Override system and method for memory access management

Abstract

A memory management system and method are described. In one embodiment, a memory management system includes a memory management unit for virtualizing context memory storage and independently controlling access to the context memory without interference from other engine activities. The shared resource management unit overrides a stream of access denials (e.g., NACKs) associated with an access problem. The memory management system and method facilitate efficient and flexible access to memory while controlling translation between virtual and physical memory “spaces”. In one embodiment the memory management system includes a translation lookaside buffer and a fill component. The translation lookaside buffer tracks information associating a virtual memory space with a physical memory space. The fill component tracks the status of an access request progress from a plurality of engines independently and faults that occur in attempting to access a memory space

What is claimed is: 
     
         1 . A shared resource management system comprising:
 a plurality of engines for performing processing;   a memory for supporting said processing; and   a memory management unit for virtualizing context information memory storage.   
     
     
         2 . A shared resource management system of  claim 1  wherein said memory management unit permits context information to be stored and retrieved from bulk storage on the fly. 
     
     
         3 . A shared resource management system of  claim 1  wherein said memory management unit allows context information to be stored in varying physical memory locations. 
     
     
         4 . A shared resource management system of  claim 1  wherein accesses to store said context information are immune to fault expediting access prevention indications. 
     
     
         5 . A shared resource management system of  claim 1  wherein said shared resource is a translation buffer resource. 
     
     
         6 . A shared resource management system of  claim 1  wherein said engines have a fault NACK restart capability. 
     
     
         7 . A shared resource management system of  claim 1  wherein said memory management unit handles a plurality of contexts. 
     
     
         8 . A memory management method comprising:
 receiving an indication of a context session initiation;   assigning a physical memory space to said context session;   performing virtual memory address to said assigned physical memory address translation for context information associated with said context session.   
     
     
         9 . A memory management method of  claim 8  further comprising preventing fault expediting access prevention indications from impacting accesses associated with said context information. 
     
     
         10 . A memory management method of  claim 8  further comprising identifying context information access requests 
     
     
         11 . A memory management method of  claim 8  further comprising preventing a negative-acknowledgement (NACK) corresponding to a fault expediting access prevention indication from being sent in response to an identified context information access request. 
     
     
         12 . A memory management method of  claim 8  wherein an attribute is added to the segmentation data or command which specifies the semantics of a MMU if a previous fault is encountered. 
     
     
         13 . A memory management method of  claim 8  wherein the MMU ignores a pending NACK if the attribute indicates the request is associated with a context specifier access. 
     
     
         14 . A memory management method of  claim 8  wherein an attribute is added to a context specifier structure which indicates a NACK should not be issued if a previous fault is encountered. 
     
     
         15 . A memory management method of  claim 8  wherein said indication of a context session initiation is associated with a context switch after a fault. 
     
     
         16 . A memory management method of  claim 8  wherein a context save is directed to a level 1 MMU unit. 
     
     
         17 . A memory management component comprising:
 a shared translation buffer for translating virtual addresses to physical addresses including translation of address associated with context information;   a fill component for coordinating page table data fetching; and   a host for sending interrupts.   
     
     
         18 . A memory management component of  claim 17  further comprising permitting memory access requests from a first requester to proceed while handling a fault from a second requester. 
     
     
         19 . A memory management component of  claim 17  wherein said shared translation buffer is a hub translation buffer. 
     
     
         20 . A memory management component of  claim 17  wherein said shared translation buffer is a level 2 translation buffer