KVM: x86: perform kvmclock updates in lockstep

Commit Message

Marcelo Tosatti May 7, 2013, 2:49 a.m. UTC

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 <[e-mail]>


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Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 94f35d2..1ef4287 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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;
 		}