Question: Behavior of L2 on eviction when an L1.5 owner silently modifies data in E state

[mujahid-10xe]

Hi, I have a question about the expected coherence behavior in the following scenario: A core holds a cache line in the Exclusive (E) state. While in E, the core can silently modify its data without informing L2 (because E → M is a silent transition according to the micro arch).

My question is: 1- If the owner silently modified the line while in E, what behavior should we expect from the L2 cache when the line is later evicted from L2? 2- How and when will the modified data be written back to memory in case of eviction if the core never explicitly sends any write-back until eviction?