From: David Woodhouse dwmw@amazon.co.uk
This effectively reverts commit 332967a3eac0 ("x86: kvm: introduce periodic global clock updates"). The periodic update was introduced to propagate NTP corrections to the guest KVM clock, when the KVM clock was based on CLOCK_MONOTONIC.
However, commit 53fafdbb8b21 ("KVM: x86: switch KVMCLOCK base to monotonic raw clock") switched to using CLOCK_MONOTONIC_RAW as the basis for the KVM clock, avoiding the NTP frequency skew altogether.
So the periodic update serves no purpose. Remove it.
Signed-off-by: David Woodhouse dwmw@amazon.co.uk --- arch/x86/kvm/x86.c | 25 ------------------------- 1 file changed, 25 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 44b3d2a0da5b..4ec4eb850c5b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -155,9 +155,6 @@ EXPORT_SYMBOL_GPL(report_ignored_msrs); unsigned int min_timer_period_us = 200; module_param(min_timer_period_us, uint, 0644);
-static bool __read_mostly kvmclock_periodic_sync = true; -module_param(kvmclock_periodic_sync, bool, 0444); - /* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */ static u32 __read_mostly tsc_tolerance_ppm = 250; module_param(tsc_tolerance_ppm, uint, 0644); @@ -3434,20 +3431,6 @@ static void kvm_gen_kvmclock_update(struct kvm_vcpu *v) KVMCLOCK_UPDATE_DELAY); }
-#define KVMCLOCK_SYNC_PERIOD (300 * HZ) - -static void kvmclock_sync_fn(struct work_struct *work) -{ - struct delayed_work *dwork = to_delayed_work(work); - struct kvm_arch *ka = container_of(dwork, struct kvm_arch, - kvmclock_sync_work); - struct kvm *kvm = container_of(ka, struct kvm, arch); - - schedule_delayed_work(&kvm->arch.kvmclock_update_work, 0); - schedule_delayed_work(&kvm->arch.kvmclock_sync_work, - KVMCLOCK_SYNC_PERIOD); -} - /* These helpers are safe iff @msr is known to be an MCx bank MSR. */ static bool is_mci_control_msr(u32 msr) { @@ -12416,8 +12399,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) { - struct kvm *kvm = vcpu->kvm; - if (mutex_lock_killable(&vcpu->mutex)) return; vcpu_load(vcpu); @@ -12428,10 +12409,6 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) vcpu->arch.msr_kvm_poll_control = 1;
mutex_unlock(&vcpu->mutex); - - if (kvmclock_periodic_sync && vcpu->vcpu_idx == 0) - schedule_delayed_work(&kvm->arch.kvmclock_sync_work, - KVMCLOCK_SYNC_PERIOD); }
void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) @@ -12804,7 +12781,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) #endif
INIT_DELAYED_WORK(&kvm->arch.kvmclock_update_work, kvmclock_update_fn); - INIT_DELAYED_WORK(&kvm->arch.kvmclock_sync_work, kvmclock_sync_fn);
kvm_apicv_init(kvm); kvm_hv_init_vm(kvm); @@ -12844,7 +12820,6 @@ static void kvm_unload_vcpu_mmus(struct kvm *kvm)
void kvm_arch_sync_events(struct kvm *kvm) { - cancel_delayed_work_sync(&kvm->arch.kvmclock_sync_work); cancel_delayed_work_sync(&kvm->arch.kvmclock_update_work); kvm_free_pit(kvm); }