[RFC v1 2/2] vfio/pci: expose only mdev interface if in pci-mdev mode

[Liu, Yi L]

If a pci device is wrapped as a mediated device. Then user should
only passthru it via vfio mdev framework. If not, there would be
conflict during the device access. This patch prevents user from
using legacy vfio-pci passthru interface. vfio-pci driver will only
expose mdev interface when working in pci-mdev mode. Thus could
prevent user from passthru device in legacy manner.

Cc: Kevin Tian <kevin.t...@intel.com>
Cc: Lu Baolu <baolu...@linux.intel.com>
Signed-off-by: Liu, Yi L <yi.l....@intel.com>
---
 drivers/vfio/pci/vfio_pci.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index d1c3fe6..422a3ff 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1273,11 +1273,15 @@ static int vfio_pci_probe(struct pci_dev *pdev, const 
struct pci_device_id *id)
        mutex_init(&vdev->ioeventfds_lock);
        INIT_LIST_HEAD(&vdev->ioeventfds_list);
 
-       ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
-       if (ret) {
-               vfio_iommu_group_put(group, &pdev->dev);
-               kfree(vdev);
-               return ret;
+       if (vfio_pci_mdev_mode) {
+               pci_set_drvdata(pdev, vdev);
+       } else {
+               ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
+               if (ret) {
+                       vfio_iommu_group_put(group, &pdev->dev);
+                       kfree(vdev);
+                       return ret;
+               }
        }
 
        ret = vfio_pci_reflck_attach(vdev);
@@ -1329,7 +1333,10 @@ static void vfio_pci_remove(struct pci_dev *pdev)
 {
        struct vfio_pci_device *vdev;
 
-       vdev = vfio_del_group_dev(&pdev->dev);
+       if (vfio_pci_mdev_mode)
+               vdev = pci_get_drvdata(pdev);
+       else
+               vdev = vfio_del_group_dev(&pdev->dev);
        if (!vdev)
                return;
 
-- 
2.7.4