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KVM: x86: perform kvmclock updates in lockstep

PATCH Marcelo Tosatti 1 participant 1 message May 7, 2013

Subsystems (3)
x86 KVM KVM x86
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Marcelo Tosatti

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It is necessary for each vcpus system_timestamp memory copy to be updated from one sample of the nanosecond kernel clock.

If this is not the case, and NTP changes frequency adjustment, different vcpus will make use of different time bases.

Signed-off-by Marcelo Tosatti <[email protected]>
arch/x86/kvm/x86.c +4 -4
index 94f35d2..1ef4287 100644
@@ -1965,7 +1965,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		kvmclock_reset(vcpu);
 
 		vcpu->arch.time = data;
-		kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
+		kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
 
 		/* we verify if the enable bit is set... */
 		if (!(data & 1))

@@ -2665,7 +2665,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	if (unlikely(vcpu->arch.tsc_offset_adjustment)) {
 		adjust_tsc_offset_host(vcpu, vcpu->arch.tsc_offset_adjustment);
 		vcpu->arch.tsc_offset_adjustment = 0;
-		set_bit(KVM_REQ_CLOCK_UPDATE, &vcpu->requests);
+		set_bit(KVM_REQ_MASTERCLOCK_UPDATE, &vcpu->requests);
 	}
 
 	if (unlikely(vcpu->cpu != cpu) || check_tsc_unstable()) {

@@ -2684,7 +2684,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		 * kvmclock on vcpu->cpu migration
 		 */
 		if (!vcpu->kvm->arch.use_master_clock || vcpu->cpu == -1)
-			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
+			kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
 		if (vcpu->cpu != cpu)
 			kvm_migrate_timers(vcpu);
 		vcpu->cpu = cpu;

@@ -5092,7 +5092,7 @@ static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long va
 		kvm_for_each_vcpu(i, vcpu, kvm) {
 			if (vcpu->cpu != freq->cpu)
 				continue;
-			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
+			kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
 			if (vcpu->cpu != smp_processor_id())
 				send_ipi = 1;
 		}