drm/i915/gt: Register the migrate contexts with their engines

Pinned contexts, like the migrate contexts need reset after resume
since their context image may have been lost. Also the GuC needs to
register pinned contexts.

Add a list to struct intel_engine_cs where we add all pinned contexts on
creation, and traverse that list at resume time to reset the pinned
contexts.

This fixes the kms_pipe_crc_basic@suspend-read-crc-pipe-a selftest for now,
but proper LMEM backup / restore is needed for full suspend functionality.
However, note that even with full LMEM backup / restore it may be
desirable to keep the reset since backing up the migrate context images
must happen using memcpy() after the migrate context has become inactive,
and for performance- and other reasons we want to avoid memcpy() from
LMEM.

Also traverse the list at guc_init_lrc_mapping() calling
guc_kernel_context_pin() for the pinned contexts, like is already done
for the kernel context.

v2:
- Don't reset the contexts on each __engine_unpark() but rather at
  resume time (Chris Wilson).
v3:
- Reset contexts in the engine sanitize callback. (Chris Wilson)

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Brost Matthew <matthew.brost@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-6-thomas.hellstrom@linux.intel.com

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

@@ -153,6 +153,14 @@ struct intel_context {
 	/** sseu: Control eu/slice partitioning */
 	struct intel_sseu sseu;
 
+	/**
+	 * pinned_contexts_link: List link for the engine's pinned contexts.
+	 * This is only used if this is a perma-pinned kernel context and
+	 * the list is assumed to only be manipulated during driver load
+	 * or unload time so no mutex protection currently.
+	 */
+	struct list_head pinned_contexts_link;
+
 	u8 wa_bb_page; /* if set, page num reserved for context workarounds */
 
 	struct {

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

@@ -320,6 +320,7 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id)
 
 	BUILD_BUG_ON(BITS_PER_TYPE(engine->mask) < I915_NUM_ENGINES);
 
+	INIT_LIST_HEAD(&engine->pinned_contexts_list);
 	engine->id = id;
 	engine->legacy_idx = INVALID_ENGINE;
 	engine->mask = BIT(id);
@@ -890,6 +891,8 @@ intel_engine_create_pinned_context(struct intel_engine_cs *engine,
 		return ERR_PTR(err);
 	}
 
+	list_add_tail(&ce->pinned_contexts_link, &engine->pinned_contexts_list);
+
 	/*
 	 * Give our perma-pinned kernel timelines a separate lockdep class,
 	 * so that we can use them from within the normal user timelines
@@ -912,6 +915,7 @@ void intel_engine_destroy_pinned_context(struct intel_context *ce)
 	list_del(&ce->timeline->engine_link);
 	mutex_unlock(&hwsp->vm->mutex);
 
+	list_del(&ce->pinned_contexts_link);
 	intel_context_unpin(ce);
 	intel_context_put(ce);
 }

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

@@ -298,6 +298,29 @@ void intel_engine_init__pm(struct intel_engine_cs *engine)
 	intel_engine_init_heartbeat(engine);
 }
 
+/**
+ * intel_engine_reset_pinned_contexts - Reset the pinned contexts of
+ * an engine.
+ * @engine: The engine whose pinned contexts we want to reset.
+ *
+ * Typically the pinned context LMEM images lose or get their content
+ * corrupted on suspend. This function resets their images.
+ */
+void intel_engine_reset_pinned_contexts(struct intel_engine_cs *engine)
+{
+	struct intel_context *ce;
+
+	list_for_each_entry(ce, &engine->pinned_contexts_list,
+			    pinned_contexts_link) {
+		/* kernel context gets reset at __engine_unpark() */
+		if (ce == engine->kernel_context)
+			continue;
+
+		dbg_poison_ce(ce);
+		ce->ops->reset(ce);
+	}
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftest_engine_pm.c"
 #endif

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

@@ -69,4 +69,6 @@ intel_engine_create_kernel_request(struct intel_engine_cs *engine)
 
 void intel_engine_init__pm(struct intel_engine_cs *engine);
 
+void intel_engine_reset_pinned_contexts(struct intel_engine_cs *engine);
+
 #endif /* INTEL_ENGINE_PM_H */

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

@@ -307,6 +307,13 @@ struct intel_engine_cs {
 
 	struct intel_context *kernel_context; /* pinned */
 
+	/**
+	 * pinned_contexts_list: List of pinned contexts. This list is only
+	 * assumed to be manipulated during driver load- or unload time and
+	 * does therefore not have any additional protection.
+	 */
+	struct list_head pinned_contexts_list;
+
 	intel_engine_mask_t saturated; /* submitting semaphores too late? */
 
 	struct {

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

@@ -2787,6 +2787,8 @@ static void execlists_sanitize(struct intel_engine_cs *engine)
 
 	/* And scrub the dirty cachelines for the HWSP */
 	clflush_cache_range(engine->status_page.addr, PAGE_SIZE);
+
+	intel_engine_reset_pinned_contexts(engine);
 }
 
 static void enable_error_interrupt(struct intel_engine_cs *engine)

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

@@ -17,6 +17,7 @@
 #include "intel_ring.h"
 #include "shmem_utils.h"
 #include "intel_engine_heartbeat.h"
+#include "intel_engine_pm.h"
 
 /* Rough estimate of the typical request size, performing a flush,
  * set-context and then emitting the batch.
@@ -292,6 +293,8 @@ static void xcs_sanitize(struct intel_engine_cs *engine)
 
 	/* And scrub the dirty cachelines for the HWSP */
 	clflush_cache_range(engine->status_page.addr, PAGE_SIZE);
+
+	intel_engine_reset_pinned_contexts(engine);
 }
 
 static void reset_prepare(struct intel_engine_cs *engine)

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

@@ -376,6 +376,8 @@ int mock_engine_init(struct intel_engine_cs *engine)
 {
 	struct intel_context *ce;
 
+	INIT_LIST_HEAD(&engine->pinned_contexts_list);
+
 	engine->sched_engine = i915_sched_engine_create(ENGINE_MOCK);
 	if (!engine->sched_engine)
 		return -ENOMEM;

drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c

@@ -2477,6 +2477,8 @@ static void guc_sanitize(struct intel_engine_cs *engine)
 
 	/* And scrub the dirty cachelines for the HWSP */
 	clflush_cache_range(engine->status_page.addr, PAGE_SIZE);
+
+	intel_engine_reset_pinned_contexts(engine);
 }
 
 static void setup_hwsp(struct intel_engine_cs *engine)
@@ -2552,9 +2554,13 @@ static inline void guc_init_lrc_mapping(struct intel_guc *guc)
 	 * and even it did this code would be run again.
 	 */
 
-	for_each_engine(engine, gt, id)
-		if (engine->kernel_context)
-			guc_kernel_context_pin(guc, engine->kernel_context);
+	for_each_engine(engine, gt, id) {
+		struct intel_context *ce;
+
+		list_for_each_entry(ce, &engine->pinned_contexts_list,
+				    pinned_contexts_link)
+			guc_kernel_context_pin(guc, ce);
+	}
 }
 
 static void guc_release(struct intel_engine_cs *engine)