[Intel-gfx] [PATCH 1/2] drm/i915: do not clear mappings beyond VMA size

[Joonas Lahtinen]

Do not to clear mappings outside the allocated VMA under any
circumstances. Only clear the smaller of VMA or object page count.

This is required to allow creating partial object VMAs which in
turn are needed for partial GGTT views.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 9041f3d..18c695b 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1730,9 +1730,14 @@ ppgtt_bind_vma(struct i915_vma *vma,
 
 static void ppgtt_unbind_vma(struct i915_vma *vma)
 {
+	struct drm_i915_gem_object *obj = vma->obj;
+	const uint64_t size = min_t(uint64_t,
+				    obj->base.size,
+				    vma->node.size);
+
 	vma->vm->clear_range(vma->vm,
 			     vma->node.start,
-			     vma->obj->base.size,
+			     size,
 			     true);
 }
 
@@ -2078,8 +2083,11 @@ static void i915_ggtt_clear_range(struct i915_address_space *vm,
 
 static void i915_ggtt_unbind_vma(struct i915_vma *vma)
 {
+	struct drm_i915_gem_object *obj = vma->obj;
 	const unsigned int first = vma->node.start >> PAGE_SHIFT;
-	const unsigned int size = vma->obj->base.size >> PAGE_SHIFT;
+	const unsigned int size = min_t(uint64_t,
+					obj->base.size,
+					vma->node.size) >> PAGE_SHIFT;
 
 	BUG_ON(!i915_is_ggtt(vma->vm));
 	vma->bound = 0;
@@ -2139,21 +2147,27 @@ static void ggtt_unbind_vma(struct i915_vma *vma)
 	struct drm_device *dev = vma->vm->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj = vma->obj;
+	const uint64_t size = min_t(uint64_t,
+				    obj->base.size,
+				    vma->node.size);
 
 	if (vma->bound & GLOBAL_BIND) {
 		vma->vm->clear_range(vma->vm,
 				     vma->node.start,
-				     obj->base.size,
+				     size,
 				     true);
+
 		vma->bound &= ~GLOBAL_BIND;
 	}
 
 	if (vma->bound & LOCAL_BIND) {
 		struct i915_hw_ppgtt *appgtt = dev_priv->mm.aliasing_ppgtt;
+
 		appgtt->base.clear_range(&appgtt->base,
 					 vma->node.start,
-					 obj->base.size,
+					 size,
 					 true);
+
 		vma->bound &= ~LOCAL_BIND;
 	}
 }
-- 
1.9.3