As recently disovered by forcing big-core (!llc) machines to use the GTT paths, we need our full GTT write flush before manipulating the GTT PTE or else the writes may be directed to the wrong page.
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Matthew Auld matthew.william.auld@gmail.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/i915/i915_gem.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index fed0bc421a55..c6ba350e6e4f 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -610,7 +610,8 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj, unsigned int page_length = PAGE_SIZE - page_offset; page_length = remain < page_length ? remain : page_length; if (node.allocated) { - wmb(); /* flush the write before we modify the GGTT */ + /* flush the write before we modify the GGTT */ + intel_gt_flush_ggtt_writes(ggtt->vm.gt); ggtt->vm.insert_page(&ggtt->vm, i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT), node.start, I915_CACHE_NONE, 0); @@ -639,8 +640,8 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj, i915_gem_object_unlock_fence(obj, fence); out_unpin: mutex_lock(&i915->drm.struct_mutex); + intel_gt_flush_ggtt_writes(ggtt->vm.gt); if (node.allocated) { - wmb(); ggtt->vm.clear_range(&ggtt->vm, node.start, node.size); remove_mappable_node(&node); } else {
On Thu, Jul 18, 2019 at 03:54:05PM +0100, Chris Wilson wrote:
As recently disovered by forcing big-core (!llc) machines to use the GTT paths, we need our full GTT write flush before manipulating the GTT PTE or else the writes may be directed to the wrong page.
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Matthew Auld matthew.william.auld@gmail.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: stable@vger.kernel.org
drivers/gpu/drm/i915/i915_gem.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index fed0bc421a55..c6ba350e6e4f 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -610,7 +610,8 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj, unsigned int page_length = PAGE_SIZE - page_offset; page_length = remain < page_length ? remain : page_length; if (node.allocated) {
wmb(); /* flush the write before we modify the GGTT */
/* flush the write before we modify the GGTT */intel_gt_flush_ggtt_writes(ggtt->vm.gt);
Matches the story told by intel_gt_flush_ggtt_writes().
Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com
ggtt->vm.insert_page(&ggtt->vm, i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT), node.start, I915_CACHE_NONE, 0);@@ -639,8 +640,8 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj, i915_gem_object_unlock_fence(obj, fence); out_unpin: mutex_lock(&i915->drm.struct_mutex);
- intel_gt_flush_ggtt_writes(ggtt->vm.gt); if (node.allocated) {
wmb();-- 2.22.0
Quoting Ville Syrjälä (2019-07-18 19:28:43)
On Thu, Jul 18, 2019 at 03:54:05PM +0100, Chris Wilson wrote:
As recently disovered by forcing big-core (!llc) machines to use the GTT paths, we need our full GTT write flush before manipulating the GTT PTE or else the writes may be directed to the wrong page.
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Matthew Auld matthew.william.auld@gmail.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: stable@vger.kernel.org
drivers/gpu/drm/i915/i915_gem.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index fed0bc421a55..c6ba350e6e4f 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -610,7 +610,8 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj, unsigned int page_length = PAGE_SIZE - page_offset; page_length = remain < page_length ? remain : page_length; if (node.allocated) {
wmb(); /* flush the write before we modify the GGTT */
/* flush the write before we modify the GGTT */intel_gt_flush_ggtt_writes(ggtt->vm.gt);Matches the story told by intel_gt_flush_ggtt_writes().
Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com
Ta, pushed to dinq. Hopefully, this may explain some mystery fails! (Not that any sane userspace does for(;;) { gem_write(); gem_read(); }) -Chris
linux-stable-mirror@lists.linaro.org
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Chris Wilson -
Ville Syrjälä