Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1425 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/selftest_timeline.c b/drivers/gpu/drm/i915/gt/selftest_timeline.c
new file mode 100644
index 000000000..522d01905
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/selftest_timeline.c
@@ -0,0 +1,1425 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2017-2018 Intel Corporation
+ */
+
+#include <linux/prime_numbers.h>
+#include <linux/string_helpers.h>
+
+#include "intel_context.h"
+#include "intel_engine_heartbeat.h"
+#include "intel_engine_pm.h"
+#include "intel_engine_regs.h"
+#include "intel_gpu_commands.h"
+#include "intel_gt.h"
+#include "intel_gt_requests.h"
+#include "intel_ring.h"
+#include "selftest_engine_heartbeat.h"
+
+#include "../selftests/i915_random.h"
+#include "../i915_selftest.h"
+
+#include "selftests/igt_flush_test.h"
+#include "selftests/lib_sw_fence.h"
+#include "selftests/mock_gem_device.h"
+#include "selftests/mock_timeline.h"
+
+static struct page *hwsp_page(struct intel_timeline *tl)
+{
+	struct drm_i915_gem_object *obj = tl->hwsp_ggtt->obj;
+
+	GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
+	return sg_page(obj->mm.pages->sgl);
+}
+
+static unsigned long hwsp_cacheline(struct intel_timeline *tl)
+{
+	unsigned long address = (unsigned long)page_address(hwsp_page(tl));
+
+	return (address + offset_in_page(tl->hwsp_offset)) / TIMELINE_SEQNO_BYTES;
+}
+
+static int selftest_tl_pin(struct intel_timeline *tl)
+{
+	struct i915_gem_ww_ctx ww;
+	int err;
+
+	i915_gem_ww_ctx_init(&ww, false);
+retry:
+	err = i915_gem_object_lock(tl->hwsp_ggtt->obj, &ww);
+	if (!err)
+		err = intel_timeline_pin(tl, &ww);
+
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(&ww);
+		if (!err)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
+	return err;
+}
+
+/* Only half of seqno's are usable, see __intel_timeline_get_seqno() */
+#define CACHELINES_PER_PAGE (PAGE_SIZE / TIMELINE_SEQNO_BYTES / 2)
+
+struct mock_hwsp_freelist {
+	struct intel_gt *gt;
+	struct radix_tree_root cachelines;
+	struct intel_timeline **history;
+	unsigned long count, max;
+	struct rnd_state prng;
+};
+
+enum {
+	SHUFFLE = BIT(0),
+};
+
+static void __mock_hwsp_record(struct mock_hwsp_freelist *state,
+			       unsigned int idx,
+			       struct intel_timeline *tl)
+{
+	tl = xchg(&state->history[idx], tl);
+	if (tl) {
+		radix_tree_delete(&state->cachelines, hwsp_cacheline(tl));
+		intel_timeline_unpin(tl);
+		intel_timeline_put(tl);
+	}
+}
+
+static int __mock_hwsp_timeline(struct mock_hwsp_freelist *state,
+				unsigned int count,
+				unsigned int flags)
+{
+	struct intel_timeline *tl;
+	unsigned int idx;
+
+	while (count--) {
+		unsigned long cacheline;
+		int err;
+
+		tl = intel_timeline_create(state->gt);
+		if (IS_ERR(tl))
+			return PTR_ERR(tl);
+
+		err = selftest_tl_pin(tl);
+		if (err) {
+			intel_timeline_put(tl);
+			return err;
+		}
+
+		cacheline = hwsp_cacheline(tl);
+		err = radix_tree_insert(&state->cachelines, cacheline, tl);
+		if (err) {
+			if (err == -EEXIST) {
+				pr_err("HWSP cacheline %lu already used; duplicate allocation!\n",
+				       cacheline);
+			}
+			intel_timeline_unpin(tl);
+			intel_timeline_put(tl);
+			return err;
+		}
+
+		idx = state->count++ % state->max;
+		__mock_hwsp_record(state, idx, tl);
+	}
+
+	if (flags & SHUFFLE)
+		i915_prandom_shuffle(state->history,
+				     sizeof(*state->history),
+				     min(state->count, state->max),
+				     &state->prng);
+
+	count = i915_prandom_u32_max_state(min(state->count, state->max),
+					   &state->prng);
+	while (count--) {
+		idx = --state->count % state->max;
+		__mock_hwsp_record(state, idx, NULL);
+	}
+
+	return 0;
+}
+
+static int mock_hwsp_freelist(void *arg)
+{
+	struct mock_hwsp_freelist state;
+	struct drm_i915_private *i915;
+	const struct {
+		const char *name;
+		unsigned int flags;
+	} phases[] = {
+		{ "linear", 0 },
+		{ "shuffled", SHUFFLE },
+		{ },
+	}, *p;
+	unsigned int na;
+	int err = 0;
+
+	i915 = mock_gem_device();
+	if (!i915)
+		return -ENOMEM;
+
+	INIT_RADIX_TREE(&state.cachelines, GFP_KERNEL);
+	state.prng = I915_RND_STATE_INITIALIZER(i915_selftest.random_seed);
+
+	state.gt = to_gt(i915);
+
+	/*
+	 * Create a bunch of timelines and check that their HWSP do not overlap.
+	 * Free some, and try again.
+	 */
+
+	state.max = PAGE_SIZE / sizeof(*state.history);
+	state.count = 0;
+	state.history = kcalloc(state.max, sizeof(*state.history), GFP_KERNEL);
+	if (!state.history) {
+		err = -ENOMEM;
+		goto err_put;
+	}
+
+	for (p = phases; p->name; p++) {
+		pr_debug("%s(%s)\n", __func__, p->name);
+		for_each_prime_number_from(na, 1, 2 * CACHELINES_PER_PAGE) {
+			err = __mock_hwsp_timeline(&state, na, p->flags);
+			if (err)
+				goto out;
+		}
+	}
+
+out:
+	for (na = 0; na < state.max; na++)
+		__mock_hwsp_record(&state, na, NULL);
+	kfree(state.history);
+err_put:
+	mock_destroy_device(i915);
+	return err;
+}
+
+struct __igt_sync {
+	const char *name;
+	u32 seqno;
+	bool expected;
+	bool set;
+};
+
+static int __igt_sync(struct intel_timeline *tl,
+		      u64 ctx,
+		      const struct __igt_sync *p,
+		      const char *name)
+{
+	int ret;
+
+	if (__intel_timeline_sync_is_later(tl, ctx, p->seqno) != p->expected) {
+		pr_err("%s: %s(ctx=%llu, seqno=%u) expected passed %s but failed\n",
+		       name, p->name, ctx, p->seqno, str_yes_no(p->expected));
+		return -EINVAL;
+	}
+
+	if (p->set) {
+		ret = __intel_timeline_sync_set(tl, ctx, p->seqno);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int igt_sync(void *arg)
+{
+	const struct __igt_sync pass[] = {
+		{ "unset", 0, false, false },
+		{ "new", 0, false, true },
+		{ "0a", 0, true, true },
+		{ "1a", 1, false, true },
+		{ "1b", 1, true, true },
+		{ "0b", 0, true, false },
+		{ "2a", 2, false, true },
+		{ "4", 4, false, true },
+		{ "INT_MAX", INT_MAX, false, true },
+		{ "INT_MAX-1", INT_MAX-1, true, false },
+		{ "INT_MAX+1", (u32)INT_MAX+1, false, true },
+		{ "INT_MAX", INT_MAX, true, false },
+		{ "UINT_MAX", UINT_MAX, false, true },
+		{ "wrap", 0, false, true },
+		{ "unwrap", UINT_MAX, true, false },
+		{},
+	}, *p;
+	struct intel_timeline tl;
+	int order, offset;
+	int ret = -ENODEV;
+
+	mock_timeline_init(&tl, 0);
+	for (p = pass; p->name; p++) {
+		for (order = 1; order < 64; order++) {
+			for (offset = -1; offset <= (order > 1); offset++) {
+				u64 ctx = BIT_ULL(order) + offset;
+
+				ret = __igt_sync(&tl, ctx, p, "1");
+				if (ret)
+					goto out;
+			}
+		}
+	}
+	mock_timeline_fini(&tl);
+
+	mock_timeline_init(&tl, 0);
+	for (order = 1; order < 64; order++) {
+		for (offset = -1; offset <= (order > 1); offset++) {
+			u64 ctx = BIT_ULL(order) + offset;
+
+			for (p = pass; p->name; p++) {
+				ret = __igt_sync(&tl, ctx, p, "2");
+				if (ret)
+					goto out;
+			}
+		}
+	}
+
+out:
+	mock_timeline_fini(&tl);
+	return ret;
+}
+
+static unsigned int random_engine(struct rnd_state *rnd)
+{
+	return i915_prandom_u32_max_state(I915_NUM_ENGINES, rnd);
+}
+
+static int bench_sync(void *arg)
+{
+	struct rnd_state prng;
+	struct intel_timeline tl;
+	unsigned long end_time, count;
+	u64 prng32_1M;
+	ktime_t kt;
+	int order, last_order;
+
+	mock_timeline_init(&tl, 0);
+
+	/* Lookups from cache are very fast and so the random number generation
+	 * and the loop itself becomes a significant factor in the per-iteration
+	 * timings. We try to compensate the results by measuring the overhead
+	 * of the prng and subtract it from the reported results.
+	 */
+	prandom_seed_state(&prng, i915_selftest.random_seed);
+	count = 0;
+	kt = ktime_get();
+	end_time = jiffies + HZ/10;
+	do {
+		u32 x;
+
+		/* Make sure the compiler doesn't optimise away the prng call */
+		WRITE_ONCE(x, prandom_u32_state(&prng));
+
+		count++;
+	} while (!time_after(jiffies, end_time));
+	kt = ktime_sub(ktime_get(), kt);
+	pr_debug("%s: %lu random evaluations, %lluns/prng\n",
+		 __func__, count, (long long)div64_ul(ktime_to_ns(kt), count));
+	prng32_1M = div64_ul(ktime_to_ns(kt) << 20, count);
+
+	/* Benchmark (only) setting random context ids */
+	prandom_seed_state(&prng, i915_selftest.random_seed);
+	count = 0;
+	kt = ktime_get();
+	end_time = jiffies + HZ/10;
+	do {
+		u64 id = i915_prandom_u64_state(&prng);
+
+		__intel_timeline_sync_set(&tl, id, 0);
+		count++;
+	} while (!time_after(jiffies, end_time));
+	kt = ktime_sub(ktime_get(), kt);
+	kt = ktime_sub_ns(kt, (count * prng32_1M * 2) >> 20);
+	pr_info("%s: %lu random insertions, %lluns/insert\n",
+		__func__, count, (long long)div64_ul(ktime_to_ns(kt), count));
+
+	/* Benchmark looking up the exact same context ids as we just set */
+	prandom_seed_state(&prng, i915_selftest.random_seed);
+	end_time = count;
+	kt = ktime_get();
+	while (end_time--) {
+		u64 id = i915_prandom_u64_state(&prng);
+
+		if (!__intel_timeline_sync_is_later(&tl, id, 0)) {
+			mock_timeline_fini(&tl);
+			pr_err("Lookup of %llu failed\n", id);
+			return -EINVAL;
+		}
+	}
+	kt = ktime_sub(ktime_get(), kt);
+	kt = ktime_sub_ns(kt, (count * prng32_1M * 2) >> 20);
+	pr_info("%s: %lu random lookups, %lluns/lookup\n",
+		__func__, count, (long long)div64_ul(ktime_to_ns(kt), count));
+
+	mock_timeline_fini(&tl);
+	cond_resched();
+
+	mock_timeline_init(&tl, 0);
+
+	/* Benchmark setting the first N (in order) contexts */
+	count = 0;
+	kt = ktime_get();
+	end_time = jiffies + HZ/10;
+	do {
+		__intel_timeline_sync_set(&tl, count++, 0);
+	} while (!time_after(jiffies, end_time));
+	kt = ktime_sub(ktime_get(), kt);
+	pr_info("%s: %lu in-order insertions, %lluns/insert\n",
+		__func__, count, (long long)div64_ul(ktime_to_ns(kt), count));
+
+	/* Benchmark looking up the exact same context ids as we just set */
+	end_time = count;
+	kt = ktime_get();
+	while (end_time--) {
+		if (!__intel_timeline_sync_is_later(&tl, end_time, 0)) {
+			pr_err("Lookup of %lu failed\n", end_time);
+			mock_timeline_fini(&tl);
+			return -EINVAL;
+		}
+	}
+	kt = ktime_sub(ktime_get(), kt);
+	pr_info("%s: %lu in-order lookups, %lluns/lookup\n",
+		__func__, count, (long long)div64_ul(ktime_to_ns(kt), count));
+
+	mock_timeline_fini(&tl);
+	cond_resched();
+
+	mock_timeline_init(&tl, 0);
+
+	/* Benchmark searching for a random context id and maybe changing it */
+	prandom_seed_state(&prng, i915_selftest.random_seed);
+	count = 0;
+	kt = ktime_get();
+	end_time = jiffies + HZ/10;
+	do {
+		u32 id = random_engine(&prng);
+		u32 seqno = prandom_u32_state(&prng);
+
+		if (!__intel_timeline_sync_is_later(&tl, id, seqno))
+			__intel_timeline_sync_set(&tl, id, seqno);
+
+		count++;
+	} while (!time_after(jiffies, end_time));
+	kt = ktime_sub(ktime_get(), kt);
+	kt = ktime_sub_ns(kt, (count * prng32_1M * 2) >> 20);
+	pr_info("%s: %lu repeated insert/lookups, %lluns/op\n",
+		__func__, count, (long long)div64_ul(ktime_to_ns(kt), count));
+	mock_timeline_fini(&tl);
+	cond_resched();
+
+	/* Benchmark searching for a known context id and changing the seqno */
+	for (last_order = 1, order = 1; order < 32;
+	     ({ int tmp = last_order; last_order = order; order += tmp; })) {
+		unsigned int mask = BIT(order) - 1;
+
+		mock_timeline_init(&tl, 0);
+
+		count = 0;
+		kt = ktime_get();
+		end_time = jiffies + HZ/10;
+		do {
+			/* Without assuming too many details of the underlying
+			 * implementation, try to identify its phase-changes
+			 * (if any)!
+			 */
+			u64 id = (u64)(count & mask) << order;
+
+			__intel_timeline_sync_is_later(&tl, id, 0);
+			__intel_timeline_sync_set(&tl, id, 0);
+
+			count++;
+		} while (!time_after(jiffies, end_time));
+		kt = ktime_sub(ktime_get(), kt);
+		pr_info("%s: %lu cyclic/%d insert/lookups, %lluns/op\n",
+			__func__, count, order,
+			(long long)div64_ul(ktime_to_ns(kt), count));
+		mock_timeline_fini(&tl);
+		cond_resched();
+	}
+
+	return 0;
+}
+
+int intel_timeline_mock_selftests(void)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(mock_hwsp_freelist),
+		SUBTEST(igt_sync),
+		SUBTEST(bench_sync),
+	};
+
+	return i915_subtests(tests, NULL);
+}
+
+static int emit_ggtt_store_dw(struct i915_request *rq, u32 addr, u32 value)
+{
+	u32 *cs;
+
+	cs = intel_ring_begin(rq, 4);
+	if (IS_ERR(cs))
+		return PTR_ERR(cs);
+
+	if (GRAPHICS_VER(rq->engine->i915) >= 8) {
+		*cs++ = MI_STORE_DWORD_IMM_GEN4 | MI_USE_GGTT;
+		*cs++ = addr;
+		*cs++ = 0;
+		*cs++ = value;
+	} else if (GRAPHICS_VER(rq->engine->i915) >= 4) {
+		*cs++ = MI_STORE_DWORD_IMM_GEN4 | MI_USE_GGTT;
+		*cs++ = 0;
+		*cs++ = addr;
+		*cs++ = value;
+	} else {
+		*cs++ = MI_STORE_DWORD_IMM | MI_MEM_VIRTUAL;
+		*cs++ = addr;
+		*cs++ = value;
+		*cs++ = MI_NOOP;
+	}
+
+	intel_ring_advance(rq, cs);
+
+	return 0;
+}
+
+static struct i915_request *
+checked_tl_write(struct intel_timeline *tl, struct intel_engine_cs *engine, u32 value)
+{
+	struct i915_request *rq;
+	int err;
+
+	err = selftest_tl_pin(tl);
+	if (err) {
+		rq = ERR_PTR(err);
+		goto out;
+	}
+
+	if (READ_ONCE(*tl->hwsp_seqno) != tl->seqno) {
+		pr_err("Timeline created with incorrect breadcrumb, found %x, expected %x\n",
+		       *tl->hwsp_seqno, tl->seqno);
+		intel_timeline_unpin(tl);
+		return ERR_PTR(-EINVAL);
+	}
+
+	rq = intel_engine_create_kernel_request(engine);
+	if (IS_ERR(rq))
+		goto out_unpin;
+
+	i915_request_get(rq);
+
+	err = emit_ggtt_store_dw(rq, tl->hwsp_offset, value);
+	i915_request_add(rq);
+	if (err) {
+		i915_request_put(rq);
+		rq = ERR_PTR(err);
+	}
+
+out_unpin:
+	intel_timeline_unpin(tl);
+out:
+	if (IS_ERR(rq))
+		pr_err("Failed to write to timeline!\n");
+	return rq;
+}
+
+static int live_hwsp_engine(void *arg)
+{
+#define NUM_TIMELINES 4096
+	struct intel_gt *gt = arg;
+	struct intel_timeline **timelines;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	unsigned long count, n;
+	int err = 0;
+
+	/*
+	 * Create a bunch of timelines and check we can write
+	 * independently to each of their breadcrumb slots.
+	 */
+
+	timelines = kvmalloc_array(NUM_TIMELINES * I915_NUM_ENGINES,
+				   sizeof(*timelines),
+				   GFP_KERNEL);
+	if (!timelines)
+		return -ENOMEM;
+
+	count = 0;
+	for_each_engine(engine, gt, id) {
+		if (!intel_engine_can_store_dword(engine))
+			continue;
+
+		intel_engine_pm_get(engine);
+
+		for (n = 0; n < NUM_TIMELINES; n++) {
+			struct intel_timeline *tl;
+			struct i915_request *rq;
+
+			tl = intel_timeline_create(gt);
+			if (IS_ERR(tl)) {
+				err = PTR_ERR(tl);
+				break;
+			}
+
+			rq = checked_tl_write(tl, engine, count);
+			if (IS_ERR(rq)) {
+				intel_timeline_put(tl);
+				err = PTR_ERR(rq);
+				break;
+			}
+
+			timelines[count++] = tl;
+			i915_request_put(rq);
+		}
+
+		intel_engine_pm_put(engine);
+		if (err)
+			break;
+	}
+
+	if (igt_flush_test(gt->i915))
+		err = -EIO;
+
+	for (n = 0; n < count; n++) {
+		struct intel_timeline *tl = timelines[n];
+
+		if (!err && READ_ONCE(*tl->hwsp_seqno) != n) {
+			GEM_TRACE_ERR("Invalid seqno:%lu stored in timeline %llu @ %x, found 0x%x\n",
+				      n, tl->fence_context, tl->hwsp_offset, *tl->hwsp_seqno);
+			GEM_TRACE_DUMP();
+			err = -EINVAL;
+		}
+		intel_timeline_put(tl);
+	}
+
+	kvfree(timelines);
+	return err;
+#undef NUM_TIMELINES
+}
+
+static int live_hwsp_alternate(void *arg)
+{
+#define NUM_TIMELINES 4096
+	struct intel_gt *gt = arg;
+	struct intel_timeline **timelines;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	unsigned long count, n;
+	int err = 0;
+
+	/*
+	 * Create a bunch of timelines and check we can write
+	 * independently to each of their breadcrumb slots with adjacent
+	 * engines.
+	 */
+
+	timelines = kvmalloc_array(NUM_TIMELINES * I915_NUM_ENGINES,
+				   sizeof(*timelines),
+				   GFP_KERNEL);
+	if (!timelines)
+		return -ENOMEM;
+
+	count = 0;
+	for (n = 0; n < NUM_TIMELINES; n++) {
+		for_each_engine(engine, gt, id) {
+			struct intel_timeline *tl;
+			struct i915_request *rq;
+
+			if (!intel_engine_can_store_dword(engine))
+				continue;
+
+			tl = intel_timeline_create(gt);
+			if (IS_ERR(tl)) {
+				err = PTR_ERR(tl);
+				goto out;
+			}
+
+			intel_engine_pm_get(engine);
+			rq = checked_tl_write(tl, engine, count);
+			intel_engine_pm_put(engine);
+			if (IS_ERR(rq)) {
+				intel_timeline_put(tl);
+				err = PTR_ERR(rq);
+				goto out;
+			}
+
+			timelines[count++] = tl;
+			i915_request_put(rq);
+		}
+	}
+
+out:
+	if (igt_flush_test(gt->i915))
+		err = -EIO;
+
+	for (n = 0; n < count; n++) {
+		struct intel_timeline *tl = timelines[n];
+
+		if (!err && READ_ONCE(*tl->hwsp_seqno) != n) {
+			GEM_TRACE_ERR("Invalid seqno:%lu stored in timeline %llu @ %x, found 0x%x\n",
+				      n, tl->fence_context, tl->hwsp_offset, *tl->hwsp_seqno);
+			GEM_TRACE_DUMP();
+			err = -EINVAL;
+		}
+		intel_timeline_put(tl);
+	}
+
+	kvfree(timelines);
+	return err;
+#undef NUM_TIMELINES
+}
+
+static int live_hwsp_wrap(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	struct intel_timeline *tl;
+	enum intel_engine_id id;
+	int err = 0;
+
+	/*
+	 * Across a seqno wrap, we need to keep the old cacheline alive for
+	 * foreign GPU references.
+	 */
+
+	tl = intel_timeline_create(gt);
+	if (IS_ERR(tl))
+		return PTR_ERR(tl);
+
+	if (!tl->has_initial_breadcrumb)
+		goto out_free;
+
+	err = selftest_tl_pin(tl);
+	if (err)
+		goto out_free;
+
+	for_each_engine(engine, gt, id) {
+		const u32 *hwsp_seqno[2];
+		struct i915_request *rq;
+		u32 seqno[2];
+
+		if (!intel_engine_can_store_dword(engine))
+			continue;
+
+		rq = intel_engine_create_kernel_request(engine);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			goto out;
+		}
+
+		tl->seqno = -4u;
+
+		mutex_lock_nested(&tl->mutex, SINGLE_DEPTH_NESTING);
+		err = intel_timeline_get_seqno(tl, rq, &seqno[0]);
+		mutex_unlock(&tl->mutex);
+		if (err) {
+			i915_request_add(rq);
+			goto out;
+		}
+		pr_debug("seqno[0]:%08x, hwsp_offset:%08x\n",
+			 seqno[0], tl->hwsp_offset);
+
+		err = emit_ggtt_store_dw(rq, tl->hwsp_offset, seqno[0]);
+		if (err) {
+			i915_request_add(rq);
+			goto out;
+		}
+		hwsp_seqno[0] = tl->hwsp_seqno;
+
+		mutex_lock_nested(&tl->mutex, SINGLE_DEPTH_NESTING);
+		err = intel_timeline_get_seqno(tl, rq, &seqno[1]);
+		mutex_unlock(&tl->mutex);
+		if (err) {
+			i915_request_add(rq);
+			goto out;
+		}
+		pr_debug("seqno[1]:%08x, hwsp_offset:%08x\n",
+			 seqno[1], tl->hwsp_offset);
+
+		err = emit_ggtt_store_dw(rq, tl->hwsp_offset, seqno[1]);
+		if (err) {
+			i915_request_add(rq);
+			goto out;
+		}
+		hwsp_seqno[1] = tl->hwsp_seqno;
+
+		/* With wrap should come a new hwsp */
+		GEM_BUG_ON(seqno[1] >= seqno[0]);
+		GEM_BUG_ON(hwsp_seqno[0] == hwsp_seqno[1]);
+
+		i915_request_add(rq);
+
+		if (i915_request_wait(rq, 0, HZ / 5) < 0) {
+			pr_err("Wait for timeline writes timed out!\n");
+			err = -EIO;
+			goto out;
+		}
+
+		if (READ_ONCE(*hwsp_seqno[0]) != seqno[0] ||
+		    READ_ONCE(*hwsp_seqno[1]) != seqno[1]) {
+			pr_err("Bad timeline values: found (%x, %x), expected (%x, %x)\n",
+			       *hwsp_seqno[0], *hwsp_seqno[1],
+			       seqno[0], seqno[1]);
+			err = -EINVAL;
+			goto out;
+		}
+
+		intel_gt_retire_requests(gt); /* recycle HWSP */
+	}
+
+out:
+	if (igt_flush_test(gt->i915))
+		err = -EIO;
+
+	intel_timeline_unpin(tl);
+out_free:
+	intel_timeline_put(tl);
+	return err;
+}
+
+static int emit_read_hwsp(struct i915_request *rq,
+			  u32 seqno, u32 hwsp,
+			  u32 *addr)
+{
+	const u32 gpr = i915_mmio_reg_offset(GEN8_RING_CS_GPR(rq->engine->mmio_base, 0));
+	u32 *cs;
+
+	cs = intel_ring_begin(rq, 12);
+	if (IS_ERR(cs))
+		return PTR_ERR(cs);
+
+	*cs++ = MI_STORE_DWORD_IMM_GEN4 | MI_USE_GGTT;
+	*cs++ = *addr;
+	*cs++ = 0;
+	*cs++ = seqno;
+	*addr += 4;
+
+	*cs++ = MI_LOAD_REGISTER_MEM_GEN8 | MI_USE_GGTT;
+	*cs++ = gpr;
+	*cs++ = hwsp;
+	*cs++ = 0;
+
+	*cs++ = MI_STORE_REGISTER_MEM_GEN8 | MI_USE_GGTT;
+	*cs++ = gpr;
+	*cs++ = *addr;
+	*cs++ = 0;
+	*addr += 4;
+
+	intel_ring_advance(rq, cs);
+
+	return 0;
+}
+
+struct hwsp_watcher {
+	struct i915_vma *vma;
+	struct i915_request *rq;
+	u32 addr;
+	u32 *map;
+};
+
+static bool cmp_lt(u32 a, u32 b)
+{
+	return a < b;
+}
+
+static bool cmp_gte(u32 a, u32 b)
+{
+	return a >= b;
+}
+
+static int setup_watcher(struct hwsp_watcher *w, struct intel_gt *gt)
+{
+	struct drm_i915_gem_object *obj;
+	struct i915_vma *vma;
+
+	obj = i915_gem_object_create_internal(gt->i915, SZ_2M);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	w->map = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WB);
+	if (IS_ERR(w->map)) {
+		i915_gem_object_put(obj);
+		return PTR_ERR(w->map);
+	}
+
+	vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, 0);
+	if (IS_ERR(vma)) {
+		i915_gem_object_put(obj);
+		return PTR_ERR(vma);
+	}
+
+	w->vma = vma;
+	w->addr = i915_ggtt_offset(vma);
+	return 0;
+}
+
+static void switch_tl_lock(struct i915_request *from, struct i915_request *to)
+{
+	/* some light mutex juggling required; think co-routines */
+
+	if (from) {
+		lockdep_unpin_lock(&from->context->timeline->mutex, from->cookie);
+		mutex_unlock(&from->context->timeline->mutex);
+	}
+
+	if (to) {
+		mutex_lock(&to->context->timeline->mutex);
+		to->cookie = lockdep_pin_lock(&to->context->timeline->mutex);
+	}
+}
+
+static int create_watcher(struct hwsp_watcher *w,
+			  struct intel_engine_cs *engine,
+			  int ringsz)
+{
+	struct intel_context *ce;
+
+	ce = intel_context_create(engine);
+	if (IS_ERR(ce))
+		return PTR_ERR(ce);
+
+	ce->ring_size = ringsz;
+	w->rq = intel_context_create_request(ce);
+	intel_context_put(ce);
+	if (IS_ERR(w->rq))
+		return PTR_ERR(w->rq);
+
+	w->addr = i915_ggtt_offset(w->vma);
+
+	switch_tl_lock(w->rq, NULL);
+
+	return 0;
+}
+
+static int check_watcher(struct hwsp_watcher *w, const char *name,
+			 bool (*op)(u32 hwsp, u32 seqno))
+{
+	struct i915_request *rq = fetch_and_zero(&w->rq);
+	u32 offset, end;
+	int err;
+
+	GEM_BUG_ON(w->addr - i915_ggtt_offset(w->vma) > w->vma->size);
+
+	i915_request_get(rq);
+	switch_tl_lock(NULL, rq);
+	i915_request_add(rq);
+
+	if (i915_request_wait(rq, 0, HZ) < 0) {
+		err = -ETIME;
+		goto out;
+	}
+
+	err = 0;
+	offset = 0;
+	end = (w->addr - i915_ggtt_offset(w->vma)) / sizeof(*w->map);
+	while (offset < end) {
+		if (!op(w->map[offset + 1], w->map[offset])) {
+			pr_err("Watcher '%s' found HWSP value %x for seqno %x\n",
+			       name, w->map[offset + 1], w->map[offset]);
+			err = -EINVAL;
+		}
+
+		offset += 2;
+	}
+
+out:
+	i915_request_put(rq);
+	return err;
+}
+
+static void cleanup_watcher(struct hwsp_watcher *w)
+{
+	if (w->rq) {
+		switch_tl_lock(NULL, w->rq);
+
+		i915_request_add(w->rq);
+	}
+
+	i915_vma_unpin_and_release(&w->vma, I915_VMA_RELEASE_MAP);
+}
+
+static bool retire_requests(struct intel_timeline *tl)
+{
+	struct i915_request *rq, *rn;
+
+	mutex_lock(&tl->mutex);
+	list_for_each_entry_safe(rq, rn, &tl->requests, link)
+		if (!i915_request_retire(rq))
+			break;
+	mutex_unlock(&tl->mutex);
+
+	return !i915_active_fence_isset(&tl->last_request);
+}
+
+static struct i915_request *wrap_timeline(struct i915_request *rq)
+{
+	struct intel_context *ce = rq->context;
+	struct intel_timeline *tl = ce->timeline;
+	u32 seqno = rq->fence.seqno;
+
+	while (tl->seqno >= seqno) { /* Cause a wrap */
+		i915_request_put(rq);
+		rq = intel_context_create_request(ce);
+		if (IS_ERR(rq))
+			return rq;
+
+		i915_request_get(rq);
+		i915_request_add(rq);
+	}
+
+	i915_request_put(rq);
+	rq = i915_request_create(ce);
+	if (IS_ERR(rq))
+		return rq;
+
+	i915_request_get(rq);
+	i915_request_add(rq);
+
+	return rq;
+}
+
+static int live_hwsp_read(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct hwsp_watcher watcher[2] = {};
+	struct intel_engine_cs *engine;
+	struct intel_timeline *tl;
+	enum intel_engine_id id;
+	int err = 0;
+	int i;
+
+	/*
+	 * If we take a reference to the HWSP for reading on the GPU, that
+	 * read may be arbitrarily delayed (either by foreign fence or
+	 * priority saturation) and a wrap can happen within 30 minutes.
+	 * When the GPU read is finally submitted it should be correct,
+	 * even across multiple wraps.
+	 */
+
+	if (GRAPHICS_VER(gt->i915) < 8) /* CS convenience [SRM/LRM] */
+		return 0;
+
+	tl = intel_timeline_create(gt);
+	if (IS_ERR(tl))
+		return PTR_ERR(tl);
+
+	if (!tl->has_initial_breadcrumb)
+		goto out_free;
+
+	for (i = 0; i < ARRAY_SIZE(watcher); i++) {
+		err = setup_watcher(&watcher[i], gt);
+		if (err)
+			goto out;
+	}
+
+	for_each_engine(engine, gt, id) {
+		struct intel_context *ce;
+		unsigned long count = 0;
+		IGT_TIMEOUT(end_time);
+
+		/* Create a request we can use for remote reading of the HWSP */
+		err = create_watcher(&watcher[1], engine, SZ_512K);
+		if (err)
+			goto out;
+
+		do {
+			struct i915_sw_fence *submit;
+			struct i915_request *rq;
+			u32 hwsp, dummy;
+
+			submit = heap_fence_create(GFP_KERNEL);
+			if (!submit) {
+				err = -ENOMEM;
+				goto out;
+			}
+
+			err = create_watcher(&watcher[0], engine, SZ_4K);
+			if (err)
+				goto out;
+
+			ce = intel_context_create(engine);
+			if (IS_ERR(ce)) {
+				err = PTR_ERR(ce);
+				goto out;
+			}
+
+			ce->timeline = intel_timeline_get(tl);
+
+			/* Ensure timeline is mapped, done during first pin */
+			err = intel_context_pin(ce);
+			if (err) {
+				intel_context_put(ce);
+				goto out;
+			}
+
+			/*
+			 * Start at a new wrap, and set seqno right before another wrap,
+			 * saving 30 minutes of nops
+			 */
+			tl->seqno = -12u + 2 * (count & 3);
+			__intel_timeline_get_seqno(tl, &dummy);
+
+			rq = i915_request_create(ce);
+			if (IS_ERR(rq)) {
+				err = PTR_ERR(rq);
+				intel_context_unpin(ce);
+				intel_context_put(ce);
+				goto out;
+			}
+
+			err = i915_sw_fence_await_dma_fence(&rq->submit,
+							    &watcher[0].rq->fence, 0,
+							    GFP_KERNEL);
+			if (err < 0) {
+				i915_request_add(rq);
+				intel_context_unpin(ce);
+				intel_context_put(ce);
+				goto out;
+			}
+
+			switch_tl_lock(rq, watcher[0].rq);
+			err = intel_timeline_read_hwsp(rq, watcher[0].rq, &hwsp);
+			if (err == 0)
+				err = emit_read_hwsp(watcher[0].rq, /* before */
+						     rq->fence.seqno, hwsp,
+						     &watcher[0].addr);
+			switch_tl_lock(watcher[0].rq, rq);
+			if (err) {
+				i915_request_add(rq);
+				intel_context_unpin(ce);
+				intel_context_put(ce);
+				goto out;
+			}
+
+			switch_tl_lock(rq, watcher[1].rq);
+			err = intel_timeline_read_hwsp(rq, watcher[1].rq, &hwsp);
+			if (err == 0)
+				err = emit_read_hwsp(watcher[1].rq, /* after */
+						     rq->fence.seqno, hwsp,
+						     &watcher[1].addr);
+			switch_tl_lock(watcher[1].rq, rq);
+			if (err) {
+				i915_request_add(rq);
+				intel_context_unpin(ce);
+				intel_context_put(ce);
+				goto out;
+			}
+
+			i915_request_get(rq);
+			i915_request_add(rq);
+
+			rq = wrap_timeline(rq);
+			intel_context_unpin(ce);
+			intel_context_put(ce);
+			if (IS_ERR(rq)) {
+				err = PTR_ERR(rq);
+				goto out;
+			}
+
+			err = i915_sw_fence_await_dma_fence(&watcher[1].rq->submit,
+							    &rq->fence, 0,
+							    GFP_KERNEL);
+			if (err < 0) {
+				i915_request_put(rq);
+				goto out;
+			}
+
+			err = check_watcher(&watcher[0], "before", cmp_lt);
+			i915_sw_fence_commit(submit);
+			heap_fence_put(submit);
+			if (err) {
+				i915_request_put(rq);
+				goto out;
+			}
+			count++;
+
+			/* Flush the timeline before manually wrapping again */
+			if (i915_request_wait(rq,
+					      I915_WAIT_INTERRUPTIBLE,
+					      HZ) < 0) {
+				err = -ETIME;
+				i915_request_put(rq);
+				goto out;
+			}
+			retire_requests(tl);
+			i915_request_put(rq);
+
+			/* Single requests are limited to half a ring at most */
+			if (8 * watcher[1].rq->ring->emit >
+			    3 * watcher[1].rq->ring->size)
+				break;
+
+		} while (!__igt_timeout(end_time, NULL) &&
+			 count < (PAGE_SIZE / TIMELINE_SEQNO_BYTES - 1) / 2);
+
+		pr_info("%s: simulated %lu wraps\n", engine->name, count);
+		err = check_watcher(&watcher[1], "after", cmp_gte);
+		if (err)
+			goto out;
+	}
+
+out:
+	for (i = 0; i < ARRAY_SIZE(watcher); i++)
+		cleanup_watcher(&watcher[i]);
+
+	if (igt_flush_test(gt->i915))
+		err = -EIO;
+
+out_free:
+	intel_timeline_put(tl);
+	return err;
+}
+
+static int live_hwsp_rollover_kernel(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	int err = 0;
+
+	/*
+	 * Run the host for long enough, and even the kernel context will
+	 * see a seqno rollover.
+	 */
+
+	for_each_engine(engine, gt, id) {
+		struct intel_context *ce = engine->kernel_context;
+		struct intel_timeline *tl = ce->timeline;
+		struct i915_request *rq[3] = {};
+		int i;
+
+		st_engine_heartbeat_disable(engine);
+		if (intel_gt_wait_for_idle(gt, HZ / 2)) {
+			err = -EIO;
+			goto out;
+		}
+
+		GEM_BUG_ON(i915_active_fence_isset(&tl->last_request));
+		tl->seqno = -2u;
+		WRITE_ONCE(*(u32 *)tl->hwsp_seqno, tl->seqno);
+
+		for (i = 0; i < ARRAY_SIZE(rq); i++) {
+			struct i915_request *this;
+
+			this = i915_request_create(ce);
+			if (IS_ERR(this)) {
+				err = PTR_ERR(this);
+				goto out;
+			}
+
+			pr_debug("%s: create fence.seqnp:%d\n",
+				 engine->name,
+				 lower_32_bits(this->fence.seqno));
+
+			GEM_BUG_ON(rcu_access_pointer(this->timeline) != tl);
+
+			rq[i] = i915_request_get(this);
+			i915_request_add(this);
+		}
+
+		/* We expected a wrap! */
+		GEM_BUG_ON(rq[2]->fence.seqno > rq[0]->fence.seqno);
+
+		if (i915_request_wait(rq[2], 0, HZ / 5) < 0) {
+			pr_err("Wait for timeline wrap timed out!\n");
+			err = -EIO;
+			goto out;
+		}
+
+		for (i = 0; i < ARRAY_SIZE(rq); i++) {
+			if (!i915_request_completed(rq[i])) {
+				pr_err("Pre-wrap request not completed!\n");
+				err = -EINVAL;
+				goto out;
+			}
+		}
+
+out:
+		for (i = 0; i < ARRAY_SIZE(rq); i++)
+			i915_request_put(rq[i]);
+		st_engine_heartbeat_enable(engine);
+		if (err)
+			break;
+	}
+
+	if (igt_flush_test(gt->i915))
+		err = -EIO;
+
+	return err;
+}
+
+static int live_hwsp_rollover_user(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	int err = 0;
+
+	/*
+	 * Simulate a long running user context, and force the seqno wrap
+	 * on the user's timeline.
+	 */
+
+	for_each_engine(engine, gt, id) {
+		struct i915_request *rq[3] = {};
+		struct intel_timeline *tl;
+		struct intel_context *ce;
+		int i;
+
+		ce = intel_context_create(engine);
+		if (IS_ERR(ce))
+			return PTR_ERR(ce);
+
+		err = intel_context_alloc_state(ce);
+		if (err)
+			goto out;
+
+		tl = ce->timeline;
+		if (!tl->has_initial_breadcrumb)
+			goto out;
+
+		err = intel_context_pin(ce);
+		if (err)
+			goto out;
+
+		tl->seqno = -4u;
+		WRITE_ONCE(*(u32 *)tl->hwsp_seqno, tl->seqno);
+
+		for (i = 0; i < ARRAY_SIZE(rq); i++) {
+			struct i915_request *this;
+
+			this = intel_context_create_request(ce);
+			if (IS_ERR(this)) {
+				err = PTR_ERR(this);
+				goto out_unpin;
+			}
+
+			pr_debug("%s: create fence.seqnp:%d\n",
+				 engine->name,
+				 lower_32_bits(this->fence.seqno));
+
+			GEM_BUG_ON(rcu_access_pointer(this->timeline) != tl);
+
+			rq[i] = i915_request_get(this);
+			i915_request_add(this);
+		}
+
+		/* We expected a wrap! */
+		GEM_BUG_ON(rq[2]->fence.seqno > rq[0]->fence.seqno);
+
+		if (i915_request_wait(rq[2], 0, HZ / 5) < 0) {
+			pr_err("Wait for timeline wrap timed out!\n");
+			err = -EIO;
+			goto out_unpin;
+		}
+
+		for (i = 0; i < ARRAY_SIZE(rq); i++) {
+			if (!i915_request_completed(rq[i])) {
+				pr_err("Pre-wrap request not completed!\n");
+				err = -EINVAL;
+				goto out_unpin;
+			}
+		}
+out_unpin:
+		intel_context_unpin(ce);
+out:
+		for (i = 0; i < ARRAY_SIZE(rq); i++)
+			i915_request_put(rq[i]);
+		intel_context_put(ce);
+		if (err)
+			break;
+	}
+
+	if (igt_flush_test(gt->i915))
+		err = -EIO;
+
+	return err;
+}
+
+static int live_hwsp_recycle(void *arg)
+{
+	struct intel_gt *gt = arg;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	unsigned long count;
+	int err = 0;
+
+	/*
+	 * Check seqno writes into one timeline at a time. We expect to
+	 * recycle the breadcrumb slot between iterations and neither
+	 * want to confuse ourselves or the GPU.
+	 */
+
+	count = 0;
+	for_each_engine(engine, gt, id) {
+		IGT_TIMEOUT(end_time);
+
+		if (!intel_engine_can_store_dword(engine))
+			continue;
+
+		intel_engine_pm_get(engine);
+
+		do {
+			struct intel_timeline *tl;
+			struct i915_request *rq;
+
+			tl = intel_timeline_create(gt);
+			if (IS_ERR(tl)) {
+				err = PTR_ERR(tl);
+				break;
+			}
+
+			rq = checked_tl_write(tl, engine, count);
+			if (IS_ERR(rq)) {
+				intel_timeline_put(tl);
+				err = PTR_ERR(rq);
+				break;
+			}
+
+			if (i915_request_wait(rq, 0, HZ / 5) < 0) {
+				pr_err("Wait for timeline writes timed out!\n");
+				i915_request_put(rq);
+				intel_timeline_put(tl);
+				err = -EIO;
+				break;
+			}
+
+			if (READ_ONCE(*tl->hwsp_seqno) != count) {
+				GEM_TRACE_ERR("Invalid seqno:%lu stored in timeline %llu @ %x found 0x%x\n",
+					      count, tl->fence_context,
+					      tl->hwsp_offset, *tl->hwsp_seqno);
+				GEM_TRACE_DUMP();
+				err = -EINVAL;
+			}
+
+			i915_request_put(rq);
+			intel_timeline_put(tl);
+			count++;
+
+			if (err)
+				break;
+		} while (!__igt_timeout(end_time, NULL));
+
+		intel_engine_pm_put(engine);
+		if (err)
+			break;
+	}
+
+	return err;
+}
+
+int intel_timeline_live_selftests(struct drm_i915_private *i915)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(live_hwsp_recycle),
+		SUBTEST(live_hwsp_engine),
+		SUBTEST(live_hwsp_alternate),
+		SUBTEST(live_hwsp_wrap),
+		SUBTEST(live_hwsp_read),
+		SUBTEST(live_hwsp_rollover_kernel),
+		SUBTEST(live_hwsp_rollover_user),
+	};
+
+	if (intel_gt_is_wedged(to_gt(i915)))
+		return 0;
+
+	return intel_gt_live_subtests(tests, to_gt(i915));
+}