From 9269c393e7a971f98c0f54d7fc350ac7636d1fa5 Mon Sep 17 00:00:00 2001 From: Antonios Motakis Date: Mon, 16 Mar 2015 14:08:52 -0600 Subject: [PATCH] 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: Antonios Motakis Signed-off-by: Baptiste Reynal Reviewed-by: Eric Auger Tested-by: Eric Auger Signed-off-by: Alex Williamson --- drivers/vfio/pci/vfio_pci_intrs.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index fa033c32e3d8..de069796b2fd 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -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;