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Subject[PATCH v13 11/18] vfio/platform: support for level sensitive interrupts
Date
From: Antonios Motakis <a.motakis@virtualopensystems.com>

Level sensitive interrupts are exposed as maskable and automasked
interrupts and are masked and disabled automatically when they fire.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
[Baptiste Reynal: Move masked interrupt initialization from "vfio/platform:
trigger an interrupt via eventfd"]
Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
---
drivers/vfio/platform/vfio_platform_irq.c | 103 +++++++++++++++++++++++++-
drivers/vfio/platform/vfio_platform_private.h | 2 +
2 files changed, 102 insertions(+), 3 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index 611ec80..e0e6388 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -23,12 +23,59 @@

#include "vfio_platform_private.h"

+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_nosync(irq_ctx->hwirq);
+ irq_ctx->masked = true;
+ }
+
+ spin_unlock_irqrestore(&irq_ctx->lock, flags);
+}
+
static int vfio_platform_set_irq_mask(struct vfio_platform_device *vdev,
unsigned index, unsigned start,
unsigned count, uint32_t flags,
void *data)
{
- return -EINVAL;
+ if (start != 0 || count != 1)
+ return -EINVAL;
+
+ if (!(vdev->irqs[index].flags & VFIO_IRQ_INFO_MASKABLE))
+ return -EINVAL;
+
+ if (flags & VFIO_IRQ_SET_DATA_EVENTFD)
+ return -EINVAL; /* not implemented yet */
+
+ if (flags & VFIO_IRQ_SET_DATA_NONE) {
+ vfio_platform_mask(&vdev->irqs[index]);
+
+ } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
+ uint8_t mask = *(uint8_t *)data;
+
+ if (mask)
+ vfio_platform_mask(&vdev->irqs[index]);
+ }
+
+ return 0;
+}
+
+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 int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev,
@@ -36,7 +83,50 @@ static int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev,
unsigned count, uint32_t flags,
void *data)
{
- return -EINVAL;
+ if (start != 0 || count != 1)
+ return -EINVAL;
+
+ if (!(vdev->irqs[index].flags & VFIO_IRQ_INFO_MASKABLE))
+ return -EINVAL;
+
+ if (flags & VFIO_IRQ_SET_DATA_EVENTFD)
+ return -EINVAL; /* not implemented yet */
+
+ if (flags & VFIO_IRQ_SET_DATA_NONE) {
+ vfio_platform_unmask(&vdev->irqs[index]);
+
+ } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
+ uint8_t unmask = *(uint8_t *)data;
+
+ if (unmask)
+ vfio_platform_unmask(&vdev->irqs[index]);
+ }
+
+ return 0;
+}
+
+static irqreturn_t vfio_automasked_irq_handler(int irq, void *dev_id)
+{
+ struct vfio_platform_irq *irq_ctx = dev_id;
+ unsigned long flags;
+ int ret = IRQ_NONE;
+
+ spin_lock_irqsave(&irq_ctx->lock, flags);
+
+ if (!irq_ctx->masked) {
+ ret = IRQ_HANDLED;
+
+ /* automask maskable interrupts */
+ disable_irq_nosync(irq_ctx->hwirq);
+ irq_ctx->masked = true;
+ }
+
+ spin_unlock_irqrestore(&irq_ctx->lock, flags);
+
+ if (ret == IRQ_HANDLED)
+ eventfd_signal(irq_ctx->trigger, 1);
+
+ return ret;
}

static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
@@ -78,6 +168,7 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,

irq->trigger = trigger;

+ irq_set_status_flags(irq->hwirq, IRQ_NOAUTOEN);
ret = request_irq(irq->hwirq, handler, 0, irq->name, irq);
if (ret) {
kfree(irq->name);
@@ -86,6 +177,9 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
return ret;
}

+ if (!irq->masked)
+ enable_irq(irq->hwirq);
+
return 0;
}

@@ -98,7 +192,7 @@ static int vfio_platform_set_irq_trigger(struct vfio_platform_device *vdev,
irq_handler_t handler;

if (vdev->irqs[index].flags & VFIO_IRQ_INFO_AUTOMASKED)
- return -EINVAL; /* not implemented */
+ handler = vfio_automasked_irq_handler;
else
handler = vfio_irq_handler;

@@ -170,6 +264,8 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev)
if (hwirq < 0)
goto err;

+ spin_lock_init(&vdev->irqs[i].lock);
+
vdev->irqs[i].flags = VFIO_IRQ_INFO_EVENTFD;

if (irq_get_trigger_type(hwirq) & IRQ_TYPE_LEVEL_MASK)
@@ -178,6 +274,7 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev)

vdev->irqs[i].count = 1;
vdev->irqs[i].hwirq = hwirq;
+ vdev->irqs[i].masked = false;
}

vdev->num_irqs = cnt;
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index aa01cc3..ff2db1d 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -33,6 +33,8 @@ struct vfio_platform_irq {
int hwirq;
char *name;
struct eventfd_ctx *trigger;
+ bool masked;
+ spinlock_t lock;
};

struct vfio_platform_region {
--
2.2.2


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