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Commit fa40a821 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
Browse files

KVM: switch irq injection/acking data structures to irq_lock 



Protect irq injection/acking data structures with a separate irq_lock
mutex. This fixes the following deadlock:

CPU A                               CPU B
kvm_vm_ioctl_deassign_dev_irq()
  mutex_lock(&kvm->lock);            worker_thread()
  -> kvm_deassign_irq()                -> kvm_assigned_dev_interrupt_work_handler()
    -> deassign_host_irq()               mutex_lock(&kvm->lock);
      -> cancel_work_sync() [blocked]

[gleb: fix ia64 path]

Reported-by: default avatarAlex Williamson <alex.williamson@hp.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 60eead79

arch/ia64/kvm/kvm-ia64.c

+2 −2
Original line number Diff line number Diff line
@@ -1000,10 +1000,10 @@ long kvm_arch_vm_ioctl(struct file *filp, 
			goto out;

		if (irqchip_in_kernel(kvm)) {

			__s32 status;

			mutex_lock(&kvm->lock);

			mutex_lock(&kvm->irq_lock);

			status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,

				    irq_event.irq, irq_event.level);

			mutex_unlock(&kvm->lock);

			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

+2 −2
Original line number Diff line number Diff line
@@ -654,10 +654,10 @@ static void __inject_pit_timer_intr(struct kvm *kvm) 
	struct kvm_vcpu *vcpu;

	int i;



	mutex_lock(&kvm->lock);

	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->lock);

	mutex_unlock(&kvm->irq_lock);



	/*

	 * Provides NMI watchdog support via Virtual Wire mode.

arch/x86/kvm/lapic.c

+4 −0
Original line number Diff line number Diff line
@@ -424,7 +424,9 @@ static void apic_set_eoi(struct kvm_lapic *apic) 
		trigger_mode = IOAPIC_LEVEL_TRIG;

	else

		trigger_mode = IOAPIC_EDGE_TRIG;

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

	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)
@@ -448,7 +450,9 @@ 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

+9 −10
Original line number Diff line number Diff line
@@ -2136,10 +2136,10 @@ long kvm_arch_vm_ioctl(struct file *filp, 
			goto out;

		if (irqchip_in_kernel(kvm)) {

			__s32 status;

			mutex_lock(&kvm->lock);

			mutex_lock(&kvm->irq_lock);

			status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,

					irq_event.irq, irq_event.level);

			mutex_unlock(&kvm->lock);

			mutex_unlock(&kvm->irq_lock);

			if (ioctl == KVM_IRQ_LINE_STATUS) {

				irq_event.status = status;

				if (copy_to_user(argp, &irq_event,
@@ -2385,12 +2385,11 @@ static int emulator_read_emulated(unsigned long addr, 
	 */

	mutex_lock(&vcpu->kvm->lock);

	mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 0);

	mutex_unlock(&vcpu->kvm->lock);

	if (mmio_dev) {

		kvm_iodevice_read(mmio_dev, gpa, bytes, val);

		mutex_unlock(&vcpu->kvm->lock);

		return X86EMUL_CONTINUE;

	}

	mutex_unlock(&vcpu->kvm->lock);



	vcpu->mmio_needed = 1;

	vcpu->mmio_phys_addr = gpa;
@@ -2440,12 +2439,11 @@ static int emulator_write_emulated_onepage(unsigned long addr, 
	 */

	mutex_lock(&vcpu->kvm->lock);

	mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 1);

	mutex_unlock(&vcpu->kvm->lock);

	if (mmio_dev) {

		kvm_iodevice_write(mmio_dev, gpa, bytes, val);

		mutex_unlock(&vcpu->kvm->lock);

		return X86EMUL_CONTINUE;

	}

	mutex_unlock(&vcpu->kvm->lock);



	vcpu->mmio_needed = 1;

	vcpu->mmio_phys_addr = gpa;
@@ -2768,7 +2766,6 @@ static void kernel_pio(struct kvm_io_device *pio_dev, 
{

	/* TODO: String I/O for in kernel device */



	mutex_lock(&vcpu->kvm->lock);

	if (vcpu->arch.pio.in)

		kvm_iodevice_read(pio_dev, vcpu->arch.pio.port,

				  vcpu->arch.pio.size,
@@ -2777,7 +2774,6 @@ static void kernel_pio(struct kvm_io_device *pio_dev, 
		kvm_iodevice_write(pio_dev, vcpu->arch.pio.port,

				   vcpu->arch.pio.size,

				   pd);

	mutex_unlock(&vcpu->kvm->lock);

}



static void pio_string_write(struct kvm_io_device *pio_dev,
@@ -2787,14 +2783,12 @@ static void pio_string_write(struct kvm_io_device *pio_dev, 
	void *pd = vcpu->arch.pio_data;

	int i;



	mutex_lock(&vcpu->kvm->lock);

	for (i = 0; i < io->cur_count; i++) {

		kvm_iodevice_write(pio_dev, io->port,

				   io->size,

				   pd);

		pd += io->size;

	}

	mutex_unlock(&vcpu->kvm->lock);

}



static struct kvm_io_device *vcpu_find_pio_dev(struct kvm_vcpu *vcpu,
@@ -2831,7 +2825,9 @@ int kvm_emulate_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, 
	val = kvm_register_read(vcpu, VCPU_REGS_RAX);

	memcpy(vcpu->arch.pio_data, &val, 4);



	mutex_lock(&vcpu->kvm->lock);

	pio_dev = vcpu_find_pio_dev(vcpu, port, size, !in);

	mutex_unlock(&vcpu->kvm->lock);

	if (pio_dev) {

		kernel_pio(pio_dev, vcpu, vcpu->arch.pio_data);

		complete_pio(vcpu);
@@ -2895,9 +2891,12 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, 


	vcpu->arch.pio.guest_gva = address;



	mutex_lock(&vcpu->kvm->lock);

	pio_dev = vcpu_find_pio_dev(vcpu, port,

				    vcpu->arch.pio.cur_count,

				    !vcpu->arch.pio.in);

	mutex_unlock(&vcpu->kvm->lock);



	if (!vcpu->arch.pio.in) {

		/* string PIO write */

		ret = pio_copy_data(vcpu);

include/linux/kvm_host.h

+2 −1
Original line number Diff line number Diff line
@@ -371,7 +371,8 @@ int kvm_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);

void kvm_unregister_irq_ack_notifier(struct kvm_irq_ack_notifier *kian);

void kvm_unregister_irq_ack_notifier(struct kvm *kvm,

				   struct kvm_irq_ack_notifier *kian);

int kvm_request_irq_source_id(struct kvm *kvm);

void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id);