Efficient Memory Management System for Computers Supporting Virtual Machines

摘要

The translation of virtual guest addresses to host physical addresses in a virtualized computer system provides a compound page table that may simultaneously support nested-paging and shadow-paging for different memory regions. Memory regions with stable address mapping, for example, holding program code, may be treated using shadow-paging while memory regions with dynamic address mapping, for example, variable storage, may be treated using nested-paging thereby obtaining the benefits of both techniques.

主权项

1. A virtualizing electronic computer comprising:
an electronic memory system holding data stored at physical addresses and adapted to store programs including at least one instance of a guest operating system, a process executing under the guest operating system, and a host operating system providing virtualization the electronic memory adapted to store page tables having first page table entries translating a guest virtual address into a host physical address, second page tables entries translating a guest virtual address into a guest physical address, and third page table entries translating a guest physical address into a host physical address; at least one processor communicating with the electronic memory for execution of the programs; and a memory management system receiving memory access requests from the processor to: (1) for a request providing a guest virtual address, determine a page table entry associated with an address of the request; (2) when the determined entry is a first page table entry, use the first page table entry to translate the guest virtual address into a host physical address used for accessing memory; and (3) when the determined entry is a second page table entry, use the second page table entry to translate the guest virtual address into a guest physical address and then use a third page table entry to translate the guest physical address into a host physical address used for accessing memory.