From: pbrobinson on
gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/2639#note_1512...
It's selected by DRM_AMDGPU_USERPTR or HSA_AMD or HSA_AMD_SVM or
INFINIBAND_ON_DEMAND_PAGING which are all enabled in common/generic so it will
be enabled by default universally.