[Intel-gfx] [PATCH 14/34] drm/i915: Embed PPGTT into the context

[Ben Widawsky]

My long term vision is for contexts to have a 1:1 relationship with a
PPGTT. Sharing objects between address spaces would work similarly to
the flink/dmabuf model if needed.

The only current code to convert is the aliasing PPGTT. The aliasing
PPGTT is just the PPGTT for the default context.

The obvious downside is until we actually do PPGTT switches, this wastes
a bit of memory. ie. by the end of the series, it's a don't care. The
other downside is PPGTT can't work without contexts, which *should* have
already been the case except for debugging scenarios. (Note the does
break the potential to easily use contexts on GEN5 since I believe our
odds of running PPGTT on GEN5 are fairly close to 0)

Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
---
 drivers/gpu/drm/i915/i915_drv.h     |  2 ++
 drivers/gpu/drm/i915/i915_gem.c     | 14 ++++++++------
 drivers/gpu/drm/i915/i915_gem_gtt.c |  1 -
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 63f58b8..6210ecd 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -475,6 +475,8 @@ struct i915_hw_context {
 	struct drm_i915_file_private *file_priv;
 	struct intel_ring_buffer *ring;
 	struct drm_i915_gem_object *obj;
+
+	struct i915_hw_ppgtt ppgtt;
 };
 
 enum no_fbc_reason {
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 670694c..fc35447 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4074,17 +4074,19 @@ int i915_gem_init(struct drm_device *dev)
 
 	if (intel_enable_ppgtt(dev) && HAS_ALIASING_PPGTT(dev)) {
 		struct i915_hw_ppgtt *ppgtt;
-		ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);
-		if (!ppgtt)
-			goto ggtt_only;
-
 
 		i915_gem_setup_global_gtt(dev, 0, dev_priv->gtt.mappable_end,
 					  dev_priv->gtt.total, false);
 		i915_gem_context_init(dev);
+		if (dev_priv->hw_contexts_disabled) {
+			drm_mm_takedown(&dev_priv->mm.gtt_space);
+			goto ggtt_only;
+		}
+
+		ppgtt = &dev_priv->ring[RCS].default_context->ppgtt;
+
 		ret = i915_gem_ppgtt_init(dev, ppgtt);
-		if (ret)  {
-			kfree(ppgtt);
+		if (ret) {
 			drm_mm_takedown(&dev_priv->mm.gtt_space);
 			goto ggtt_only;
 		}
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 2ca113a..a126955 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -260,7 +260,6 @@ static void gen6_ppgtt_cleanup(struct i915_hw_ppgtt *ppgtt)
 	for (i = 0; i < ppgtt->num_pd_entries; i++)
 		__free_page(ppgtt->pt_pages[i]);
 	kfree(ppgtt->pt_pages);
-	kfree(ppgtt);
 }
 
 static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
-- 
1.8.2.3