MSHR: fix bug when aliasTask is AcquireBlock NtoT and L2 is Branch (#77)

* MHSR: fix bug when aliasTask is AcquireBlock NtoT and self_state is Branch
use data in RefillBuffer not ReleaseBuffer

* Update MSHR.scala

---------

Co-authored-by: Chen Xi <48302201+Ivyfeather@users.noreply.github.com>

src/main/scala/coupledL2/MSHR.scala

@@ -354,9 +354,14 @@ class MSHR(implicit p: Parameters) extends L2Module {
     val aliasFinal = Mux(req_get || req_prefetch, meta.alias.getOrElse(0.U), req.alias.getOrElse(0.U))
     mp_grant.alias.foreach(_ := aliasFinal)
     mp_grant.aliasTask.foreach(_ := req.aliasTask.getOrElse(false.B))
-    // [Alias] write probeData into DS for alias-caused Probe,
-    // but not replacement-cased Probe
-    mp_grant.useProbeData := dirResult.hit && req_get || req.aliasTask.getOrElse(false.B)
+    // [Alias] write probeData into DS for alias-caused Probe, but not replacement-caused Probe
+    // Exception case when multi-core: if aliasTask is AcquireBlock NtoT and self_state is Branch, 
+    // and there is a nested Probe toN from L3 (means the data Granted from L3 in the future may be a new data),
+    // useProbeData will be set false to use data in RefillBuffer
+    mp_grant.useProbeData := (dirResult.hit && req_get) || 
+      (req.aliasTask.getOrElse(false.B) && 
+        !(dirResult.meta.state === BRANCH && req_needT) 
+      )
     mp_grant.dirty := false.B
 
     mp_grant.meta := MetaEntry(

src/test/scala/TestTop.scala

@@ -370,6 +370,7 @@ class TestTop_L2L3L2()(implicit p: Parameters) extends LazyModule {
       TLFragmenter(32, 64) :=*
       TLCacheCork() :=*
       TLDelayer(delayFactor) :=*
+      TLLogger(s"MEM_L3", true) :=*
       l3.node :=* xbar
 
   lazy val module = new LazyModuleImp(this) {