KVM: arm64: nv: Invalidate TLBs based on shadow S2 TTL-like information

In order to be able to make S2 TLB invalidations more performant on NV,
let's use a scheme derived from the FEAT_TTL extension.

If bits [56:55] in the leaf descriptor translating the address in the
corresponding shadow S2 are non-zero, they indicate a level which can
be used as an invalidation range. This allows further reduction of the
systematic over-invalidation that takes place otherwise.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-14-maz@kernel.org


Signed-off-by: Oliver Upton <oliver.upton@linux.dev>