Commit ba446f74 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/selftests: Exercise rc6 w/a handling 



Reading from CTX_INFO upsets rc6, requiring us to detect and prevent
possible rc6 context corruption. Poke at the bear!

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarAndi Shyti <andi.shyti@intel.com>
Tested-by: default avatarAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191119154723.3311814-1-chris@chris-wilson.co.uk
parent f4ba0707

drivers/gpu/drm/i915/gt/intel_rc6.c

+4 −0
Original line number Diff line number Diff line
@@ -783,3 +783,7 @@ u64 intel_rc6_residency_us(struct intel_rc6 *rc6, i915_reg_t reg) 
{

	return DIV_ROUND_UP_ULL(intel_rc6_residency_ns(rc6, reg), 1000);

}



#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)

#include "selftest_rc6.c"

#endif

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

+18 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 */



#include "selftest_llc.h"

#include "selftest_rc6.h"



static int live_gt_resume(void *arg)

{
@@ -58,3 +59,20 @@ int intel_gt_pm_live_selftests(struct drm_i915_private *i915) 


	return intel_gt_live_subtests(tests, &i915->gt);

}



int intel_gt_pm_late_selftests(struct drm_i915_private *i915)

{

	static const struct i915_subtest tests[] = {

		/*

		 * These tests may leave the system in an undesirable state.

		 * They are intended to be run last in CI and the system

		 * rebooted afterwards.

		 */

		SUBTEST(live_rc6_ctx_wa),

	};



	if (intel_gt_is_wedged(&i915->gt))

		return 0;



	return intel_gt_live_subtests(tests, &i915->gt);

}

drivers/gpu/drm/i915/gt/selftest_rc6.c

0 → 100644
+146 −0
Original line number Diff line number Diff line 
/*

 * SPDX-License-Identifier: MIT

 *

 * Copyright © 2019 Intel Corporation

 */



#include "intel_context.h"

#include "intel_engine_pm.h"

#include "intel_gt_requests.h"

#include "intel_ring.h"

#include "selftest_rc6.h"



#include "selftests/i915_random.h"



static const u32 *__live_rc6_ctx(struct intel_context *ce)

{

	struct i915_request *rq;

	const u32 *result;

	u32 cmd;

	u32 *cs;



	rq = intel_context_create_request(ce);

	if (IS_ERR(rq))

		return ERR_CAST(rq);



	cs = intel_ring_begin(rq, 4);

	if (IS_ERR(cs)) {

		i915_request_add(rq);

		return cs;

	}



	cmd = MI_STORE_REGISTER_MEM | MI_USE_GGTT;

	if (INTEL_GEN(rq->i915) >= 8)

		cmd++;



	*cs++ = cmd;

	*cs++ = i915_mmio_reg_offset(GEN8_RC6_CTX_INFO);

	*cs++ = ce->timeline->hwsp_offset + 8;

	*cs++ = 0;

	intel_ring_advance(rq, cs);



	result = rq->hwsp_seqno + 2;

	i915_request_add(rq);



	return result;

}



static struct intel_engine_cs **

randomised_engines(struct intel_gt *gt,

		   struct rnd_state *prng,

		   unsigned int *count)

{

	struct intel_engine_cs *engine, **engines;

	enum intel_engine_id id;

	int n;



	n = 0;

	for_each_engine(engine, gt, id)

		n++;

	if (!n)

		return NULL;



	engines = kmalloc_array(n, sizeof(*engines), GFP_KERNEL);

	if (!engines)

		return NULL;



	n = 0;

	for_each_engine(engine, gt, id)

		engines[n++] = engine;



	i915_prandom_shuffle(engines, sizeof(*engines), n, prng);



	*count = n;

	return engines;

}



int live_rc6_ctx_wa(void *arg)

{

	struct intel_gt *gt = arg;

	struct intel_engine_cs **engines;

	unsigned int n, count;

	I915_RND_STATE(prng);

	int err = 0;



	/* A read of CTX_INFO upsets rc6. Poke the bear! */

	if (INTEL_GEN(gt->i915) < 8)

		return 0;



	engines = randomised_engines(gt, &prng, &count);

	if (!engines)

		return 0;



	for (n = 0; n < count; n++) {

		struct intel_engine_cs *engine = engines[n];

		int pass;



		for (pass = 0; pass < 2; pass++) {

			struct intel_context *ce;

			unsigned int resets =

				i915_reset_engine_count(&gt->i915->gpu_error,

							engine);

			const u32 *res;



			/* Use a sacrifical context */

			ce = intel_context_create(engine->kernel_context->gem_context,

						  engine);

			if (IS_ERR(ce)) {

				err = PTR_ERR(ce);

				goto out;

			}



			intel_engine_pm_get(engine);

			res = __live_rc6_ctx(ce);

			intel_engine_pm_put(engine);

			intel_context_put(ce);

			if (IS_ERR(res)) {

				err = PTR_ERR(res);

				goto out;

			}



			if (intel_gt_wait_for_idle(gt, HZ / 5) == -ETIME) {

				intel_gt_set_wedged(gt);

				err = -ETIME;

				goto out;

			}



			intel_gt_pm_wait_for_idle(gt);

			pr_debug("%s: CTX_INFO=%0x\n",

				 engine->name, READ_ONCE(*res));



			if (resets !=

			    i915_reset_engine_count(&gt->i915->gpu_error,

						    engine)) {

				pr_err("%s: GPU reset required\n",

				       engine->name);

				add_taint_for_CI(TAINT_WARN);

				err = -EIO;

				goto out;

			}

		}

	}



out:

	kfree(engines);

	return err;

}

drivers/gpu/drm/i915/gt/selftest_rc6.h

0 → 100644
+12 −0
Original line number Diff line number Diff line 
/*

 * SPDX-License-Identifier: MIT

 *

 * Copyright © 2019 Intel Corporation

 */



#ifndef SELFTEST_RC6_H

#define SELFTEST_RC6_H



int live_rc6_ctx_wa(void *arg);



#endif /* SELFTEST_RC6_H */

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

+2 −0
Original line number Diff line number Diff line
@@ -39,3 +39,5 @@ selftest(hangcheck, intel_hangcheck_live_selftests) 
selftest(execlists, intel_execlists_live_selftests)

selftest(guc, intel_guc_live_selftest)

selftest(perf, i915_perf_live_selftests)

/* Here be dragons: keep last to run last! */

selftest(late_gt_pm, intel_gt_pm_late_selftests)