diff options
| -rw-r--r-- | drivers/vfio/pci/vfio_pci_intrs.c | 47 |
1 files changed, 41 insertions, 6 deletions
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index 867327e159c1..cbb4bcbfbf83 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -381,27 +381,55 @@ static int vfio_msi_enable(struct vfio_pci_core_device *vdev, int nvec, bool msi return 0; } +/* + * vfio_msi_alloc_irq() returns the Linux IRQ number of an MSI or MSI-X device + * interrupt vector. If a Linux IRQ number is not available then a new + * interrupt is allocated if dynamic MSI-X is supported. + * + * Where is vfio_msi_free_irq()? Allocated interrupts are maintained, + * essentially forming a cache that subsequent allocations can draw from. + * Interrupts are freed using pci_free_irq_vectors() when MSI/MSI-X is + * disabled. + */ +static int vfio_msi_alloc_irq(struct vfio_pci_core_device *vdev, + unsigned int vector, bool msix) +{ + struct pci_dev *pdev = vdev->pdev; + struct msi_map map; + int irq; + u16 cmd; + + irq = pci_irq_vector(pdev, vector); + if (WARN_ON_ONCE(irq == 0)) + return -EINVAL; + if (irq > 0 || !msix || !vdev->has_dyn_msix) + return irq; + + cmd = vfio_pci_memory_lock_and_enable(vdev); + map = pci_msix_alloc_irq_at(pdev, vector, NULL); + vfio_pci_memory_unlock_and_restore(vdev, cmd); + + return map.index < 0 ? map.index : map.virq; +} + static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev, unsigned int vector, int fd, bool msix) { struct pci_dev *pdev = vdev->pdev; struct vfio_pci_irq_ctx *ctx; struct eventfd_ctx *trigger; - int irq, ret; + int irq = -EINVAL, ret; u16 cmd; - irq = pci_irq_vector(pdev, vector); - if (irq < 0) - return -EINVAL; - ctx = vfio_irq_ctx_get(vdev, vector); if (ctx) { irq_bypass_unregister_producer(&ctx->producer); - + irq = pci_irq_vector(pdev, vector); cmd = vfio_pci_memory_lock_and_enable(vdev); free_irq(irq, ctx->trigger); vfio_pci_memory_unlock_and_restore(vdev, cmd); + /* Interrupt stays allocated, will be freed at MSI-X disable. */ kfree(ctx->name); eventfd_ctx_put(ctx->trigger); vfio_irq_ctx_free(vdev, ctx, vector); @@ -410,6 +438,13 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev, if (fd < 0) return 0; + if (irq == -EINVAL) { + /* Interrupt stays allocated, will be freed at MSI-X disable. */ + irq = vfio_msi_alloc_irq(vdev, vector, msix); + if (irq < 0) + return irq; + } + ctx = vfio_irq_ctx_alloc(vdev, vector); if (!ctx) return -ENOMEM; |