[PATCH 077/104] KVM: Migrate lapic hrtimer when vcpu moves to another cpu

Avi Kivity
2007-09-17T08:48:07Z

From: Eddie Dong <eddie.dong@intel.com>

This reduces overhead by accessing cachelines from the wrong node, as well
as simplifying locking.

[Qing: fix for inactive or expired one-shot timer]

Signed-off-by: Yaozu (Eddie) Dong <Eddie.Dong@intel.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---
drivers/kvm/irq.h | 1 +
drivers/kvm/lapic.c | 14 ++++++++++++++
drivers/kvm/svm.c | 1 +
drivers/kvm/vmx.c | 4 +++-
4 files changed, 19 insertions(+), 1 deletions(-)

diff --git a/drivers/kvm/irq.h b/drivers/kvm/irq.h
index 87baf7e..f324cfb 100644
--- a/drivers/kvm/irq.h
+++ b/drivers/kvm/irq.h
@@ -158,5 +158,6 @@ void kvm_apic_timer_intr_post(struct kvm_vcpu *vcpu, int vec);
void kvm_timer_intr_post(struct kvm_vcpu *vcpu, int vec);
void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu);
void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu);
+void kvm_migrate_apic_timer(struct kvm_vcpu *vcpu);

#endif
diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c
index 490d493..2706ec3 100644
--- a/drivers/kvm/lapic.c
+++ b/drivers/kvm/lapic.c
@@ -979,3 +979,17 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu)
update_divide_count(apic);
start_apic_timer(apic);
}
+
+void kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->apic;
+ struct hrtimer *timer;
+
+ if (!apic)
+ return;
+
+ timer = &apic->timer.dev;
+ if (hrtimer_cancel(timer))
+ hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
+}
+EXPORT_SYMBOL_GPL(kvm_migrate_apic_timer);
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 00119ec..3de9ec3 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -633,6 +633,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
delta = vcpu->host_tsc - tsc_this;
svm->vmcb->control.tsc_offset += delta;
vcpu->cpu = cpu;
+ kvm_migrate_apic_timer(vcpu);
}

for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index eeecadf..f4618b9 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -441,8 +441,10 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
u64 phys_addr = __pa(vmx->vmcs);
u64 tsc_this, delta;

- if (vcpu->cpu != cpu)
+ if (vcpu->cpu != cpu) {
vcpu_clear(vmx);
+ kvm_migrate_apic_timer(vcpu);
+ }

if (per_cpu(current_vmcs, cpu) != vmx->vmcs) {
u8 error;
--
1.5.3