amd_iommu: Helper to decode size of page invalidation command

The size of the region to invalidate depends on the S bit and address
encoded in the command. Add a helper to extract this information, which
will be used to sync shadow page tables in upcoming changes.

Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20250919213515.917111-5-alejandro.j.jimenez@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2 files changed