Metadata Processing Domain for Secure Instruction Execution

The processing system is divided into two distinct domains: a host processing domain for instruction execution and a metadata processing domain for security policy enforcement. This segmentation separates security-critical functions from general processing, ensuring that security policies are enforced by a dedicated domain that cannot be compromised by application-level attacks.

A processor interlock acts as an intermediary between the host processor and memory system. It interceptors memory access requests from the host processor, validates them against security policies, and either permits or blocks the requests. This intermediary layer provides security enforcement without requiring modifications to the host processor architecture.

The metadata processing domain and host processing domain share common resources including memory, I/O devices, and a unified instruction set architecture. The processor interlock is integrated into the existing memory interface, allowing security enforcement to be added without creating entirely separate hardware paths. This merging approach reduces the complexity increase that would result from complete isolation.

The processor interlock serves multiple functions: it acts as a security policy enforcement mechanism, a memory access controller, and a communication bridge between the host processor and memory system. By designing the interlock to handle multiple responsibilities, the overall system complexity is reduced compared to having separate dedicated components for each function.

Security policies are pre-loaded into the processor interlock before the host processor begins execution. The interlock maintains pre-computed security rules and metadata in on-chip memory, allowing it to perform rapid lookups during instruction validation. This preliminary preparation eliminates the need for time-consuming policy evaluations during runtime instruction processing.

The processor interlock maintains copies of security policies and metadata in its own memory space, separate from the host processor's memory. This allows the interlock to validate instructions against local copies without requiring access to the host processor's memory hierarchy, reducing validation latency. The host processor continues executing instructions while the interlock independently validates them against its cached policy information.