This patch populates the IRQ bypass callacks:
- stop/start producer simply consist in disabling/enabling the host irq
- add/del consumer: basically set the automasked flag to false/true
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
v3 -> v4:
- use vfio_platform_set_forwarded in place of vfio_platform_set_automasked
- use vfio_platform_irq_is_active and its returned value
- reword comments related to auto/explicit VFIO masking
v2 -> v3:
- vfio_platform_irq_bypass_add_consumer now returns an error in case
the IRQ is recognized as active
- active boolean not set anymore
- do not VFIO mask the IRQ anymore on unforward
v1 -> v2:
- device handle caching in vfio_platform_device is introduced in a
separate patch
- use container_of
---
drivers/vfio/platform/vfio_platform_irq.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index cb7d5e9..e486c32 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -224,23 +224,49 @@ out:
static void vfio_platform_irq_bypass_stop(struct irq_bypass_producer *prod)
{
+ disable_irq(prod->irq);
}
static void vfio_platform_irq_bypass_start(struct irq_bypass_producer *prod)
{
+ enable_irq(prod->irq);
}
static int vfio_platform_irq_bypass_add_consumer(
struct irq_bypass_producer *prod,
struct irq_bypass_consumer *cons)
{
- return 0;
+ struct vfio_platform_irq *irq =
+ container_of(prod, struct vfio_platform_irq, producer);
+ int ret;
+
+ /*
+ * if the IRQ is active at irqchip level or masked by VFIO
+ * this means the host IRQ may be under injection and
+ * it is not safe to change the forwarding state at that time.
+ * It is not possible to discriminate VFIO explicit masking
+ * from VFIO auto-masking, leading to possible false detection of
+ * IRQ activity. It is up to the user-space to avoid VFIO explicit
+ * masking situation. In case of failure, no retry is attempted and
+ * bypass setup simply fails.
+ */
+ ret = vfio_platform_irq_is_active(irq);
+ if (ret < 0)
+ return ret;
+ else if (ret == 1)
+ return -EAGAIN;
+
+ return vfio_platform_set_forwarded(irq, true);
}
static void vfio_platform_irq_bypass_del_consumer(
struct irq_bypass_producer *prod,
struct irq_bypass_consumer *cons)
{
+ struct vfio_platform_irq *irq =
+ container_of(prod, struct vfio_platform_irq, producer);
+
+ vfio_platform_set_forwarded(irq, false);
}
static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
--
1.9.1
--
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