Commit 43ddbf16 authored by Lei Chen's avatar Lei Chen Committed by Sean Christopherson
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Revert "x86: kvm: introduce periodic global clock updates" 



This reverts commit 332967a3.

Commit 332967a3 ("x86: kvm: introduce periodic global clock
updates") introduced a 300s interval work to sync ntp corrections
across all vcpus.

Since commit 53fafdbb ("KVM: x86: switch KVMCLOCK base to
monotonic raw clock"), kvmclock switched to mono raw clock,
we can no longer take ntp into consideration.

Signed-off-by: default avatarLei Chen <lei.chen@smartx.com>
Link: https://patch.msgid.link/20250819152027.1687487-2-lei.chen@smartx.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent a091fe60

arch/x86/include/asm/kvm_host.h

+0 −1
Original line number Diff line number Diff line
@@ -1457,7 +1457,6 @@ struct kvm_arch { 
	u64 master_kernel_ns;

	u64 master_cycle_now;

	struct delayed_work kvmclock_update_work;

	struct delayed_work kvmclock_sync_work;



#ifdef CONFIG_KVM_HYPERV

	struct kvm_hv hyperv;

arch/x86/kvm/x86.c

+0 −25
Original line number Diff line number Diff line
@@ -159,9 +159,6 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(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);
@@ -3558,20 +3555,6 @@ 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)

{
@@ -12757,8 +12740,6 @@ 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);
@@ -12769,10 +12750,6 @@ 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)
@@ -13187,7 +13164,6 @@ 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);
@@ -13295,7 +13271,6 @@ void kvm_arch_pre_destroy_vm(struct kvm *kvm) 
	 * is unsafe, i.e. will lead to use-after-free.  The PIT also needs to

	 * be stopped before IRQ routing is freed.

	 */

	cancel_delayed_work_sync(&kvm->arch.kvmclock_sync_work);

	cancel_delayed_work_sync(&kvm->arch.kvmclock_update_work);



#ifdef CONFIG_KVM_IOAPIC