# Node ID 46ad52c66c874586162b9952265dce28186b58c9
# Parent  cd09bde69eefb21140e6edf81c77dbf96e3ec2ed
diff --git a/src/arch/x86/system.hh b/src/arch/x86/system.hh
--- a/src/arch/x86/system.hh
+++ b/src/arch/x86/system.hh
@@ -75,6 +75,11 @@
     const uint64_t ISTPhysAddr = 0x64000;
 
     const uint64_t pageTablePhysAddr = 0x70000;
+
+    /* pseudo I/O port used by syscall handler */
+    const uint16_t syscallPort = 0x0248;
+    /* pseudo I/O port used by page fault handler */
+    const uint16_t faultPort = 0x0244;
 }
 
 class X86System : public System
diff --git a/src/cpu/kvm/base.hh b/src/cpu/kvm/base.hh
--- a/src/cpu/kvm/base.hh
+++ b/src/cpu/kvm/base.hh
@@ -666,6 +666,7 @@
      * contain other data such as the MMIO ring buffer.
      */
     struct kvm_run *_kvmRun;
+  private:
     /**
      * Coalesced MMIO ring buffer. NULL if coalesced MMIO is not
      * supported.
diff --git a/src/cpu/kvm/base.cc b/src/cpu/kvm/base.cc
--- a/src/cpu/kvm/base.cc
+++ b/src/cpu/kvm/base.cc
@@ -85,8 +85,14 @@
         panic("KVM: Failed to determine host page size (%i)\n",
               errno);
 
-    thread = new SimpleThread(this, 0, params->system,
-                              params->itb, params->dtb, params->isa[0]);
+    if (FullSystem)
+        thread = new SimpleThread(this, 0, params->system, params->itb, params->dtb,
+                                  params->isa[0]);
+    else
+        thread = new SimpleThread(this, /* thread_num */ 0, params->system,
+                                  params->workload[0], params->itb,
+                                  params->dtb, params->isa[0]);
+
     thread->setStatus(ThreadContext::Halted);
     tc = thread->getTC();
     threadContexts.push_back(tc);
diff --git a/src/cpu/kvm/x86_cpu.hh b/src/cpu/kvm/x86_cpu.hh
--- a/src/cpu/kvm/x86_cpu.hh
+++ b/src/cpu/kvm/x86_cpu.hh
@@ -148,6 +148,17 @@
     Tick handleKvmExitIRQWindowOpen();
 
     /**
+     * Handle exit caused by executing a syscall in SE mode.
+     */
+    Tick handleKvmExitSysCall();
+
+    /**
+     * Handle exit caused by a page fault, as a consequence
+     * of stack growth, in SE mode.
+     */
+    Tick handleKvmExitPageFault();
+
+    /**
      * Check if there are pending events in the vCPU that prevents it
      * from being drained.
      *
diff --git a/src/cpu/kvm/x86_cpu.cc b/src/cpu/kvm/x86_cpu.cc
--- a/src/cpu/kvm/x86_cpu.cc
+++ b/src/cpu/kvm/x86_cpu.cc
@@ -38,8 +38,10 @@
 #include "arch/x86/cpuid.hh"
 #include "arch/x86/utility.hh"
 #include "arch/registers.hh"
+#include "arch/x86/system.hh"
 #include "cpu/kvm/base.hh"
 #include "cpu/kvm/x86_cpu.hh"
+#include "sim/sim_exit.hh"
 #include "debug/Drain.hh"
 #include "debug/Kvm.hh"
 #include "debug/KvmContext.hh"
@@ -1309,10 +1311,17 @@
 X86KvmCPU::handleKvmExitIO()
 {
     struct kvm_run &kvm_run(*getKvmRunState());
+    uint16_t port(kvm_run.io.port);
+
+    if (port == syscallPort)
+        return handleKvmExitSysCall();
+    else if (port == faultPort)
+        return handleKvmExitPageFault();
+
     bool isWrite(kvm_run.io.direction == KVM_EXIT_IO_OUT);
     unsigned char *guestData(getGuestData(kvm_run.io.data_offset));
     Tick delay(0);
-    uint16_t port(kvm_run.io.port);
+
     Addr pAddr;
     const int count(kvm_run.io.count);
 
@@ -1367,6 +1376,70 @@
 }
 
 Tick
+X86KvmCPU::handleKvmExitSysCall()
+{
+    /** updating the thread context with vCPU state */
+    updateThreadContext();
+
+    struct kvm_regs regs;
+    getRegisters(regs);
+
+    /** restoring rdx from r11
+     * the syscall handler uses r11 to
+     * temporarly store rdx
+     */
+    regs.rdx = tc->readIntReg(INTREG_R11);
+    tc->setIntReg(INTREG_RDX, regs.rdx);
+
+    /** emulating system call */
+    thread->syscall(regs.rax);
+
+    /** updating vCPU's rax, rflags and r11 */
+    regs.rax = tc->readIntReg(INTREG_RAX);
+    regs.rflags &= ~(1<<16);
+    regs.r11 = regs.rflags;
+
+    setRegisters(regs);
+
+    /** updating vCPU's special registers
+     * some syscalls update segemnt descriptors
+     */
+    updateKvmStateSRegs();
+
+    if (DTRACE(KvmContext))
+        dump();
+
+    return 0;
+}
+
+Tick
+X86KvmCPU::handleKvmExitPageFault()
+{
+    struct kvm_sregs sregs;
+    getSpecialRegisters(sregs);
+
+    Process *p = tc->getProcessPtr();
+    if ( p->fixupStackFault(sregs.cr2) ) {
+        uint64_t IST[10];
+
+        PortProxy physProxy = system->physProxy;
+        physProxy.readBlob(ISTPhysAddr + VMPageSize - sizeof(IST),
+                            (uint8_t *)(&IST), sizeof(IST));
+
+        DPRINTF(Kvm, "IST: %#x %#x %#x %#x %#x %#x %#x %#x %#x %#x\n",
+                            IST[0], IST[1], IST[2], IST[3], IST[4],
+                            IST[5], IST[6], IST[7], IST[8], IST[9]);
+
+        if (DTRACE(KvmContext))
+            dump();
+    } else {
+        panic("Page fault at %#x ", sregs.cr2);
+    }
+
+    return 0;
+}
+
+Tick
 X86KvmCPU::handleKvmExitIRQWindowOpen()
 {
     // We don't need to do anything here since this is caught the next