Volatile Meta Page for Secure Non-Volatile Memory Invalidation

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Solution Overview

Problem

Non-volatile memory devices face challenges in securely managing invalidated data, as data marked as invalid may still be readable, posing security risks and requiring robust techniques to track and handle such data effectively.

Innovation Solution

Implementing a meta page in volatile memory to track commands, including invalidation commands, which stores information about non-volatile memory superblocks, allowing for the determination of physical pages corresponding to logical addresses and tracking the history of trim commands, enabling secure handling of invalidated data by transferring this information to non-volatile memory during triggering events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data is marked as invalid in non-volatile memory, then storage space is freed for reuse, but the invalidated data may still be readable posing security risks

Engineering Contradiction:

Improvestorage space reuse efficiencyVSAvoidsecurity risk from readable invalidated data

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by maintaining a meta page in volatile memory that tracks invalidation commands before they are permanently committed to non-volatile memory. This allows the system to record which logical addresses have been invalidated and their corresponding physical locations in advance, so that when power is lost or the system crashes, the tracking information is already captured and can be used to prevent reading of invalidated data.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism - the meta page structure in volatile memory - that sits between the invalidation command and the actual data in non-volatile memory. This meta page contains index entries that map logical addresses to physical pages and track invalidation status. The intermediary allows the system to manage invalidated data securely without directly modifying the actual data blocks, resolving the contradiction between freeing storage space and preventing unauthorized reading.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a meta page is maintained in volatile memory to track invalidation commands, then secure handling of invalidated data is enabled, but memory usage and system complexity increase

Engineering Contradiction:

Improvedata security during power lossVSAvoidmemory management structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the memory management into distinct components: the main data storage in non-volatile memory, the mapping information in the FTL, and the invalidation tracking in the meta page structure. The meta page itself is segmented into index entries, each tracking a specific logical address and its invalidation status. This segmentation allows the system to maintain security information without overwhelming complexity in any single component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses parameter changes by storing additional metadata parameters in the meta page structure, such as invalidation status flags and physical page mappings. These parameters are updated dynamically as invalidation commands are received, allowing the system to track security-relevant information without fundamentally changing the underlying storage architecture. The parameters enable efficient querying and enforcement of invalidation status.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If invalidation commands are tracked in volatile memory, then accurate mapping tables are maintained during power loss, but transfer of tracking information to non-volatile memory is required

Engineering Contradiction:

Improvemapping table accuracy during power lossVSAvoidperformance overhead of data transfer

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies periodic action by transferring the meta page contents from volatile to non-volatile memory at regular intervals or under specific conditions (such as when the meta page is full or at defined checkpoints). This periodic synchronization ensures that the tracking information is persisted reliably without requiring continuous transfer operations, thus maintaining mapping table accuracy while minimizing performance overhead.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent uses preliminary action by pre-allocating and pre-structuring the meta page in volatile memory with all necessary tracking fields and index entries before they are needed. This preliminary setup allows the system to quickly record invalidation commands without requiring complex real-time allocation or restructuring operations, reducing the overhead of tracking and transferring information to non-volatile memory.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9880770B2Supporting invalidation commands for non-volatile memory

Publication Date: 2018.01.30 SK HYNIX INC

AI summary

Techniques and systems are provided for tracking commands. Such methods and systems can include maintaining a meta page in a volatile memory to track commands. The meta page can comprise information associated with a non-volatile memory superblock. When an invalidation command is received for a first logical address, the first logical address can be stored along with an indication that the data associated with the first logical address is invalid, in a first location in the meta page.