diff options
| -rw-r--r-- | drivers/vfio/pci/vfio_pci_intrs.c | 145 |
1 files changed, 78 insertions, 67 deletions
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index 75c85eec21b3..fb5392b749ff 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -90,11 +90,15 @@ static void vfio_send_intx_eventfd(void *opaque, void *unused) if (likely(is_intx(vdev) && !vdev->virq_disabled)) { struct vfio_pci_irq_ctx *ctx; + struct eventfd_ctx *trigger; ctx = vfio_irq_ctx_get(vdev, 0); if (WARN_ON_ONCE(!ctx)) return; - eventfd_signal(ctx->trigger); + + trigger = READ_ONCE(ctx->trigger); + if (likely(trigger)) + eventfd_signal(trigger); } } @@ -253,100 +257,100 @@ static irqreturn_t vfio_intx_handler(int irq, void *dev_id) return ret; } -static int vfio_intx_enable(struct vfio_pci_core_device *vdev) +static int vfio_intx_enable(struct vfio_pci_core_device *vdev, + struct eventfd_ctx *trigger) { + struct pci_dev *pdev = vdev->pdev; struct vfio_pci_irq_ctx *ctx; + unsigned long irqflags; + char *name; + int ret; if (!is_irq_none(vdev)) return -EINVAL; - if (!vdev->pdev->irq) + if (!pdev->irq) return -ENODEV; + name = kasprintf(GFP_KERNEL_ACCOUNT, "vfio-intx(%s)", pci_name(pdev)); + if (!name) + return -ENOMEM; + ctx = vfio_irq_ctx_alloc(vdev, 0); if (!ctx) return -ENOMEM; + ctx->name = name; + ctx->trigger = trigger; + /* - * If the virtual interrupt is masked, restore it. Devices - * supporting DisINTx can be masked at the hardware level - * here, non-PCI-2.3 devices will have to wait until the - * interrupt is enabled. + * Fill the initial masked state based on virq_disabled. After + * enable, changing the DisINTx bit in vconfig directly changes INTx + * masking. igate prevents races during setup, once running masked + * is protected via irqlock. + * + * Devices supporting DisINTx also reflect the current mask state in + * the physical DisINTx bit, which is not affected during IRQ setup. + * + * Devices without DisINTx support require an exclusive interrupt. + * IRQ masking is performed at the IRQ chip. Again, igate protects + * against races during setup and IRQ handlers and irqfds are not + * yet active, therefore masked is stable and can be used to + * conditionally auto-enable the IRQ. + * + * irq_type must be stable while the IRQ handler is registered, + * therefore it must be set before request_irq(). */ ctx->masked = vdev->virq_disabled; - if (vdev->pci_2_3) - pci_intx(vdev->pdev, !ctx->masked); + if (vdev->pci_2_3) { + pci_intx(pdev, !ctx->masked); + irqflags = IRQF_SHARED; + } else { + irqflags = ctx->masked ? IRQF_NO_AUTOEN : 0; + } vdev->irq_type = VFIO_PCI_INTX_IRQ_INDEX; + ret = request_irq(pdev->irq, vfio_intx_handler, + irqflags, ctx->name, vdev); + if (ret) { + vdev->irq_type = VFIO_PCI_NUM_IRQS; + kfree(name); + vfio_irq_ctx_free(vdev, ctx, 0); + return ret; + } + return 0; } -static int vfio_intx_set_signal(struct vfio_pci_core_device *vdev, int fd) +static int vfio_intx_set_signal(struct vfio_pci_core_device *vdev, + struct eventfd_ctx *trigger) { struct pci_dev *pdev = vdev->pdev; - unsigned long irqflags = IRQF_SHARED; struct vfio_pci_irq_ctx *ctx; - struct eventfd_ctx *trigger; - unsigned long flags; - int ret; + struct eventfd_ctx *old; ctx = vfio_irq_ctx_get(vdev, 0); if (WARN_ON_ONCE(!ctx)) return -EINVAL; - if (ctx->trigger) { - free_irq(pdev->irq, vdev); - kfree(ctx->name); - eventfd_ctx_put(ctx->trigger); - ctx->trigger = NULL; - } - - if (fd < 0) /* Disable only */ - return 0; - - ctx->name = kasprintf(GFP_KERNEL_ACCOUNT, "vfio-intx(%s)", - pci_name(pdev)); - if (!ctx->name) - return -ENOMEM; - - trigger = eventfd_ctx_fdget(fd); - if (IS_ERR(trigger)) { - kfree(ctx->name); - return PTR_ERR(trigger); - } + old = ctx->trigger; - ctx->trigger = trigger; + WRITE_ONCE(ctx->trigger, trigger); - /* - * Devices without DisINTx support require an exclusive interrupt, - * IRQ masking is performed at the IRQ chip. The masked status is - * protected by vdev->irqlock. Setup the IRQ without auto-enable and - * unmask as necessary below under lock. DisINTx is unmodified by - * the IRQ configuration and may therefore use auto-enable. - */ - if (!vdev->pci_2_3) - irqflags = IRQF_NO_AUTOEN; - - ret = request_irq(pdev->irq, vfio_intx_handler, - irqflags, ctx->name, vdev); - if (ret) { - ctx->trigger = NULL; - kfree(ctx->name); - eventfd_ctx_put(trigger); - return ret; + /* Releasing an old ctx requires synchronizing in-flight users */ + if (old) { + synchronize_irq(pdev->irq); + vfio_virqfd_flush_thread(&ctx->unmask); + eventfd_ctx_put(old); } - spin_lock_irqsave(&vdev->irqlock, flags); - if (!vdev->pci_2_3 && !ctx->masked) - enable_irq(pdev->irq); - spin_unlock_irqrestore(&vdev->irqlock, flags); - return 0; } static void vfio_intx_disable(struct vfio_pci_core_device *vdev) { + struct pci_dev *pdev = vdev->pdev; struct vfio_pci_irq_ctx *ctx; ctx = vfio_irq_ctx_get(vdev, 0); @@ -354,10 +358,13 @@ static void vfio_intx_disable(struct vfio_pci_core_device *vdev) if (ctx) { vfio_virqfd_disable(&ctx->unmask); vfio_virqfd_disable(&ctx->mask); + free_irq(pdev->irq, vdev); + if (ctx->trigger) + eventfd_ctx_put(ctx->trigger); + kfree(ctx->name); + vfio_irq_ctx_free(vdev, ctx, 0); } - vfio_intx_set_signal(vdev, -1); vdev->irq_type = VFIO_PCI_NUM_IRQS; - vfio_irq_ctx_free(vdev, ctx, 0); } /* @@ -641,19 +648,23 @@ static int vfio_pci_set_intx_trigger(struct vfio_pci_core_device *vdev, return -EINVAL; if (flags & VFIO_IRQ_SET_DATA_EVENTFD) { + struct eventfd_ctx *trigger = NULL; int32_t fd = *(int32_t *)data; int ret; - if (is_intx(vdev)) - return vfio_intx_set_signal(vdev, fd); + if (fd >= 0) { + trigger = eventfd_ctx_fdget(fd); + if (IS_ERR(trigger)) + return PTR_ERR(trigger); + } - ret = vfio_intx_enable(vdev); - if (ret) - return ret; + if (is_intx(vdev)) + ret = vfio_intx_set_signal(vdev, trigger); + else + ret = vfio_intx_enable(vdev, trigger); - ret = vfio_intx_set_signal(vdev, fd); - if (ret) - vfio_intx_disable(vdev); + if (ret && trigger) + eventfd_ctx_put(trigger); return ret; } |