On 16/06/20 01:07, Jim Mattson wrote:
> + } else if (vcpu->arch.this_tsc_generation !=
> + kvm->arch.cur_tsc_generation) {
> u64 tsc_exp = kvm->arch.last_tsc_write +
> nsec_to_cycles(vcpu, elapsed);
> u64 tsc_hz = vcpu->arch.virtual_tsc_khz * 1000LL;
Can this cause the same vCPU to be counted multiple times in
nr_vcpus_matched_tsc? I think you need to keep already_matched (see
also the commit message for 0d3da0d26e3c, "KVM: x86: fix TSC matching",
2014-07-09, which introduced that variable).
Thanks,
Paolo
> @@ -2062,7 +2062,6 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
> offset = kvm_compute_tsc_offset(vcpu, data);
> }
> matched = true;
> - already_matched = (vcpu->arch.this_tsc_generation == kvm->arch.cur_tsc_generation);
> } else {
> /*
> * We split periods of matched TSC writes into generations.
> @@ -2102,12 +2101,10 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
> raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
>
> spin_lock(&kvm->arch.pvclock_gtod_sync_lock);
> - if (!matched) {
> - kvm->arch.nr_vcpus_matched_tsc = 0;
> - } else if (!already_matched) {
> + if (matched)
> kvm->arch.nr_vcpus_matched_tsc++;
> - }
> -
> + else
> + kvm->arch.nr_vcpus_matched_tsc = 0;
