[PATCHv7 20/26] vfio/platform: trigger an interrupt via eventfd

From: Antonios Motakis
Date: Tue Sep 23 2014 - 10:49:13 EST


This patch allows to set an eventfd for a patform device's interrupt,
and also to trigger the interrupt eventfd from userspace for testing.

Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
---
drivers/vfio/platform/vfio_platform_irq.c | 89 ++++++++++++++++++++++++++-
drivers/vfio/platform/vfio_platform_private.h | 2 +
2 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index 007b386..25a7825 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -45,11 +45,91 @@ 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)
+{
+ 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, vfio_irq_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];
+ uint8_t irq_bitmap;
+ int32_t fd;
+
+ switch (flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
+ case VFIO_IRQ_SET_DATA_NONE:
+ if (count == 0)
+ return vfio_set_trigger(vdev, index, -1);
+
+ vfio_irq_handler(irq->hwirq, irq);
+ return 0;
+
+ case VFIO_IRQ_SET_DATA_BOOL:
+ if (copy_from_user(&irq_bitmap, data, sizeof(uint8_t)))
+ return -EFAULT;
+
+ if (irq_bitmap == 0x1) {
+ vfio_irq_handler(irq->hwirq, irq);
+ return 0;
+ }
+
+ return -EINVAL;
+
+ case VFIO_IRQ_SET_DATA_EVENTFD:
+ if (copy_from_user(&fd, data, sizeof(int32_t)))
+ return -EFAULT;
+
+ return vfio_set_trigger(vdev, index, fd);
+ }
+
+ return -EFAULT;
}

int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
@@ -95,7 +175,7 @@ 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;
vdev->irqs[i].count = 1;
vdev->irqs[i].hwirq = hwirq;
}
@@ -110,6 +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);
+
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 4201b94..765b371 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -28,6 +28,8 @@ struct vfio_platform_irq {
u32 flags;
u32 count;
int hwirq;
+ char *name;
+ struct eventfd_ctx *trigger;
};

struct vfio_platform_region {
--
1.8.3.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/