PCI passthrough: rdm_policy=relaxed (shared RMRR device)

We do have an USB controller that needs to be passed through to domU. In /var/log/xen/hypervisor.log we do see 'It's disallowed to assign...' for the device IDs.

It works with the rdm_policy=relaxed option when passed manually with xl pci-attach, but it seems there is no way to pass rdm_policy option via other-config:pci parameter.

Some way to do this should exist IMO.