[PATCH v9 10/11] vfio/pci: Register and allow DMA FAULT IRQ signaling

[Eric Auger]

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@xxxxxxxxxx>
---
 drivers/vfio/pci/vfio_pci.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index dcc246202094..a9df964e40c6 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -344,7 +344,7 @@ int vfio_pci_iommu_dev_fault_handler(struct iommu_fault *fault, void *data)
 	struct iommu_fault *new =
 		(struct iommu_fault *)(vdev->fault_pages + reg->offset +
 			reg->head * reg->entry_size);
-	int head, tail, size;
+	int head, tail, size, ext_irq_index;
 	int ret = 0;
 
 	if (fault->type != IOMMU_FAULT_DMA_UNRECOV)
@@ -365,7 +365,19 @@ int vfio_pci_iommu_dev_fault_handler(struct iommu_fault *fault, void *data)
 	reg->head = (head + 1) % size;
 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
@@ -518,6 +530,12 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
 	if (ret)
 		goto disable_exit;
 
+	ret = vfio_pci_register_irq(vdev, VFIO_IRQ_TYPE_NESTED,
+				    VFIO_IRQ_SUBTYPE_DMA_FAULT,
+				    VFIO_IRQ_INFO_EVENTFD);
+	if (ret)
+		goto disable_exit;
+
 	vfio_pci_probe_mmaps(vdev);
 
 	return 0;
-- 
2.20.1