[PATCH 4.16 10/26] drm/i915/gvt: throw error on unhandled vfio ioctls

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gerd Hoffmann <kraxel@xxxxxxxxxx>

commit 9f591ae60e1be026901398ef99eede91237aa3a1 upstream.

On unknown/unhandled ioctls the driver should return an error, so
userspace knows it tried to use something unsupported.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Reviewed-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Signed-off-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/i915/gvt/kvmgt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1284,7 +1284,7 @@ static long intel_vgpu_ioctl(struct mdev
 
 	}
 
-	return 0;
+	return -ENOTTY;
 }
 
 static ssize_t