Memory Controller Row Hammer Mitigation via Dummy Rows
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Solution Overview
Problem
Current memory systems face challenges in preventing data corruption due to Row Hammer and RAS clobber attacks, which are exacerbated by advancements in memory density and protocols like Compute Express Link (CXL).
Innovation Solution
A memory device with a controller configured to execute a deterministic protocol in conjunction with or sequentially to a probabilistic protocol to mitigate Row Hammer and RAS clobber risks. The controller uses specific algorithms and counter mechanisms to manage memory access patterns and prevent data corruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory density is increased to improve storage capacity, then storage capacity is improved, but electrical isolation between memory cells deteriorates, leading to increased charge leakage and data corruption risk
Solution Approach 1:
The system performs preliminary actions by activating dummy rows adjacent to victim rows before and after the actual memory access. This preliminary activation creates a protective effect that prevents charge leakage from affecting the victim row data, thereby mitigating the harmful effect of increased density without reducing storage capacity
2Object-affected harmful factors
If Row Hammer attacks are performed to corrupt memory data, then data integrity is compromised, but the attack relies on inherent architectural weaknesses that cannot be easily changed
Solution Approach 1:
The system introduces intermediary dummy rows between the attacker's target row and adjacent rows. These intermediary rows act as a buffer that absorbs the charge leakage effects, preventing direct correlation between the attacker's actions and the victim data. This mediator approach complexifies the attack path without requiring complex hardware changes
3Speed
If CXL protocol is used to achieve low latency and high bandwidth, then communication performance is improved, but memory access patterns that trigger charge leakage increase
Solution Approach 1:
The system implements feedback mechanisms where the memory controller monitors and responds to access patterns. When patterns indicative of potential charge leakage are detected, the controller dynamically adjusts access sequences by inserting dummy row activations. This feedback loop maintains CXL performance benefits while mitigating the increased leakage risk from high-frequency accesses
4Reliability
If deterministic protocols are added to mitigate Row Hammer and RAS clobber risks, then data integrity is improved, but device complexity increases
Solution Approach 1:
The system merges the deterministic mitigation protocol with existing memory control operations. The dummy row activation sequences are integrated into the standard read/write access流程, combining security functions with existing operations rather than adding separate complex subsystems. This merging approach improves data integrity while minimizing the increase in overall device complexity
Data Source
AI summary
There are provided systems and methods that include at least one memory that has a plurality of memory cells. The cells may be disposed in rows and columns. The device can further include a controller that is communicatively coupled to the at least one memory, and the controller may be configured by its hardware topology and its instruction set and/or by a communicatively coupled processor or higher-level system or subsystem to maintain data integrity in the at least one memory and/or to prevent or mitigate malicious access patterns that may compromise the at least one memory. The controller may be configured to execute a deterministic protocol in conjunction with or sequentially to a probabilistic protocol to achieve one or more of the above-noted functions.