Virtual Machine Function Page Table Trampoline Security

The patent segments the virtual machine memory space into distinct page types (trampoline pages, protected pages, regular pages) with different access privilege requirements. Each page type has specific access controls that restrict or allow certain operations, enabling flexible access where needed while maintaining security boundaries. The page table is divided into multiple sections that can be independently configured with different privilege levels.

Different access privilege rules are applied to different regions of the virtual machine memory space. Trampoline pages have specific access rules allowing certain privileged operations, protected pages have restricted access rules for sensitive data, and regular pages have standard access rules. This localized application of quality control allows the system to be versatile where needed while maintaining security where required.

The patent implements a universal page table structure that handles multiple access control scenarios through a single unified mechanism. The same page table infrastructure manages access to trampoline pages, protected pages, and regular pages, as well as handling privilege transitions and memory mapping. This multi-functional approach reduces the need for separate complex control mechanisms for each security requirement.

The patent introduces trampoline pages as intermediary structures that facilitate secure privilege transitions. These trampoline pages act as mediators between different privilege levels, providing a controlled transition path that simplifies the access control mechanism. Instead of directly managing complex privilege transitions, the system uses these intermediary pages to handle the transition securely and systematically.

The patent pre-configures the page table with clearly defined sections for different page types (trampoline, protected, regular) during virtual machine initialization. Access privilege rules are established in advance for each page type, so that during execution, the system can quickly determine the appropriate access rules without complex real-time analysis. The page table structure itself is prepared beforehand to facilitate fast lookups.

The patent uses distinct page table entry types or markers (analogous to color coding) to identify different page types. Each page type has unique identifiers in the page table that allow the system to quickly recognize and apply the appropriate access rules. This classification system enables rapid determination of access privileges without extensive processing, as the page type is immediately identifiable through its marker.