drm/i915/selftests: Add coverage of mocs registers

Probe the mocs registers for new contexts and across GPU resets. Similar
to intel_workarounds, we have tables of what register values we expect
to see, so verify that user contexts are affected by them. In the
future, we should add tests similar to intel_sseu to cover dynamic
reconfigurations.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191112223600.30993-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_mocs.c

@@ -452,3 +452,7 @@ void intel_mocs_init(struct intel_gt *gt)
 	if (HAS_GLOBAL_MOCS_REGISTERS(gt->i915))
 		init_global_mocs(gt);
 }
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftest_mocs.c"
+#endif

drivers/gpu/drm/i915/gt/selftest_mocs.c

+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "gt/intel_engine_pm.h"
+#include "i915_selftest.h"
+
+#include "gem/selftests/mock_context.h"
+#include "selftests/igt_reset.h"
+#include "selftests/igt_spinner.h"
+
+struct live_mocs {
+	struct drm_i915_mocs_table table;
+	struct i915_vma *scratch;
+	void *vaddr;
+};
+
+static int request_add_sync(struct i915_request *rq, int err)
+{
+	i915_request_get(rq);
+	i915_request_add(rq);
+	if (i915_request_wait(rq, 0, HZ / 5) < 0)
+		err = -ETIME;
+	i915_request_put(rq);
+
+	return err;
+}
+
+static int request_add_spin(struct i915_request *rq, struct igt_spinner *spin)
+{
+	int err = 0;
+
+	i915_request_get(rq);
+	i915_request_add(rq);
+	if (spin && !igt_wait_for_spinner(spin, rq))
+		err = -ETIME;
+	i915_request_put(rq);
+
+	return err;
+}
+
+static struct i915_vma *create_scratch(struct intel_gt *gt)
+{
+	struct drm_i915_gem_object *obj;
+	struct i915_vma *vma;
+	int err;
+
+	obj = i915_gem_object_create_internal(gt->i915, PAGE_SIZE);
+	if (IS_ERR(obj))
+		return ERR_CAST(obj);
+
+	i915_gem_object_set_cache_coherency(obj, I915_CACHING_CACHED);
+
+	vma = i915_vma_instance(obj, &gt->ggtt->vm, NULL);
+	if (IS_ERR(vma)) {
+		i915_gem_object_put(obj);
+		return vma;
+	}
+
+	err = i915_vma_pin(vma, 0, 0, PIN_GLOBAL);
+	if (err) {
+		i915_gem_object_put(obj);
+		return ERR_PTR(err);
+	}
+
+	return vma;
+}
+
+static int live_mocs_init(struct live_mocs *arg, struct intel_gt *gt)
+{
+	int err;
+
+	if (!get_mocs_settings(gt->i915, &arg->table))
+		return -EINVAL;
+
+	arg->scratch = create_scratch(gt);
+	if (IS_ERR(arg->scratch))
+		return PTR_ERR(arg->scratch);
+
+	arg->vaddr = i915_gem_object_pin_map(arg->scratch->obj, I915_MAP_WB);
+	if (IS_ERR(arg->vaddr)) {
+		err = PTR_ERR(arg->vaddr);
+		goto err_scratch;
+	}
+
+	return 0;
+
+err_scratch:
+	i915_vma_unpin_and_release(&arg->scratch, 0);
+	return err;
+}
+
+static void live_mocs_fini(struct live_mocs *arg)
+{
+	i915_vma_unpin_and_release(&arg->scratch, I915_VMA_RELEASE_MAP);
+}
+
+static int read_regs(struct i915_request *rq,
+		     u32 addr, unsigned int count,
+		     uint32_t *offset)
+{
+	unsigned int i;
+	u32 *cs;
+
+	GEM_BUG_ON(!IS_ALIGNED(*offset, sizeof(u32)));
+
+	cs = intel_ring_begin(rq, 4 * count);
+	if (IS_ERR(cs))
+		return PTR_ERR(cs);
+
+	for (i = 0; i < count; i++) {
+		*cs++ = MI_STORE_REGISTER_MEM_GEN8 | MI_USE_GGTT;
+		*cs++ = addr;
+		*cs++ = *offset;
+		*cs++ = 0;
+
+		addr += sizeof(u32);
+		*offset += sizeof(u32);
+	}
+
+	intel_ring_advance(rq, cs);
+
+	return 0;
+}
+
+static int read_mocs_table(struct i915_request *rq,
+			   const struct drm_i915_mocs_table *table,
+			   uint32_t *offset)
+{
+	u32 addr;
+
+	if (HAS_GLOBAL_MOCS_REGISTERS(rq->i915))
+		addr = global_mocs_offset();
+	else
+		addr = mocs_offset(rq->engine);
+
+	return read_regs(rq, addr, table->n_entries, offset);
+}
+
+static int read_l3cc_table(struct i915_request *rq,
+			   const struct drm_i915_mocs_table *table,
+			   uint32_t *offset)
+{
+	u32 addr = i915_mmio_reg_offset(GEN9_LNCFCMOCS(0));
+
+	return read_regs(rq, addr, (table->n_entries + 1) / 2, offset);
+}
+
+static int check_mocs_table(struct intel_engine_cs *engine,
+			    const struct drm_i915_mocs_table *table,
+			    uint32_t **vaddr)
+{
+	unsigned int i;
+	u32 expect;
+
+	for_each_mocs(expect, table, i) {
+		if (**vaddr != expect) {
+			pr_err("%s: Invalid MOCS[%d] entry, found %08x, expected %08x\n",
+			       engine->name, i, **vaddr, expect);
+			return -EINVAL;
+		}
+		++*vaddr;
+	}
+
+	return 0;
+}
+
+static bool mcr_range(struct drm_i915_private *i915, u32 offset)
+{
+	/*
+	 * Registers in this range are affected by the MCR selector
+	 * which only controls CPU initiated MMIO. Routing does not
+	 * work for CS access so we cannot verify them on this path.
+	 */
+	return INTEL_GEN(i915) >= 8 && offset >= 0xb000 && offset <= 0xb4ff;
+}
+
+static int check_l3cc_table(struct intel_engine_cs *engine,
+			    const struct drm_i915_mocs_table *table,
+			    uint32_t **vaddr)
+{
+	/* Can we read the MCR range 0xb00 directly? See intel_workarounds! */
+	u32 reg = i915_mmio_reg_offset(GEN9_LNCFCMOCS(0));
+	unsigned int i;
+	u32 expect;
+
+	for_each_l3cc(expect, table, i) {
+		if (!mcr_range(engine->i915, reg) && **vaddr != expect) {
+			pr_err("%s: Invalid L3CC[%d] entry, found %08x, expected %08x\n",
+			       engine->name, i, **vaddr, expect);
+			return -EINVAL;
+		}
+		++*vaddr;
+		reg += 4;
+	}
+
+	return 0;
+}
+
+static int check_mocs_engine(struct live_mocs *arg,
+			     struct intel_context *ce)
+{
+	struct i915_vma *vma = arg->scratch;
+	struct i915_request *rq;
+	u32 offset;
+	u32 *vaddr;
+	int err;
+
+	memset32(arg->vaddr, STACK_MAGIC, PAGE_SIZE / sizeof(u32));
+
+	rq = intel_context_create_request(ce);
+	if (IS_ERR(rq))
+		return PTR_ERR(rq);
+
+	i915_vma_lock(vma);
+	err = i915_request_await_object(rq, vma->obj, true);
+	if (!err)
+		err = i915_vma_move_to_active(vma, rq, EXEC_OBJECT_WRITE);
+	i915_vma_unlock(vma);
+
+	/* Read the mocs tables back using SRM */
+	offset = i915_ggtt_offset(vma);
+	if (!err)
+		err = read_mocs_table(rq, &arg->table, &offset);
+	if (!err && ce->engine->class == RENDER_CLASS)
+		err = read_l3cc_table(rq, &arg->table, &offset);
+	offset -= i915_ggtt_offset(vma);
+	GEM_BUG_ON(offset > PAGE_SIZE);
+
+	err = request_add_sync(rq, err);
+	if (err)
+		return err;
+
+	/* Compare the results against the expected tables */
+	vaddr = arg->vaddr;
+	if (!err)
+		err = check_mocs_table(ce->engine, &arg->table, &vaddr);
+	if (!err && ce->engine->class == RENDER_CLASS)
+		err = check_l3cc_table(ce->engine, &arg->table, &vaddr);
+	if (err)
+		return err;
+
+	GEM_BUG_ON(arg->vaddr + offset != vaddr);
+	return 0;
+}
+
+static int live_mocs_kernel(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	struct live_mocs mocs;
+	int err;
+
+	/* Basic check the system is configured with the expected mocs table */
+
+	err = live_mocs_init(&mocs, gt);
+	if (err)
+		return err;
+
+	for_each_engine(engine, gt, id) {
+		err = check_mocs_engine(&mocs, engine->kernel_context);
+		if (err)
+			break;
+	}
+
+	live_mocs_fini(&mocs);
+	return err;
+}
+
+static int live_mocs_clean(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	struct live_mocs mocs;
+	int err;
+
+	/* Every new context should see the same mocs table */
+
+	err = live_mocs_init(&mocs, gt);
+	if (err)
+		return err;
+
+	for_each_engine(engine, gt, id) {
+		struct intel_context *ce;
+
+		ce = intel_context_create(engine->kernel_context->gem_context,
+					  engine);
+		if (IS_ERR(ce)) {
+			err = PTR_ERR(ce);
+			break;
+		}
+
+		err = check_mocs_engine(&mocs, ce);
+		intel_context_put(ce);
+		if (err)
+			break;
+	}
+
+	live_mocs_fini(&mocs);
+	return err;
+}
+
+static int active_engine_reset(struct intel_context *ce,
+			       const char *reason)
+{
+	struct igt_spinner spin;
+	struct i915_request *rq;
+	int err;
+
+	err = igt_spinner_init(&spin, ce->engine->gt);
+	if (err)
+		return err;
+
+	rq = igt_spinner_create_request(&spin, ce, MI_NOOP);
+	if (IS_ERR(rq)) {
+		igt_spinner_fini(&spin);
+		return PTR_ERR(rq);
+	}
+
+	err = request_add_spin(rq, &spin);
+	if (err == 0)
+		err = intel_engine_reset(ce->engine, reason);
+
+	igt_spinner_end(&spin);
+	igt_spinner_fini(&spin);
+
+	return err;
+}
+
+static int __live_mocs_reset(struct live_mocs *mocs,
+			     struct intel_context *ce)
+{
+	int err;
+
+	err = intel_engine_reset(ce->engine, "mocs");
+	if (err)
+		return err;
+
+	err = check_mocs_engine(mocs, ce);
+	if (err)
+		return err;
+
+	err = active_engine_reset(ce, "mocs");
+	if (err)
+		return err;
+
+	err = check_mocs_engine(mocs, ce);
+	if (err)
+		return err;
+
+	intel_gt_reset(ce->engine->gt, ce->engine->mask, "mocs");
+
+	err = check_mocs_engine(mocs, ce);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int live_mocs_reset(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	struct live_mocs mocs;
+	int err = 0;
+
+	/* Check the mocs setup is retained over per-engine and global resets */
+
+	if (!intel_has_reset_engine(gt))
+		return 0;
+
+	err = live_mocs_init(&mocs, gt);
+	if (err)
+		return err;
+
+	igt_global_reset_lock(gt);
+	for_each_engine(engine, gt, id) {
+		struct intel_context *ce;
+
+		ce = intel_context_create(engine->kernel_context->gem_context,
+					  engine);
+		if (IS_ERR(ce)) {
+			err = PTR_ERR(ce);
+			break;
+		}
+
+		intel_engine_pm_get(engine);
+		err = __live_mocs_reset(&mocs, ce);
+		intel_engine_pm_put(engine);
+
+		intel_context_put(ce);
+		if (err)
+			break;
+	}
+	igt_global_reset_unlock(gt);
+
+	live_mocs_fini(&mocs);
+	return err;
+}
+
+int intel_mocs_live_selftests(struct drm_i915_private *i915)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(live_mocs_kernel),
+		SUBTEST(live_mocs_clean),
+		SUBTEST(live_mocs_reset),
+	};
+	struct drm_i915_mocs_table table;
+
+	if (!get_mocs_settings(i915, &table))
+		return 0;
+
+	return intel_gt_live_subtests(tests, &i915->gt);
+}

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

@@ -16,6 +16,7 @@ selftest(gt_engines, intel_engine_live_selftests)
 selftest(gt_timelines, intel_timeline_live_selftests)
 selftest(gt_contexts, intel_context_live_selftests)
 selftest(gt_lrc, intel_lrc_live_selftests)
+selftest(gt_mocs, intel_mocs_live_selftests)
 selftest(gt_pm, intel_gt_pm_live_selftests)
 selftest(gt_heartbeat, intel_heartbeat_live_selftests)
 selftest(requests, i915_request_live_selftests)