3 files changed, 45 insertions, 5 deletions

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 59ebd37ad79e..580cc1d01c7d 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -603,10 +603,25 @@ void kvm_free_pit(struct kvm *kvm)
 
 static void __inject_pit_timer_intr(struct kvm *kvm)
 {
+        struct kvm_vcpu *vcpu;
+        int i;
+
         mutex_lock(&kvm->lock);
         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
         mutex_unlock(&kvm->lock);
+
+        /*
+         * Provides NMI watchdog support in IOAPIC mode.
+         * The route is: PIT -> PIC -> LVT0 in NMI mode,
+         * timer IRQs will continue to flow through the IOAPIC.
+         */
+        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+                vcpu = kvm->vcpus[i];
+                if (!vcpu)
+                        continue;
+                kvm_apic_local_deliver(vcpu, APIC_LVT0);
+        }
 }
 
 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h
index f17c8f5bbf31..71e37a530cf7 100644
--- a/arch/x86/kvm/irq.h
+++ b/arch/x86/kvm/irq.h
@@ -87,6 +87,7 @@ void kvm_pic_reset(struct kvm_kpic_state *s);
 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);
+int kvm_apic_local_deliver(struct kvm_vcpu *vcpu, int lvt_type);
 void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu);
 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu);
 void __kvm_migrate_timers(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 0fc3cab48943..206cc11a1c97 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -380,6 +380,14 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
                 }
                 break;
 
+        case APIC_DM_EXTINT:
+                /*
+                 * Should only be called by kvm_apic_local_deliver() with LVT0,
+                 * before NMI watchdog was enabled. Already handled by
+                 * kvm_apic_accept_pic_intr().
+                 */
+                break;
+
         default:
                 printk(KERN_ERR "TODO: unsupported delivery mode %x\n",
                        delivery_mode);
@@ -743,10 +751,13 @@ static void apic_mmio_write(struct kvm_io_device *this,
                 apic_set_reg(apic, APIC_ICR2, val & 0xff000000);
                 break;
 
+        case APIC_LVT0:
+                if (val == APIC_DM_NMI)
+                        apic_debug("Receive NMI setting on APIC_LVT0 "
+                                "for cpu %d\n", apic->vcpu->vcpu_id);
         case APIC_LVTT:
         case APIC_LVTTHMR:
         case APIC_LVTPC:
-        case APIC_LVT0:
         case APIC_LVT1:
         case APIC_LVTERR:
                 /* TODO: Check vector */
@@ -961,12 +972,25 @@ int apic_has_pending_timer(struct kvm_vcpu *vcpu)
         return 0;
 }
 
-static int __inject_apic_timer_irq(struct kvm_lapic *apic)
+int kvm_apic_local_deliver(struct kvm_vcpu *vcpu, int lvt_type)
 {
-        int vector;
+        struct kvm_lapic *apic = vcpu->arch.apic;
+        int vector, mode, trig_mode;
+        u32 reg;
+
+        if (apic && apic_enabled(apic)) {
+                reg = apic_get_reg(apic, lvt_type);
+                vector = reg & APIC_VECTOR_MASK;
+                mode = reg & APIC_MODE_MASK;
+                trig_mode = reg & APIC_LVT_LEVEL_TRIGGER;
+                return __apic_accept_irq(apic, mode, vector, 1, trig_mode);
+        }
+        return 0;
+}
 
-        vector = apic_lvt_vector(apic, APIC_LVTT);
-        return __apic_accept_irq(apic, APIC_DM_FIXED, vector, 1, 0);
+static inline int __inject_apic_timer_irq(struct kvm_lapic *apic)
+{
+        return kvm_apic_local_deliver(apic->vcpu, APIC_LVTT);
 }
 
 static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)