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Commit 27ebe308 authored by Anthony Liguori's avatar Anthony Liguori Committed by Rusty Russell
Browse files

virtio: Use spin_lock_irqsave/restore for virtio-pci 



virtio-pci acquires its spin lock in an interrupt context so it's necessary
to use spin_lock_irqsave/restore variants.  This patch fixes guest SMP when
using virtio devices in KVM.

Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent a978b30a

drivers/virtio/virtio_pci.c

+9 −6
Original line number Diff line number Diff line
@@ -177,6 +177,7 @@ static irqreturn_t vp_interrupt(int irq, void *opaque) 
	struct virtio_pci_device *vp_dev = opaque;

	struct virtio_pci_vq_info *info;

	irqreturn_t ret = IRQ_NONE;

	unsigned long flags;

	u8 isr;



	/* reading the ISR has the effect of also clearing it so it's very
@@ -197,12 +198,12 @@ static irqreturn_t vp_interrupt(int irq, void *opaque) 
			drv->config_changed(&vp_dev->vdev);

	}



	spin_lock(&vp_dev->lock);

	spin_lock_irqsave(&vp_dev->lock, flags);

	list_for_each_entry(info, &vp_dev->virtqueues, node) {

		if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)

			ret = IRQ_HANDLED;

	}

	spin_unlock(&vp_dev->lock);

	spin_unlock_irqrestore(&vp_dev->lock, flags);



	return ret;

}
@@ -214,6 +215,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, 
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	struct virtio_pci_vq_info *info;

	struct virtqueue *vq;

	unsigned long flags;

	u16 num;

	int err;
@@ -255,9 +257,9 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, 
	vq->priv = info;

	info->vq = vq;



	spin_lock(&vp_dev->lock);

	spin_lock_irqsave(&vp_dev->lock, flags);

	list_add(&info->node, &vp_dev->virtqueues);

	spin_unlock(&vp_dev->lock);

	spin_unlock_irqrestore(&vp_dev->lock, flags);



	return vq;
@@ -274,10 +276,11 @@ static void vp_del_vq(struct virtqueue *vq) 
{

	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);

	struct virtio_pci_vq_info *info = vq->priv;

	unsigned long flags;



	spin_lock(&vp_dev->lock);

	spin_lock_irqsave(&vp_dev->lock, flags);

	list_del(&info->node);

	spin_unlock(&vp_dev->lock);

	spin_unlock_irqrestore(&vp_dev->lock, flags);



	vring_del_virtqueue(vq);