[$] Memory protection keys for the kernel

The memory protection keys feature wasadded to the 4.6 kernel in 2016; it allows user space to group pages into"protection domains" that can have their access restricted independently ofthe normal page protections. There is no equivalent feature for kernelspace; access to memory in the kernel's portion of the address space iscontrolled exclusively by the page protections. That situation maybe aboutto change, though, as a result of the protectionkeys supervisor (PKS) patch set posted by Ira Weiny (with many patcheswritten by Fenghua Yu).