Reclaiming existing fields in address translation data structures to extend control over memory accesses

An apparatus comprising:

• a guest address translation data structure to translate virtual memory addresses into physical memory addresses by guest software;
• an active address translation data structure to derive partial content from the guest address translation data structure, the partial content excluding a field designated for operational use by guest software within each of a plurality of entries in the guest address translation data structure, the designated field remaining unchanged when a corresponding entry in the active address translation data structure is modified to conform to content of the guest address translation data structure;
• and
• a translation-look aside buffer (TLB) to store address translations obtained from the active address translation data structure by a processor.

A machine-readable medium containing instructions which, when executed by a processing system, cause the processing system to perform a method, the method comprising:

• determining that a modification of content of an active address translation data structure is required;
• and
• modifying an entry in the active address translation data structure to conform to a corresponding entry in a guest address translation data;
• and
• keeping a portion of the entry in the active address translation data structure unchanged while modifying the entry in the active address translation data structure, the unchanged portion of the entry in the active address translation data structure including at least one access control indicator and corresponding to a field designated for operational use by guest software within the entry of the guest address translation data structure.