diff --git a/rocket/src/main/scala/tlb.scala b/rocket/src/main/scala/tlb.scala
index 8c369c9b..78254acb 100644
--- a/rocket/src/main/scala/tlb.scala
+++ b/rocket/src/main/scala/tlb.scala
@@ -76,23 +76,26 @@ class PseudoLRU(n: Int)
   }
 }
 
-class TLBReq extends TLBBundle {
+class TLBReq extends CoreBundle {
   val asid = UInt(width = asIdBits)
   val vpn = UInt(width = vpnBits+1)
   val passthrough = Bool()
   val instruction = Bool()
 }
 
-class TLBResp(cnt: Option[Int] = None) extends TLBBundle {
+class TLBRespNoHitIndex extends CoreBundle {
   // lookup responses
   val miss = Bool(OUTPUT)
-  val hit_idx = UInt(OUTPUT, cnt.getOrElse(entries))
   val ppn = UInt(OUTPUT, ppnBits)
   val xcpt_ld = Bool(OUTPUT)
   val xcpt_st = Bool(OUTPUT)
   val xcpt_if = Bool(OUTPUT)
 }
 
+class TLBResp extends TLBRespNoHitIndex with TLBParameters {
+  val hit_idx = UInt(OUTPUT, entries)
+}
+
 class TLB extends TLBModule {
   val io = new Bundle {
     val req = Decoupled(new TLBReq).flip