linux-kernel - [PATCH v11 06/10] drm/i915: ttm move/clear logic fix

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20220713135022.3710682-7-bob.beckett@collabora.com>
Date:   Wed, 13 Jul 2022 14:50:18 +0100
From:   Robert Beckett <bob.beckett@...labora.com>
To:     dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>
Cc:     kernel@...labora.com, Robert Beckett <bob.beckett@...labora.com>,
        Matthew Auld <matthew.auld@...el.com>,
        Thomas Hellström 
        <thomas.hellstrom@...ux.intel.com>, linux-kernel@...r.kernel.org
Subject: [PATCH v11 06/10] drm/i915: ttm move/clear logic fix

ttm managed buffers start off with system resource definitions and ttm_tt
tracking structures allocated (though unpopulated).
currently this prevents clearing of buffers on first move to desired
placements.

The desired behaviour is to clear user allocated buffers and any kernel
buffers that specifically requests it only.
Make the logic match the desired behaviour.

Signed-off-by: Robert Beckett <bob.beckett@...labora.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@...ux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c | 22 +++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
index 18d574ac167f..6671345b2abe 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -3,6 +3,7 @@
  * Copyright © 2021 Intel Corporation
  */
 
+#include "drm/ttm/ttm_tt.h"
 #include <drm/ttm/ttm_bo_driver.h>
 
 #include "i915_deps.h"
@@ -546,6 +547,25 @@ __i915_ttm_move(struct ttm_buffer_object *bo,
 	return fence;
 }
 
+static bool
+allow_clear(struct drm_i915_gem_object *obj, struct ttm_tt *ttm, struct ttm_resource *dst_mem)
+{
+	/* never clear stolen */
+	if (dst_mem->mem_type == I915_PL_STOLEN)
+		return false;
+	/*
+	 * we want to clear user buffers and any kernel buffers
+	 * that specifically request clearing.
+	 */
+	if (obj->flags & I915_BO_ALLOC_USER)
+		return true;
+
+	if (ttm && ttm->page_flags & TTM_TT_FLAG_ZERO_ALLOC)
+		return true;
+
+	return false;
+}
+
 /**
  * i915_ttm_move - The TTM move callback used by i915.
  * @bo: The buffer object.
@@ -596,7 +616,7 @@ int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
 		return PTR_ERR(dst_rsgt);
 
 	clear = !i915_ttm_cpu_maps_iomem(bo->resource) && (!ttm || !ttm_tt_is_populated(ttm));
-	if (!(clear && ttm && !(ttm->page_flags & TTM_TT_FLAG_ZERO_ALLOC))) {
+	if (!clear || allow_clear(obj, ttm, dst_mem)) {
 		struct i915_deps deps;
 
 		i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
-- 
2.25.1