drm/i915/selftests: Always flush before unpining after writing

Be consistent, and even when we know we had used a WC, flush the mapped
object after writing into it. The flush understands the mapping type and
will only clflush if !I915_MAP_WC, but will always insert a wmb [sfence]
so that we can be sure that all writes are visible.

v2: Add the unconditional wmb so we are know that we always flush the
writes to memory/HW at that point.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200511141304.599-1-chris@chris-wilson.co.uk

7 files changed, 21 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c b/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
index 2fc7737ef5f4..f457d7130491 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
@@ -78,10 +78,12 @@ struct i915_vma *intel_emit_vma_fill_blt(struct intel_context *ce,
 	} while (rem);
 
 	*cmd = MI_BATCH_BUFFER_END;
-	intel_gt_chipset_flush(ce->vm->gt);
 
+	i915_gem_object_flush_map(pool->obj);
 	i915_gem_object_unpin_map(pool->obj);
 
+	intel_gt_chipset_flush(ce->vm->gt);
+
 	batch = i915_vma_instance(pool->obj, ce->vm, NULL);
 	if (IS_ERR(batch)) {
 		err = PTR_ERR(batch);
@@ -289,10 +291,12 @@ struct i915_vma *intel_emit_vma_copy_blt(struct intel_context *ce,
 	} while (rem);
 
 	*cmd = MI_BATCH_BUFFER_END;
-	intel_gt_chipset_flush(ce->vm->gt);
 
+	i915_gem_object_flush_map(pool->obj);
 	i915_gem_object_unpin_map(pool->obj);
 
+	intel_gt_chipset_flush(ce->vm->gt);
+
 	batch = i915_vma_instance(pool->obj, ce->vm, NULL);
 	if (IS_ERR(batch)) {
 		err = PTR_ERR(batch);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 5d855fcd5c0f..af9e48ee4a33 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -391,6 +391,7 @@ void __i915_gem_object_flush_map(struct drm_i915_gem_object *obj,
 	GEM_BUG_ON(range_overflows_t(typeof(obj->base.size),
 				     offset, size, obj->base.size));
 
+	wmb(); /* let all previous writes be visible to coherent partners */
 	obj->mm.dirty = true;
 
 	if (obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
index 3f6079e1dfb6..87d7d8aa080f 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
@@ -158,6 +158,8 @@ static int wc_set(struct context *ctx, unsigned long offset, u32 v)
 		return PTR_ERR(map);
 
 	map[offset / sizeof(*map)] = v;
+
+	__i915_gem_object_flush_map(ctx->obj, offset, sizeof(*map));
 	i915_gem_object_unpin_map(ctx->obj);
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/gem/selftests/igt_gem_utils.c b/drivers/gpu/drm/i915/gem/selftests/igt_gem_utils.c
index 8b3925b4036f..e21b5023ca7d 100644
--- a/drivers/gpu/drm/i915/gem/selftests/igt_gem_utils.c
+++ b/drivers/gpu/drm/i915/gem/selftests/igt_gem_utils.c
@@ -84,6 +84,7 @@ igt_emit_store_dw(struct i915_vma *vma,
 	}
 	*cmd = MI_BATCH_BUFFER_END;
 
+	i915_gem_object_flush_map(obj);
 	i915_gem_object_unpin_map(obj);
 
 	intel_gt_chipset_flush(vma->vm->gt);
diff --git a/drivers/gpu/drm/i915/gt/selftest_ring_submission.c b/drivers/gpu/drm/i915/gt/selftest_ring_submission.c
index 9995faadd7e8..3350e7c995bc 100644
--- a/drivers/gpu/drm/i915/gt/selftest_ring_submission.c
+++ b/drivers/gpu/drm/i915/gt/selftest_ring_submission.c
@@ -54,6 +54,8 @@ static struct i915_vma *create_wally(struct intel_engine_cs *engine)
 	*cs++ = STACK_MAGIC;
 
 	*cs++ = MI_BATCH_BUFFER_END;
+
+	i915_gem_object_flush_map(obj);
 	i915_gem_object_unpin_map(obj);
 
 	vma->private = intel_context_create(engine); /* dummy residuals */
diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.c b/drivers/gpu/drm/i915/gt/selftest_rps.c
index bfa1a15564f7..6275d69aa9cc 100644
--- a/drivers/gpu/drm/i915/gt/selftest_rps.c
+++ b/drivers/gpu/drm/i915/gt/selftest_rps.c
@@ -727,6 +727,7 @@ int live_rps_frequency_cs(void *arg)
 
 err_vma:
 		*cancel = MI_BATCH_BUFFER_END;
+		i915_gem_object_flush_map(vma->obj);
 		i915_gem_object_unpin_map(vma->obj);
 		i915_vma_unpin(vma);
 		i915_vma_put(vma);
@@ -868,6 +869,7 @@ int live_rps_frequency_srm(void *arg)
 
 err_vma:
 		*cancel = MI_BATCH_BUFFER_END;
+		i915_gem_object_flush_map(vma->obj);
 		i915_gem_object_unpin_map(vma->obj);
 		i915_vma_unpin(vma);
 		i915_vma_put(vma);
diff --git a/drivers/gpu/drm/i915/selftests/i915_request.c b/drivers/gpu/drm/i915/selftests/i915_request.c
index ffdfcb3805b5..6014e8dfcbb1 100644
--- a/drivers/gpu/drm/i915/selftests/i915_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_request.c
@@ -816,10 +816,12 @@ static int recursive_batch_resolve(struct i915_vma *batch)
 		return PTR_ERR(cmd);
 
 	*cmd = MI_BATCH_BUFFER_END;
-	intel_gt_chipset_flush(batch->vm->gt);
 
+	__i915_gem_object_flush_map(batch->obj, 0, sizeof(*cmd));
 	i915_gem_object_unpin_map(batch->obj);
 
+	intel_gt_chipset_flush(batch->vm->gt);
+
 	return 0;
 }
 
@@ -1060,9 +1062,12 @@ out_request:
 					      I915_MAP_WC);
 		if (!IS_ERR(cmd)) {
 			*cmd = MI_BATCH_BUFFER_END;
-			intel_gt_chipset_flush(engine->gt);
 
+			__i915_gem_object_flush_map(request[idx]->batch->obj,
+						    0, sizeof(*cmd));
 			i915_gem_object_unpin_map(request[idx]->batch->obj);
+
+			intel_gt_chipset_flush(engine->gt);
 		}
 
 		i915_vma_put(request[idx]->batch);