[Intel-gfx] [PATCH] drm/i915: Assert that we never create a vma for the aliasing_ppgtt

[Chris Wilson]

The aliasing_ppgtt is just a container for the HW context that mirrors
the global gtt. It should never be used directly, so assert if we make
the mistake of trying to allocate a VMA for it.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_vma.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 341c3f82ec1f..0dc994b76924 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -78,6 +78,9 @@ vma_create(struct drm_i915_gem_object *obj,
 	struct rb_node *rb, **p;
 	int i;
 
+	/* The aliasing_ppgtt should never be used directly! */
+	GEM_BUG_ON(vm == &vm->i915->mm.aliasing_ppgtt->base);
+
 	vma = kmem_cache_zalloc(vm->i915->vmas, GFP_KERNEL);
 	if (vma == NULL)
 		return ERR_PTR(-ENOMEM);
-- 
2.11.0