Patent ID: 7310721
Filing Date: 2007-12-18
Classification: G06F

Abstract:
1. A computer-readable storage medium having encoded thereon computer-executable instructions to perform a method of creating shadow pages for an address translation map, the address translation map comprising a page directory and a plurality of page tables, the page directory comprising links to the plurality of page tables, each of the page tables comprising links to a plurality of data pages, the page directory and page tables each being stored in one of the data pages, the method comprising: for at least one of the plurality of page tables, creating a first shadow page table based on said one of the plurality of page tables, said first shadow page table differing from said one of the plurality of page tables in at least one of the following respects: creating a shadow page directory based on the page directory, the page directory comprising a link to said one of the plurality of page tables, said shadow page directory comprising a link to said shadow page table instead of the link to said one of said plurality of page tables, wherein an item of software uses said page table to perform a non-address-mapping action that depends, for correct operation of said item of software, on data being present, in said one of said plurality of page tables, that said item of software has previously written to said one of said plurality of page tables and that said item of software expects to be present in said one of said plurality of page tables, said data having a characteristic that is present in said one of the plurality of page tables but not present in said first shadow page table, wherein said first shadow page table is used to translate addresses for said item of software and said one of the plurality of page tables is not used to translate addresses for said item of software.