[Intel-gfx] [PATCH v2 21/22] drm/i915: Only preallocate the aliasing GTT to the extents of the global GTT

[Chris Wilson]

As the aliasing GTT is only accessed via the global GTT, we will never
use more of it than we expose via the Global GTT and so we only need to
preallocate sufficient space within the ppgtt for the full GTT. Equally,
if the aliasing GTT is smaller than the global GTT, we have a serious
issue and must bail.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index d71aaccb35ac..ae34a692bf87 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2379,9 +2379,14 @@ int i915_gem_init_aliasing_ppgtt(struct drm_i915_private *i915)
 	if (IS_ERR(ppgtt))
 		return PTR_ERR(ppgtt);
 
+	if (WARN_ON(ppgtt->base.total < ggtt->base.total)) {
+		err = -ENODEV;
+		goto err_ppgtt;
+	}
+
 	if (ppgtt->base.allocate_va_range) {
 		err = ppgtt->base.allocate_va_range(&ppgtt->base,
-						    0, ppgtt->base.total);
+						    0, ggtt->base.total);
 		if (err)
 			goto err_ppgtt;
 	}
-- 
2.11.0