drm/i915: Reserve shadow batch VMA analogue to others

If not pinned VMA can become an eviction target just before it needs to be
executed which breaks the internal object lifetime rules.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=87399
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -1084,6 +1084,7 @@ i915_gem_execbuffer_parse(struct intel_engine_cs *ring,
 {
 	struct drm_i915_private *dev_priv = to_i915(batch_obj->base.dev);
 	struct drm_i915_gem_object *shadow_batch_obj;
+	bool need_reloc = false;
 	int ret;
 
 	shadow_batch_obj = i915_gem_batch_pool_get(&dev_priv->mm.batch_pool,
@@ -1109,6 +1110,7 @@ i915_gem_execbuffer_parse(struct intel_engine_cs *ring,
 		vma->exec_entry = shadow_exec_entry;
 		vma->exec_entry->flags = __EXEC_OBJECT_PURGEABLE;
 		drm_gem_object_reference(&shadow_batch_obj->base);
+		i915_gem_execbuffer_reserve_vma(vma, ring, &need_reloc);
 		list_add_tail(&vma->exec_list, &eb->vmas);
 
 		shadow_batch_obj->base.pending_read_domains =