From 117a041466b3af8368506ae3ab7b8d26fc07d9b7 Mon Sep 17 00:00:00 2001
From: Alexandre Derumier <aderumier@odiso.com>
Date: Mon, 16 Mar 2015 05:57:45 +0100
Subject: [PATCH] add kvm_pv_unhalt cpu flag

require pvticketlocks from kernel 3.12 (backported in redhat 3.10 kernel)

see:
http://lwn.net/Articles/493402/

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
---
 PVE/QemuServer.pm | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index a4ea225b..329b283b 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -2909,6 +2909,11 @@ sub config_to_command {
 
     push @$cpuFlags, '+sep' if $cpu eq 'kvm64' || $cpu eq 'kvm32';
 
+    if (qemu_machine_feature_enabled ($machine_type, $kvmver, 2, 3)) {
+
+	push @$cpuFlags , '+kvm_pv_unhalt' if !$nokvm;
+    }
+
     $cpu .= "," . join(',', @$cpuFlags) if scalar(@$cpuFlags);
 
     # Note: enforce needs kernel 3.10, so we do not use it for now