Re:Reading privileged memory with a side-channel
by j_coder on Thursday January 04, 2018 @02:36PM
(#16073339)
You are right.
The best approach is to evict all user space pages from cache when an invalid page access happens if the page fault was caused by the software trying to read/write kernel space pages.
Massive performance hit but only to misbehaved software. Normal software will not have the performance hit of the current solution.
Kernel could even switch to unmapped kernel pages solution if too many read/write attempts.
The best approach is to evict all user space pages from cache when an invalid page access happens if the page fault was caused by the software trying to read/write kernel space pages.
Massive performance hit but only to misbehaved software. Normal software will not have the performance hit of the current solution.
Kernel could even switch to unmapped kernel pages solution if too many read/write attempts.