Matthew GarrettMay 8, 2024
My annual plea for a thing: I want a type 1 hypervisor that just has a small isolated VM and then passes through the rest of the hardware to the main VM which runs Linux. The small VM is intended to be used to run small pieces of code that the main OS should not be able to interfere with. Does such a thing exist? (Think Xen, but with a Dom0 that can't see into DomUs)
Show threadHoward Chu @ SymasMay 8, 2024
@mjg59 sounds like something you'd need Secure Encrypted Virtualization for https://www.amd.com/en/developer/sev.html
Show threadMatthew GarrettMay 8, 2024
@hyc No, once you're in SEV-land you're not really in a good place to do hardware passthrough
Show threadbalooMay 8, 2024
@mjg59 @hyc
Curious: what kind of hardware should the security VM need to access?
(I can only guess TPM? For state bootstrap or something?)
Show threadMatthew GarrettMay 8, 2024
@baloo @hyc Potentially the TPM, but otherwise nothing - just CPU, RAM, and some sort of simple intra-VM communication channel.
Show threadbalooMay 8, 2024

@mjg59 @hyc
I know you already dismissed SEV, but https://github.com/project-oak/oak seems vaguely related?

This is a VM inside the main OS, but the binary inside the TEE is available over grpc.

GitHub - project-oak/oak: Meaningful control of data in distributed systems.

Meaningful control of data in distributed systems. - project-oak/oak

GitHub
Show threadMatthew Garrett
@baloo @hyc Right, you can do it the other way around with SEV, but that then leaves you with very restricted hardware support at the moment
May 8, 2024 at 8:38pmWeb
Show threadbalooMay 8, 2024
@mjg59 @hyc yeah definitely. You will need a piece of code in the main os to make the bridge for any hardware resource you might need.