[Intel-gfx] [PATCH] drm/i915: Catch attempting to use the aliasing_gtt's drm_mm

Chris Wilson chris at chris-wilson.co.uk
Sun Jan 15 13:47:46 UTC 2017


The aliasing_gtt is just that, an alias of the global GTT. We do not
populate it directly, instead we always use the global GTT. Catch any
attempt to incorrectly allocate ranges from the aliasing_gtt.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 26a4460e16c3..9bc1788fac5b 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3134,6 +3134,7 @@ int i915_gem_gtt_reserve(struct i915_address_space *vm,
 	GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));
 	GEM_BUG_ON(!IS_ALIGNED(offset, I915_GTT_MIN_ALIGNMENT));
 	GEM_BUG_ON(range_overflows(offset, size, vm->total));
+	GEM_BUG_ON(vm == &vm->i915->mm.aliasing_ppgtt->base);
 
 	node->size = size;
 	node->start = offset;
@@ -3229,6 +3230,7 @@ int i915_gem_gtt_insert(struct i915_address_space *vm,
 	GEM_BUG_ON(start >= end);
 	GEM_BUG_ON(start > 0  && !IS_ALIGNED(start, I915_GTT_PAGE_SIZE));
 	GEM_BUG_ON(end < U64_MAX && !IS_ALIGNED(end, I915_GTT_PAGE_SIZE));
+	GEM_BUG_ON(vm == &vm->i915->mm.aliasing_ppgtt->base);
 
 	if (unlikely(range_overflows(start, size, end)))
 		return -ENOSPC;
-- 
2.11.0



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