[Intel-gfx] [PATCH v2 2/4] drm/i915: Introduce guard pages to i915_vma

[Andi Shyti]

> > > @@ -768,6 +768,9 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
> > >   	GEM_BUG_ON(!IS_ALIGNED(alignment, I915_GTT_MIN_ALIGNMENT));
> > >   	GEM_BUG_ON(!is_power_of_2(alignment));
> > > +	guard = vma->guard; /* retain guard across rebinds */
> > > +	guard = ALIGN(guard, alignment);
> > 
> > Why does guard area needs the same alignment as the requested mapping? What about the fact on 32-bit builds guard is 32-bit and alignment u64?
> 
> I guess this just to round up/down guard to something, not
> necessarily to that alignment.
> 
> Shall I remove it?

or we could just add a comment to explain that this is just to do
some rounding in order to avoid weird values of guard.

Andi