diff options
| -rw-r--r-- | arch/x86/kvm/x86.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 14e7efdd74ed..4180e18e0cbb 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1798,12 +1798,11 @@ static void kvm_setup_guest_pvclock(struct pvclock_vcpu_time_info *ref_hv_clock, int kvm_guest_time_update(struct kvm_vcpu *v) { + u64 tgt_tsc_hz, tsc_timestamp, host_tsc, master_tsc, master_ns; struct kvm_arch *ka __maybe_unused = &v->kvm->arch; struct pvclock_vcpu_time_info hv_clock = {}; - u64 tgt_tsc_hz; struct kvm_vcpu_arch *vcpu = &v->arch; s64 kernel_ns; - u64 tsc_timestamp, host_tsc; /* * If the host uses TSC clock, then passthrough TSC as stable @@ -1816,10 +1815,16 @@ int kvm_guest_time_update(struct kvm_vcpu *v) do { seq = read_seqcount_begin(&ka->pvclock_sc); use_master_clock = ka->use_master_clock; - if (use_master_clock) { - host_tsc = ka->master_cycle_now; - kernel_ns = ka->master_kernel_ns; + if (!use_master_clock) + continue; + + if (!kvm_get_time_and_clockread(&kernel_ns, &host_tsc)) { + use_master_clock = false; + continue; } + + master_tsc = ka->master_cycle_now; + master_ns = ka->master_kernel_ns; } while (read_seqcount_retry(&ka->pvclock_sc, seq)); #else const bool use_master_clock = false; @@ -1885,8 +1890,18 @@ int kvm_guest_time_update(struct kvm_vcpu *v) hv_clock.tsc_shift = vcpu->pvclock_tsc_shift; hv_clock.tsc_to_system_mul = vcpu->pvclock_tsc_mul; - hv_clock.tsc_timestamp = tsc_timestamp; - hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset; + /* + * If the master clock is NOT in use, the reference time placed in the + * hv_clock is "now". If master clock is in use, the reference time is + * the master clock's snapshot from some time in the past, not "now". + */ + if (use_master_clock) { + hv_clock.tsc_timestamp = kvm_read_l1_tsc(v, master_tsc); + hv_clock.system_time = master_ns + v->kvm->arch.kvmclock_offset; + } else { + hv_clock.tsc_timestamp = tsc_timestamp; + hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset; + } /* If the host uses TSC clocksource, then it is stable */ hv_clock.flags = 0; |