launch: direct: Make sure we pass lpj= parameter when using TCG.

I have verified that 'refined-jiffies' is the clock source when using
TCG (ie. not kvm-clock which seems only to be used for KVM).

src/launch-direct.c

@@ -276,6 +276,7 @@ launch_direct (guestfs_h *g, void *datav, const char *arg)
   CLEANUP_FREE_STRINGSBUF DECLARE_STRINGSBUF (cmdline);
   int daemon_accept_sock = -1, console_sock = -1;
   int r;
+  int flags;
   int sv[2];
   char guestfsd_sock[256];
   struct sockaddr_un addr;
@@ -635,7 +636,11 @@ launch_direct (guestfs_h *g, void *datav, const char *arg)
   }
 
   ADD_CMDLINE ("-append");
-  ADD_CMDLINE_STRING_NODUP (guestfs___appliance_command_line (g, appliance_dev, 0));
+  flags = 0;
+  if (!has_kvm || force_tcg)
+    flags |= APPLIANCE_COMMAND_LINE_IS_TCG;
+  ADD_CMDLINE_STRING_NODUP (guestfs___appliance_command_line (g, appliance_dev,
+                                                              flags));
 
   /* Note: custom command line parameters must come last so that
    * qemu -set parameters can modify previously added options.

src/lpj.c

@@ -40,10 +40,15 @@
  * posted a patch asking for this to be added to /proc/cpuinfo too.
  *
  * Notes:
+ *
  * - We only try to calculate lpj once.
+ *
  * - Trying to calculate lpj must not fail.  If the return value is
  *   <= 0, it is ignored by the caller.
  *
+ * - KVM uses kvm-clock, but TCG uses some sort of jiffies source,
+ *   which is why this is needed only for TCG appliances.
+ *
  * (Suggested by Marcelo Tosatti)
  */