On 07/13/2010 05:25 AM, Zachary Amsden wrote:
This simplifies much of the init code; we can now simply always
call tsc_khz_changed, optionally passing it a new value, or letting
it figure out the existing value (while interrupts are disabled, and
thus, by inference from the rule, not raceful against CPU hotplug or
frequency updates, which will issue IPIs to the local CPU to perform
this very same task).
@@ -893,6 +893,15 @@ static void kvm_set_time_scale(uint32_t tsc_khz, struct pvclock_vcpu_time_info *
static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz);
+static inline int kvm_tsc_changes_freq(void)
+{
+ int cpu = get_cpu();
+ int ret = !boot_cpu_has(X86_FEATURE_CONSTANT_TSC)&&
+ cpufreq_quick_get(cpu) != 0;
+ put_cpu();
+ return ret;
+}
+
void guest_write_tsc(struct kvm_vcpu *vcpu, u64 data)
{
struct kvm *kvm = vcpu->kvm;
@@ -937,7 +946,7 @@ void guest_write_tsc(struct kvm_vcpu *vcpu, u64 data)
}
EXPORT_SYMBOL_GPL(guest_write_tsc);
-static void kvm_write_guest_time(struct kvm_vcpu *v)
+static int kvm_write_guest_time(struct kvm_vcpu *v)
{
struct timespec ts;
unsigned long flags;
@@ -946,24 +955,27 @@ static void kvm_write_guest_time(struct kvm_vcpu *v)
unsigned long this_tsc_khz;
if ((!vcpu->time_page))
- return;
-
- this_tsc_khz = get_cpu_var(cpu_tsc_khz);
- if (unlikely(vcpu->hv_clock_tsc_khz != this_tsc_khz)) {
- kvm_set_time_scale(this_tsc_khz,&vcpu->hv_clock);
- vcpu->hv_clock_tsc_khz = this_tsc_khz;
- }
- put_cpu_var(cpu_tsc_khz);
+ return 0;
/* Keep irq disabled to prevent changes to the clock */
local_irq_save(flags);
kvm_get_msr(v, MSR_IA32_TSC,&vcpu->hv_clock.tsc_timestamp);
ktime_get_ts(&ts);
monotonic_to_bootbased(&ts);
+ this_tsc_khz = __get_cpu_var(cpu_tsc_khz);
local_irq_restore(flags);
- /* With all the info we got, fill in the values */
+ if (unlikely(this_tsc_khz == 0)) {
+ kvm_make_request(KVM_REQ_KVMCLOCK_UPDATE, v);
+ return 1;
+ }
Presumably, this will spin until cpufreq writes the frequency?
@@ -4131,9 +4138,23 @@ int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size, unsigned short port)
}
EXPORT_SYMBOL_GPL(kvm_fast_pio_out);
-static void bounce_off(void *info)
+static void tsc_bad(void *info)
+{
+ __get_cpu_var(cpu_tsc_khz) = 0;
+}
+
+static void tsc_khz_changed(void *data)
{
- /* nothing */
+ struct cpufreq_freqs *freq = data;
+ unsigned long khz = 0;
+
+ if (data)
+ khz = freq->new;
+ else if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
+ khz = cpufreq_quick_get(raw_smp_processor_id());
+ if (!khz)
+ khz = tsc_khz;
+ __get_cpu_var(cpu_tsc_khz) = khz;
}
Do we really need to cache cpufreq_quick_get()? If it's really quick,
why not just use it everywhere instead of cacheing it? Not a comment on
this patch.
--
error compiling committee.c: too many arguments to function
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