diff options
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/trace.h | 39 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 57 |
2 files changed, 88 insertions, 8 deletions
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h index 1d652685608..fe5e00ed703 100644 --- a/arch/x86/kvm/trace.h +++ b/arch/x86/kvm/trace.h @@ -764,21 +764,54 @@ TRACE_EVENT( {VCLOCK_HPET, "hpet"} \ TRACE_EVENT(kvm_update_master_clock, - TP_PROTO(bool use_master_clock, unsigned int host_clock), - TP_ARGS(use_master_clock, host_clock), + TP_PROTO(bool use_master_clock, unsigned int host_clock, bool offset_matched), + TP_ARGS(use_master_clock, host_clock, offset_matched), TP_STRUCT__entry( __field( bool, use_master_clock ) __field( unsigned int, host_clock ) + __field( bool, offset_matched ) ), TP_fast_assign( __entry->use_master_clock = use_master_clock; __entry->host_clock = host_clock; + __entry->offset_matched = offset_matched; ), - TP_printk("masterclock %d hostclock %s", + TP_printk("masterclock %d hostclock %s offsetmatched %u", __entry->use_master_clock, + __print_symbolic(__entry->host_clock, host_clocks), + __entry->offset_matched) +); + +TRACE_EVENT(kvm_track_tsc, + TP_PROTO(unsigned int vcpu_id, unsigned int nr_matched, + unsigned int online_vcpus, bool use_master_clock, + unsigned int host_clock), + TP_ARGS(vcpu_id, nr_matched, online_vcpus, use_master_clock, + host_clock), + + TP_STRUCT__entry( + __field( unsigned int, vcpu_id ) + __field( unsigned int, nr_vcpus_matched_tsc ) + __field( unsigned int, online_vcpus ) + __field( bool, use_master_clock ) + __field( unsigned int, host_clock ) + ), + + TP_fast_assign( + __entry->vcpu_id = vcpu_id; + __entry->nr_vcpus_matched_tsc = nr_matched; + __entry->online_vcpus = online_vcpus; + __entry->use_master_clock = use_master_clock; + __entry->host_clock = host_clock; + ), + + TP_printk("vcpu_id %u masterclock %u offsetmatched %u nr_online %u" + " hostclock %s", + __entry->vcpu_id, __entry->use_master_clock, + __entry->nr_vcpus_matched_tsc, __entry->online_vcpus, __print_symbolic(__entry->host_clock, host_clocks)) ); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f3c069efc72..422ef5ed219 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1103,12 +1103,40 @@ static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns) return tsc; } +void kvm_track_tsc_matching(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_X86_64 + bool vcpus_matched; + bool do_request = false; + struct kvm_arch *ka = &vcpu->kvm->arch; + struct pvclock_gtod_data *gtod = &pvclock_gtod_data; + + vcpus_matched = (ka->nr_vcpus_matched_tsc + 1 == + atomic_read(&vcpu->kvm->online_vcpus)); + + if (vcpus_matched && gtod->clock.vclock_mode == VCLOCK_TSC) + if (!ka->use_master_clock) + do_request = 1; + + if (!vcpus_matched && ka->use_master_clock) + do_request = 1; + + if (do_request) + kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu); + + trace_kvm_track_tsc(vcpu->vcpu_id, ka->nr_vcpus_matched_tsc, + atomic_read(&vcpu->kvm->online_vcpus), + ka->use_master_clock, gtod->clock.vclock_mode); +#endif +} + void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) { struct kvm *kvm = vcpu->kvm; u64 offset, ns, elapsed; unsigned long flags; s64 usdiff; + bool matched; raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); offset = kvm_x86_ops->compute_tsc_offset(vcpu, data); @@ -1151,6 +1179,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) offset = kvm_x86_ops->compute_tsc_offset(vcpu, data); pr_debug("kvm: adjusted tsc offset by %llu\n", delta); } + matched = true; } else { /* * We split periods of matched TSC writes into generations. @@ -1165,6 +1194,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) kvm->arch.cur_tsc_nsec = ns; kvm->arch.cur_tsc_write = data; kvm->arch.cur_tsc_offset = offset; + matched = false; pr_debug("kvm: new tsc generation %u, clock %llu\n", kvm->arch.cur_tsc_generation, data); } @@ -1188,6 +1218,15 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) kvm_x86_ops->write_tsc_offset(vcpu, offset); 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++; + else + kvm->arch.nr_vcpus_matched_tsc = 0; + + kvm_track_tsc_matching(vcpu); + spin_unlock(&kvm->arch.pvclock_gtod_sync_lock); } EXPORT_SYMBOL_GPL(kvm_write_tsc); @@ -1279,8 +1318,9 @@ static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now) /* * - * Assuming a stable TSC across physical CPUS, the following condition - * is possible. Each numbered line represents an event visible to both + * Assuming a stable TSC across physical CPUS, and a stable TSC + * across virtual CPUs, the following condition is possible. + * Each numbered line represents an event visible to both * CPUs at the next numbered event. * * "timespecX" represents host monotonic time. "tscX" represents @@ -1313,7 +1353,7 @@ static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now) * copy of host monotonic time values. Update that master copy * in lockstep. * - * Rely on synchronization of host TSCs for monotonicity. + * Rely on synchronization of host TSCs and guest TSCs for monotonicity. * */ @@ -1322,20 +1362,27 @@ static void pvclock_update_vm_gtod_copy(struct kvm *kvm) #ifdef CONFIG_X86_64 struct kvm_arch *ka = &kvm->arch; int vclock_mode; + bool host_tsc_clocksource, vcpus_matched; + + vcpus_matched = (ka->nr_vcpus_matched_tsc + 1 == + atomic_read(&kvm->online_vcpus)); /* * If the host uses TSC clock, then passthrough TSC as stable * to the guest. */ - ka->use_master_clock = kvm_get_time_and_clockread( + host_tsc_clocksource = kvm_get_time_and_clockread( &ka->master_kernel_ns, &ka->master_cycle_now); + ka->use_master_clock = host_tsc_clocksource & vcpus_matched; + if (ka->use_master_clock) atomic_set(&kvm_guest_has_master_clock, 1); vclock_mode = pvclock_gtod_data.clock.vclock_mode; - trace_kvm_update_master_clock(ka->use_master_clock, vclock_mode); + trace_kvm_update_master_clock(ka->use_master_clock, vclock_mode, + vcpus_matched); #endif } |