Workaround a bug with KVM, Qemu >= 2.4 and Intel CPU

Fix #685

gns3server/modules/qemu/qemu_vm.py

@@ -1424,6 +1424,11 @@ class QemuVM(BaseVM):
         command.extend(["-smp", "cpus={}".format(self._cpus)])
         if self._run_with_kvm(self.qemu_path, self._options):
             command.extend(["-enable-kvm"])
+            version = yield from self.manager.get_qemu_version(self.qemu_path)
+            # Issue on some combo Intel CPU + KVM + Qemu 2.4.0
+            # https://github.com/GNS3/gns3-server/issues/685
+            if version and parse_version(version) >= parse_version("2.4.0"):
+                command.extend(["-machine smm=off"])
         command.extend(["-boot", "order={}".format(self._boot_priority)])
         cdrom_option = self._cdrom_option()
         command.extend(cdrom_option)