drm/i915/selftests: Add initial GuC selftest for scrubbing lost G2H

While debugging an issue with full GT resets I went down a rabbit hole
thinking the scrubbing of lost G2H wasn't working correctly. This proved
to be incorrect as this was working just fine but this chase inspired me
to write a selftest to prove that this works. This simple selftest
injects errors dropping various G2H and then issues a full GT reset
proving that the scrubbing of these G2H doesn't blow up.

v2:
 (Daniel Vetter)
  - Use ifdef instead of macros for selftests
v3:
 (Checkpatch)
  - A space after 'switch' statement
v4:
 (Daniele)
  - A comment saying GT won't idle if G2H are lost

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-12-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index e54351a170e2cbf4b5ea6359a55c9c08162e2f8d..3a73f31178734e374d846a7fe908d644d739c64d 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -198,6 +198,24 @@ struct intel_context {
         */
        u8 guc_prio;
        u32 guc_prio_count[GUC_CLIENT_PRIORITY_NUM];
+
+#ifdef CONFIG_DRM_I915_SELFTEST
+       /**
+        * @drop_schedule_enable: Force drop of schedule enable G2H for selftest
+        */
+       bool drop_schedule_enable;
+
+       /**
+        * @drop_schedule_disable: Force drop of schedule disable G2H for
+        * selftest
+        */
+       bool drop_schedule_disable;
+
+       /**
+        * @drop_deregister: Force drop of deregister G2H for selftest
+        */
+       bool drop_deregister;
+#endif
 };
 
 #endif /* __INTEL_CONTEXT_TYPES__ */

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index f5bee833ee7dc61456ab7a45f4238aecd3683532..5970c54a2e729932ce1610e0260fb3c6103e570b 100644 (file)
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -2639,6 +2639,13 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
 
        trace_intel_context_deregister_done(ce);
 
+#ifdef CONFIG_DRM_I915_SELFTEST
+       if (unlikely(ce->drop_deregister)) {
+               ce->drop_deregister = false;
+               return 0;
+       }
+#endif
+
        if (context_wait_for_deregister_to_register(ce)) {
                struct intel_runtime_pm *runtime_pm =
                        &ce->engine->gt->i915->runtime_pm;
@@ -2693,10 +2700,24 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
        trace_intel_context_sched_done(ce);
 
        if (context_pending_enable(ce)) {
+#ifdef CONFIG_DRM_I915_SELFTEST
+               if (unlikely(ce->drop_schedule_enable)) {
+                       ce->drop_schedule_enable = false;
+                       return 0;
+               }
+#endif
+
                clr_context_pending_enable(ce);
        } else if (context_pending_disable(ce)) {
                bool banned;
 
+#ifdef CONFIG_DRM_I915_SELFTEST
+               if (unlikely(ce->drop_schedule_disable)) {
+                       ce->drop_schedule_disable = false;
+                       return 0;
+               }
+#endif
+
                /*
                 * Unpin must be done before __guc_signal_context_fence,
                 * otherwise a race exists between the requests getting
@@ -3073,3 +3094,7 @@ bool intel_guc_virtual_engine_has_heartbeat(const struct intel_engine_cs *ve)
 
        return false;
 }
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftest_guc.c"
+#endif

diff --git a/drivers/gpu/drm/i915/gt/uc/selftest_guc.c b/drivers/gpu/drm/i915/gt/uc/selftest_guc.c
new file mode 100644 (file)
index 0000000..fb0e4a7
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/uc/selftest_guc.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright �� 2021 Intel Corporation
+ */
+
+#include "selftests/intel_scheduler_helpers.h"
+
+static struct i915_request *nop_user_request(struct intel_context *ce,
+                                            struct i915_request *from)
+{
+       struct i915_request *rq;
+       int ret;
+
+       rq = intel_context_create_request(ce);
+       if (IS_ERR(rq))
+               return rq;
+
+       if (from) {
+               ret = i915_sw_fence_await_dma_fence(&rq->submit,
+                                                   &from->fence, 0,
+                                                   I915_FENCE_GFP);
+               if (ret < 0) {
+                       i915_request_put(rq);
+                       return ERR_PTR(ret);
+               }
+       }
+
+       i915_request_get(rq);
+       i915_request_add(rq);
+
+       return rq;
+}
+
+static int intel_guc_scrub_ctbs(void *arg)
+{
+       struct intel_gt *gt = arg;
+       int ret = 0;
+       int i;
+       struct i915_request *last[3] = {NULL, NULL, NULL}, *rq;
+       intel_wakeref_t wakeref;
+       struct intel_engine_cs *engine;
+       struct intel_context *ce;
+
+       wakeref = intel_runtime_pm_get(gt->uncore->rpm);
+       engine = intel_selftest_find_any_engine(gt);
+
+       /* Submit requests and inject errors forcing G2H to be dropped */
+       for (i = 0; i < 3; ++i) {
+               ce = intel_context_create(engine);
+               if (IS_ERR(ce)) {
+                       ret = PTR_ERR(ce);
+                       pr_err("Failed to create context, %d: %d\n", i, ret);
+                       goto err;
+               }
+
+               switch (i) {
+               case 0:
+                       ce->drop_schedule_enable = true;
+                       break;
+               case 1:
+                       ce->drop_schedule_disable = true;
+                       break;
+               case 2:
+                       ce->drop_deregister = true;
+                       break;
+               }
+
+               rq = nop_user_request(ce, NULL);
+               intel_context_put(ce);
+
+               if (IS_ERR(rq)) {
+                       ret = PTR_ERR(rq);
+                       pr_err("Failed to create request, %d: %d\n", i, ret);
+                       goto err;
+               }
+
+               last[i] = rq;
+       }
+
+       for (i = 0; i < 3; ++i) {
+               ret = i915_request_wait(last[i], 0, HZ);
+               if (ret < 0) {
+                       pr_err("Last request failed to complete: %d\n", ret);
+                       goto err;
+               }
+               i915_request_put(last[i]);
+               last[i] = NULL;
+       }
+
+       /* Force all H2G / G2H to be submitted / processed */
+       intel_gt_retire_requests(gt);
+       msleep(500);
+
+       /* Scrub missing G2H */
+       intel_gt_handle_error(engine->gt, -1, 0, "selftest reset");
+
+       /* GT will not idle if G2H are lost */
+       ret = intel_gt_wait_for_idle(gt, HZ);
+       if (ret < 0) {
+               pr_err("GT failed to idle: %d\n", ret);
+               goto err;
+       }
+
+err:
+       for (i = 0; i < 3; ++i)
+               if (last[i])
+                       i915_request_put(last[i]);
+       intel_runtime_pm_put(gt->uncore->rpm, wakeref);
+
+       return ret;
+}
+
+int intel_guc_live_selftests(struct drm_i915_private *i915)
+{
+       static const struct i915_subtest tests[] = {
+               SUBTEST(intel_guc_scrub_ctbs),
+       };
+       struct intel_gt *gt = &i915->gt;
+
+       if (intel_gt_is_wedged(gt))
+               return 0;
+
+       if (!intel_uc_uses_guc_submission(&gt->uc))
+               return 0;
+
+       return intel_gt_live_subtests(tests, gt);
+}

diff --git a/drivers/gpu/drm/i915/selftests/i915_live_selftests.h b/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
index cfa5c4165a4fa07a71c577ed2864036409c76b28..3cf6758931f971c11ebea1d981ca2e982bf74c31 100644 (file)
--- a/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
+++ b/drivers/gpu/drm/i915/selftests/i915_live_selftests.h
@@ -47,5 +47,6 @@ selftest(execlists, intel_execlists_live_selftests)
 selftest(ring_submission, intel_ring_submission_live_selftests)
 selftest(perf, i915_perf_live_selftests)
 selftest(slpc, intel_slpc_live_selftests)
+selftest(guc, intel_guc_live_selftests)
 /* Here be dragons: keep last to run last! */
 selftest(late_gt_pm, intel_gt_pm_late_selftests)

diff --git a/drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.c b/drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.c
index 4b328346b48a2f73d16d96f19e242ca9b4237cfd..310fb83c527ebcaddbf57dd09235f85758488a1f 100644 (file)
--- a/drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.c
+++ b/drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.c
@@ -14,6 +14,18 @@
 #define REDUCED_PREEMPT                10
 #define WAIT_FOR_RESET_TIME    10000
 
+struct intel_engine_cs *intel_selftest_find_any_engine(struct intel_gt *gt)
+{
+       struct intel_engine_cs *engine;
+       enum intel_engine_id id;
+
+       for_each_engine(engine, gt, id)
+               return engine;
+
+       pr_err("No valid engine found!\n");
+       return NULL;
+}
+
 int intel_selftest_modify_policy(struct intel_engine_cs *engine,
                                 struct intel_selftest_saved_policy *saved,
                                 u32 modify_type)

diff --git a/drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.h b/drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.h
index 35c098601ac029b373176a2d80d594cd24ad73dd..ae60bb507f45ae956ea7fec2e771e08eadfb06fa 100644 (file)
--- a/drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.h
+++ b/drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.h
@@ -10,6 +10,7 @@
 
 struct i915_request;
 struct intel_engine_cs;
+struct intel_gt;
 
 struct intel_selftest_saved_policy {
        u32 flags;
@@ -23,6 +24,7 @@ enum selftest_scheduler_modify {
        SELFTEST_SCHEDULER_MODIFY_FAST_RESET,
 };
 
+struct intel_engine_cs *intel_selftest_find_any_engine(struct intel_gt *gt);
 int intel_selftest_modify_policy(struct intel_engine_cs *engine,
                                 struct intel_selftest_saved_policy *saved,
                                 enum selftest_scheduler_modify modify_type);