[PATCH v11 10/13] vfio/pci: Register and allow DMA FAULT IRQ signaling

Eric Auger
2020-11-16T12:37:32Z

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 93e03a4a5f32..65a83fd0e8c0 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -397,6 +397,7 @@ int 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;

@@ -422,7 +423,19 @@ int 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
@@ -474,6 +487,12 @@ 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);
--
2.21.3