Re: [PATCH 5/7] drm/i915: Initialize the aliasing ppgtt as part of global gtt

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Jul 31, 2014 at 07:15:52PM +0300, Ville Syrjälä wrote:
> On Wed, Jul 30, 2014 at 09:42:02PM +0200, Daniel Vetter wrote:
> > Stuffing this into the context setup code doesn't make a lot of sense.
> > Also reusing the real ppgtt setup code makes even less sense since the
> > aliasing ppgtt isn't a real address space. Leaving all that stuff
> > unitialized will make sure that we catch any abusers promptly.
> > 
> > This is also a prep work to clean up the context->ppgtt link.
> > 
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_context.c | 13 +------------
> >  drivers/gpu/drm/i915/i915_gem_gtt.c     | 31 +++++++++++++++++++++++++------
> >  2 files changed, 26 insertions(+), 18 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> > index 3b8367aa8404..7a455fcee3a7 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_context.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> > @@ -276,17 +276,6 @@ i915_gem_create_context(struct drm_device *dev,
> >  			goto err_unpin;
> >  		} else
> >  			ctx->vm = &ppgtt->base;
> > -
> > -		/* This case is reserved for the global default context and
> > -		 * should only happen once. */
> > -		if (is_global_default_ctx) {
> > -			if (WARN_ON(dev_priv->mm.aliasing_ppgtt)) {
> > -				ret = -EEXIST;
> > -				goto err_unpin;
> > -			}
> > -
> > -			dev_priv->mm.aliasing_ppgtt = ppgtt;
> > -		}
> >  	} else if (USES_PPGTT(dev)) {
> >  		/* For platforms which only have aliasing PPGTT, we fake the
> >  		 * address space and refcounting. */
> > @@ -361,7 +350,7 @@ int i915_gem_context_init(struct drm_device *dev)
> >  		}
> >  	}
> >  
> > -	ctx = i915_gem_create_context(dev, NULL, USES_PPGTT(dev));
> > +	ctx = i915_gem_create_context(dev, NULL, USES_FULL_PPGTT(dev));
> >  	if (IS_ERR(ctx)) {
> >  		DRM_ERROR("Failed to create default global context (error %ld)\n",
> >  			  PTR_ERR(ctx));
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 4fa7807ed4d5..cb9bb13ff20a 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -1191,23 +1191,27 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
> >  	return 0;
> >  }
> >  
> > -int i915_ppgtt_init(struct drm_device *dev, struct i915_hw_ppgtt *ppgtt)
> > +int __hw_ppgtt_init(struct drm_device *dev, struct i915_hw_ppgtt *ppgtt)
> >  {
> >  	struct drm_i915_private *dev_priv = dev->dev_private;
> > -	int ret = 0;
> >  
> >  	ppgtt->base.dev = dev;
> >  	ppgtt->base.scratch = dev_priv->gtt.base.scratch;
> >  
> >  	if (INTEL_INFO(dev)->gen < 8)
> > -		ret = gen6_ppgtt_init(ppgtt);
> > +		return gen6_ppgtt_init(ppgtt);
> >  	else if (IS_GEN8(dev))
> > -		ret = gen8_ppgtt_init(ppgtt, dev_priv->gtt.base.total);
> > +		return gen8_ppgtt_init(ppgtt, dev_priv->gtt.base.total);
> >  	else
> >  		BUG();
> > +}
> > +int i915_ppgtt_init(struct drm_device *dev, struct i915_hw_ppgtt *ppgtt)
> > +{
> > +	struct drm_i915_private *dev_priv = dev->dev_private;
> > +	int ret = 0;
> >  
> > +	ret = __hw_ppgtt_init(dev, ppgtt);
> >  	if (!ret) {
> > -		struct drm_i915_private *dev_priv = dev->dev_private;
> >  		kref_init(&ppgtt->ref);
> >  		drm_mm_init(&ppgtt->base.mm, ppgtt->base.start,
> >  			    ppgtt->base.total);
> > @@ -1728,6 +1732,7 @@ int i915_gem_setup_global_gtt(struct drm_device *dev,
> >  	struct drm_mm_node *entry;
> >  	struct drm_i915_gem_object *obj;
> >  	unsigned long hole_start, hole_end;
> > +	int ret;
> >  
> >  	BUG_ON(mappable_end > end);
> >  
> > @@ -1739,7 +1744,7 @@ int i915_gem_setup_global_gtt(struct drm_device *dev,
> >  	/* Mark any preallocated objects as occupied */
> >  	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
> >  		struct i915_vma *vma = i915_gem_obj_to_vma(obj, ggtt_vm);
> > -		int ret;
> > +
> >  		DRM_DEBUG_KMS("reserving preallocated space: %lx + %zx\n",
> >  			      i915_gem_obj_ggtt_offset(obj), obj->base.size);
> >  
> > @@ -1766,6 +1771,20 @@ int i915_gem_setup_global_gtt(struct drm_device *dev,
> >  	/* And finally clear the reserved guard page */
> >  	ggtt_vm->clear_range(ggtt_vm, end - PAGE_SIZE, PAGE_SIZE, true);
> >  
> > +	if (HAS_ALIASING_PPGTT(dev) && USES_FULL_PPGTT(dev)) {
> 
> Should that be !USES_FULL_PPGTT ?

Yup. And since I've also fumbled the check for __hw_ppgtt_init I really
wonder what exactly I've tested on my gen6 here ...

Time to hide and lick wounds I think ;-)
-Daniel

> 
> > +		struct i915_hw_ppgtt *ppgtt;
> > +
> > +		ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);
> > +		if (!ppgtt)
> > +			return -ENOMEM;
> > +
> > +		ret = __hw_ppgtt_init(dev, ppgtt);
> > +		if (!ret)
> > +			return ret;
> > +
> > +		dev_priv->mm.aliasing_ppgtt = ppgtt;
> > +	}
> > +
> >  	return 0;
> >  }
> >  
> > -- 
> > 1.9.3
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch