From 57f972e2b341dd6a73533f9293ec55d584a5d833 Mon Sep 17 00:00:00 2001 From: Antonios Motakis Date: Mon, 16 Mar 2015 14:08:50 -0600 Subject: [PATCH] vfio/platform: trigger an interrupt via eventfd This patch allows to set an eventfd for a platform device's interrupt, and also to trigger the interrupt eventfd from userspace for testing. Level sensitive interrupts are marked as maskable and are handled in a later patch. Edge triggered interrupts are not advertised as maskable and are implemented here using a simple and efficient IRQ handler. Signed-off-by: Antonios Motakis [Baptiste Reynal: fix masked interrupt initialization] Signed-off-by: Baptiste Reynal Reviewed-by: Eric Auger Tested-by: Eric Auger Signed-off-by: Alex Williamson --- drivers/vfio/platform/vfio_platform_irq.c | 94 ++++++++++++++++++- drivers/vfio/platform/vfio_platform_private.h | 2 + 2 files changed, 94 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c index df5c91936a68..611ec80db63a 100644 --- a/drivers/vfio/platform/vfio_platform_irq.c +++ b/drivers/vfio/platform/vfio_platform_irq.c @@ -39,12 +39,92 @@ static int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev, return -EINVAL; } +static irqreturn_t vfio_irq_handler(int irq, void *dev_id) +{ + struct vfio_platform_irq *irq_ctx = dev_id; + + eventfd_signal(irq_ctx->trigger, 1); + + return IRQ_HANDLED; +} + +static int vfio_set_trigger(struct vfio_platform_device *vdev, int index, + int fd, irq_handler_t handler) +{ + struct vfio_platform_irq *irq = &vdev->irqs[index]; + struct eventfd_ctx *trigger; + int ret; + + if (irq->trigger) { + free_irq(irq->hwirq, irq); + kfree(irq->name); + eventfd_ctx_put(irq->trigger); + irq->trigger = NULL; + } + + if (fd < 0) /* Disable only */ + return 0; + + irq->name = kasprintf(GFP_KERNEL, "vfio-irq[%d](%s)", + irq->hwirq, vdev->name); + if (!irq->name) + return -ENOMEM; + + trigger = eventfd_ctx_fdget(fd); + if (IS_ERR(trigger)) { + kfree(irq->name); + return PTR_ERR(trigger); + } + + irq->trigger = trigger; + + ret = request_irq(irq->hwirq, handler, 0, irq->name, irq); + if (ret) { + kfree(irq->name); + eventfd_ctx_put(trigger); + irq->trigger = NULL; + return ret; + } + + return 0; +} + static int vfio_platform_set_irq_trigger(struct vfio_platform_device *vdev, unsigned index, unsigned start, unsigned count, uint32_t flags, void *data) { - return -EINVAL; + struct vfio_platform_irq *irq = &vdev->irqs[index]; + irq_handler_t handler; + + if (vdev->irqs[index].flags & VFIO_IRQ_INFO_AUTOMASKED) + return -EINVAL; /* not implemented */ + else + handler = vfio_irq_handler; + + if (!count && (flags & VFIO_IRQ_SET_DATA_NONE)) + return vfio_set_trigger(vdev, index, -1, handler); + + if (start != 0 || count != 1) + return -EINVAL; + + if (flags & VFIO_IRQ_SET_DATA_EVENTFD) { + int32_t fd = *(int32_t *)data; + + return vfio_set_trigger(vdev, index, fd, handler); + } + + if (flags & VFIO_IRQ_SET_DATA_NONE) { + handler(irq->hwirq, irq); + + } else if (flags & VFIO_IRQ_SET_DATA_BOOL) { + uint8_t trigger = *(uint8_t *)data; + + if (trigger) + handler(irq->hwirq, irq); + } + + return 0; } int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev, @@ -90,7 +170,12 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev) if (hwirq < 0) goto err; - vdev->irqs[i].flags = 0; + vdev->irqs[i].flags = VFIO_IRQ_INFO_EVENTFD; + + if (irq_get_trigger_type(hwirq) & IRQ_TYPE_LEVEL_MASK) + vdev->irqs[i].flags |= VFIO_IRQ_INFO_MASKABLE + | VFIO_IRQ_INFO_AUTOMASKED; + vdev->irqs[i].count = 1; vdev->irqs[i].hwirq = hwirq; } @@ -105,6 +190,11 @@ err: void vfio_platform_irq_cleanup(struct vfio_platform_device *vdev) { + int i; + + for (i = 0; i < vdev->num_irqs; i++) + vfio_set_trigger(vdev, i, -1, NULL); + vdev->num_irqs = 0; kfree(vdev->irqs); } diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h index b119a6c5ac23..aa01cc36af53 100644 --- a/drivers/vfio/platform/vfio_platform_private.h +++ b/drivers/vfio/platform/vfio_platform_private.h @@ -31,6 +31,8 @@ struct vfio_platform_irq { u32 flags; u32 count; int hwirq; + char *name; + struct eventfd_ctx *trigger; }; struct vfio_platform_region { -- 2.20.1