From 19b6a85b78a5d4b466c537bdbf0eaecae5e2c4e2 Mon Sep 17 00:00:00 2001 From: Arjan Koers <0h61vkll2ly8@xutrox.com> Date: Mon, 2 Aug 2010 23:35:28 +0200 Subject: [PATCH] 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 --- arch/x86/kernel/kvmclock.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) 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 -- 2.20.1