KVM: avoid taking ioapic mutex for non-ioapic EOIs

Commit Message

Avi Kivity Dec. 28, 2009, 12:08 p.m. UTC

None

Patch

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index f01392f..a2edfd1 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -100,6 +100,19 @@  static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
 	return injected;
 }
 
+static void update_handled_vectors(struct kvm_ioapic *ioapic)
+{
+	DECLARE_BITMAP(handled_vectors, 256);
+	int i;
+
+	memset(handled_vectors, 0, sizeof(handled_vectors));
+	for (i = 0; i < IOAPIC_NUM_PINS; ++i)
+		__set_bit(ioapic->redirtbl[i].fields.vector, handled_vectors);
+	memcpy(ioapic->handled_vectors, handled_vectors,
+	       sizeof(handled_vectors));
+	smp_wmb();
+}
+
 static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 {
 	unsigned index;
@@ -134,6 +147,7 @@  static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
 			e->bits |= (u32) val;
 			e->fields.remote_irr = 0;
 		}
+		update_handled_vectors(ioapic);
 		mask_after = e->fields.mask;
 		if (mask_before != mask_after)
 			kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after);
@@ -241,6 +255,9 @@  void kvm_ioapic_update_eoi(struct kvm *kvm, int vector, int trigger_mode)
 {
 	struct kvm_ioapic *ioapic = kvm->arch.vioapic;
 
+	smp_rmb();
+	if (!test_bit(vector, ioapic->handled_vectors))
+		return;
 	mutex_lock(&ioapic->lock);
 	__kvm_ioapic_update_eoi(ioapic, vector, trigger_mode);
 	mutex_unlock(&ioapic->lock);
@@ -352,6 +369,7 @@  void kvm_ioapic_reset(struct kvm_ioapic *ioapic)
 	ioapic->ioregsel = 0;
 	ioapic->irr = 0;
 	ioapic->id = 0;
+	update_handled_vectors(ioapic);
 }
 
 static const struct kvm_io_device_ops ioapic_mmio_ops = {
@@ -401,6 +419,7 @@  int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state)
 
 	mutex_lock(&ioapic->lock);
 	memcpy(ioapic, state, sizeof(struct kvm_ioapic_state));
+	update_handled_vectors(ioapic);
 	mutex_unlock(&ioapic->lock);
 	return 0;
 }
diff --git a/virt/kvm/ioapic.h b/virt/kvm/ioapic.h
index 419c43b..a505ce9 100644
--- a/virt/kvm/ioapic.h
+++ b/virt/kvm/ioapic.h
@@ -46,6 +46,7 @@  struct kvm_ioapic {
 	struct kvm *kvm;
 	void (*ack_notifier)(void *opaque, int irq);
 	struct mutex lock;
+	DECLARE_BITMAP(handled_vectors, 256);
 };
 
 #ifdef DEBUG