Safely discovering secure monitors and hypervisor implementations in systems operable at multiple hierarchical privilege levels

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 i...

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Bibliographic Details
Main Authors Tuch Harvey, Warkentin Andrei
Format Patent
LanguageEnglish
Published 09.01.2018
Subjects
CALCULATING
COMPUTING
COUNTING
ELECTRIC DIGITAL DATA PROCESSING
INFORMATION STORAGE
PHYSICS
STATIC STORES
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Summary: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.
Bibliography:Application Number: US201414572511