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Commit 680b3648 authored by Gleb Natapov's avatar Gleb Natapov Committed by Avi Kivity
Browse files

KVM: Drop kvm->irq_lock lock from irq injection path 



The only thing it protects now is interrupt injection into lapic and
this can work lockless. Even now with kvm->irq_lock in place access
to lapic is not entirely serialized since vcpu access doesn't take
kvm->irq_lock.

Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent eba0226b

arch/ia64/kvm/kvm-ia64.c

+0 −2
Original line number Diff line number Diff line
@@ -982,10 +982,8 @@ long kvm_arch_vm_ioctl(struct file *filp, 
			goto out;

		if (irqchip_in_kernel(kvm)) {

			__s32 status;

			mutex_lock(&kvm->irq_lock);

			status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,

				    irq_event.irq, irq_event.level);

			mutex_unlock(&kvm->irq_lock);

			if (ioctl == KVM_IRQ_LINE_STATUS) {

				irq_event.status = status;

				if (copy_to_user(argp, &irq_event,

arch/x86/kvm/i8254.c

+0 −2
Original line number Diff line number Diff line
@@ -688,10 +688,8 @@ static void __inject_pit_timer_intr(struct kvm *kvm) 
	struct kvm_vcpu *vcpu;

	int i;



	mutex_lock(&kvm->irq_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->irq_lock);



	/*

	 * Provides NMI watchdog support via Virtual Wire mode.

arch/x86/kvm/lapic.c

+0 −2
Original line number Diff line number Diff line
@@ -501,9 +501,7 @@ static void apic_send_ipi(struct kvm_lapic *apic) 
		   irq.trig_mode, irq.level, irq.dest_mode, irq.delivery_mode,

		   irq.vector);



	mutex_lock(&apic->vcpu->kvm->irq_lock);

	kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq);

	mutex_unlock(&apic->vcpu->kvm->irq_lock);

}



static u32 apic_get_tmcct(struct kvm_lapic *apic)

arch/x86/kvm/x86.c

+0 −2
Original line number Diff line number Diff line
@@ -2286,10 +2286,8 @@ long kvm_arch_vm_ioctl(struct file *filp, 
			goto out;

		if (irqchip_in_kernel(kvm)) {

			__s32 status;

			mutex_lock(&kvm->irq_lock);

			status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,

					irq_event.irq, irq_event.level);

			mutex_unlock(&kvm->irq_lock);

			if (ioctl == KVM_IRQ_LINE_STATUS) {

				irq_event.status = status;

				if (copy_to_user(argp, &irq_event,

virt/kvm/eventfd.c

+0 −2
Original line number Diff line number Diff line
@@ -61,10 +61,8 @@ irqfd_inject(struct work_struct *work) 
	struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);

	struct kvm *kvm = irqfd->kvm;



	mutex_lock(&kvm->irq_lock);

	kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1);

	kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);

	mutex_unlock(&kvm->irq_lock);

}



/*