diff options
| -rw-r--r-- | arch/x86/kvm/x86.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b26699cf302d..789d96991026 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1653,12 +1653,16 @@ static unsigned long get_cpu_tsc_khz(void) } /* Called within read_seqcount_begin/retry for kvm->pvclock_sc. */ -static void __get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) +static bool __get_kvmclock_master_clock(struct kvm *kvm, + struct kvm_clock_data *data) { struct kvm_arch *ka = &kvm->arch; struct pvclock_vcpu_time_info hv_clock; u64 tsc_hz; + if (!ka->use_master_clock) + return false; + /* * Snapshot and validate the TSC frequency as kvmclock_cpu_down_prep() * zeros the per-CPU value when a CPU is going offline. @@ -1667,8 +1671,10 @@ static void __get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) tsc_hz = (u64)get_cpu_tsc_khz() * HZ_PER_KHZ; put_cpu(); - data->flags = 0; - if (ka->use_master_clock && tsc_hz) { + if (!tsc_hz) + return false; + + { #ifdef CONFIG_X86_64 struct timespec64 ts; @@ -1686,9 +1692,9 @@ static void __get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) &hv_clock.tsc_shift, &hv_clock.tsc_to_system_mul); data->clock = __pvclock_read_cycles(&hv_clock, data->host_tsc); - } else { - data->clock = get_kvmclock_base_ns() + ka->kvmclock_offset; } + + return true; } static void get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) @@ -1697,8 +1703,11 @@ static void get_kvmclock(struct kvm *kvm, struct kvm_clock_data *data) unsigned seq; do { + data->flags = 0; + seq = read_seqcount_begin(&ka->pvclock_sc); - __get_kvmclock(kvm, data); + if (!__get_kvmclock_master_clock(kvm, data)) + data->clock = get_kvmclock_base_ns() + ka->kvmclock_offset; } while (read_seqcount_retry(&ka->pvclock_sc, seq)); } |