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;