[PATCH v12 10/13] vfio/pci: Register and allow DMA FAULT IRQ signaling

[Eric Auger <eric.auger@redhat.com>]

Register the VFIO_IRQ_TYPE_NESTED/VFIO_IRQ_SUBTYPE_DMA_FAULT
IRQ that allows to signal a nested mode DMA fault.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v10 -> v11:
- the irq now is registered in vfio_pci_dma_fault_init()
  in case the domain is nested
---
 drivers/vfio/pci/vfio_pci.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index e6b94bad77da..f3fa6d4318ae 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -396,6 +396,7 @@ vfio_pci_iommu_dev_fault_handler(struct iommu_fault *fault, void *data)
 		(struct vfio_region_dma_fault *)vdev->fault_pages;
 	struct iommu_fault *new;
 	u32 head, tail, size;
+	int ext_irq_index;
 	int ret = -EINVAL;
 
 	if (WARN_ON(!reg))
@@ -420,7 +421,19 @@ vfio_pci_iommu_dev_fault_handler(struct iommu_fault *fault, void *data)
 	ret = 0;
 unlock:
 	mutex_unlock(&vdev->fault_queue_lock);
-	return ret;
+	if (ret)
+		return ret;
+
+	ext_irq_index = vfio_pci_get_ext_irq_index(vdev, VFIO_IRQ_TYPE_NESTED,
+						   VFIO_IRQ_SUBTYPE_DMA_FAULT);
+	if (ext_irq_index < 0)
+		return -EINVAL;
+
+	mutex_lock(&vdev->igate);
+	if (vdev->ext_irqs[ext_irq_index].trigger)
+		eventfd_signal(vdev->ext_irqs[ext_irq_index].trigger, 1);
+	mutex_unlock(&vdev->igate);
+	return 0;
 }
 
 #define DMA_FAULT_RING_LENGTH 512
@@ -475,6 +488,12 @@ static int vfio_pci_dma_fault_init(struct vfio_pci_device *vdev)
 	if (ret) /* the dma fault region is freed in vfio_pci_disable() */
 		goto out;
 
+	ret = vfio_pci_register_irq(vdev, VFIO_IRQ_TYPE_NESTED,
+				    VFIO_IRQ_SUBTYPE_DMA_FAULT,
+				    VFIO_IRQ_INFO_EVENTFD);
+	if (ret) /* the fault handler is also freed in vfio_pci_disable() */
+		goto out;
+
 	return 0;
 out:
 	kfree(vdev->fault_pages);
-- 
2.26.2