On Fri, Jul 17, 2020 at 12:20:51AM -0700, ira.weiny@xxxxxxxxx wrote: > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > Device managed memory exposes itself to the kernel direct map which > allows stray pointers to access these device memories. > > Stray pointers to normal memory may result in a crash or other > undesirable behavior which, while unfortunate, are usually recoverable > with a reboot. Stray writes to areas such as non-volatile memory are > permanent in nature and thus are more likely to result in permanent user > data loss vs a stray write to other memory areas > + pks_update_protection(dev_page_pkey, PKEY_DISABLE_ACCESS); So on the one hand you talk about the problem of stray writes, but then you disable all access.