Background

Problems

• Modern Intel processors use undisclosed hash functions to map blocks into LLC slices.
• Knowing the mapping will help the attacker to mount an attack and the defender to do page coloring.
• Recover the hash function for a 6-core processor.

Insights

• For processors with a core count of a power of 2, the hash function does not depend on the set index bits. This, however, does not hold true for non-power-of-two cases.
• Use access timing variations.

Approach

• Evict the line from L1 and L2 before measuring.

Takeaway

Questions