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US 7,814,287 B2Granted
Using writeable page tables for memory address translation in a hypervisor environment
AssigneeXenSource, Inc.
InventorIan Pratt
Life of this patent
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AssigneeXenSource, Inc.
InventorIan Pratt
Estimating the term…
A method and system for using writeable page tables to increase performance of memory address translation in computing environments utilizing a hypervisor. Guest operating systems are given temporary write-access to a page table page after the system confirms that such page is not part of the current address space (i.e., confirming that the page is part of a different page table from the one that is currently in use, such as a different user-space process). Alternatively, if the page is part of the currently running page table, the system invalidates the appropriate entry in the root page directory, thus “unlinking” it, and ensuring that the appropriate region of virtual address space is flushed from the translation lookaside buffer (TLB) in the current CPU and others that may be using it. After giving the OS write-access, the page is added to a validation queue. Validation of all 1024 entries and “re-hooking” of the page occurs whenever a page fault is taken due to the page being unhooked, or before context switching to another page table.
A method of managing memory in a processing system capable of simultaneously executing, within at least one virtual machine, multiple instantiations of one or more guest operating systems, without duplication of page tables provided by the processing system, said method comprising:
A memory having computer readable program code means embodied therein for causing simultaneous execution, within at least one virtual machine, of multiple instantiations of one or more guest operating systems, without duplication of page tables provided by a processing system, the memory comprising:
A processing system for simultaneous execution, within at least one virtual machine, of multiple instantiations of one or more guest operating systems, without duplication of page tables provided by the processing system, comprising:
Dependencies are inferred from the claim text.