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* Laszlo Ersek (lersek at redhat.com) wrote:
> On 01/07/21 18:33, Dr. David Alan Gilbert wrote:
> 
> > in some ways you're trading
> > off host-guest security against guest security there.
> 
> This is a great way to put it IMO; the question is whether SB --
> normally, a barrier between guest components -- buys the guest owner any
> actual security in this use case. If the guest owner controls both the
> guest firmware and the guest OS completely, there likely is no threat
> that the guest OS might somehow undermine the guest firmware (e.g., get
> hacked and install a permanent UEFI rootkit on the UEFI system
> partition, or whatever).

It doesn't help if the guest gets compromised by something it's doing;
you can imagine a guest-owner who runs a VM that processes externally
provided data;  they want protection against the cloud-vendor (hence
SEV), but they know there's a chance that while processing externally
provided data they could get compromised; SB would give them some
protection.

> TBH the *intersections* of these security technologies / threat models
> are a bit mind-boggling, to me anyway.

Heck yes, well and truly boggled.

Dave

> Laszlo
-- 
Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK