From 1d7136f27bb842dde00a2ec0dc2943eb16588cb4 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Wed, 14 Aug 2013 15:25:17 +0100
Subject: [PATCH] launch: libvirt: Don't enable <cpu mode="host-model"> on TCG.

It's fairly pointless to do this with TCG, since all we would be doing
is emulating a more complicated processor slowly.  Also it may be the
cause of subtle problems we see during testing.

This updates commit 6f76fdb41eb6bd124fbc3d084f5c2a3371b37d9b.

(cherry picked from commit 46763bcc0b9d04ada367f29ca07bd3e11e264a8e)
---
 src/launch-libvirt.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/launch-libvirt.c b/src/launch-libvirt.c
index e6f6b0b..ff3d720 100644
--- a/src/launch-libvirt.c
+++ b/src/launch-libvirt.c
@@ -823,17 +823,21 @@ construct_libvirt_xml_cpu (guestfs_h *g,
   /* It is faster to pass the CPU host model to the appliance,
    * allowing maximum speed for things like checksums, encryption.
    * Note this may cause problems on some CPUs.  See: RHBZ#870071.
+   * Only do this with KVM.  It is broken in subtle ways on TCG, and
+   * fairly pointless anyway.
    */
-  XMLERROR (-1, xmlTextWriterStartElement (xo, BAD_CAST "cpu"));
-  XMLERROR (-1,
-            xmlTextWriterWriteAttribute (xo, BAD_CAST "mode",
-                                         BAD_CAST "host-model"));
-  XMLERROR (-1, xmlTextWriterStartElement (xo, BAD_CAST "model"));
-  XMLERROR (-1,
-            xmlTextWriterWriteAttribute (xo, BAD_CAST "fallback",
-                                         BAD_CAST "allow"));
-  XMLERROR (-1, xmlTextWriterEndElement (xo));
-  XMLERROR (-1, xmlTextWriterEndElement (xo));
+  if (params->is_kvm) {
+    XMLERROR (-1, xmlTextWriterStartElement (xo, BAD_CAST "cpu"));
+    XMLERROR (-1,
+	      xmlTextWriterWriteAttribute (xo, BAD_CAST "mode",
+					   BAD_CAST "host-model"));
+    XMLERROR (-1, xmlTextWriterStartElement (xo, BAD_CAST "model"));
+    XMLERROR (-1,
+	      xmlTextWriterWriteAttribute (xo, BAD_CAST "fallback",
+					   BAD_CAST "allow"));
+    XMLERROR (-1, xmlTextWriterEndElement (xo));
+    XMLERROR (-1, xmlTextWriterEndElement (xo));
+  }
 
   XMLERROR (-1, xmlTextWriterStartElement (xo, BAD_CAST "vcpu"));
   XMLERROR (-1, xmlTextWriterWriteFormatString (xo, "%d", g->smp));
-- 
1.8.3.1