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vfio/platform: trigger an interrupt via eventfd

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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 <a.motakis@virtualopensystems.com>
[Baptiste Reynal: fix masked interrupt initialization]
Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Antonios Motakis 2015-03-16 14:08:50 -06:00 committed by Alex Williamson
parent 9a36321c8d
commit 57f972e2b3
2 changed files with 94 additions and 2 deletions
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94
drivers/vfio/platform/vfio_platform_irq.c
View file

@ -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 @@ 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);
}

2
drivers/vfio/platform/vfio_platform_private.h
View file

@ -31,6 +31,8 @@ struct vfio_platform_irq {
u32 flags;
u32 count;
int hwirq;
char *name;
struct eventfd_ctx *trigger;
};
struct vfio_platform_region {