Hi David, > >> I think it makes sense to have a generic (non-GUP) version of > >> check_and_migrate_movable_pages() available in migration.h that > >> drivers can use to ensure that they don't break memory hotunplug > >> accidentally. > > > > Definately not. > > > > Either use the VMA and pin_user_pages(), or implement > > pin_user_pages_fd() in core code. > > > > Do not open code something wonky in drivers. > > Agreed. pin_user_pages_fd() might become relevant in the context of > vfio/mdev + KVM gmem -- don't mmap guest memory but instead provide it > via a special memfd to the kernel. > > So there might be value in having such a core infrastructure. Ok, I'll work on adding pin_user_pages_fd() soon. Thanks, Vivek > > -- > Cheers, > > David / dhildenb