it.