On Wed, Apr 07, 2021 at 12:34:59PM -0500, Brijesh Singh wrote: > The feature is part of the GHCB version 2 and is enforced by the > hypervisor. I guess it can be extended for the ES. Since this feature > was not available in GHCB version 1 (base ES) so it should be presented > as an optional for the ES ? Yeah, it probably is not worth the effort. If an attacker controls the guest kernel, then it can re-register a new GHCB so it doesn't really matter. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette