Deferred shadowing of segment descriptors in a virtual machine monitor for a segmented computer architecture
US6785886B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 2000 |
| Grant date | Aug 31, 2004 |
| Priority date | — |
| Expiry date | Aug 20, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/45533
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
One or more virtual machines (VM's) run via a virtual machine monitor (VMM) on a hardware platform that has a segmented memory architecture. Each VM has at least one VM descriptor table that has, as entries, VM segment descriptors. At least one VMM descriptor table is established, including at least one shadow descriptor table that stores shadow descriptors for certain of the VM segment descriptors, which are then shadowed descriptors. The VMM compares the shadow descriptors with their respective corresponding shadowed VM descriptors, detects any lack of correspondence between the shadow descriptor table and the corresponding VM descriptor table, and updates and thereby synchronizes each shadow descriptor with its respective shadowed VM descriptor no later than, and preferably only upon the first use of, the respective descriptor by the VM. Whenever the VMM detects any attempt by the VM to load an usynchronized shadowed descriptor, the VMM verifies that the VM is allowed to load it, and then establishes synchronization for the pair of descriptors. One detection mechanism is the tracing of entire memory pages in which VM descriptors are stored; another involves sensing and setting t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.