3 files changed, 43 insertions, 6 deletions

diff --git a/src/arch/x86/X86TLB.py b/src/arch/x86/X86TLB.py
index a08dbb138..b652118ce 100644
--- a/src/arch/x86/X86TLB.py
+++ b/src/arch/x86/X86TLB.py
@@ -47,6 +47,8 @@ class X86PagetableWalker(MemObject):
     cxx_header = 'arch/x86/pagetable_walker.hh'
     port = MasterPort("Port for the hardware table walker")
     system = Param.System(Parent.any, "system object")
+    num_squash_per_cycle = Param.Unsigned(4,
+            "Number of outstanding walks that can be squashed per cycle")
 
 class X86TLB(BaseTLB):
     type = 'X86TLB'
diff --git a/src/arch/x86/pagetable_walker.cc b/src/arch/x86/pagetable_walker.cc
index 853e062e7..45f902999 100644
--- a/src/arch/x86/pagetable_walker.cc
+++ b/src/arch/x86/pagetable_walker.cc
@@ -139,11 +139,8 @@ Walker::recvTimingResp(PacketPtr pkt)
         delete senderWalk;
         // Since we block requests when another is outstanding, we
         // need to check if there is a waiting request to be serviced
-        if (currStates.size()) {
-            WalkerState * newState = currStates.front();
-            if (!newState->wasStarted())
-                newState->startWalk();
-        }
+        if (currStates.size())
+            startWalkWrapper();
     }
     return true;
 }
@@ -192,6 +189,36 @@ Walker::WalkerState::initState(ThreadContext * _tc,
     timing = _isTiming;
 }
 
+void
+Walker::startWalkWrapper()
+{
+    unsigned num_squashed = 0;
+    WalkerState *currState = currStates.front();
+    while ((num_squashed < numSquashable) && currState &&
+        currState->translation->squashed()) {
+        currStates.pop_front();
+        num_squashed++;
+
+        DPRINTF(PageTableWalker, "Squashing table walk for address %#x\n",
+            currState->req->getVaddr());
+
+        // finish the translation which will delete the translation object
+        currState->translation->finish(new UnimpFault("Squashed Inst"),
+                currState->req, currState->tc, currState->mode);
+
+        // delete the current request
+        delete currState;
+
+        // check the next translation request, if it exists
+        if (currStates.size())
+            currState = currStates.front();
+        else
+            currState = NULL;
+    }
+    if (currState && !currState->wasStarted())
+        currState->startWalk();
+}
+
 Fault
 Walker::WalkerState::startWalk()
 {
diff --git a/src/arch/x86/pagetable_walker.hh b/src/arch/x86/pagetable_walker.hh
index c2781ca1b..c6766689b 100644
--- a/src/arch/x86/pagetable_walker.hh
+++ b/src/arch/x86/pagetable_walker.hh
@@ -87,6 +87,7 @@ namespace X86ISA
         // State to track each walk of the page table
         class WalkerState
         {
+          friend class Walker;
           private:
             enum State {
                 Ready,
@@ -176,6 +177,12 @@ namespace X86ISA
         System * sys;
         MasterID masterId;
 
+        // The number of outstanding walks that can be squashed per cycle.
+        unsigned numSquashable;
+
+        // Wrapper for checking for squashes before starting a translation.
+        void startWalkWrapper();
+
         // Functions for dealing with packets.
         bool recvTimingResp(PacketPtr pkt);
         void recvRetry();
@@ -199,7 +206,8 @@ namespace X86ISA
         Walker(const Params *params) :
             MemObject(params), port(name() + ".port", this),
             funcState(this, NULL, NULL, true), tlb(NULL), sys(params->system),
-            masterId(sys->getMasterId(name()))
+            masterId(sys->getMasterId(name())),
+            numSquashable(params->num_squash_per_cycle)
         {
         }
     };