17 Jul
2020
17 Jul
'20
9:20 a.m.
On Fri, Jul 17, 2020 at 12:20:51AM -0700, ira.weiny@intel.com wrote:
From: Ira Weiny ira.weiny@intel.com
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.