[v4:,1/4] Code motion. Separate timer intialization into an indepedent function.

Commit Message

Zachary Amsden Sept. 29, 2009, 9:38 p.m. UTC

None

Comments

Avi Kivity Sept. 30, 2009, 3:56 p.m. UTC | #1

On 09/30/2009 05:51 PM, Zachary Amsden wrote:
>> Is anything preventing us from unifying the constant_tsc and !same 
>> paths?  We could just do a quick check in the notifier, see the tsc 
>> frequency hasn't changed, and return.
>
>
> Actually, yes.  On constant_tsc processors, the processor frequency 
> may still change, however the TSC frequency does not change with it.
>
> I actually have both of these kinds of processors (freq changes with 
> constant TSC and freq changes with variable TSC) so I was able to test 
> both of these cases.

If the API allows us to query the tsc frequency, it would simply return 
the same values in all cases, which we'd ignore.

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fedac9d..15d2ace 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3116,9 +3116,22 @@  static struct notifier_block kvmclock_cpufreq_notifier_block = {
         .notifier_call  = kvmclock_cpufreq_notifier
 };
 
+static void kvm_timer_init(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		per_cpu(cpu_tsc_khz, cpu) = tsc_khz;
+	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
+		tsc_khz_ref = tsc_khz;
+		cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block,
+					  CPUFREQ_TRANSITION_NOTIFIER);
+	}
+}
+
 int kvm_arch_init(void *opaque)
 {
-	int r, cpu;
+	int r;
 	struct kvm_x86_ops *ops = (struct kvm_x86_ops *)opaque;
 
 	if (kvm_x86_ops) {
@@ -3150,13 +3163,7 @@  int kvm_arch_init(void *opaque)
 	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
 			PT_DIRTY_MASK, PT64_NX_MASK, 0);
 
-	for_each_possible_cpu(cpu)
-		per_cpu(cpu_tsc_khz, cpu) = tsc_khz;
-	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
-		tsc_khz_ref = tsc_khz;
-		cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block,
-					  CPUFREQ_TRANSITION_NOTIFIER);
-	}
+	kvm_timer_init();
 
 	return 0;