MEMORY SHARING METHOD OF VIRTUAL MACHINES BASED ON COMBINATION OF KSM AND PASS-THROUGH

A memory sharing method of virtual machines through the combination of KSM and pass-through, including: a virtual machine manager judging whether operating systems of guests use IOMMU, if not, not participating in shared mapping of a KSM technology; if yes, judging memory pages of each guest to confirm whether the pages are mapping pages, if yes, remain the mapping pages into a host; and if not, on the premise of keeping the properties of Pass-through, using the KSM technology for all non-mapping pages to merge the memory pages with same contents among various virtual machines and perform write protection processing simultaneously. The guest memory pages are divided into those special for DMA and those for non-DMA purpose, then the KSM technology is only selectively applied to the non-DMA pages, and on the premise of keeping the properties of Pass-through, the object of saving memory resources is achieved simultaneously.