KVM: arm64: nv: Tag shadow S2 entries with guest's leaf S2 level

KVM: arm64: nv: Tag shadow S2 entries with guest's leaf S2 level

Populate bits [56:55] of the leaf entry with the level provided
by the guest's S2 translation. This will allow us to better scope
the invalidation by remembering the mapping size.

Of course, this assume that the guest will issue an invalidation
with an address that falls into the same leaf. If the guest doesn't,
we'll over-invalidate.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-13-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>