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vfio: add local lock for virqfd instead of depending on VFIO PCI

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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: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Antonios Motakis 2015-03-16 14:08:52 -06:00 committed by Alex Williamson
parent bb78e9eaab
commit 9269c393e7
1 changed files with 16 additions and 15 deletions
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31
drivers/vfio/pci/vfio_pci_intrs.c
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@ -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 @@ err_fd:
}
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;