From: Arjan Koers <0h61vkll2ly8@xutrox.com>
Date: Mon, 2 Aug 2010 21:35:28 +0000 (+0200)
Subject: KVM guest: Move a printk that's using the clock before it's ready
X-Git-Tag: v2.6.37-rc1~142^2~18
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=19b6a85b78a5d4b466c537bdbf0eaecae5e2c4e2;p=linux.git

KVM guest: Move a printk that's using the clock before it's ready

Fix a hang during SMP kernel boot on KVM that showed up
after commit 489fb490dbf8dab0249ad82b56688ae3842a79e8
(2.6.35) and 59aab522154a2f17b25335b63c1cf68a51fb6ae0
(2.6.34.1). The problem only occurs when
CONFIG_PRINTK_TIME is set.

KVM-Stable-Tag.
Signed-off-by: Arjan Koers <0h61vkll2ly8@xutrox.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index eb9b76c716c2..ca43ce31a19c 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -128,13 +128,15 @@ static struct clocksource kvm_clock = {
 static int kvm_register_clock(char *txt)
 {
 	int cpu = smp_processor_id();
-	int low, high;
+	int low, high, ret;
+
 	low = (int)__pa(&per_cpu(hv_clock, cpu)) | 1;
 	high = ((u64)__pa(&per_cpu(hv_clock, cpu)) >> 32);
+	ret = native_write_msr_safe(msr_kvm_system_time, low, high);
 	printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n",
 	       cpu, high, low, txt);
 
-	return native_write_msr_safe(msr_kvm_system_time, low, high);
+	return ret;
 }
 
 #ifdef CONFIG_X86_LOCAL_APIC