mem: Always use SenderState for response routing in RubyPort

This patch aligns how the response routing is done in the RubyPort,
using the SenderState for both memory and I/O accesses. Before this
patch, only the I/O used the SenderState, whereas the memory accesses
relied on the src field in the packet. With this patch we shift to
using SenderState in both cases, thus not relying on the src field any
longer.

src/mem/ruby/system/RubyPort.cc

@@ -180,11 +180,6 @@ bool RubyPort::MemMasterPort::recvTimingResp(PacketPtr pkt)
     // got a response from a device
     assert(pkt->isResponse());
 
-    // In FS mode, ruby memory will receive pio responses from devices
-    // and it must forward these responses back to the particular CPU.
-    DPRINTF(RubyPort,  "Pio response for address %#x, going to %d\n",
-            pkt->getAddr(), pkt->getDest());
-
     // First we must retrieve the request port from the sender State
     RubyPort::SenderState *senderState =
         safe_cast<RubyPort::SenderState *>(pkt->popSenderState());
@@ -192,6 +187,11 @@ bool RubyPort::MemMasterPort::recvTimingResp(PacketPtr pkt)
     assert(port != NULL);
     delete senderState;
 
+    // In FS mode, ruby memory will receive pio responses from devices
+    // and it must forward these responses back to the particular CPU.
+    DPRINTF(RubyPort,  "Pio response for address %#x, going to %s\n",
+            pkt->getAddr(), port->name());
+
     // attempt to send the response in the next cycle
     port->schedTimingResp(pkt, curTick() + g_system_ptr->clockPeriod());
 
@@ -246,9 +246,6 @@ RubyPort::MemSlavePort::recvTimingReq(PacketPtr pkt)
         return true;
     }
 
-    // Save the port id to be used later to route the response
-    pkt->setSrc(id);
-
     assert(Address(pkt->getAddr()).getOffset() + pkt->getSize() <=
            RubySystem::getBlockSizeBytes());
 
@@ -259,6 +256,10 @@ RubyPort::MemSlavePort::recvTimingReq(PacketPtr pkt)
     // Otherwise, we need to tell the port to retry at a later point
     // and return false.
     if (requestStatus == RequestStatus_Issued) {
+        // Save the port in the sender state object to be used later to
+        // route the response
+        pkt->pushSenderState(new SenderState(this));
+
         DPRINTF(RubyPort, "Request %s 0x%x issued\n", pkt->cmdString(),
                 pkt->getAddr());
         return true;
@@ -343,11 +344,14 @@ RubyPort::ruby_hit_callback(PacketPtr pkt)
     assert(system->isMemAddr(pkt->getAddr()));
     assert(pkt->isRequest());
 
-    // As it has not yet been turned around, the source field tells us
-    // which port it came from.
-    assert(pkt->getSrc() < slave_ports.size());
+    // First we must retrieve the request port from the sender State
+    RubyPort::SenderState *senderState =
+        safe_cast<RubyPort::SenderState *>(pkt->popSenderState());
+    MemSlavePort *port = senderState->port;
+    assert(port != NULL);
+    delete senderState;
 
-    slave_ports[pkt->getSrc()]->hitCallback(pkt);
+    port->hitCallback(pkt);
 
     //
     // If we had to stall the MemSlavePorts, wake them up because the sequencer

src/mem/ruby/system/Sequencer.cc

@@ -547,6 +547,8 @@ Sequencer::hitCallback(SequencerRequest* srequest, DataBlock& data,
     // subBlock with the recieved data.  The tester will later access
     // this state.
     if (m_usingRubyTester) {
+        DPRINTF(RubySequencer, "hitCallback %s 0x%x using RubyTester\n",
+                pkt->cmdString(), pkt->getAddr());
         RubyTester::SenderState* testerSenderState =
             pkt->findNextSenderState<RubyTester::SenderState>();
         assert(testerSenderState);