drm/i915/gvt: hold reference of VFIO group during opening of vgpu

hold reference count of the VFIO group for each vgpu at vgpu opening and
release the reference at vgpu releasing.

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Reviewed-by: Zhenyu Wang<zhenyuw@linux.intel.com>
Signed-off-by: Zhenyu Wang<zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200313031025.7936-1-yan.y.zhao@intel.com

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 074c4efb58eb96e7d25045ddfd1b6a76c1995973..811cee28ae06a7f96a0157597f3599c7917668c8 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -131,6 +131,7 @@ struct kvmgt_vdev {
        struct work_struct release_work;
        atomic_t released;
        struct vfio_device *vfio_device;
+       struct vfio_group *vfio_group;
 };
 
 static inline struct kvmgt_vdev *kvmgt_vdev(struct intel_vgpu *vgpu)
@@ -792,6 +793,7 @@ static int intel_vgpu_open(struct mdev_device *mdev)
        struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu);
        unsigned long events;
        int ret;
+       struct vfio_group *vfio_group;
 
        vdev->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier;
        vdev->group_notifier.notifier_call = intel_vgpu_group_notifier;
@@ -814,6 +816,14 @@ static int intel_vgpu_open(struct mdev_device *mdev)
                goto undo_iommu;
        }
 
+       vfio_group = vfio_group_get_external_user_from_dev(mdev_dev(mdev));
+       if (IS_ERR_OR_NULL(vfio_group)) {
+               ret = !vfio_group ? -EFAULT : PTR_ERR(vfio_group);
+               gvt_vgpu_err("vfio_group_get_external_user_from_dev failed\n");
+               goto undo_register;
+       }
+       vdev->vfio_group = vfio_group;
+
        /* Take a module reference as mdev core doesn't take
         * a reference for vendor driver.
         */
@@ -830,6 +840,10 @@ static int intel_vgpu_open(struct mdev_device *mdev)
        return ret;
 
 undo_group:
+       vfio_group_put_external_user(vdev->vfio_group);
+       vdev->vfio_group = NULL;
+
+undo_register:
        vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
                                        &vdev->group_notifier);
 
@@ -884,6 +898,7 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
        kvmgt_guest_exit(info);
 
        intel_vgpu_release_msi_eventfd_ctx(vgpu);
+       vfio_group_put_external_user(vdev->vfio_group);
 
        vdev->kvm = NULL;
        vgpu->handle = 0;