This reverts commit 332967a3eac06f6379283cf155c84fe7cd0537c2. Commit 332967a3eac0 ("x86: kvm: introduce periodic global clock updates") introduced a 300s interval work to sync ntp corrections across all vcpus. Since commit 53fafdbb8b21 ("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: Lei Chen --- arch/x86/include/asm/kvm_host.h | 1 - arch/x86/kvm/x86.c | 25 ------------------------- 2 files changed, 26 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f19a76d3ca0e..e41e4fe91f5e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1436,7 +1436,6 @@ 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; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a1c49bc681c4..399045a384d4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -157,9 +157,6 @@ 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); @@ -3439,20 +3436,6 @@ 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) { @@ -12327,8 +12310,6 @@ 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); @@ -12339,10 +12320,6 @@ 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) @@ -12722,7 +12699,6 @@ 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); @@ -12830,7 +12806,6 @@ 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 -- 2.44.0 This reverts commit 7e44e4495a398eb553ce561f29f9148f40a3448f. Commit 7e44e4495a39 ("x86: kvm: rate-limit global clock updates") intends to use a kvmclock_update_work to sync ntp corretion across all vcpus kvmclock, which is based on commit 0061d53daf26f ("KVM: x86: limit difference between kvmclock updates") Since kvmclock has been switched to mono raw, this commit can be reverted. Signed-off-by: Lei Chen --- arch/x86/include/asm/kvm_host.h | 1 - arch/x86/kvm/x86.c | 29 ++++------------------------- 2 files changed, 4 insertions(+), 26 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index e41e4fe91f5e..0a1165f40ff1 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1435,7 +1435,6 @@ struct kvm_arch { bool use_master_clock; u64 master_kernel_ns; u64 master_cycle_now; - struct delayed_work kvmclock_update_work; #ifdef CONFIG_KVM_HYPERV struct kvm_hv hyperv; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 399045a384d4..d526e9e285f1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3404,22 +3404,14 @@ uint64_t kvm_get_wall_clock_epoch(struct kvm *kvm) * the others. * * So in those cases, request a kvmclock update for all vcpus. - * We need to rate-limit these requests though, as they can - * considerably slow guests that have a large number of vcpus. - * The time for a remote vcpu to update its kvmclock is bound - * by the delay we use to rate-limit the updates. + * The worst case for a remote vcpu to update its kvmclock + * is then bounded by maximum nohz sleep latency. */ - -#define KVMCLOCK_UPDATE_DELAY msecs_to_jiffies(100) - -static void kvmclock_update_fn(struct work_struct *work) +static void kvm_gen_kvmclock_update(struct kvm_vcpu *v) { unsigned long i; - struct delayed_work *dwork = to_delayed_work(work); - struct kvm_arch *ka = container_of(dwork, struct kvm_arch, - kvmclock_update_work); - struct kvm *kvm = container_of(ka, struct kvm, arch); struct kvm_vcpu *vcpu; + struct kvm *kvm = v->kvm; kvm_for_each_vcpu(i, vcpu, kvm) { kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); @@ -3427,15 +3419,6 @@ static void kvmclock_update_fn(struct work_struct *work) } } -static void kvm_gen_kvmclock_update(struct kvm_vcpu *v) -{ - struct kvm *kvm = v->kvm; - - kvm_make_request(KVM_REQ_CLOCK_UPDATE, v); - schedule_delayed_work(&kvm->arch.kvmclock_update_work, - KVMCLOCK_UPDATE_DELAY); -} - /* These helpers are safe iff @msr is known to be an MCx bank MSR. */ static bool is_mci_control_msr(u32 msr) { @@ -12698,8 +12681,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.hv_root_tdp = INVALID_PAGE; #endif - INIT_DELAYED_WORK(&kvm->arch.kvmclock_update_work, kvmclock_update_fn); - kvm_apicv_init(kvm); kvm_hv_init_vm(kvm); kvm_xen_init_vm(kvm); @@ -12806,8 +12787,6 @@ 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_update_work); - #ifdef CONFIG_KVM_IOAPIC kvm_free_pit(kvm); #endif -- 2.44.0 Since vcpu local clock is no longer affected by ntp, remove comment about ntp correction sync for function kvm_gen_kvmclock_update. Signed-off-by: Lei Chen --- arch/x86/kvm/x86.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d526e9e285f1..f85611f59218 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3399,9 +3399,7 @@ uint64_t kvm_get_wall_clock_epoch(struct kvm *kvm) /* * kvmclock updates which are isolated to a given vcpu, such as * vcpu->cpu migration, should not allow system_timestamp from - * the rest of the vcpus to remain static. Otherwise ntp frequency - * correction applies to one vcpu's system_timestamp but not - * the others. + * the rest of the vcpus to remain static. * * So in those cases, request a kvmclock update for all vcpus. * The worst case for a remote vcpu to update its kvmclock -- 2.44.0