[Intel-gfx] [PATCH 09/10] drm/i915: Reject < 8 byte batches on 830/845

[Daniel Vetter]

On Wed, Dec 16, 2015 at 10:43:54AM +0000, Chris Wilson wrote:
> On Wed, Dec 16, 2015 at 11:36:31AM +0100, Daniel Vetter wrote:
> > On Mon, Dec 14, 2015 at 06:23:48PM +0200, ville.syrjala at linux.intel.com wrote:
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > 
> > > We use MI_BATCH_BUFFER on 830/845, which means we need to know
> > > the batch length. If the user passes a bad batch length (< 8)
> > > the results is most likely a GPU hang. Rejct such batches.
> > > 
> > > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > Can't we just reject a 0 batch_len everywhere? Well fix up igt first ofc.
> > Slipping a 0 through really shouldn't be allowed.
> 
> No, I sneaked that bit of ABI abuse passed you. Sorry.

Hm, still should augment gem_exec_params to at least attempt ugly stuff
like batch_len = 4 or batch_len = 3.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch