Patent ID: 8825984

Claim:
A method, comprising: creating a first address translation table hierarchy for a first virtual address domain of a plurality of virtual address domains of a processing system; creating a second address translation table hierarchy for the first virtual address domain, for use when a second virtual address domain is a target of data communication from the first virtual address domain, the second address translation table hierarchy incorporating part of the first address translation table hierarchy; and using the second address translation table hierarchy to communicate data between the first and second virtual address domains, wherein the first address translation table hierarchy provides read-write permission to access a corresponding memory space, and the second address translation table hierarchy provides read-only permission to access the corresponding memory space; wherein the first address translation hierarchy includes a first to level, and first lower levels include at least a page directory level and a page table level, the page directory level including page directories comprising pointers to page tables of the page table level, the page tables comprising pointers to memory pages; wherein the first top level includes an access permission indicator for the corresponding memory space, the access permission indicator governing access to the corresponding memory space regardless of permission indicators of the first lower levels; wherein the second address translation hierarchy includes a second to level that has at least one directory entry pointing to directories of the first lower levels of the first address translation hierarchy, the second address translation hierarchy including levels of the first address translation hierarchy below the first to level; wherein the second to level of the second address translation hierarchy includes an access permission indicator that is set differently from the access permission indicator in the first to level of the first translation hierarchy.