Re: 2.6.35-rc1 regression with pvclock and smp guests

[Arjan Koers <0h61vkll2ly8@xutrox.com>]

On 2010-07-31 13:53, Arjan Koers wrote:
> 
> The kernel boots successfully when CONFIG_PRINTK_TIME is not set.
> 

The problem occurs when this message is printed:

[    0.016000] kvm-clock: cpu 1, msr 0:1511c01, secondary cpu clock

When I disable that printk, the kernel boots with
CONFIG_PRINTK_TIME=y

--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -131,8 +131,8 @@ static int kvm_register_clock(char *txt)
 	int low, high;
 	low = (int)__pa(&per_cpu(hv_clock, cpu)) | 1;
 	high = ((u64)__pa(&per_cpu(hv_clock, cpu)) >> 32);
-	printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n",
-	       cpu, high, low, txt);
+	/*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);
 }

So the problem appears to be that the clock of the second CPU
is used too soon (or that clock setup should finish earlier).