x86/hvm: block speculative out-of-bound accesses

x86/hvm: block speculative out-of-bound accesses

There are multiple arrays in the HVM interface that are accessed
with indices that are provided by the guest. To avoid speculative
out-of-bound accesses, we use the array_index_nospec macro.

When blocking speculative out-of-bound accesses, we can classify arrays
into dynamic arrays and static arrays. Where the former are allocated
during run time, the size of the latter is known during compile time.
On static arrays, compiler might be able to block speculative accesses
in the future.

This is part of the speculative hardening effort.

Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Signed-off-by: Norbert Manthey <nmanthey@amazon.de>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Juergen Gross <jgross@suse.com>