From fb018c896dd657163d04049ba7d9fe7faba572da Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 6 Jul 2020 23:43:08 +0100
Subject: drm/i915: Update dma-attributes for our sg DMA
Git-commit: a3a402840662a7449b1ca0baa58eddf36ef23158
Patch-mainline: v5.9-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Looking through the attributes for DMA mappings, it appears that by
default dma_map_sg will try and create a kernel accessible map of the
page. We never access this, as we either have a struct page already or
an iomap, so we can request that the dma mapper does not create one.
Without a kernel map in place, one presumes the rest of the memory
control attributes do not apply. We also explicitly control the caches
around the mappings, so we can ask it not to bother synchronising itself.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200706224308.22636-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index cb43381b0d37..c5ee1567f3d1 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -31,6 +31,8 @@ int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj,
 		if (dma_map_sg_attrs(&obj->base.dev->pdev->dev,
 				     pages->sgl, pages->nents,
 				     PCI_DMA_BIDIRECTIONAL,
+				     DMA_ATTR_SKIP_CPU_SYNC |
+				     DMA_ATTR_NO_KERNEL_MAPPING |
 				     DMA_ATTR_NO_WARN))
 			return 0;
 
-- 
2.29.2