I think the pointer-masking extension would ignore upper bits in a virtual address - but only for the canonicality check. 

Of course, when virtual memory systems are not enabled then they are the same but I do not recall if pointer-masking

is applicable when virtual memory systems are not enabled.

regards

ved

On Wed, Aug 10, 2022 at 9:03 AM Allen Baum <allen.baum@...> wrote:

Note that the (unratified)  pointer masking extension would permit upper bits to be ignored (but not "simply" be ignored).

On Wed, Aug 10, 2022 at 5:26 AM Scott Johnson <scott.johnson@...> wrote:

Ignoring the high bits is not acceptable. It must take an access fault.

I agree the specs do not make this entirely clear.