We always try to work with Citrix ("XenServer" division now), to push things upstream and manage to get it merged.

@maxcuttins There are two packages. User level blktap driver that you referred blktap and a builtin kernel driver blktap2. Said patch is against mainline kernel as additional driver. You still need to have user land blktap from https://github.com/xapi-project/blktap There are instructions lying around https://xcp-ng.org/forum/topic/122/how-to-build-blktap-from-sources/ to build user land blktap (its without patch).