On 8/15/21 9:39 AM, Borislav Petkov wrote:

On Sun, Aug 15, 2021 at 08:53:31AM -0500, Tom Lendacky wrote:

quoted

It's not a cross-vendor thing as opposed to a KVM or other hypervisor
thing where the family doesn't have to be reported as AMD or HYGON.

What would be the use case? A HV starts a guest which is supposed to be
encrypted using the AMD's confidential guest technology but the HV tells
the guest that it is not running on an AMD SVM HV but something else?

Is that even an actual use case?

Or am I way off?

I know we have talked about this in the past but this still sounds
insane.

Maybe the KVM folks have a better understanding of it...

I can change it to be an AMD/HYGON check...  although, I'll have to check
to see if any (very) early use of the function will work with that.

At a minimum, the check in arch/x86/kernel/head64.c will have to be
changed or removed. I'll take a closer look.

Thanks,
Tom