Commit a035154d authored by Matthew Auld's avatar Matthew Auld
Browse files

drm/i915/dmabuf: add paranoid flush-on-acquire 



As pointed out by Thomas, we likely need to flush the pages here if the
GPU can read the page contents directly from main memory. Underneath we
don't know what the sg_table is pointing to, so just add a
wbinvd_on_all_cpus() here, for now.

Reported-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: default avatarMatthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211018174508.2137279-4-matthew.auld@intel.com
parent 30f1dccd

drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c

+5 −1
Original line number Diff line number Diff line
@@ -232,6 +232,7 @@ struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags) 


static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)

{

	struct drm_i915_private *i915 = to_i915(obj->base.dev);

	struct sg_table *pages;

	unsigned int sg_page_sizes;
@@ -242,8 +243,11 @@ static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj) 
	if (IS_ERR(pages))

		return PTR_ERR(pages);



	sg_page_sizes = i915_sg_dma_sizes(pages->sgl);

	/* XXX: consider doing a vmap flush or something */

	if (!HAS_LLC(i915) || i915_gem_object_can_bypass_llc(obj))

		wbinvd_on_all_cpus();



	sg_page_sizes = i915_sg_dma_sizes(pages->sgl);

	__i915_gem_object_set_pages(obj, pages, sg_page_sizes);



	return 0;