From: David Woodhouse <dwmw@xxxxxxxxxxxx>
When the KVM clock is in master clock mode, updating the KVM clock is
pointless. Let the periodic work 'expire', and start it running again
from kvm_end_pvclock_update() if the master clock mode is ever turned
off again.
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index dd53860ca284..10b82f1b110d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -158,6 +158,8 @@ module_param(min_timer_period_us, uint, 0644);
static bool __read_mostly kvmclock_periodic_sync = true;
module_param(kvmclock_periodic_sync, bool, 0444);
+#define KVMCLOCK_SYNC_PERIOD (300 * HZ)
+
/* 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);
@@ -3187,6 +3189,10 @@ static void kvm_end_pvclock_update(struct kvm *kvm)
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
+ if (kvmclock_periodic_sync && !kvm->arch.use_master_clock)
+ schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
+ KVMCLOCK_SYNC_PERIOD);
+
/* guest entries allowed */
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_clear_request(KVM_REQ_MCLOCK_INPROGRESS, vcpu);
@@ -3555,8 +3561,6 @@ 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);
@@ -3564,6 +3568,9 @@ static void kvmclock_sync_fn(struct work_struct *work)
kvmclock_sync_work);
struct kvm *kvm = container_of(ka, struct kvm, arch);
+ if (!kvm->arch.use_master_clock)
+ return;
+
schedule_delayed_work(&kvm->arch.kvmclock_update_work, 0);
schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
KVMCLOCK_SYNC_PERIOD);
@@ -12551,7 +12558,8 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
mutex_unlock(&vcpu->mutex);
- if (kvmclock_periodic_sync && vcpu->vcpu_idx == 0)
+ if (kvmclock_periodic_sync && !kvm->arch.use_master_clock &&
+ vcpu->vcpu_idx == 0)
schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
KVMCLOCK_SYNC_PERIOD);
}
--
2.44.0
