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Commit 57f972e2 authored by Antonios Motakis's avatar Antonios Motakis Committed by Alex Williamson
Browse files

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: default avatarAntonios Motakis <a.motakis@virtualopensystems.com>
[Baptiste Reynal: fix masked interrupt initialization]
Signed-off-by: default avatarBaptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: default avatarEric Auger <eric.auger@linaro.org>
Tested-by: default avatarEric Auger <eric.auger@linaro.org>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 9a36321c

drivers/vfio/platform/vfio_platform_irq.c

+92 −2
Original line number Diff line number Diff line
@@ -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)

{

	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 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev) 


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);

}

drivers/vfio/platform/vfio_platform_private.h

+2 −0
Original line number Diff line number Diff line
@@ -31,6 +31,8 @@ struct vfio_platform_irq { 
	u32			flags;

	u32			count;

	int			hwirq;

	char			*name;

	struct eventfd_ctx	*trigger;

};



struct vfio_platform_region {