[SOLVED] Set-associative TLB on Rocket Chip

Set-associative TLB on Rocket Chip

I am trying to address if Rocket Chip Generator supports a set-associative TLB (both for L1 and L2 TLB) but I cannot find any straightforward code about that in RocketCore.scala or PTW.scala. On the other hand changing the associativity of the Caches in HellaCache.scala is pretty straight-forward.

From my understanding L1 TLB is fully-associative and L2 TLB is direct-mapped.

Is there a straightforward way to change the set-associativity of the TLB on Rocket Chip that I am missing? If not, are there any resources that you could provide in order to help me add these features in Rocket Chip?

Thank you.

Solution

I implemented the configurable L1/L2 TLB on Rocket Chip myself, my code is upstream and merged in the official Rocket Chip repository.

In order to change the associativity and size of the L1 TLB you can tweak nTLBSets, nTLBWays in /src/main/scala/rocket/HellaCache.scala(only power of 2 sets/ways are allowed for now).

For the L2 TLB, you can tweak nL2TLBSets, nL2TLBWays in /src/main/scala/rocket/RocketCore.scala.