[RFC v5 06/13] VFIO: platform: add vfio_external_{mask|is_active|set_automasked}

[Eric Auger]

Introduces 3 new external functions aimed at doining some actions
on VFIO platform devices:
- mask a VFIO IRQ
- get the active status of a VFIO IRQ (active at interrupt
  controller level or masked by the level-sensitive automasking).
- change the automasked property and the VFIO handler

Note there is no way to discriminate between user-space
masking and automasked handler masking. As a consequence, is_active
will return true in case the IRQ was masked by the user-space.

Signed-off-by: Eric Auger <eric.auger at linaro.org>

---

V4: creation
---
 drivers/vfio/platform/vfio_platform_irq.c | 43 +++++++++++++++++++++++++++++++
 include/linux/vfio.h                      | 14 ++++++++++
 2 files changed, 57 insertions(+)

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index 8eb65c1..49994cb 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -231,6 +231,49 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
 	return 0;
 }
 
+void vfio_external_mask(struct vfio_platform_device *vdev, int index)
+{
+	vfio_platform_mask(&vdev->irqs[index]);
+}
+EXPORT_SYMBOL_GPL(vfio_external_mask);
+
+bool vfio_external_is_active(struct vfio_platform_device *vdev, int index)
+{
+	unsigned long flags;
+	struct vfio_platform_irq *irq = &vdev->irqs[index];
+	bool active, masked, outstanding;
+	int ret;
+
+	spin_lock_irqsave(&irq->lock, flags);
+
+	ret = irq_get_irqchip_state(irq->hwirq, IRQCHIP_STATE_ACTIVE, &active);
+	BUG_ON(ret);
+	masked = irq->masked;
+	outstanding = active || masked;
+
+	spin_unlock_irqrestore(&irq->lock, flags);
+	return outstanding;
+}
+EXPORT_SYMBOL_GPL(vfio_external_is_active);
+
+void vfio_external_set_automasked(struct vfio_platform_device *vdev,
+				  int index, bool automasked)
+{
+	unsigned long flags;
+	struct vfio_platform_irq *irq = &vdev->irqs[index];
+
+	spin_lock_irqsave(&irq->lock, flags);
+	if (automasked) {
+		irq->flags |= VFIO_IRQ_INFO_AUTOMASKED;
+		irq->handler = vfio_automasked_irq_handler;
+	} else {
+		irq->flags &= ~VFIO_IRQ_INFO_AUTOMASKED;
+		irq->handler = vfio_irq_handler;
+	}
+	spin_unlock_irqrestore(&irq->lock, flags);
+}
+EXPORT_SYMBOL_GPL(vfio_external_set_automasked);
+
 static int vfio_platform_set_irq_trigger(struct vfio_platform_device *vdev,
 					 unsigned index, unsigned start,
 					 unsigned count, uint32_t flags,
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index b18c38f..7aa6330 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -105,6 +105,20 @@ extern struct vfio_device *vfio_device_get_external_user(struct file *filep);
 extern void vfio_device_put_external_user(struct vfio_device *vdev);
 extern struct device *vfio_external_base_device(struct vfio_device *vdev);
 
+struct vfio_platform_device;
+extern void vfio_external_mask(struct vfio_platform_device *vdev, int index);
+/*
+ * returns whether the VFIO IRQ is active:
+ * true if not yet deactivated at interrupt controller level or if
+ * automasked (level sensitive IRQ). Unfortunately there is no way to
+ * discriminate between handler auto-masking and user-space masking
+ */
+extern bool vfio_external_is_active(struct vfio_platform_device *vdev,
+				    int index);
+
+extern void vfio_external_set_automasked(struct vfio_platform_device *vdev,
+					 int index, bool automasked);
+
 struct pci_dev;
 #ifdef CONFIG_EEH
 extern void vfio_spapr_pci_eeh_open(struct pci_dev *pdev);
-- 
1.9.1