[08/11] Move IO APIC to its own lock.

Commit Message

Gleb Natapov July 16, 2009, 2:03 p.m. UTC

Introduce new function kvm_notifier_set_irq() that should be used
to change irq line level from irq notifiers. When irq notifier
change irq line level it calls into irq chip code recursively. The
function avoids taking a lock recursively.

Signed-off-by: Gleb Natapov <[e-mail]>
---
 arch/ia64/kvm/kvm-ia64.c        |   27 ++++++++++++++-----
 arch/x86/include/asm/kvm_host.h |    2 +-
 arch/x86/kvm/i8259.c            |    2 +-
 arch/x86/kvm/lapic.c            |    5 +---
 arch/x86/kvm/x86.c              |   30 ++++++++++++++-------
 include/linux/kvm_host.h        |    3 +-
 virt/kvm/ioapic.c               |   53 ++++++++++++++++++++++++--------------
 virt/kvm/ioapic.h               |    4 ++-
 virt/kvm/irq_comm.c             |   25 ++++++++++++++----
 virt/kvm/kvm_main.c             |    2 +-
 10 files changed, 101 insertions(+), 52 deletions(-)

Patch

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 0ad09f0..dd7ef2d 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -850,9 +850,16 @@  static int kvm_vm_ioctl_get_irqchip(struct kvm *kvm,
 
 	r = 0;
 	switch (chip->chip_id) {
-	case KVM_IRQCHIP_IOAPIC:
-		memcpy(&chip->chip.ioapic, ioapic_irqchip(kvm),
-				sizeof(struct kvm_ioapic_state));
+	case KVM_IRQCHIP_IOAPIC: {
+		struct kvm_ioapic *ioapic = ioapic_irqchip(kvm);
+		if (ioapic) {
+			spin_lock(&ioapic->lock);
+			memcpy(&chip->chip.ioapic, ioapic,
+			       sizeof(struct kvm_ioapic_state));
+			spin_unlock(&ioapic->lock);
+		} else
+			r = -EINVAL;
+	}
 		break;
 	default:
 		r = -EINVAL;
@@ -867,10 +874,16 @@  static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
 
 	r = 0;
 	switch (chip->chip_id) {
-	case KVM_IRQCHIP_IOAPIC:
-		memcpy(ioapic_irqchip(kvm),
-				&chip->chip.ioapic,
-				sizeof(struct kvm_ioapic_state));
+	case KVM_IRQCHIP_IOAPIC: {
+		struct kvm_ioapic *ioapic = ioapic_irqchip(kvm);
+		if (ioapic) {
+			spin_lock(&ioapic->lock);
+			memcpy(ioapic, &chip->chip.ioapic,
+			       sizeof(struct kvm_ioapic_state));
+			spin_unlock(&ioapic->lock);
+		} else
+			r = -EINVAL;
+	}
 		break;
 	default:
 		r = -EINVAL;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index eb723a7..cce2071 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -621,7 +621,7 @@  void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
 void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long cr2,
 			   u32 error_code);
 
-int kvm_pic_set_irq(void *opaque, int irq, int level);
+int kvm_pic_set_irq(void *opaque, int irq, int level, bool notifier);
 
 void kvm_inject_nmi(struct kvm_vcpu *vcpu);
 
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index daf4606..d9baad7 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -182,7 +182,7 @@  void kvm_pic_update_irq(struct kvm_pic *s)
 	pic_unlock(s);
 }
 
-int kvm_pic_set_irq(void *opaque, int irq, int level)
+int kvm_pic_set_irq(void *opaque, int irq, int level, bool notifier)
 {
 	struct kvm_pic *s = opaque;
 	int ret = -1;
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e2e2849..61ffcfc 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -471,11 +471,8 @@  static void apic_set_eoi(struct kvm_lapic *apic)
 		trigger_mode = IOAPIC_LEVEL_TRIG;
 	else
 		trigger_mode = IOAPIC_EDGE_TRIG;
-	if (!(apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_DIRECTED_EOI)) {
-		mutex_lock(&apic->vcpu->kvm->irq_lock);
+	if (!(apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_DIRECTED_EOI))
 		kvm_ioapic_update_eoi(apic->vcpu->kvm, vector, trigger_mode);
-		mutex_unlock(&apic->vcpu->kvm->irq_lock);
-	}
 }
 
 static void apic_send_ipi(struct kvm_lapic *apic)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 48567fa..de99b84 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2010,10 +2010,16 @@  static int kvm_vm_ioctl_get_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
 			&pic_irqchip(kvm)->pics[1],
 			sizeof(struct kvm_pic_state));
 		break;
-	case KVM_IRQCHIP_IOAPIC:
-		memcpy(&chip->chip.ioapic,
-			ioapic_irqchip(kvm),
-			sizeof(struct kvm_ioapic_state));
+	case KVM_IRQCHIP_IOAPIC: {
+		struct kvm_ioapic *ioapic = ioapic_irqchip(kvm);
+		if (ioapic) {
+			spin_lock(&ioapic->lock);
+			memcpy(&chip->chip.ioapic, ioapic,
+			       sizeof(struct kvm_ioapic_state));
+			spin_unlock(&ioapic->lock);
+		} else
+			r = -EINVAL;
+	}
 		break;
 	default:
 		r = -EINVAL;
@@ -2042,12 +2048,16 @@  static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
 			sizeof(struct kvm_pic_state));
 		spin_unlock(&pic_irqchip(kvm)->lock);
 		break;
-	case KVM_IRQCHIP_IOAPIC:
-		mutex_lock(&kvm->irq_lock);
-		memcpy(ioapic_irqchip(kvm),
-			&chip->chip.ioapic,
-			sizeof(struct kvm_ioapic_state));
-		mutex_unlock(&kvm->irq_lock);
+	case KVM_IRQCHIP_IOAPIC: {
+		struct kvm_ioapic *ioapic = ioapic_irqchip(kvm);
+		if (ioapic) {
+			spin_lock(&ioapic->lock);
+			memcpy(ioapic, &chip->chip.ioapic,
+			       sizeof(struct kvm_ioapic_state));
+			spin_unlock(&ioapic->lock);
+		} else
+			r = -EINVAL;
+	}
 		break;
 	default:
 		r = -EINVAL;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4eb5c85..c9824e0 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -120,7 +120,7 @@  struct kvm_memory_slot {
 struct kvm_kernel_irq_routing_entry {
 	u32 gsi;
 	int (*set)(struct kvm_kernel_irq_routing_entry *e,
-		    struct kvm *kvm, int level);
+		   struct kvm *kvm, int level, bool notifier);
 	union {
 		struct {
 			unsigned irqchip;
@@ -399,6 +399,7 @@  void kvm_get_intr_delivery_bitmask(struct kvm_ioapic *ioapic,
 				   unsigned long *deliver_bitmask);
 #endif
 int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level);
+int kvm_notifier_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level);
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian);
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index fa05f67..5a74649 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -175,13 +175,17 @@  static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
 	return kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe);
 }
 
-int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
+int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level,
+		       bool notifier)
 {
 	u32 old_irr = ioapic->irr;
 	u32 mask = 1 << irq;
 	union kvm_ioapic_redirect_entry entry;
 	int ret = 1;
 
+	/* notifier may call ioapic recursively */
+	if (!notifier)
+		spin_lock(&ioapic->lock);
 	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
 		entry = ioapic->redirtbl[irq];
 		level ^= entry.fields.polarity;
@@ -196,34 +200,42 @@  int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
 		}
 		trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
 	}
+	if (!notifier)
+		spin_unlock(&ioapic->lock);
+
 	return ret;
 }
 
-static void __kvm_ioapic_update_eoi(struct kvm_ioapic *ioapic, int pin,
-				    int trigger_mode)
+static void __kvm_ioapic_update_eoi(struct kvm_ioapic *ioapic, int vector,
+				     int trigger_mode)
 {
-	union kvm_ioapic_redirect_entry *ent;
+	int i;
+
+	for (i = 0; i < IOAPIC_NUM_PINS; i++) {
+		union kvm_ioapic_redirect_entry *ent = &ioapic->redirtbl[i];
+
+		if (ent->fields.vector != vector)
+			continue;
 
-	ent = &ioapic->redirtbl[pin];
+		kvm_notify_acked_irq(ioapic->kvm, KVM_IRQCHIP_IOAPIC, i);
 
-	kvm_notify_acked_irq(ioapic->kvm, KVM_IRQCHIP_IOAPIC, pin);
+		if (trigger_mode != IOAPIC_LEVEL_TRIG)
+			continue;
 
-	if (trigger_mode == IOAPIC_LEVEL_TRIG) {
 		ASSERT(ent->fields.trig_mode == IOAPIC_LEVEL_TRIG);
 		ent->fields.remote_irr = 0;
-		if (!ent->fields.mask && (ioapic->irr & (1 << pin)))
-			ioapic_service(ioapic, pin);
+		if (!ent->fields.mask && (ioapic->irr & (1 << i)))
+			ioapic_service(ioapic, i);
 	}
 }
 
 void kvm_ioapic_update_eoi(struct kvm *kvm, int vector, int trigger_mode)
 {
 	struct kvm_ioapic *ioapic = kvm->arch.vioapic;
-	int i;
 
-	for (i = 0; i < IOAPIC_NUM_PINS; i++)
-		if (ioapic->redirtbl[i].fields.vector == vector)
-			__kvm_ioapic_update_eoi(ioapic, i, trigger_mode);
+	spin_lock(&ioapic->lock);
+	__kvm_ioapic_update_eoi(ioapic, vector, trigger_mode);
+	spin_unlock(&ioapic->lock);
 }
 
 static inline struct kvm_ioapic *to_ioapic(struct kvm_io_device *dev)
@@ -248,8 +260,8 @@  static int ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
 	ioapic_debug("addr %lx\n", (unsigned long)addr);
 	ASSERT(!(addr & 0xf));	/* check alignment */
 
-	mutex_lock(&ioapic->kvm->irq_lock);
 	addr &= 0xff;
+	spin_lock(&ioapic->lock);
 	switch (addr) {
 	case IOAPIC_REG_SELECT:
 		result = ioapic->ioregsel;
@@ -263,6 +275,8 @@  static int ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
 		result = 0;
 		break;
 	}
+	spin_unlock(&ioapic->lock);
+
 	switch (len) {
 	case 8:
 		*(u64 *) val = result;
@@ -275,7 +289,6 @@  static int ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
 	default:
 		printk(KERN_WARNING "ioapic: wrong length %d\n", len);
 	}
-	mutex_unlock(&ioapic->kvm->irq_lock);
 	return 0;
 }
 
@@ -291,15 +304,15 @@  static int ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
 		     (void*)addr, len, val);
 	ASSERT(!(addr & 0xf));	/* check alignment */
 
-	mutex_lock(&ioapic->kvm->irq_lock);
 	if (len == 4 || len == 8)
 		data = *(u32 *) val;
 	else {
 		printk(KERN_WARNING "ioapic: Unsupported size %d\n", len);
-		goto unlock;
+		return 0;
 	}
 
 	addr &= 0xff;
+	spin_lock(&ioapic->lock);
 	switch (addr) {
 	case IOAPIC_REG_SELECT:
 		ioapic->ioregsel = data;
@@ -310,15 +323,14 @@  static int ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
 		break;
 #ifdef	CONFIG_IA64
 	case IOAPIC_REG_EOI:
-		kvm_ioapic_update_eoi(ioapic->kvm, data, IOAPIC_LEVEL_TRIG);
+		__kvm_ioapic_update_eoi(ioapic, data, IOAPIC_LEVEL_TRIG);
 		break;
 #endif
 
 	default:
 		break;
 	}
-unlock:
-	mutex_unlock(&ioapic->kvm->irq_lock);
+	spin_unlock(&ioapic->lock);
 	return 0;
 }
 
@@ -347,6 +359,7 @@  int kvm_ioapic_init(struct kvm *kvm)
 	ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL);
 	if (!ioapic)
 		return -ENOMEM;
+	spin_lock_init(&ioapic->lock);
 	kvm->arch.vioapic = ioapic;
 	kvm_ioapic_reset(ioapic);
 	kvm_iodevice_init(&ioapic->dev, &ioapic_mmio_ops);
diff --git a/virt/kvm/ioapic.h b/virt/kvm/ioapic.h
index 7080b71..2cfa662 100644
--- a/virt/kvm/ioapic.h
+++ b/virt/kvm/ioapic.h
@@ -44,6 +44,7 @@  struct kvm_ioapic {
 	struct kvm_io_device dev;
 	struct kvm *kvm;
 	void (*ack_notifier)(void *opaque, int irq);
+	spinlock_t lock;
 };
 
 #ifdef DEBUG
@@ -69,7 +70,8 @@  int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
 int kvm_apic_compare_prio(struct kvm_vcpu *vcpu1, struct kvm_vcpu *vcpu2);
 void kvm_ioapic_update_eoi(struct kvm *kvm, int vector, int trigger_mode);
 int kvm_ioapic_init(struct kvm *kvm);
-int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level);
+int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level,
+		       bool notifier);
 void kvm_ioapic_reset(struct kvm_ioapic *ioapic);
 int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 		struct kvm_lapic_irq *irq);
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 59c1cde..7a2b9db 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -32,19 +32,21 @@ 
 #include "ioapic.h"
 
 static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
-			   struct kvm *kvm, int level)
+			   struct kvm *kvm, int level, bool notifier)
 {
 #ifdef CONFIG_X86
-	return kvm_pic_set_irq(pic_irqchip(kvm), e->irqchip.pin, level);
+	return kvm_pic_set_irq(pic_irqchip(kvm), e->irqchip.pin, level,
+			       notifier);
 #else
 	return -1;
 #endif
 }
 
 static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
-			      struct kvm *kvm, int level)
+			      struct kvm *kvm, int level, bool notifier)
 {
-	return kvm_ioapic_set_irq(kvm->arch.vioapic, e->irqchip.pin, level);
+	return kvm_ioapic_set_irq(kvm->arch.vioapic, e->irqchip.pin, level,
+		notifier);
 }
 
 inline static bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
@@ -122,7 +124,8 @@  static int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
  *  = 0   Interrupt was coalesced (previous irq is still pending)
  *  > 0   Number of CPUs interrupt was delivered to
  */
-int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
+static int __kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level,
+	bool notifier)
 {
 	struct kvm_kernel_irq_routing_entry *e;
 	unsigned long *irq_state, sig_level;
@@ -153,7 +156,7 @@  int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
 	rcu_read_lock();
 	for (e = rcu_dereference(kvm->irq_routing); e && e->set; e++) {
 		if (e->gsi == irq) {
-			int r = e->set(e, kvm, sig_level);
+			int r = e->set(e, kvm, sig_level, notifier);
 			if (r < 0)
 				continue;
 
@@ -164,6 +167,16 @@  int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
 	return ret;
 }
 
+int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
+{
+	return __kvm_set_irq(kvm, irq_source_id, irq, level, 0);
+}
+
+int kvm_notifier_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
+{
+	return __kvm_set_irq(kvm, irq_source_id, irq, level, 1);
+}
+
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 {
 	struct kvm_kernel_irq_routing_entry *e;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 9553444..d2f2fa5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -198,7 +198,7 @@  static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)
 	dev = container_of(kian, struct kvm_assigned_dev_kernel,
 			   ack_notifier);
 
-	kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0);
+	kvm_notifier_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0);
 
 	/* The guest irq may be shared so this ack may be
 	 * from another device.