Intel 9560 CM8063101049716 Data Sheet

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Protection Keys provide a method to restrict permission by tagging each virtual page 
with a unique protection domain identifier. The Protection Key Registers (PKR) 
represent a register cache of all protection keys required by a process. The operating 
system is responsible for management and replacement polices of the protection key 
cache. Before a memory access (including IA-32) is permitted, the processor compares 
a translation’s key value against all keys contained in the PKRs. If a matching key is not 
found, the processor raises a Key Miss fault. If a matching Key is found, access to the 
page is qualified by additional read, write and execute protection checks specified by 
the matching protection key register. If these checks fail, a Key Permission fault is 
raised. Upon receipt of a Key Miss or Key Permission fault, software can implement the 
desired security policy for the protection domain. Some processor models may 
implement additional protection key registers and protection key bits. Unimplemented 
bits and registers are reserved. Please see the processor-specific documentation for 
further information on the number of protection key registers and protection key bits 
implemented on the processor.