Isolated memory is implemented by controlling changes to address
translation maps. Control over the maps can be exercised in such a way
that no virtual address referring to an isolated page is exposed to any
untrusted process. Requests to edit an entry in a map are evaluated to
ensure that the edit will not cause the map to point to isolated memory.
Requests to change which map is active are evaluated to ensure that the
map to be activated does not point to isolated memory. Preferably, these
evaluations are performed by a trusted component in a trusted
environment, since isolation of the memory depends on the evaluation
component not being compromised. In systems that require all memory
access requests to identify their target by virtual address, preventing
the address translation maps from pointing to a portion of memory
effectively prevents access to that portion of memory, thereby creating
an isolated memory.