AMD/IOMMU: add "ivmd=" command line option
Just like VT-d's "rmrr=" it can be used to cover for firmware omissions.
Since systems surfacing IVMDs seem to be rare, it is also meant to allow
testing of the involved code.
Only the IVMD flavors actually understood by the IVMD parsing logic can
be generated, and for this initial implementation there's also no way to
control the flags field - unity r/w mappings are assumed.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>