On Sun, Jun 06, 2021 at 08:22:14PM +0300, Nick Kossifidis wrote:

This patch violates the Privilege Spec section 4.4.1 that clearly states:

"Bits63–54 are reserved for future standard use and must be zeroed by 
software for forward compatibility"

Standard use means that valid values can only be defined by the Priv. Spec, 
not by the vendor (otherwise they'd be marked as "custom use" or "platform 
use"), and since they "must" be zeroed by software we 'll be violating the 
Privilege Spec if we do otherwise.

Yes, that is why I think it is a no-go.