drm/i915/gem: Introduce a selftest for the gem object migrate functionality

A selftest for the gem object migrate functionality. Slightly adapted
from the original by Matthew to the new interface and new fill blit
code.

v4:
- Initialize buffers and check contents after migration
  (Suggested by Matthew Auld)
- Perform async migration (if implemented) in the igt_lmem_pages_migrate
  test
- Test also migration to the current region.
Co-developed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com> #v3
Link: https://patchwork.freedesktop.org/patch/msgid/20210629151203.209465-3-thomas.hellstrom@linux.intel.com

drivers/gpu/drm/i915/gem/i915_gem_object.c

@@ -665,6 +665,7 @@ static const struct drm_gem_object_funcs i915_gem_object_funcs = {
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/huge_gem_object.c"
 #include "selftests/huge_pages.c"
+#include "selftests/i915_gem_migrate.c"
 #include "selftests/i915_gem_object.c"
 #include "selftests/i915_gem_coherency.c"
 #endif

drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c

+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2020-2021 Intel Corporation
+ */
+
+#include "gt/intel_migrate.h"
+
+static int igt_fill_check_buffer(struct drm_i915_gem_object *obj,
+				 bool fill)
+{
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	unsigned int i, count = obj->base.size / sizeof(u32);
+	enum i915_map_type map_type =
+		i915_coherent_map_type(i915, obj, false);
+	u32 *cur;
+	int err = 0;
+
+	assert_object_held(obj);
+	cur = i915_gem_object_pin_map(obj, map_type);
+	if (IS_ERR(cur))
+		return PTR_ERR(cur);
+
+	if (fill)
+		for (i = 0; i < count; ++i)
+			*cur++ = i;
+	else
+		for (i = 0; i < count; ++i)
+			if (*cur++ != i) {
+				pr_err("Object content mismatch at location %d of %d\n", i, count);
+				err = -EINVAL;
+				break;
+			}
+
+	i915_gem_object_unpin_map(obj);
+
+	return err;
+}
+
+static int igt_create_migrate(struct intel_gt *gt, enum intel_region_id src,
+			      enum intel_region_id dst)
+{
+	struct drm_i915_private *i915 = gt->i915;
+	struct intel_memory_region *src_mr = i915->mm.regions[src];
+	struct drm_i915_gem_object *obj;
+	struct i915_gem_ww_ctx ww;
+	int err = 0;
+
+	GEM_BUG_ON(!src_mr);
+
+	/* Switch object backing-store on create */
+	obj = i915_gem_object_create_region(src_mr, PAGE_SIZE, 0);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	for_i915_gem_ww(&ww, err, true) {
+		err = i915_gem_object_lock(obj, &ww);
+		if (err)
+			continue;
+
+		err = igt_fill_check_buffer(obj, true);
+		if (err)
+			continue;
+
+		if (!i915_gem_object_can_migrate(obj, dst)) {
+			err = -EINVAL;
+			continue;
+		}
+
+		err = i915_gem_object_migrate(obj, &ww, dst);
+		if (err)
+			continue;
+
+		err = i915_gem_object_pin_pages(obj);
+		if (err)
+			continue;
+
+		if (i915_gem_object_can_migrate(obj, src))
+			err = -EINVAL;
+
+		i915_gem_object_unpin_pages(obj);
+		err = i915_gem_object_wait_migration(obj, true);
+		if (err)
+			continue;
+
+		err = igt_fill_check_buffer(obj, false);
+	}
+	i915_gem_object_put(obj);
+
+	return err;
+}
+
+static int igt_smem_create_migrate(void *arg)
+{
+	return igt_create_migrate(arg, INTEL_REGION_LMEM, INTEL_REGION_SMEM);
+}
+
+static int igt_lmem_create_migrate(void *arg)
+{
+	return igt_create_migrate(arg, INTEL_REGION_SMEM, INTEL_REGION_LMEM);
+}
+
+static int igt_same_create_migrate(void *arg)
+{
+	return igt_create_migrate(arg, INTEL_REGION_LMEM, INTEL_REGION_LMEM);
+}
+
+static int lmem_pages_migrate_one(struct i915_gem_ww_ctx *ww,
+				  struct drm_i915_gem_object *obj)
+{
+	int err;
+
+	err = i915_gem_object_lock(obj, ww);
+	if (err)
+		return err;
+
+	if (i915_gem_object_is_lmem(obj)) {
+		if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM)) {
+			pr_err("object can't migrate to smem.\n");
+			return -EINVAL;
+		}
+
+		err = i915_gem_object_migrate(obj, ww, INTEL_REGION_SMEM);
+		if (err) {
+			pr_err("Object failed migration to smem\n");
+			if (err)
+				return err;
+		}
+
+		if (i915_gem_object_is_lmem(obj)) {
+			pr_err("object still backed by lmem\n");
+			err = -EINVAL;
+		}
+
+		if (!i915_gem_object_has_struct_page(obj)) {
+			pr_err("object not backed by struct page\n");
+			err = -EINVAL;
+		}
+
+	} else {
+		if (!i915_gem_object_can_migrate(obj, INTEL_REGION_LMEM)) {
+			pr_err("object can't migrate to lmem.\n");
+			return -EINVAL;
+		}
+
+		err = i915_gem_object_migrate(obj, ww, INTEL_REGION_LMEM);
+		if (err) {
+			pr_err("Object failed migration to lmem\n");
+			if (err)
+				return err;
+		}
+
+		if (i915_gem_object_has_struct_page(obj)) {
+			pr_err("object still backed by struct page\n");
+			err = -EINVAL;
+		}
+
+		if (!i915_gem_object_is_lmem(obj)) {
+			pr_err("object not backed by lmem\n");
+			err = -EINVAL;
+		}
+	}
+
+	return err;
+}
+
+static int igt_lmem_pages_migrate(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct drm_i915_private *i915 = gt->i915;
+	struct drm_i915_gem_object *obj;
+	struct i915_gem_ww_ctx ww;
+	struct i915_request *rq;
+	int err;
+	int i;
+
+	/* From LMEM to shmem and back again */
+
+	obj = i915_gem_object_create_lmem(i915, SZ_2M, 0);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	/* Initial GPU fill, sync, CPU initialization. */
+	for_i915_gem_ww(&ww, err, true) {
+		err = i915_gem_object_lock(obj, &ww);
+		if (err)
+			continue;
+
+		err = ____i915_gem_object_get_pages(obj);
+		if (err)
+			continue;
+
+		err = intel_migrate_clear(&gt->migrate, &ww, NULL,
+					  obj->mm.pages->sgl, obj->cache_level,
+					  i915_gem_object_is_lmem(obj),
+					  0xdeadbeaf, &rq);
+		if (rq) {
+			dma_resv_add_excl_fence(obj->base.resv, &rq->fence);
+			i915_request_put(rq);
+		}
+		if (err)
+			continue;
+
+		err = i915_gem_object_wait(obj, I915_WAIT_INTERRUPTIBLE,
+					   5 * HZ);
+		if (err)
+			continue;
+
+		err = igt_fill_check_buffer(obj, true);
+		if (err)
+			continue;
+	}
+	if (err)
+		goto out_put;
+
+	/*
+	 * Migrate to and from smem without explicitly syncing.
+	 * Finalize with data in smem for fast readout.
+	 */
+	for (i = 1; i <= 5; ++i) {
+		for_i915_gem_ww(&ww, err, true)
+			err = lmem_pages_migrate_one(&ww, obj);
+		if (err)
+			goto out_put;
+	}
+
+	err = i915_gem_object_lock_interruptible(obj, NULL);
+	if (err)
+		goto out_put;
+
+	/* Finally sync migration and check content. */
+	err = i915_gem_object_wait_migration(obj, true);
+	if (err)
+		goto out_unlock;
+
+	err = igt_fill_check_buffer(obj, false);
+
+out_unlock:
+	i915_gem_object_unlock(obj);
+out_put:
+	i915_gem_object_put(obj);
+
+	return err;
+}
+
+int i915_gem_migrate_live_selftests(struct drm_i915_private *i915)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(igt_smem_create_migrate),
+		SUBTEST(igt_lmem_create_migrate),
+		SUBTEST(igt_same_create_migrate),
+		SUBTEST(igt_lmem_pages_migrate),
+	};
+
+	if (!HAS_LMEM(i915))
+		return 0;
+
+	return intel_gt_live_subtests(tests, &i915->gt);
+}

drivers/gpu/drm/i915/selftests/i915_live_selftests.h

@@ -40,6 +40,7 @@ selftest(hugepages, i915_gem_huge_page_live_selftests)
 selftest(gem_contexts, i915_gem_context_live_selftests)
 selftest(gem_execbuf, i915_gem_execbuffer_live_selftests)
 selftest(client, i915_gem_client_blt_live_selftests)
+selftest(gem_migrate, i915_gem_migrate_live_selftests)
 selftest(reset, intel_reset_live_selftests)
 selftest(memory_region, intel_memory_region_live_selftests)
 selftest(hangcheck, intel_hangcheck_live_selftests)