KVM: Keep track of missed timer irq injections

APIC timer IRQ is set every time when a certain period
expires at host time, but the guest may be descheduled
at that time and thus the irq be overwritten by later fire.
This patch keep track of firing irq numbers and decrease
only when the IRQ is injected to guest or buffered in
APIC.

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>

diff --git a/drivers/kvm/irq.c b/drivers/kvm/irq.c
index e09cd65925d6f53a253bbb9c21ab69483d0033cf..b88e50115588cfa8033d9f591a15af0f9d3972cc 100644 (file)
--- a/drivers/kvm/irq.c
+++ b/drivers/kvm/irq.c
@@ -78,3 +78,16 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
                smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0, 0);
 }
 
+void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
+{
+       kvm_inject_apic_timer_irqs(vcpu);
+       /* TODO: PIT, RTC etc. */
+}
+EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
+
+void kvm_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
+{
+       kvm_apic_timer_intr_post(vcpu, vec);
+       /* TODO: PIT, RTC etc. */
+}
+EXPORT_SYMBOL_GPL(kvm_timer_intr_post);

diff --git a/drivers/kvm/irq.h b/drivers/kvm/irq.h
index 07035e8279d4e5966821d1c50cd1475668a47a69..87baf7e69ea2ea1327566f83568f2817835d5237 100644 (file)
--- a/drivers/kvm/irq.h
+++ b/drivers/kvm/irq.h
@@ -154,5 +154,9 @@ int kvm_ioapic_init(struct kvm *kvm);
 void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level);
 int kvm_lapic_enabled(struct kvm_vcpu *vcpu);
 int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu);
+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);
 
 #endif

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index d56964a6eb801ced082377816a4b2d62e65abed6..8f8bfc9160e32d42907f35812bd5fcee2aad4b87 100644 (file)
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -283,6 +283,8 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_init);
 void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
 {
        kvm_mmu_destroy(vcpu);
+       if (vcpu->apic)
+               hrtimer_cancel(&vcpu->apic->timer.dev);
        kvm_free_apic(vcpu->apic);
        free_page((unsigned long)vcpu->pio_data);
        free_page((unsigned long)vcpu->run);

diff --git a/drivers/kvm/lapic.c b/drivers/kvm/lapic.c
index 68bbbb38edadc212388ff41de4ffdc83389c1909..490d4939dba7b6060d0e0676f384a1f345f2cc12 100644 (file)
--- a/drivers/kvm/lapic.c
+++ b/drivers/kvm/lapic.c
@@ -313,6 +313,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
                             int vector, int level, int trig_mode)
 {
        int result = 0;
+       int orig_irr;
 
        switch (delivery_mode) {
        case APIC_DM_FIXED:
@@ -321,7 +322,8 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
                if (unlikely(!apic_enabled(apic)))
                        break;
 
-               if (apic_test_and_set_irr(vector, apic) && trig_mode) {
+               orig_irr = apic_test_and_set_irr(vector, apic);
+               if (orig_irr && trig_mode) {
                        apic_debug("level trig mode repeatedly for vector %d",
                                   vector);
                        break;
@@ -335,7 +337,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
 
                kvm_vcpu_kick(apic->vcpu);
 
-               result = 1;
+               result = (orig_irr == 0);
                break;
 
        case APIC_DM_REMRD:
@@ -831,38 +833,33 @@ EXPORT_SYMBOL_GPL(kvm_lapic_enabled);
  * timer interface
  *----------------------------------------------------------------------
  */
+
+/* TODO: make sure __apic_timer_fn runs in current pCPU */
 static int __apic_timer_fn(struct kvm_lapic *apic)
 {
-       u32 vector;
        int result = 0;
+       wait_queue_head_t *q = &apic->vcpu->wq;
 
-       if (unlikely(!apic_enabled(apic) ||
-                    !apic_lvt_enabled(apic, APIC_LVTT))) {
-               apic_debug("%s: time interrupt although apic is down\n",
-                          __FUNCTION__);
-               return 0;
-       }
-
-       vector = apic_lvt_vector(apic, APIC_LVTT);
-       apic->timer.last_update = apic->timer.dev.expires;
        atomic_inc(&apic->timer.pending);
-       __apic_accept_irq(apic, APIC_DM_FIXED, vector, 1, 0);
-
+       if (waitqueue_active(q))
+               wake_up_interruptible(q);
        if (apic_lvtt_period(apic)) {
-               u32 offset;
-               u32 tmict = apic_get_reg(apic, APIC_TMICT);
-
-               offset = APIC_BUS_CYCLE_NS * apic->timer.divide_count * tmict;
-
                result = 1;
                apic->timer.dev.expires = ktime_add_ns(
                                        apic->timer.dev.expires,
                                        apic->timer.period);
        }
-
        return result;
 }
 
+static int __inject_apic_timer_irq(struct kvm_lapic *apic)
+{
+       int vector;
+
+       vector = apic_lvt_vector(apic, APIC_LVTT);
+       return __apic_accept_irq(apic, APIC_DM_FIXED, vector, 1, 0);
+}
+
 static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
 {
        struct kvm_lapic *apic;
@@ -935,6 +932,27 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
        return highest_irr;
 }
 
+void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
+{
+       struct kvm_lapic *apic = vcpu->apic;
+
+       if (apic && apic_lvt_enabled(apic, APIC_LVTT) &&
+               atomic_read(&apic->timer.pending) > 0) {
+               if (__inject_apic_timer_irq(apic))
+                       atomic_dec(&apic->timer.pending);
+       }
+}
+
+void kvm_apic_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
+{
+       struct kvm_lapic *apic = vcpu->apic;
+
+       if (apic && apic_lvt_vector(apic, APIC_LVTT) == vec)
+               apic->timer.last_update = ktime_add_ns(
+                               apic->timer.last_update,
+                               apic->timer.period);
+}
+
 int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
 {
        int vector = kvm_apic_has_interrupt(vcpu);

diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index c8cd242f36ff6dca2ea0c29743615a0a9a53b8b7..00119ec4166985fe5447a47188c77592d9e74f35 100644 (file)
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1331,7 +1331,9 @@ static void svm_intr_assist(struct vcpu_svm *svm)
 {
        struct vmcb *vmcb = svm->vmcb;
        int intr_vector = -1;
+       struct kvm_vcpu *vcpu = &svm->vcpu;
 
+       kvm_inject_pending_timer_irqs(vcpu);
        if ((vmcb->control.exit_int_info & SVM_EVTINJ_VALID) &&
            ((vmcb->control.exit_int_info & SVM_EVTINJ_TYPE_MASK) == 0)) {
                intr_vector = vmcb->control.exit_int_info &
@@ -1344,7 +1346,7 @@ static void svm_intr_assist(struct vcpu_svm *svm)
        if (vmcb->control.int_ctl & V_IRQ_MASK)
                return;
 
-       if (!kvm_cpu_has_interrupt(&svm->vcpu))
+       if (!kvm_cpu_has_interrupt(vcpu))
                return;
 
        if (!(vmcb->save.rflags & X86_EFLAGS_IF) ||
@@ -1356,8 +1358,9 @@ static void svm_intr_assist(struct vcpu_svm *svm)
                return;
        }
        /* Okay, we can deliver the interrupt: grab it and update PIC state. */
-       intr_vector = kvm_cpu_get_interrupt(&svm->vcpu);
+       intr_vector = kvm_cpu_get_interrupt(vcpu);
        svm_inject_irq(svm, intr_vector);
+       kvm_timer_intr_post(vcpu, intr_vector);
 }
 
 static void kvm_reput_irq(struct vcpu_svm *svm)

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 5c2c6e71abf263746a80e454460839623b394f65..eeecadf5da4670b36a058973fe7defc89ba0a369 100644 (file)
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -2151,7 +2151,9 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
 {
        u32 idtv_info_field, intr_info_field;
        int has_ext_irq, interrupt_window_open;
+       int vector;
 
+       kvm_inject_pending_timer_irqs(vcpu);
        update_tpr_threshold(vcpu);
 
        has_ext_irq = kvm_cpu_has_interrupt(vcpu);
@@ -2183,9 +2185,11 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
        interrupt_window_open =
                ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
                 (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0);
-       if (interrupt_window_open)
-               vmx_inject_irq(vcpu, kvm_cpu_get_interrupt(vcpu));
-       else
+       if (interrupt_window_open) {
+               vector = kvm_cpu_get_interrupt(vcpu);
+               vmx_inject_irq(vcpu, vector);
+               kvm_timer_intr_post(vcpu, vector);
+       } else
                enable_irq_window(vcpu);
 }