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Commit 9269c393 authored by Antonios Motakis's avatar Antonios Motakis Committed by Alex Williamson
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vfio: add local lock for virqfd instead of depending on VFIO PCI 



The Virqfd code needs to keep accesses to any struct *virqfd safe, but
this comes into play only when creating or destroying eventfds, so sharing
the same spinlock with the VFIO bus driver is not necessary.

Signed-off-by: default avatarAntonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: default avatarBaptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: default avatarEric Auger <eric.auger@linaro.org>
Tested-by: default avatarEric Auger <eric.auger@linaro.org>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent bb78e9ea

drivers/vfio/pci/vfio_pci_intrs.c

+16 −15
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ struct virqfd { 
};



static struct workqueue_struct *vfio_irqfd_cleanup_wq;

DEFINE_SPINLOCK(virqfd_lock);



int __init vfio_virqfd_init(void)

{
@@ -80,21 +81,21 @@ static int virqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key) 


	if (flags & POLLHUP) {

		unsigned long flags;

		spin_lock_irqsave(&virqfd->vdev->irqlock, flags);

		spin_lock_irqsave(&virqfd_lock, flags);



		/*

		 * The eventfd is closing, if the virqfd has not yet been

		 * queued for release, as determined by testing whether the

		 * vdev pointer to it is still valid, queue it now.  As

		 * virqfd pointer to it is still valid, queue it now.  As

		 * with kvm irqfds, we know we won't race against the virqfd

		 * going away because we hold wqh->lock to get here.

		 * going away because we hold the lock to get here.

		 */

		if (*(virqfd->pvirqfd) == virqfd) {

			*(virqfd->pvirqfd) = NULL;

			virqfd_deactivate(virqfd);

		}



		spin_unlock_irqrestore(&virqfd->vdev->irqlock, flags);

		spin_unlock_irqrestore(&virqfd_lock, flags);

	}



	return 0;
@@ -170,16 +171,16 @@ int vfio_virqfd_enable(struct vfio_pci_device *vdev, 
	 * we update the pointer to the virqfd under lock to avoid

	 * pushing multiple jobs to release the same virqfd.

	 */

	spin_lock_irq(&vdev->irqlock);

	spin_lock_irq(&virqfd_lock);



	if (*pvirqfd) {

		spin_unlock_irq(&vdev->irqlock);

		spin_unlock_irq(&virqfd_lock);

		ret = -EBUSY;

		goto err_busy;

	}

	*pvirqfd = virqfd;



	spin_unlock_irq(&vdev->irqlock);

	spin_unlock_irq(&virqfd_lock);



	/*

	 * Install our own custom wake-up handling so we are notified via
@@ -217,18 +218,18 @@ int vfio_virqfd_enable(struct vfio_pci_device *vdev, 
}

EXPORT_SYMBOL_GPL(vfio_virqfd_enable);



void vfio_virqfd_disable(struct vfio_pci_device *vdev, struct virqfd **pvirqfd)

void vfio_virqfd_disable(struct virqfd **pvirqfd)

{

	unsigned long flags;



	spin_lock_irqsave(&vdev->irqlock, flags);

	spin_lock_irqsave(&virqfd_lock, flags);



	if (*pvirqfd) {

		virqfd_deactivate(*pvirqfd);

		*pvirqfd = NULL;

	}



	spin_unlock_irqrestore(&vdev->irqlock, flags);

	spin_unlock_irqrestore(&virqfd_lock, flags);



	/*

	 * Block until we know all outstanding shutdown jobs have completed.
@@ -441,8 +442,8 @@ static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd) 
static void vfio_intx_disable(struct vfio_pci_device *vdev)

{

	vfio_intx_set_signal(vdev, -1);

	vfio_virqfd_disable(vdev, &vdev->ctx[0].unmask);

	vfio_virqfd_disable(vdev, &vdev->ctx[0].mask);

	vfio_virqfd_disable(&vdev->ctx[0].unmask);

	vfio_virqfd_disable(&vdev->ctx[0].mask);

	vdev->irq_type = VFIO_PCI_NUM_IRQS;

	vdev->num_ctx = 0;

	kfree(vdev->ctx);
@@ -606,8 +607,8 @@ static void vfio_msi_disable(struct vfio_pci_device *vdev, bool msix) 
	vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);



	for (i = 0; i < vdev->num_ctx; i++) {

		vfio_virqfd_disable(vdev, &vdev->ctx[i].unmask);

		vfio_virqfd_disable(vdev, &vdev->ctx[i].mask);

		vfio_virqfd_disable(&vdev->ctx[i].unmask);

		vfio_virqfd_disable(&vdev->ctx[i].mask);

	}



	if (msix) {
@@ -645,7 +646,7 @@ static int vfio_pci_set_intx_unmask(struct vfio_pci_device *vdev, 
						  vfio_send_intx_eventfd, NULL,

						  &vdev->ctx[0].unmask, fd);



		vfio_virqfd_disable(vdev, &vdev->ctx[0].unmask);

		vfio_virqfd_disable(&vdev->ctx[0].unmask);

	}



	return 0;