[Intel-gfx] [PATCH] drm/i915: clear the end of the shadow batch if needed

[Matthew Auld]

The shadow batch is an internal object, which doesn't have any page
clearing, and since the batch_len might be within a page, we should take
care to clear any unused dwords before making it visible in the ppGTT.

Testcase: igt/gen9_exec_parse/shadow-peek
Signed-off-by: Matthew Auld <matthew.auld at intel.com>
---
 drivers/gpu/drm/i915/i915_cmd_parser.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index 8d88402387bd..6506ed30b444 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -1139,6 +1139,7 @@ static u32 *copy_batch(struct drm_i915_gem_object *dst_obj,
 		       struct drm_i915_gem_object *src_obj,
 		       unsigned long offset, unsigned long length)
 {
+	unsigned long orig_length = length;
 	bool needs_clflush;
 	void *dst, *src;
 	int ret;
@@ -1199,6 +1200,12 @@ static u32 *copy_batch(struct drm_i915_gem_object *dst_obj,
 		}
 	}
 
+	if (offset_in_page(orig_length)) {
+		memset(dst + orig_length, 0,
+		       PAGE_SIZE - offset_in_page(orig_length));
+		i915_gem_object_flush_map(dst_obj);
+	}
+
 	i915_gem_object_unpin_pages(src_obj);
 
 	/* dst_obj is returned with vmap pinned */
-- 
2.26.2