kvm: Maintain a local instruction counter and update totalNumInsts

Update the system's totalNumInst counter when exiting from KVM and
maintain an internal absolute instruction count instead of relying on
the one from perf.

src/cpu/kvm/base.cc

@@ -80,7 +80,8 @@ BaseKvmCPU::BaseKvmCPU(BaseKvmCPUParams *params)
       pageSize(sysconf(_SC_PAGE_SIZE)),
       tickEvent(*this),
       perfControlledByTimer(params->usePerfOverflow),
-      hostFactor(params->hostFactor)
+      hostFactor(params->hostFactor),
+      ctrInsts(0)
 {
     if (pageSize == -1)
         panic("KVM: Failed to determine host page size (%i)\n",
@@ -416,14 +417,14 @@ BaseKvmCPU::getContext(int tn)
 Counter
 BaseKvmCPU::totalInsts() const
 {
-    return hwInstructions.read();
+    return ctrInsts;
 }
 
 Counter
 BaseKvmCPU::totalOps() const
 {
     hack_once("Pretending totalOps is equivalent to totalInsts()\n");
-    return hwInstructions.read();
+    return ctrInsts;
 }
 
 void
@@ -522,6 +523,8 @@ BaseKvmCPU::kvmRun(Tick ticks)
     numCycles += simCyclesExecuted;;
     ++numVMExits;
     numInsts += instsExecuted;
+    ctrInsts += instsExecuted;
+    system->totalNumInsts += instsExecuted;
 
     DPRINTF(KvmRun, "KVM: Executed %i instructions in %i cycles (%i ticks, sim cycles: %i).\n",
             instsExecuted, hostCyclesExecuted, ticksExecuted, simCyclesExecuted);

src/cpu/kvm/base.hh

@@ -561,6 +561,9 @@ class BaseKvmCPU : public BaseCPU
     Stats::Scalar numInterrupts;
     Stats::Scalar numHypercalls;
     /* @} */
+
+    /** Number of instructions executed by the CPU */
+    Counter ctrInsts;
 };
 
 #endif