Safely discovering secure monitors and hypervisor implementations in systems operable at multiple hierarchical privilege levels
US9864708B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 2014 |
| Grant date | Jan 9, 2018 |
| Priority date | — |
| Expiry date | Feb 12, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2009/45587
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In a computer system operable at multiple hierarchical privilege levels, a “wait-for-event” (WFE) communication channel between components operating at different privilege levels is established. Initially, a central processing unit (CPU) is configured to “trap” WFE instructions issued by a client, such as an operating system, operating at one privilege level to an agent, such as a hypervisor, operating at a more privileged level. After storing a predefined special sequence in a storage component (e.g., a register), the client executes a WFE instruction. As part of trapping the WFE instruction, the agent reads and interprets the special sequence from the storage component and may respond to the special sequence by storing another special sequence in a storage component that is accessible to the client. Advantageously, a client may leverage this WFE communication channel to safely and reliably detect whether an agent is present.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.