[RFC PATCH v6 20/20] vfio/platform: implement IRQ masking/unmasking via an eventfd

Antonios Motakis
2014-06-05T17:06:26Z

With this patch the VFIO user will be able to set an eventfd that can be
used in order to mask and unmask IRQs of platform devices.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
---
drivers/vfio/platform/vfio_platform_irq.c | 86 ++++++++++++++++++++++-----
drivers/vfio/platform/vfio_platform_private.h | 2 +
2 files changed, 72 insertions(+), 16 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index 10dfbf0..6768508 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -108,6 +108,52 @@ static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
return ret;
}

+static void vfio_platform_unmask(struct vfio_platform_irq *irq_ctx)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&irq_ctx->lock, flags);
+
+ if (irq_ctx->masked) {
+ enable_irq(irq_ctx->hwirq);
+ irq_ctx->masked = false;
+ }
+
+ spin_unlock_irqrestore(&irq_ctx->lock, flags);
+}
+
+static void vfio_platform_mask(struct vfio_platform_irq *irq_ctx)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&irq_ctx->lock, flags);
+
+ if (!irq_ctx->masked) {
+ disable_irq(irq_ctx->hwirq);
+ irq_ctx->masked = true;
+ }
+
+ spin_unlock_irqrestore(&irq_ctx->lock, flags);
+}
+
+static int vfio_platform_unmask_handler(void *opaque, void *unused)
+{
+ struct vfio_platform_irq *irq_ctx = opaque;
+
+ vfio_platform_unmask(irq_ctx);
+
+ return 0;
+}
+
+static int vfio_platform_mask_handler(void *opaque, void *unused)
+{
+ struct vfio_platform_irq *irq_ctx = opaque;
+
+ vfio_platform_mask(irq_ctx);
+
+ return 0;
+}
+
static int vfio_set_trigger(struct vfio_platform_device *vdev,
int index, int fd)
{
@@ -191,6 +237,7 @@ static int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev,
unsigned count, uint32_t flags, void *data)
{
uint8_t arr;
+ int32_t fd;

if (start != 0 || count != 1)
return -EINVAL;
@@ -204,19 +251,22 @@ static int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev,
return -EINVAL;

case VFIO_IRQ_SET_DATA_NONE:
+ vfio_platform_unmask(&vdev->irq[index]);
+ return 0;

- spin_lock_irq(&vdev->irq[index].lock);
-
- if (vdev->irq[index].masked) {
- enable_irq(vdev->irq[index].hwirq);
- vdev->irq[index].masked = false;
- }
+ case VFIO_IRQ_SET_DATA_EVENTFD:
+ if (copy_from_user(&fd, data, sizeof(int32_t)))
+ return -EFAULT;

- spin_unlock_irq(&vdev->irq[index].lock);
+ if (fd >= 0)
+ return virqfd_enable((void *) &vdev->irq[index],
+ vfio_platform_unmask_handler,
+ NULL, NULL,
+ &vdev->irq[index].unmask, fd);

+ virqfd_disable(&vdev->irq[index].unmask);
return 0;

- case VFIO_IRQ_SET_DATA_EVENTFD: /* XXX not implemented yet */
default:
return -ENOTTY;
}
@@ -229,6 +279,7 @@ static int vfio_platform_set_irq_mask(struct vfio_platform_device *vdev,
unsigned count, uint32_t flags, void *data)
{
uint8_t arr;
+ int32_t fd;

if (start != 0 || count != 1)
return -EINVAL;
@@ -242,19 +293,22 @@ static int vfio_platform_set_irq_mask(struct vfio_platform_device *vdev,
return -EINVAL;

case VFIO_IRQ_SET_DATA_NONE:
+ vfio_platform_mask(&vdev->irq[index]);
+ return 0;

- spin_lock_irq(&vdev->irq[index].lock);
-
- if (!vdev->irq[index].masked) {
- disable_irq(vdev->irq[index].hwirq);
- vdev->irq[index].masked = true;
- }
+ case VFIO_IRQ_SET_DATA_EVENTFD:
+ if (copy_from_user(&fd, data, sizeof(int32_t)))
+ return -EFAULT;

- spin_unlock_irq(&vdev->irq[index].lock);
+ if (fd >= 0)
+ return virqfd_enable((void *) &vdev->irq[index],
+ vfio_platform_mask_handler,
+ NULL, NULL,
+ &vdev->irq[index].mask, fd);

+ virqfd_disable(&vdev->irq[index].mask);
return 0;

- case VFIO_IRQ_SET_DATA_EVENTFD: /* XXX not implemented yet */
default:
return -ENOTTY;
}
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 4d887fd..86a9201 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -32,6 +32,8 @@ struct vfio_platform_irq {
char *name;
bool masked;
spinlock_t lock;
+ struct virqfd *unmask;
+ struct virqfd *mask;
};

struct vfio_platform_region {
--
1.8.3.2