On Wed, 21 Mar 2018 10:08:03 +0100 Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote: > 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> > --- > drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c > index 021f722e24..be881d53c2 100644 > --- 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_device *mdev, unsigned int cmd, > > } > > - return 0; > + return -EINVAL; > } > > static ssize_t Absolutely, but I'd prefer to continue the standard behavior among other vfio drivers, and adopted from elsewhere in the kernel, to use -ENOTTY for an unhandled ioctl, reserving -EINVAL as an error in options for a supported ioctl. Thanks, Alex