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

diff --git a/drivers/gpu/drm/i915/gt/intel_rc6.c b/drivers/gpu/drm/i915/gt/intel_rc6.c
index 977a617..7a0bc6d 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_rc6.c
+++ b/drivers/gpu/drm/i915/gt/intel_rc6.c
@@ -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

diff --git a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
index d1752f1..5e563b8 100644 (file)
--- a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c
@@ -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);
+}

diff --git a/drivers/gpu/drm/i915/gt/selftest_rc6.c b/drivers/gpu/drm/i915/gt/selftest_rc6.c
new file mode 100644 (file)
index 0000000..67b7a6b
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/selftest_rc6.c
@@ -0,0 +1,146 @@
+/*
+ * 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;
+}

diff --git a/drivers/gpu/drm/i915/gt/selftest_rc6.h b/drivers/gpu/drm/i915/gt/selftest_rc6.h
new file mode 100644 (file)
index 0000000..f907e7b
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/selftest_rc6.h
@@ -0,0 +1,12 @@
+/*
+ * 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 */

diff --git a/drivers/gpu/drm/i915/selftests/i915_live_selftests.h b/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
index 11b40bc..c7c50aa 100644 (file)
--- a/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
+++ b/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
@@ -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)