Per IO DMA Redirection for PCIe Storage Error Containment

The patent introduces an intermediary mechanism (the redirection mechanism in the PCIe switch or root complex) that sits between the storage device and system memory. This intermediary intercepts DMA requests, validates them against allowed memory ranges, and redirects legitimate requests to the correct memory locations. This resolves the contradiction by providing strong memory access security through a dedicated intermediary layer without requiring complex changes to the storage device itself.

The patent segments memory access control on a per-IO basis, creating distinct control mechanisms for different types of memory accesses. By segmenting the memory space and access control into manageable units (per-IO redirection tables, per-device filters), the system achieves comprehensive security while keeping individual control structures relatively simple and manageable.

The patent implements feedback mechanisms that track the status of each DMA transaction and provide completion information back to the host. The system monitors whether data transfers completed successfully, detects partial transfers or failures, and can trigger retry mechanisms or error handling procedures. This feedback loop ensures both memory protection and data transfer completeness by continuously verifying transaction outcomes.

The patent performs preliminary validation of DMA requests before they execute, checking address ranges, permission bits, and transaction parameters in advance. By performing these validation actions beforehand, the system prevents unauthorized accesses while ensuring that legitimate requests have all necessary information to complete successfully, thus addressing both memory protection and data completeness concerns.

The patent positions the redirection mechanism as an intermediary layer between the storage device and system memory that actively prevents memory corruption before it occurs. This intermediary validates each memory access request, checks it against allowed ranges and permissions, and blocks or redirects unauthorized accesses. This resolves the contradiction by providing proactive memory protection that prevents corruption rather than merely containing errors after they occur.

The patent applies preliminary anti-action by validating and potentially blocking unauthorized DMA requests before they can execute and cause memory corruption. The system preemptively checks address ranges, permission attributes, and transaction validity, and prevents harmful actions from reaching the memory subsystem. This preliminary prevention approach eliminates memory corruption while maintaining error containment capabilities.

The patent performs scatter/gather list translation and address mapping in advance, before the actual data transfer begins. By pre-computing the translation tables and validating address mappings beforehand, the system establishes accurate transfer paths without adding delay during the actual data movement. This preliminary processing resolves the contradiction by performing accuracy-critical tasks before the time-sensitive data transfer operation.

The patent maintains continuous tracking of IO requests and their corresponding memory ranges throughout the data transfer process, ensuring accuracy without interrupting the transfer flow. The per-IO tracking mechanism operates continuously in the background, validating addresses and monitoring progress without blocking the data transfer path, thus maintaining both accuracy and throughput.