This driver is for testing device private memory migration and devices
which use hmm_range_fault() to access system memory via device page tables.

Link: https://lore.kernel.org/r/20200422195028.3684-2-rcampbell@nvidia.com
Link: https://lore.kernel.org/r/20200516010424.2013-1-rcampbell@nvidia.comSigned-off-by: NRalph Campbell <rcampbell@nvidia.com>
Signed-off-by: NJérôme Glisse <jglisse@redhat.com>
Link: https://lore.kernel.org/r/20200509030225.14592-1-weiyongjun1@huawei.com
Link: https://lore.kernel.org/r/20200509030234.14747-1-weiyongjun1@huawei.comSigned-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20200511183704.GA225608@mwandaSigned-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>