From 31e7e931cdc27f76dc68444edc4df1c0d1bfa6cc Mon Sep 17 00:00:00 2001
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date: Fri, 1 Oct 2010 17:35:46 +0100
Subject: [PATCH] xen: do not initialize PV timers on HVM if
!xen_have_vector_callback
if !xen_have_vector_callback do not initialize PV timer unconditionally
because we still don't know how many cpus are available and if there is
more than one we won't be able to receive the timer interrupts on
cpu > 0.
This patch fixes an hang at boot when Xen does not support vector
callbacks and the guest has multiple vcpus.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
---
arch/x86/xen/time.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 1a5353a753fcd..b2bb5aa3b0540 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -489,8 +489,9 @@ static void xen_hvm_setup_cpu_clockevents(void)
__init void xen_hvm_init_time_ops(void)
{
/* vector callback is needed otherwise we cannot receive interrupts
- * on cpu > 0 */
- if (!xen_have_vector_callback && num_present_cpus() > 1)
+ * on cpu > 0 and at this point we don't know how many cpus are
+ * available */
+ if (!xen_have_vector_callback)
return;
if (!xen_feature(XENFEAT_hvm_safe_pvclock)) {
printk(KERN_INFO "Xen doesn't support pvclock on HVM,"
--
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