Patent ID: 7571318

Claim:
A method for controlling access to data stored within memory segments in a computer system having a plurality of first privilege levels, the memory segments including insecure data accessible by processes associated with a first privilege level which has limited rights to access the resources of the computer system, the method, comprising: storing, in a hint directory, first information indicating whether secure data is stored in any location within a first preselected segment of memory; storing a plurality of second information elements, each second information element indicating whether secure data is stored in a corresponding one of a plurality of second preselected segments of memory, wherein said second preselected segments of memory are subsets of said first preselected segment of memory; receiving, at the hint directory, an address from a requesting agent; determining if at least a portion of the received address is within the first preselected segment of memory; providing said address to a paging mechanism and bypassing a security check unit in response to said first stored information indicating that said first preselected segment of memory is free from secure data, the paging mechanism being configured to translate said address to a physical address within said first preselected segment of memory; providing said address to the security check unit in response to determining from said first stored information that said first preselected segment of memory contains secure data; providing, from the security check unit to the paging mechanism, said received address when the security check unit determines that the second stored information element associated with the identified second preselected segment of memory indicates that said second preselected segment of memory is free from secure data; and providing, from the security check unit to the paging mechanism, said received address when the security check unit determines that the second stored in information element associated with the identified second preselected segment of memory indicates that said second preselected segment of memory contains secure data dependent on the requesting agent having a selected one of the plurality of first privilege levels and a selected one of a plurality of second privilege levels.