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Commit cf9eeac4 authored by Jan Kiszka's avatar Jan Kiszka Committed by Avi Kivity
Browse files

KVM: Convert intx_mask_lock to spin lock 



As kvm_notify_acked_irq calls kvm_assigned_dev_ack_irq under
rcu_read_lock, we cannot use a mutex in the latter function. Switch to a
spin lock to address this.

Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 02626b6a

include/linux/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -556,7 +556,7 @@ struct kvm_assigned_dev_kernel { 
	struct pci_dev *dev;

	struct kvm *kvm;

	spinlock_t intx_lock;

	struct mutex intx_mask_lock;

	spinlock_t intx_mask_lock;

	char irq_name[32];

	struct pci_saved_state *pci_saved_state;

};

virt/kvm/assigned-dev.c

+7 −7
Original line number Diff line number Diff line
@@ -77,11 +77,11 @@ kvm_assigned_dev_raise_guest_irq(struct kvm_assigned_dev_kernel *assigned_dev, 
{

	if (unlikely(assigned_dev->irq_requested_type &

		     KVM_DEV_IRQ_GUEST_INTX)) {

		mutex_lock(&assigned_dev->intx_mask_lock);

		spin_lock(&assigned_dev->intx_mask_lock);

		if (!(assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX))

			kvm_set_irq(assigned_dev->kvm,

				    assigned_dev->irq_source_id, vector, 1);

		mutex_unlock(&assigned_dev->intx_mask_lock);

		spin_unlock(&assigned_dev->intx_mask_lock);

	} else

		kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,

			    vector, 1);
@@ -141,7 +141,7 @@ static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian) 


	kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0);



	mutex_lock(&dev->intx_mask_lock);

	spin_lock(&dev->intx_mask_lock);



	if (!(dev->flags & KVM_DEV_ASSIGN_MASK_INTX)) {

		bool reassert = false;
@@ -165,7 +165,7 @@ static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian) 
				    dev->guest_irq, 1);

	}



	mutex_unlock(&dev->intx_mask_lock);

	spin_unlock(&dev->intx_mask_lock);

}



static void deassign_guest_irq(struct kvm *kvm,
@@ -707,7 +707,7 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm, 
	match->flags = assigned_dev->flags;

	match->dev = dev;

	spin_lock_init(&match->intx_lock);

	mutex_init(&match->intx_mask_lock);

	spin_lock_init(&match->intx_mask_lock);

	match->irq_source_id = -1;

	match->kvm = kvm;

	match->ack_notifier.irq_acked = kvm_assigned_dev_ack_irq;
@@ -868,7 +868,7 @@ static int kvm_vm_ioctl_set_pci_irq_mask(struct kvm *kvm, 
		goto out;

	}



	mutex_lock(&match->intx_mask_lock);

	spin_lock(&match->intx_mask_lock);



	match->flags &= ~KVM_DEV_ASSIGN_MASK_INTX;

	match->flags |= assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX;
@@ -895,7 +895,7 @@ static int kvm_vm_ioctl_set_pci_irq_mask(struct kvm *kvm, 
		}

	}



	mutex_unlock(&match->intx_mask_lock);

	spin_unlock(&match->intx_mask_lock);



out:

	mutex_unlock(&kvm->lock);