VFIO-AER: Vfio-pci driver changes for supporting AER

- New VFIO_SET_IRQ ioctl option to pass the eventfd that is signaled when
  an error occurs in the vfio_pci_device

- Register pci_error_handler for the vfio_pci driver

- When the device encounters an error, the error handler registered by
  the vfio_pci driver gets invoked by the AER infrastructure

- In the error handler, signal the eventfd registered for the device.

- This results in the qemu eventfd handler getting invoked and
  appropriate action taken for the guest.

Signed-off-by: Vijay Mohan Pandarathil <vijaymohan.pandarathil@hp.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 3639371fa697..b84bf2210a91 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -745,6 +745,63 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_device *vdev,
 	return 0;
 }
 
+static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
+				    unsigned index, unsigned start,
+				    unsigned count, uint32_t flags, void *data)
+{
+	int32_t fd = *(int32_t *)data;
+	struct pci_dev *pdev = vdev->pdev;
+
+	if ((index != VFIO_PCI_ERR_IRQ_INDEX) ||
+	    !(flags & VFIO_IRQ_SET_DATA_TYPE_MASK))
+		return -EINVAL;
+
+	/*
+	 * device_lock synchronizes setting and checking of
+	 * err_trigger. The vfio_pci_aer_err_detected() is also
+	 * called with device_lock held.
+	 */
+
+	/* DATA_NONE/DATA_BOOL enables loopback testing */
+
+	if (flags & VFIO_IRQ_SET_DATA_NONE) {
+		device_lock(&pdev->dev);
+		if (vdev->err_trigger)
+			eventfd_signal(vdev->err_trigger, 1);
+		device_unlock(&pdev->dev);
+		return 0;
+	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
+		uint8_t trigger = *(uint8_t *)data;
+		device_lock(&pdev->dev);
+		if (trigger && vdev->err_trigger)
+			eventfd_signal(vdev->err_trigger, 1);
+		device_unlock(&pdev->dev);
+		return 0;
+	}
+
+	/* Handle SET_DATA_EVENTFD */
+
+	if (fd == -1) {
+		device_lock(&pdev->dev);
+		if (vdev->err_trigger)
+			eventfd_ctx_put(vdev->err_trigger);
+		vdev->err_trigger = NULL;
+		device_unlock(&pdev->dev);
+		return 0;
+	} else if (fd >= 0) {
+		struct eventfd_ctx *efdctx;
+		efdctx = eventfd_ctx_fdget(fd);
+		if (IS_ERR(efdctx))
+			return PTR_ERR(efdctx);
+		device_lock(&pdev->dev);
+		if (vdev->err_trigger)
+			eventfd_ctx_put(vdev->err_trigger);
+		vdev->err_trigger = efdctx;
+		device_unlock(&pdev->dev);
+		return 0;
+	} else
+		return -EINVAL;
+}
 int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
 			    unsigned index, unsigned start, unsigned count,
 			    void *data)
@@ -779,6 +836,13 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
 			break;
 		}
 		break;
+	case VFIO_PCI_ERR_IRQ_INDEX:
+		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
+		case VFIO_IRQ_SET_ACTION_TRIGGER:
+			if (pci_is_pcie(vdev->pdev))
+				func = vfio_pci_set_err_trigger;
+			break;
+		}
 	}
 
 	if (!func)