[PATCH v1 06/10] iommufd/viommu: Add iommufd_viommu_report_irq helper

[Nicolin Chen <nicolinc@xxxxxxxxxx>]

This allows IOMMU drivers to report to user space hypervisors IRQs/events
that belong to a viommu.

Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
 drivers/iommu/iommufd/viommu_api.c | 40 ++++++++++++++++++++++++++++++
 include/linux/iommufd.h            |  8 ++++++
 2 files changed, 48 insertions(+)

diff --git a/drivers/iommu/iommufd/viommu_api.c b/drivers/iommu/iommufd/viommu_api.c
index 82eb33e047cf..d075727a1b38 100644
--- a/drivers/iommu/iommufd/viommu_api.c
+++ b/drivers/iommu/iommufd/viommu_api.c
@@ -65,3 +65,43 @@ struct device *iommufd_vdev_id_to_dev(struct iommufd_vdev_id *vdev_id)
 	return vdev_id->idev->dev;
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_vdev_id_to_dev, IOMMUFD);
+
+/**
+ * IOMMU drivers can call this helper to report a per-VIOMMU virtual IRQ. Caller
+ * must ensure the lifecycle of the viommu object, likely by passing it from a
+ * vdev_id structure that was set via a set_vdev_id callback and by holding the
+ * same driver-level lock to protect the passed-in vdev_id from any race against
+ * a potential unset_vdev_id callback.
+ */
+void iommufd_viommu_report_irq(struct iommufd_viommu *viommu, unsigned int type,
+			       void *irq_ptr, size_t irq_len)
+{
+	struct iommufd_event_virq *event_virq;
+	struct iommufd_viommu_irq *virq;
+	void *irq_data;
+
+	might_sleep();
+
+	if (!viommu)
+		return;
+
+	down_read(&viommu->virqs_rwsem);
+
+	event_virq = iommufd_viommu_find_event_virq(viommu, type);
+	if (!event_virq)
+		goto out_unlock_vdev_ids;
+
+	virq = kzalloc(sizeof(*virq) + irq_len, GFP_KERNEL);
+	if (!virq)
+		goto out_unlock_vdev_ids;
+	irq_data = (void *)virq + sizeof(*virq);
+	memcpy(irq_data, irq_ptr, irq_len);
+
+	virq->event_virq = event_virq;
+	virq->irq_len = irq_len;
+
+	iommufd_event_virq_handler(virq);
+out_unlock_vdev_ids:
+	up_read(&viommu->virqs_rwsem);
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_viommu_report_irq, IOMMUFD);
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 88d6586a424f..346a6257ed0c 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -108,6 +108,8 @@ void iommufd_viommu_unlock_vdev_id(struct iommufd_viommu *viommu);
 struct device *iommufd_viommu_find_device(struct iommufd_viommu *viommu, u64 id);
 struct iommu_domain *
 iommufd_viommu_to_parent_domain(struct iommufd_viommu *viommu);
+void iommufd_viommu_report_irq(struct iommufd_viommu *viommu, unsigned int type,
+			       void *irq_ptr, size_t irq_len);
 #else /* !CONFIG_IOMMUFD */
 static inline struct iommufd_ctx *iommufd_ctx_from_file(struct file *file)
 {
@@ -173,5 +175,11 @@ iommufd_viommu_to_parent_domain(struct iommufd_viommu *viommu)
 {
 	return NULL;
 }
+
+static inline void
+iommufd_viommu_report_irq(struct iommufd_viommu *viommu, unsigned int type,
+			  void *irq_ptr, size_t irq_len)
+{
+}
 #endif /* CONFIG_IOMMUFD */
 #endif
-- 
2.43.0