drm/i915: Mark all non-vma being inserted into the address spaces

We need to distinguish between full i915_vma structs and simple
drm_mm_nodes when considering eviction (i.e. we must be careful not to
treat a mere drm_mm_node as a much larger i915_vma causing memory
corruption, if we are lucky). To do this, color these not-a-vma with -1
(I915_COLOR_UNEVICTABLE).

v2...v200: New name for -1.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161205142941.21965-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gvt/aperture_gm.c

@@ -73,12 +73,15 @@ static int alloc_gm(struct intel_vgpu *vgpu, bool high_gm)
 	mutex_lock(&dev_priv->drm.struct_mutex);
 search_again:
 	ret = drm_mm_insert_node_in_range_generic(&dev_priv->ggtt.base.mm,
-						  node, size, 4096, 0,
+						  node, size, 4096,
+						  I915_COLOR_UNEVICTABLE,
 						  start, end, search_flag,
 						  alloc_flag);
 	if (ret) {
 		ret = i915_gem_evict_something(&dev_priv->ggtt.base,
-					       size, 4096, 0, start, end, 0);
+					       size, 4096,
+					       I915_COLOR_UNEVICTABLE,
+					       start, end, 0);
 		if (ret == 0 && ++retried < 3)
 			goto search_again;
 

drivers/gpu/drm/i915/i915_drv.h

@@ -934,6 +934,8 @@ enum i915_cache_level {
 	I915_CACHE_WT, /* hsw:gt3e WriteThrough for scanouts */
 };
 
+#define I915_COLOR_UNEVICTABLE (-1) /* a non-vma sharing the address space */
+
 #define DEFAULT_CONTEXT_HANDLE 0
 
 /**

drivers/gpu/drm/i915/i915_gem.c

@@ -70,7 +70,8 @@ insert_mappable_node(struct i915_ggtt *ggtt,
 {
 	memset(node, 0, sizeof(*node));
 	return drm_mm_insert_node_in_range_generic(&ggtt->base.mm, node,
-						   size, 0, -1,
+						   size, 0,
+						   I915_COLOR_UNEVICTABLE,
 						   0, ggtt->mappable_end,
 						   DRM_MM_SEARCH_DEFAULT,
 						   DRM_MM_CREATE_DEFAULT);

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -437,7 +437,7 @@ static void *reloc_iomap(struct drm_i915_gem_object *obj,
 			memset(&cache->node, 0, sizeof(cache->node));
 			ret = drm_mm_insert_node_in_range_generic
 				(&ggtt->base.mm, &cache->node,
-				 4096, 0, 0,
+				 4096, 0, I915_COLOR_UNEVICTABLE,
 				 0, ggtt->mappable_end,
 				 DRM_MM_SEARCH_DEFAULT,
 				 DRM_MM_CREATE_DEFAULT);

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -2071,15 +2071,15 @@ static int gen6_ppgtt_allocate_page_directories(struct i915_hw_ppgtt *ppgtt)
 		return ret;
 
 alloc:
-	ret = drm_mm_insert_node_in_range_generic(&ggtt->base.mm,
-						  &ppgtt->node, GEN6_PD_SIZE,
-						  GEN6_PD_ALIGN, 0,
+	ret = drm_mm_insert_node_in_range_generic(&ggtt->base.mm, &ppgtt->node,
+						  GEN6_PD_SIZE, GEN6_PD_ALIGN,
+						  I915_COLOR_UNEVICTABLE,
 						  0, ggtt->base.total,
 						  DRM_MM_TOPDOWN);
 	if (ret == -ENOSPC && !retried) {
 		ret = i915_gem_evict_something(&ggtt->base,
 					       GEN6_PD_SIZE, GEN6_PD_ALIGN,
-					       I915_CACHE_NONE,
+					       I915_COLOR_UNEVICTABLE,
 					       0, ggtt->base.total,
 					       0);
 		if (ret)
@@ -2755,7 +2755,8 @@ int i915_gem_init_ggtt(struct drm_i915_private *dev_priv)
 	/* Reserve a mappable slot for our lockless error capture */
 	ret = drm_mm_insert_node_in_range_generic(&ggtt->base.mm,
 						  &ggtt->error_capture,
-						  4096, 0, -1,
+						  4096, 0,
+						  I915_COLOR_UNEVICTABLE,
 						  0, ggtt->mappable_end,
 						  0, 0);
 	if (ret)