[Intel-gfx] [RFC 05/38] drm/i915: Split out aliasing binds

[Daniel Vetter]

On Tue, Oct 07, 2014 at 06:11:01PM +0100, Michel Thierry wrote:
> From: Ben Widawsky <benjamin.widawsky at intel.com>
>
> This patch finishes off  actually separating the aliasing and global
> finds. Prior to this, all global binds would be aliased. Now if aliasing
> binds are required, they must be explicitly asked for. So far, we have
> no users of this outside of execbuf - but Mika has already submitted a
> patch requiring just this.
>
> A nice benefit of this is we should no longer be able to clobber GTT
> only objects from the aliasing PPGTT.
>
> v2: Only add aliasing binds for the GGTT/Aliasing PPGTT at execbuf
>
> v3: Rebase resolution with changed size of flags
>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> Signed-off-by: Michel Thierry <michel.thierry at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h            | 2 +-
>  drivers/gpu/drm/i915/i915_gem.c            | 6 ++++--
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c | 5 +++--
>  drivers/gpu/drm/i915/i915_gem_gtt.c        | 3 +++
>  4 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 6b60e90..c0fea18 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2620,7 +2620,7 @@ i915_gem_obj_ggtt_pin(struct drm_i915_gem_object *obj,
>        unsigned flags)
>  {
>   return i915_gem_object_pin(obj, i915_obj_to_ggtt(obj),
> -   alignment, flags | PIN_GLOBAL_ALIASED);
> +   alignment, flags | PIN_GLOBAL);

This hunk looks like a patch split mixup and should probably be in the
previous patch.

Also I'm not really clear on all these flags and what they should do with
pure ppgtt/pure ggtt address spaces. We probably need to lock down abuse
(well, potential bugs) through copious sprinkling of WARN_ONs.
-Daniel

>  }
>
>  static inline int
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index dfb20e6..98186b2 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3512,8 +3512,10 @@ search_free:
>
>   WARN_ON(flags & PIN_MAPPABLE && !obj->map_and_fenceable);
>
> - if (flags & PIN_GLOBAL_ALIASED)
> - vma_bind_flags = GLOBAL_BIND | ALIASING_BIND;
> + if (flags & PIN_ALIASING)
> + vma_bind_flags = ALIASING_BIND;
> + if (flags & PIN_GLOBAL)
> + vma_bind_flags = GLOBAL_BIND;
>
>   trace_i915_vma_bind(vma, flags);
>   i915_gem_vma_bind(vma, obj->cache_level, vma_bind_flags);
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 92191f0..d3a89e6 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -527,10 +527,11 @@ i915_gem_execbuffer_reserve_vma(struct i915_vma *vma,
>  {
>   struct drm_i915_gem_object *obj = vma->obj;
>   struct drm_i915_gem_exec_object2 *entry = vma->exec_entry;
> - uint64_t flags;
> + uint64_t flags = 0;
>   int ret;
>
> - flags = 0;
> + if (i915_is_ggtt(vma->vm))
> + flags = PIN_ALIASING;
>   if (entry->flags & __EXEC_OBJECT_NEEDS_MAP)
>   flags |= PIN_MAPPABLE;
>   /* FIXME: What kind of bind does Chris want? */
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index d725883..ac0197f 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -1597,6 +1597,9 @@ static void ggtt_bind_vma(struct i915_vma *vma,
>   }
>   }
>
> + if (!(flags & ALIASING_BIND))
> + return;
> +
>   if (dev_priv->mm.aliasing_ppgtt &&
>      (!obj->has_aliasing_ppgtt_mapping ||
>       (cache_level != obj->cache_level))) {
> --
> 2.0.3
>
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch