[PATCH 0/8] Prep work for next GuC release

[PATCH 0/8] Prep work for next GuC release

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

The next GuC firmware release includes some significant backwards
breaking API changes. One such is that there is no longer an LRC
descriptor pool. A bunch of prep work for that change can be done in
advance - the descriptor pool was being used for things it shouldn't
really have been used for anyway.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>


John Harrison (8):
  drm/i915/guc: Do not conflate lrc_desc with GuC id for registration
  drm/i915/guc: Add an explicit 'submission_initialized' flag
  drm/i915/guc: Better name for context id limit
  drm/i915/guc: Split guc_lrc_desc_pin apart
  drm/i915/guc: Move lrc desc setup to where it is needed
  drm/i915/guc: Rename desc_idx to ctx_id
  drm/i915/guc: Drop obsolete H2G definitions
  drm/i915/guc: Fix potential invalid pointer dereferences when decoding
    G2Hs

 drivers/gpu/drm/i915/gt/intel_context.c       |   2 +-
 .../gpu/drm/i915/gt/uc/abi/guc_actions_abi.h  |   2 -
 drivers/gpu/drm/i915/gt/uc/intel_guc.h        |   2 +
 drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h   |   4 +-
 .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 183 ++++++++++--------
 drivers/gpu/drm/i915/gt/uc/selftest_guc.c     |   2 +-
 6 files changed, 112 insertions(+), 83 deletions(-)

-- 
2.25.1

[PATCH 1/8] drm/i915/guc: Do not conflate lrc_desc with GuC id for registration

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

The LRC descriptor pool is going away. So, stop using it as a check for
context registration, use the GuC id instead (being the thing that
actually gets registered with the GuC).

Also, rename the set/clear/query helper functions for context id
mappings to better reflect their purpose and to differentiate from
other registration related helper functions.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 69 ++++++++++---------
 1 file changed, 38 insertions(+), 31 deletions(-)

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 b3a429a92c0d..7fb889e14995 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -514,31 +514,20 @@ static inline bool guc_submission_initialized(struct intel_guc *guc)
 	return !!guc->lrc_desc_pool_vaddr;
 }
 
-static inline void reset_lrc_desc(struct intel_guc *guc, u32 id)
+static inline void _reset_lrc_desc(struct intel_guc *guc, u32 id)
 {
-	if (likely(guc_submission_initialized(guc))) {
-		struct guc_lrc_desc *desc = __get_lrc_desc(guc, id);
-		unsigned long flags;
-
-		memset(desc, 0, sizeof(*desc));
+	struct guc_lrc_desc *desc = __get_lrc_desc(guc, id);
 
-		/*
-		 * xarray API doesn't have xa_erase_irqsave wrapper, so calling
-		 * the lower level functions directly.
-		 */
-		xa_lock_irqsave(&guc->context_lookup, flags);
-		__xa_erase(&guc->context_lookup, id);
-		xa_unlock_irqrestore(&guc->context_lookup, flags);
-	}
+	memset(desc, 0, sizeof(*desc));
 }
 
-static inline bool lrc_desc_registered(struct intel_guc *guc, u32 id)
+static inline bool ctx_id_mapped(struct intel_guc *guc, u32 id)
 {
 	return __get_context(guc, id);
 }
 
-static inline void set_lrc_desc_registered(struct intel_guc *guc, u32 id,
-					   struct intel_context *ce)
+static inline void set_ctx_id_mapping(struct intel_guc *guc, u32 id,
+				      struct intel_context *ce)
 {
 	unsigned long flags;
 
@@ -551,6 +540,24 @@ static inline void set_lrc_desc_registered(struct intel_guc *guc, u32 id,
 	xa_unlock_irqrestore(&guc->context_lookup, flags);
 }
 
+static inline void clr_ctx_id_mapping(struct intel_guc *guc, u32 id)
+{
+	unsigned long flags;
+
+	if (unlikely(!guc_submission_initialized(guc)))
+		return;
+
+	_reset_lrc_desc(guc, id);
+
+	/*
+	 * xarray API doesn't have xa_erase_irqsave wrapper, so calling
+	 * the lower level functions directly.
+	 */
+	xa_lock_irqsave(&guc->context_lookup, flags);
+	__xa_erase(&guc->context_lookup, id);
+	xa_unlock_irqrestore(&guc->context_lookup, flags);
+}
+
 static void decr_outstanding_submission_g2h(struct intel_guc *guc)
 {
 	if (atomic_dec_and_test(&guc->outstanding_submission_g2h))
@@ -795,7 +802,7 @@ static int __guc_wq_item_append(struct i915_request *rq)
 	GEM_BUG_ON(!atomic_read(&ce->guc_id.ref));
 	GEM_BUG_ON(context_guc_id_invalid(ce));
 	GEM_BUG_ON(context_wait_for_deregister_to_register(ce));
-	GEM_BUG_ON(!lrc_desc_registered(ce_to_guc(ce), ce->guc_id.id));
+	GEM_BUG_ON(!ctx_id_mapped(ce_to_guc(ce), ce->guc_id.id));
 
 	/* Insert NOOP if this work queue item will wrap the tail pointer. */
 	if (wqi_size > wq_space_until_wrap(ce)) {
@@ -923,7 +930,7 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
 	if (submit) {
 		struct intel_context *ce = request_to_scheduling_context(last);
 
-		if (unlikely(!lrc_desc_registered(guc, ce->guc_id.id) &&
+		if (unlikely(!ctx_id_mapped(guc, ce->guc_id.id) &&
 			     !intel_context_is_banned(ce))) {
 			ret = guc_lrc_desc_pin(ce, false);
 			if (unlikely(ret == -EPIPE)) {
@@ -1897,7 +1904,7 @@ static bool need_tasklet(struct intel_guc *guc, struct i915_request *rq)
 
 	return submission_disabled(guc) || guc->stalled_request ||
 		!i915_sched_engine_is_empty(sched_engine) ||
-		!lrc_desc_registered(guc, ce->guc_id.id);
+		!ctx_id_mapped(guc, ce->guc_id.id);
 }
 
 static void guc_submit_request(struct i915_request *rq)
@@ -1954,7 +1961,7 @@ static void __release_guc_id(struct intel_guc *guc, struct intel_context *ce)
 		else
 			ida_simple_remove(&guc->submission_state.guc_ids,
 					  ce->guc_id.id);
-		reset_lrc_desc(guc, ce->guc_id.id);
+		clr_ctx_id_mapping(guc, ce->guc_id.id);
 		set_context_guc_id_invalid(ce);
 	}
 	if (!list_empty(&ce->guc_id.link))
@@ -2250,10 +2257,10 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
 	GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) !=
 		   i915_gem_object_is_lmem(ce->ring->vma->obj));
 
-	context_registered = lrc_desc_registered(guc, desc_idx);
+	context_registered = ctx_id_mapped(guc, desc_idx);
 
-	reset_lrc_desc(guc, desc_idx);
-	set_lrc_desc_registered(guc, desc_idx, ce);
+	clr_ctx_id_mapping(guc, desc_idx);
+	set_ctx_id_mapping(guc, desc_idx, ce);
 
 	desc = __get_lrc_desc(guc, desc_idx);
 	desc->engine_class = engine_class_to_guc_class(engine->class);
@@ -2324,7 +2331,7 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
 		}
 		spin_unlock_irqrestore(&ce->guc_state.lock, flags);
 		if (unlikely(disabled)) {
-			reset_lrc_desc(guc, desc_idx);
+			clr_ctx_id_mapping(guc, desc_idx);
 			return 0;	/* Will get registered later */
 		}
 
@@ -2340,9 +2347,9 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
 		with_intel_runtime_pm(runtime_pm, wakeref)
 			ret = register_context(ce, loop);
 		if (unlikely(ret == -EBUSY)) {
-			reset_lrc_desc(guc, desc_idx);
+			clr_ctx_id_mapping(guc, desc_idx);
 		} else if (unlikely(ret == -ENODEV)) {
-			reset_lrc_desc(guc, desc_idx);
+			clr_ctx_id_mapping(guc, desc_idx);
 			ret = 0;	/* Will get registered later */
 		}
 	}
@@ -2529,7 +2536,7 @@ static bool context_cant_unblock(struct intel_context *ce)
 
 	return (ce->guc_state.sched_state & SCHED_STATE_NO_UNBLOCK) ||
 		context_guc_id_invalid(ce) ||
-		!lrc_desc_registered(ce_to_guc(ce), ce->guc_id.id) ||
+		!ctx_id_mapped(ce_to_guc(ce), ce->guc_id.id) ||
 		!intel_context_is_pinned(ce);
 }
 
@@ -2699,7 +2706,7 @@ static inline void guc_lrc_desc_unpin(struct intel_context *ce)
 	bool disabled;
 
 	GEM_BUG_ON(!intel_gt_pm_is_awake(gt));
-	GEM_BUG_ON(!lrc_desc_registered(guc, ce->guc_id.id));
+	GEM_BUG_ON(!ctx_id_mapped(guc, ce->guc_id.id));
 	GEM_BUG_ON(ce != __get_context(guc, ce->guc_id.id));
 	GEM_BUG_ON(context_enabled(ce));
 
@@ -2816,7 +2823,7 @@ static void guc_context_destroy(struct kref *kref)
 	 */
 	spin_lock_irqsave(&guc->submission_state.lock, flags);
 	destroy = submission_disabled(guc) || context_guc_id_invalid(ce) ||
-		!lrc_desc_registered(guc, ce->guc_id.id);
+		!ctx_id_mapped(guc, ce->guc_id.id);
 	if (likely(!destroy)) {
 		if (!list_empty(&ce->guc_id.link))
 			list_del_init(&ce->guc_id.link);
@@ -3059,7 +3066,7 @@ static void guc_signal_context_fence(struct intel_context *ce)
 static bool context_needs_register(struct intel_context *ce, bool new_guc_id)
 {
 	return (new_guc_id || test_bit(CONTEXT_LRCA_DIRTY, &ce->flags) ||
-		!lrc_desc_registered(ce_to_guc(ce), ce->guc_id.id)) &&
+		!ctx_id_mapped(ce_to_guc(ce), ce->guc_id.id)) &&
 		!submission_disabled(ce_to_guc(ce));
 }
 
-- 
2.25.1

[PATCH 2/8] drm/i915/guc: Add an explicit 'submission_initialized' flag

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

The LRC descriptor pool is going away. So, stop using it as a check
for whether submission has been initialised or not.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc.h            | 2 ++
 drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 8 +++++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index 9d779de16613..568eb6352ef0 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -137,6 +137,8 @@ struct intel_guc {
 	bool submission_supported;
 	/** @submission_selected: tracks whether the user enabled GuC submission */
 	bool submission_selected;
+	/** @submission_initialized: tracks whether GuC submission has been initialised */
+	bool submission_initialized;
 	/**
 	 * @rc_supported: tracks whether we support GuC rc on the current platform
 	 */
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 7fb889e14995..11bf56b5a266 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -511,7 +511,7 @@ static void guc_lrc_desc_pool_destroy(struct intel_guc *guc)
 
 static inline bool guc_submission_initialized(struct intel_guc *guc)
 {
-	return !!guc->lrc_desc_pool_vaddr;
+	return guc->submission_initialized;
 }
 
 static inline void _reset_lrc_desc(struct intel_guc *guc, u32 id)
@@ -1813,7 +1813,7 @@ int intel_guc_submission_init(struct intel_guc *guc)
 	struct intel_gt *gt = guc_to_gt(guc);
 	int ret;
 
-	if (guc->lrc_desc_pool)
+	if (guc->submission_initialized)
 		return 0;
 
 	ret = guc_lrc_desc_pool_create(guc);
@@ -1845,19 +1845,21 @@ int intel_guc_submission_init(struct intel_guc *guc)
 	INIT_DELAYED_WORK(&guc->timestamp.work, guc_timestamp_ping);
 	guc->timestamp.ping_delay = (POLL_TIME_CLKS / gt->clock_frequency + 1) * HZ;
 	guc->timestamp.shift = gpm_timestamp_shift(gt);
+	guc->submission_initialized = true;
 
 	return 0;
 }
 
 void intel_guc_submission_fini(struct intel_guc *guc)
 {
-	if (!guc->lrc_desc_pool)
+	if (!guc->submission_initialized)
 		return;
 
 	guc_flush_destroyed_contexts(guc);
 	guc_lrc_desc_pool_destroy(guc);
 	i915_sched_engine_put(guc->sched_engine);
 	bitmap_free(guc->submission_state.guc_ids_bitmap);
+	guc->submission_initialized = false;
 }
 
 static inline void queue_request(struct i915_sched_engine *sched_engine,
-- 
2.25.1

[PATCH 3/8] drm/i915/guc: Better name for context id limit

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

The LRC descriptor pool is going away. So, stop using it as the limit
for how many context ids are available.

While at it, also update a kzalloc(sizeof()*count) to be a
kcalloc(count,size).

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 drivers/gpu/drm/i915/gt/intel_context.c          |  2 +-
 drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h      |  4 ++--
 .../gpu/drm/i915/gt/uc/intel_guc_submission.c    | 16 ++++++++--------
 drivers/gpu/drm/i915/gt/uc/selftest_guc.c        |  2 +-
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
index 5d0ec7c49b6a..d87145b8fca0 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -400,7 +400,7 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
 	INIT_LIST_HEAD(&ce->guc_state.fences);
 	INIT_LIST_HEAD(&ce->guc_state.requests);
 
-	ce->guc_id.id = GUC_INVALID_LRC_ID;
+	ce->guc_id.id = GUC_INVALID_CONTEXT_ID;
 	INIT_LIST_HEAD(&ce->guc_id.link);
 
 	INIT_LIST_HEAD(&ce->destroyed_link);
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
index 6a4612a852e2..11099f0320ce 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
@@ -32,8 +32,8 @@
 #define GUC_CLIENT_PRIORITY_NORMAL	3
 #define GUC_CLIENT_PRIORITY_NUM		4
 
-#define GUC_MAX_LRC_DESCRIPTORS		65535
-#define	GUC_INVALID_LRC_ID		GUC_MAX_LRC_DESCRIPTORS
+#define GUC_MAX_CONTEXT_ID		65535
+#define	GUC_INVALID_CONTEXT_ID		GUC_MAX_CONTEXT_ID
 
 #define GUC_RENDER_ENGINE		0
 #define GUC_VIDEO_ENGINE		1
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 11bf56b5a266..ad784e8068c7 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -354,12 +354,12 @@ request_to_scheduling_context(struct i915_request *rq)
 
 static inline bool context_guc_id_invalid(struct intel_context *ce)
 {
-	return ce->guc_id.id == GUC_INVALID_LRC_ID;
+	return ce->guc_id.id == GUC_INVALID_CONTEXT_ID;
 }
 
 static inline void set_context_guc_id_invalid(struct intel_context *ce)
 {
-	ce->guc_id.id = GUC_INVALID_LRC_ID;
+	ce->guc_id.id = GUC_INVALID_CONTEXT_ID;
 }
 
 static inline struct intel_guc *ce_to_guc(struct intel_context *ce)
@@ -474,7 +474,7 @@ static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, u32 index)
 {
 	struct guc_lrc_desc *base = guc->lrc_desc_pool_vaddr;
 
-	GEM_BUG_ON(index >= GUC_MAX_LRC_DESCRIPTORS);
+	GEM_BUG_ON(index >= GUC_MAX_CONTEXT_ID);
 
 	return &base[index];
 }
@@ -483,7 +483,7 @@ static inline struct intel_context *__get_context(struct intel_guc *guc, u32 id)
 {
 	struct intel_context *ce = xa_load(&guc->context_lookup, id);
 
-	GEM_BUG_ON(id >= GUC_MAX_LRC_DESCRIPTORS);
+	GEM_BUG_ON(id >= GUC_MAX_CONTEXT_ID);
 
 	return ce;
 }
@@ -494,7 +494,7 @@ static int guc_lrc_desc_pool_create(struct intel_guc *guc)
 	int ret;
 
 	size = PAGE_ALIGN(sizeof(struct guc_lrc_desc) *
-			  GUC_MAX_LRC_DESCRIPTORS);
+			  GUC_MAX_CONTEXT_ID);
 	ret = intel_guc_allocate_and_map_vma(guc, size, &guc->lrc_desc_pool,
 					     (void **)&guc->lrc_desc_pool_vaddr);
 	if (ret)
@@ -2441,7 +2441,7 @@ static void __guc_context_sched_disable(struct intel_guc *guc,
 		GUC_CONTEXT_DISABLE
 	};
 
-	GEM_BUG_ON(guc_id == GUC_INVALID_LRC_ID);
+	GEM_BUG_ON(guc_id == GUC_INVALID_CONTEXT_ID);
 
 	GEM_BUG_ON(intel_context_is_child(ce));
 	trace_intel_context_sched_disable(ce);
@@ -3840,7 +3840,7 @@ static bool __guc_submission_selected(struct intel_guc *guc)
 
 void intel_guc_submission_init_early(struct intel_guc *guc)
 {
-	guc->submission_state.num_guc_ids = GUC_MAX_LRC_DESCRIPTORS;
+	guc->submission_state.num_guc_ids = GUC_MAX_CONTEXT_ID;
 	guc->submission_supported = __guc_submission_supported(guc);
 	guc->submission_selected = __guc_submission_selected(guc);
 }
@@ -3850,7 +3850,7 @@ g2h_context_lookup(struct intel_guc *guc, u32 desc_idx)
 {
 	struct intel_context *ce;
 
-	if (unlikely(desc_idx >= GUC_MAX_LRC_DESCRIPTORS)) {
+	if (unlikely(desc_idx >= GUC_MAX_CONTEXT_ID)) {
 		drm_err(&guc_to_gt(guc)->i915->drm,
 			"Invalid desc_idx %u", desc_idx);
 		return NULL;
diff --git a/drivers/gpu/drm/i915/gt/uc/selftest_guc.c b/drivers/gpu/drm/i915/gt/uc/selftest_guc.c
index a115894d5896..1df71d0796ae 100644
--- a/drivers/gpu/drm/i915/gt/uc/selftest_guc.c
+++ b/drivers/gpu/drm/i915/gt/uc/selftest_guc.c
@@ -148,7 +148,7 @@ static int intel_guc_steal_guc_ids(void *arg)
 	struct i915_request *spin_rq = NULL, *rq, *last = NULL;
 	int number_guc_id_stolen = guc->number_guc_id_stolen;
 
-	ce = kzalloc(sizeof(*ce) * GUC_MAX_LRC_DESCRIPTORS, GFP_KERNEL);
+	ce = kcalloc(GUC_MAX_CONTEXT_ID, sizeof(*ce), GFP_KERNEL);
 	if (!ce) {
 		pr_err("Context array allocation failed\n");
 		return -ENOMEM;
-- 
2.25.1

[PATCH 4/8] drm/i915/guc: Split guc_lrc_desc_pin apart

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

The LRC descriptor pool is going away. Further, the function that was
populating it was also doing a bunch of logic about the context
registration sequence. So, split that code apart into separate state
setup and try to register functions. Note that some of those 'try to
register' code paths actually undo the state setup and leave it to be
redone again later (with potentially different values). This is
inefficient. The next patch will correct this.

Also, move a comment about ignoring return values to the place where
the return values are actually ignored.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 45 ++++++++++++-------
 1 file changed, 28 insertions(+), 17 deletions(-)

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 ad784e8068c7..0ab2d1a24bf6 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -634,7 +634,7 @@ int intel_guc_wait_for_idle(struct intel_guc *guc, long timeout)
 					      true, timeout);
 }
 
-static int guc_lrc_desc_pin(struct intel_context *ce, bool loop);
+static int try_context_registration(struct intel_context *ce, bool loop);
 
 static int __guc_add_request(struct intel_guc *guc, struct i915_request *rq)
 {
@@ -932,7 +932,7 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
 
 		if (unlikely(!ctx_id_mapped(guc, ce->guc_id.id) &&
 			     !intel_context_is_banned(ce))) {
-			ret = guc_lrc_desc_pin(ce, false);
+			ret = try_context_registration(ce, false);
 			if (unlikely(ret == -EPIPE)) {
 				goto deadlk;
 			} else if (ret == -EBUSY) {
@@ -2237,17 +2237,13 @@ static void guc_context_policy_init(struct intel_engine_cs *engine,
 	desc->preemption_timeout = engine->props.preempt_timeout_ms * 1000;
 }
 
-static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
+static void prepare_context_registration_info(struct intel_context *ce)
 {
 	struct intel_engine_cs *engine = ce->engine;
-	struct intel_runtime_pm *runtime_pm = engine->uncore->rpm;
 	struct intel_guc *guc = &engine->gt->uc.guc;
 	u32 desc_idx = ce->guc_id.id;
 	struct guc_lrc_desc *desc;
-	bool context_registered;
-	intel_wakeref_t wakeref;
 	struct intel_context *child;
-	int ret = 0;
 
 	GEM_BUG_ON(!engine->mask);
 	GEM_BUG_ON(!sched_state_is_init(ce));
@@ -2259,8 +2255,6 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
 	GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) !=
 		   i915_gem_object_is_lmem(ce->ring->vma->obj));
 
-	context_registered = ctx_id_mapped(guc, desc_idx);
-
 	clr_ctx_id_mapping(guc, desc_idx);
 	set_ctx_id_mapping(guc, desc_idx, ce);
 
@@ -2308,6 +2302,21 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
 
 		clear_children_join_go_memory(ce);
 	}
+}
+
+static int try_context_registration(struct intel_context *ce, bool loop)
+{
+	struct intel_engine_cs *engine = ce->engine;
+	struct intel_runtime_pm *runtime_pm = engine->uncore->rpm;
+	struct intel_guc *guc = &engine->gt->uc.guc;
+	intel_wakeref_t wakeref;
+	u32 desc_idx = ce->guc_id.id;
+	bool context_registered;
+	int ret = 0;
+
+	context_registered = ctx_id_mapped(guc, desc_idx);
+
+	prepare_context_registration_info(ce);
 
 	/*
 	 * The context_lookup xarray is used to determine if the hardware
@@ -3145,7 +3154,7 @@ static int guc_request_alloc(struct i915_request *rq)
 	if (unlikely(ret < 0))
 		return ret;
 	if (context_needs_register(ce, !!ret)) {
-		ret = guc_lrc_desc_pin(ce, true);
+		ret = try_context_registration(ce, true);
 		if (unlikely(ret)) {	/* unwind */
 			if (ret == -EPIPE) {
 				disable_submission(guc);
@@ -3633,9 +3642,17 @@ static void guc_set_default_submission(struct intel_engine_cs *engine)
 static inline void guc_kernel_context_pin(struct intel_guc *guc,
 					  struct intel_context *ce)
 {
+	/*
+	 * Note: we purposefully do not check the returns below because
+	 * the registration can only fail if a reset is just starting.
+	 * This is called at the end of reset so presumably another reset
+	 * isn't happening and even it did this code would be run again.
+	 */
+
 	if (context_guc_id_invalid(ce))
 		pin_guc_id(guc, ce);
-	guc_lrc_desc_pin(ce, true);
+
+	try_context_registration(ce, true);
 }
 
 static inline void guc_init_lrc_mapping(struct intel_guc *guc)
@@ -3653,13 +3670,7 @@ static inline void guc_init_lrc_mapping(struct intel_guc *guc)
 	 * Also, after a reset the of the GuC we want to make sure that the
 	 * information shared with GuC is properly reset. The kernel LRCs are
 	 * not attached to the gem_context, so they need to be added separately.
-	 *
-	 * Note: we purposefully do not check the return of guc_lrc_desc_pin,
-	 * because that function can only fail if a reset is just starting. This
-	 * is at the end of reset so presumably another reset isn't happening
-	 * and even it did this code would be run again.
 	 */
-
 	for_each_engine(engine, gt, id) {
 		struct intel_context *ce;
 
-- 
2.25.1

[PATCH 5/8] drm/i915/guc: Move lrc desc setup to where it is needed

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

The LRC descriptor was being initialised early on in the context
registration sequence. It could then be determined that the actual
registration needs to be delayed and the descriptor would be wiped
out. This is inefficient, so move the setup to later in the process
after the point of no return.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

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 0ab2d1a24bf6..aa74ec74194a 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -2153,6 +2153,8 @@ static int __guc_action_register_context(struct intel_guc *guc,
 					     0, loop);
 }
 
+static void prepare_context_registration_info(struct intel_context *ce);
+
 static int register_context(struct intel_context *ce, bool loop)
 {
 	struct intel_guc *guc = ce_to_guc(ce);
@@ -2163,6 +2165,8 @@ static int register_context(struct intel_context *ce, bool loop)
 	GEM_BUG_ON(intel_context_is_child(ce));
 	trace_intel_context_register(ce);
 
+	prepare_context_registration_info(ce);
+
 	if (intel_context_is_parent(ce))
 		ret = __guc_action_register_multi_lrc(guc, ce, ce->guc_id.id,
 						      offset, loop);
@@ -2246,7 +2250,6 @@ static void prepare_context_registration_info(struct intel_context *ce)
 	struct intel_context *child;
 
 	GEM_BUG_ON(!engine->mask);
-	GEM_BUG_ON(!sched_state_is_init(ce));
 
 	/*
 	 * Ensure LRC + CT vmas are is same region as write barrier is done
@@ -2314,9 +2317,13 @@ static int try_context_registration(struct intel_context *ce, bool loop)
 	bool context_registered;
 	int ret = 0;
 
+	GEM_BUG_ON(!sched_state_is_init(ce));
+
 	context_registered = ctx_id_mapped(guc, desc_idx);
 
-	prepare_context_registration_info(ce);
+	if (context_registered)
+		clr_ctx_id_mapping(guc, desc_idx);
+	set_ctx_id_mapping(guc, desc_idx, ce);
 
 	/*
 	 * The context_lookup xarray is used to determine if the hardware
-- 
2.25.1

[PATCH 6/8] drm/i915/guc: Rename desc_idx to ctx_id

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

The LRC descriptor pool is going away. So, stop naming context ids as
descriptor pool indecies.

While at it, add a bunch of missing line feeds to some error messages.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 56 +++++++++----------
 1 file changed, 28 insertions(+), 28 deletions(-)

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 aa74ec74194a..b70b1ff46418 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -2245,7 +2245,7 @@ static void prepare_context_registration_info(struct intel_context *ce)
 {
 	struct intel_engine_cs *engine = ce->engine;
 	struct intel_guc *guc = &engine->gt->uc.guc;
-	u32 desc_idx = ce->guc_id.id;
+	u32 ctx_id = ce->guc_id.id;
 	struct guc_lrc_desc *desc;
 	struct intel_context *child;
 
@@ -2258,10 +2258,10 @@ static void prepare_context_registration_info(struct intel_context *ce)
 	GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) !=
 		   i915_gem_object_is_lmem(ce->ring->vma->obj));
 
-	clr_ctx_id_mapping(guc, desc_idx);
-	set_ctx_id_mapping(guc, desc_idx, ce);
+	clr_ctx_id_mapping(guc, ctx_id);
+	set_ctx_id_mapping(guc, ctx_id, ce);
 
-	desc = __get_lrc_desc(guc, desc_idx);
+	desc = __get_lrc_desc(guc, ctx_id);
 	desc->engine_class = engine_class_to_guc_class(engine->class);
 	desc->engine_submit_mask = engine->logical_mask;
 	desc->hw_context_desc = ce->lrc.lrca;
@@ -2313,17 +2313,17 @@ static int try_context_registration(struct intel_context *ce, bool loop)
 	struct intel_runtime_pm *runtime_pm = engine->uncore->rpm;
 	struct intel_guc *guc = &engine->gt->uc.guc;
 	intel_wakeref_t wakeref;
-	u32 desc_idx = ce->guc_id.id;
+	u32 ctx_id = ce->guc_id.id;
 	bool context_registered;
 	int ret = 0;
 
 	GEM_BUG_ON(!sched_state_is_init(ce));
 
-	context_registered = ctx_id_mapped(guc, desc_idx);
+	context_registered = ctx_id_mapped(guc, ctx_id);
 
 	if (context_registered)
-		clr_ctx_id_mapping(guc, desc_idx);
-	set_ctx_id_mapping(guc, desc_idx, ce);
+		clr_ctx_id_mapping(guc, ctx_id);
+	set_ctx_id_mapping(guc, ctx_id, ce);
 
 	/*
 	 * The context_lookup xarray is used to determine if the hardware
@@ -2349,7 +2349,7 @@ static int try_context_registration(struct intel_context *ce, bool loop)
 		}
 		spin_unlock_irqrestore(&ce->guc_state.lock, flags);
 		if (unlikely(disabled)) {
-			clr_ctx_id_mapping(guc, desc_idx);
+			clr_ctx_id_mapping(guc, ctx_id);
 			return 0;	/* Will get registered later */
 		}
 
@@ -2365,9 +2365,9 @@ static int try_context_registration(struct intel_context *ce, bool loop)
 		with_intel_runtime_pm(runtime_pm, wakeref)
 			ret = register_context(ce, loop);
 		if (unlikely(ret == -EBUSY)) {
-			clr_ctx_id_mapping(guc, desc_idx);
+			clr_ctx_id_mapping(guc, ctx_id);
 		} else if (unlikely(ret == -ENODEV)) {
-			clr_ctx_id_mapping(guc, desc_idx);
+			clr_ctx_id_mapping(guc, ctx_id);
 			ret = 0;	/* Will get registered later */
 		}
 	}
@@ -3864,26 +3864,26 @@ void intel_guc_submission_init_early(struct intel_guc *guc)
 }
 
 static inline struct intel_context *
-g2h_context_lookup(struct intel_guc *guc, u32 desc_idx)
+g2h_context_lookup(struct intel_guc *guc, u32 ctx_id)
 {
 	struct intel_context *ce;
 
-	if (unlikely(desc_idx >= GUC_MAX_CONTEXT_ID)) {
+	if (unlikely(ctx_id >= GUC_MAX_CONTEXT_ID)) {
 		drm_err(&guc_to_gt(guc)->i915->drm,
-			"Invalid desc_idx %u", desc_idx);
+			"Invalid ctx_id %u\n", ctx_id);
 		return NULL;
 	}
 
-	ce = __get_context(guc, desc_idx);
+	ce = __get_context(guc, ctx_id);
 	if (unlikely(!ce)) {
 		drm_err(&guc_to_gt(guc)->i915->drm,
-			"Context is NULL, desc_idx %u", desc_idx);
+			"Context is NULL, ctx_id %u\n", ctx_id);
 		return NULL;
 	}
 
 	if (unlikely(intel_context_is_child(ce))) {
 		drm_err(&guc_to_gt(guc)->i915->drm,
-			"Context is child, desc_idx %u", desc_idx);
+			"Context is child, ctx_id %u\n", ctx_id);
 		return NULL;
 	}
 
@@ -3895,14 +3895,14 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
 					  u32 len)
 {
 	struct intel_context *ce;
-	u32 desc_idx = msg[0];
+	u32 ctx_id = msg[0];
 
 	if (unlikely(len < 1)) {
-		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
+		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u\n", len);
 		return -EPROTO;
 	}
 
-	ce = g2h_context_lookup(guc, desc_idx);
+	ce = g2h_context_lookup(guc, ctx_id);
 	if (unlikely(!ce))
 		return -EPROTO;
 
@@ -3946,14 +3946,14 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
 {
 	struct intel_context *ce;
 	unsigned long flags;
-	u32 desc_idx = msg[0];
+	u32 ctx_id = msg[0];
 
 	if (unlikely(len < 2)) {
-		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
+		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u\n", len);
 		return -EPROTO;
 	}
 
-	ce = g2h_context_lookup(guc, desc_idx);
+	ce = g2h_context_lookup(guc, ctx_id);
 	if (unlikely(!ce))
 		return -EPROTO;
 
@@ -3961,8 +3961,8 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
 		     (!context_pending_enable(ce) &&
 		     !context_pending_disable(ce)))) {
 		drm_err(&guc_to_gt(guc)->i915->drm,
-			"Bad context sched_state 0x%x, desc_idx %u",
-			ce->guc_state.sched_state, desc_idx);
+			"Bad context sched_state 0x%x, ctx_id %u\n",
+			ce->guc_state.sched_state, ctx_id);
 		return -EPROTO;
 	}
 
@@ -4061,14 +4061,14 @@ int intel_guc_context_reset_process_msg(struct intel_guc *guc,
 {
 	struct intel_context *ce;
 	unsigned long flags;
-	int desc_idx;
+	int ctx_id;
 
 	if (unlikely(len != 1)) {
 		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
 		return -EPROTO;
 	}
 
-	desc_idx = msg[0];
+	ctx_id = msg[0];
 
 	/*
 	 * The context lookup uses the xarray but lookups only require an RCU lock
@@ -4077,7 +4077,7 @@ int intel_guc_context_reset_process_msg(struct intel_guc *guc,
 	 * asynchronously until the reset is done.
 	 */
 	xa_lock_irqsave(&guc->context_lookup, flags);
-	ce = g2h_context_lookup(guc, desc_idx);
+	ce = g2h_context_lookup(guc, ctx_id);
 	if (ce)
 		intel_context_get(ce);
 	xa_unlock_irqrestore(&guc->context_lookup, flags);
-- 
2.25.1

[PATCH 7/8] drm/i915/guc: Drop obsolete H2G definitions

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

The CTB registration process changed significantly a while back using
a single KLV based H2G. So drop the original and now obsolete H2G
definitions.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
index 7afdadc7656f..e77f955435ce 100644
--- a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
+++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
@@ -131,8 +131,6 @@ enum intel_guc_action {
 	INTEL_GUC_ACTION_AUTHENTICATE_HUC = 0x4000,
 	INTEL_GUC_ACTION_REGISTER_CONTEXT = 0x4502,
 	INTEL_GUC_ACTION_DEREGISTER_CONTEXT = 0x4503,
-	INTEL_GUC_ACTION_REGISTER_COMMAND_TRANSPORT_BUFFER = 0x4505,
-	INTEL_GUC_ACTION_DEREGISTER_COMMAND_TRANSPORT_BUFFER = 0x4506,
 	INTEL_GUC_ACTION_DEREGISTER_CONTEXT_DONE = 0x4600,
 	INTEL_GUC_ACTION_REGISTER_CONTEXT_MULTI_LRC = 0x4601,
 	INTEL_GUC_ACTION_CLIENT_SOFT_RESET = 0x5507,
-- 
2.25.1

[PATCH 8/8] drm/i915/guc: Fix potential invalid pointer dereferences when decoding G2Hs

[John.C.Harrison]

From: John Harrison <John.C.Harrison@Intel.com>

Some G2H handlers were reading the context id field from the payload
before checking the payload met the minimum length required.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

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 b70b1ff46418..ea17dca68674 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -3895,12 +3895,13 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
 					  u32 len)
 {
 	struct intel_context *ce;
-	u32 ctx_id = msg[0];
+	u32 ctx_id;
 
 	if (unlikely(len < 1)) {
 		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u\n", len);
 		return -EPROTO;
 	}
+	ctx_id = msg[0];
 
 	ce = g2h_context_lookup(guc, ctx_id);
 	if (unlikely(!ce))
@@ -3946,12 +3947,13 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
 {
 	struct intel_context *ce;
 	unsigned long flags;
-	u32 ctx_id = msg[0];
+	u32 ctx_id;
 
 	if (unlikely(len < 2)) {
 		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u\n", len);
 		return -EPROTO;
 	}
+	ctx_id = msg[0];
 
 	ce = g2h_context_lookup(guc, ctx_id);
 	if (unlikely(!ce))
-- 
2.25.1

Re: [PATCH 1/8] drm/i915/guc: Do not conflate lrc_desc with GuC id for registration

[Ceraolo Spurio, Daniele]

On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The LRC descriptor pool is going away. So, stop using it as a check for
> context registration, use the GuC id instead (being the thing that
> actually gets registered with the GuC).
>
> Also, rename the set/clear/query helper functions for context id
> mappings to better reflect their purpose and to differentiate from
> other registration related helper functions.
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

> ---
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 69 ++++++++++---------
>   1 file changed, 38 insertions(+), 31 deletions(-)
>
> 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 b3a429a92c0d..7fb889e14995 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -514,31 +514,20 @@ static inline bool guc_submission_initialized(struct intel_guc *guc)
>   	return !!guc->lrc_desc_pool_vaddr;
>   }
>   
> -static inline void reset_lrc_desc(struct intel_guc *guc, u32 id)
> +static inline void _reset_lrc_desc(struct intel_guc *guc, u32 id)
>   {
> -	if (likely(guc_submission_initialized(guc))) {
> -		struct guc_lrc_desc *desc = __get_lrc_desc(guc, id);
> -		unsigned long flags;
> -
> -		memset(desc, 0, sizeof(*desc));
> +	struct guc_lrc_desc *desc = __get_lrc_desc(guc, id);
>   
> -		/*
> -		 * xarray API doesn't have xa_erase_irqsave wrapper, so calling
> -		 * the lower level functions directly.
> -		 */
> -		xa_lock_irqsave(&guc->context_lookup, flags);
> -		__xa_erase(&guc->context_lookup, id);
> -		xa_unlock_irqrestore(&guc->context_lookup, flags);
> -	}
> +	memset(desc, 0, sizeof(*desc));
>   }
>   
> -static inline bool lrc_desc_registered(struct intel_guc *guc, u32 id)
> +static inline bool ctx_id_mapped(struct intel_guc *guc, u32 id)
>   {
>   	return __get_context(guc, id);
>   }
>   
> -static inline void set_lrc_desc_registered(struct intel_guc *guc, u32 id,
> -					   struct intel_context *ce)
> +static inline void set_ctx_id_mapping(struct intel_guc *guc, u32 id,
> +				      struct intel_context *ce)
>   {
>   	unsigned long flags;
>   
> @@ -551,6 +540,24 @@ static inline void set_lrc_desc_registered(struct intel_guc *guc, u32 id,
>   	xa_unlock_irqrestore(&guc->context_lookup, flags);
>   }
>   
> +static inline void clr_ctx_id_mapping(struct intel_guc *guc, u32 id)
> +{
> +	unsigned long flags;
> +
> +	if (unlikely(!guc_submission_initialized(guc)))
> +		return;
> +
> +	_reset_lrc_desc(guc, id);
> +
> +	/*
> +	 * xarray API doesn't have xa_erase_irqsave wrapper, so calling
> +	 * the lower level functions directly.
> +	 */
> +	xa_lock_irqsave(&guc->context_lookup, flags);
> +	__xa_erase(&guc->context_lookup, id);
> +	xa_unlock_irqrestore(&guc->context_lookup, flags);
> +}
> +
>   static void decr_outstanding_submission_g2h(struct intel_guc *guc)
>   {
>   	if (atomic_dec_and_test(&guc->outstanding_submission_g2h))
> @@ -795,7 +802,7 @@ static int __guc_wq_item_append(struct i915_request *rq)
>   	GEM_BUG_ON(!atomic_read(&ce->guc_id.ref));
>   	GEM_BUG_ON(context_guc_id_invalid(ce));
>   	GEM_BUG_ON(context_wait_for_deregister_to_register(ce));
> -	GEM_BUG_ON(!lrc_desc_registered(ce_to_guc(ce), ce->guc_id.id));
> +	GEM_BUG_ON(!ctx_id_mapped(ce_to_guc(ce), ce->guc_id.id));
>   
>   	/* Insert NOOP if this work queue item will wrap the tail pointer. */
>   	if (wqi_size > wq_space_until_wrap(ce)) {
> @@ -923,7 +930,7 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
>   	if (submit) {
>   		struct intel_context *ce = request_to_scheduling_context(last);
>   
> -		if (unlikely(!lrc_desc_registered(guc, ce->guc_id.id) &&
> +		if (unlikely(!ctx_id_mapped(guc, ce->guc_id.id) &&
>   			     !intel_context_is_banned(ce))) {
>   			ret = guc_lrc_desc_pin(ce, false);
>   			if (unlikely(ret == -EPIPE)) {
> @@ -1897,7 +1904,7 @@ static bool need_tasklet(struct intel_guc *guc, struct i915_request *rq)
>   
>   	return submission_disabled(guc) || guc->stalled_request ||
>   		!i915_sched_engine_is_empty(sched_engine) ||
> -		!lrc_desc_registered(guc, ce->guc_id.id);
> +		!ctx_id_mapped(guc, ce->guc_id.id);
>   }
>   
>   static void guc_submit_request(struct i915_request *rq)
> @@ -1954,7 +1961,7 @@ static void __release_guc_id(struct intel_guc *guc, struct intel_context *ce)
>   		else
>   			ida_simple_remove(&guc->submission_state.guc_ids,
>   					  ce->guc_id.id);
> -		reset_lrc_desc(guc, ce->guc_id.id);
> +		clr_ctx_id_mapping(guc, ce->guc_id.id);
>   		set_context_guc_id_invalid(ce);
>   	}
>   	if (!list_empty(&ce->guc_id.link))
> @@ -2250,10 +2257,10 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
>   	GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) !=
>   		   i915_gem_object_is_lmem(ce->ring->vma->obj));
>   
> -	context_registered = lrc_desc_registered(guc, desc_idx);
> +	context_registered = ctx_id_mapped(guc, desc_idx);
>   
> -	reset_lrc_desc(guc, desc_idx);
> -	set_lrc_desc_registered(guc, desc_idx, ce);
> +	clr_ctx_id_mapping(guc, desc_idx);
> +	set_ctx_id_mapping(guc, desc_idx, ce);
>   
>   	desc = __get_lrc_desc(guc, desc_idx);
>   	desc->engine_class = engine_class_to_guc_class(engine->class);
> @@ -2324,7 +2331,7 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
>   		}
>   		spin_unlock_irqrestore(&ce->guc_state.lock, flags);
>   		if (unlikely(disabled)) {
> -			reset_lrc_desc(guc, desc_idx);
> +			clr_ctx_id_mapping(guc, desc_idx);
>   			return 0;	/* Will get registered later */
>   		}
>   
> @@ -2340,9 +2347,9 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
>   		with_intel_runtime_pm(runtime_pm, wakeref)
>   			ret = register_context(ce, loop);
>   		if (unlikely(ret == -EBUSY)) {
> -			reset_lrc_desc(guc, desc_idx);
> +			clr_ctx_id_mapping(guc, desc_idx);
>   		} else if (unlikely(ret == -ENODEV)) {
> -			reset_lrc_desc(guc, desc_idx);
> +			clr_ctx_id_mapping(guc, desc_idx);
>   			ret = 0;	/* Will get registered later */
>   		}
>   	}
> @@ -2529,7 +2536,7 @@ static bool context_cant_unblock(struct intel_context *ce)
>   
>   	return (ce->guc_state.sched_state & SCHED_STATE_NO_UNBLOCK) ||
>   		context_guc_id_invalid(ce) ||
> -		!lrc_desc_registered(ce_to_guc(ce), ce->guc_id.id) ||
> +		!ctx_id_mapped(ce_to_guc(ce), ce->guc_id.id) ||
>   		!intel_context_is_pinned(ce);
>   }
>   
> @@ -2699,7 +2706,7 @@ static inline void guc_lrc_desc_unpin(struct intel_context *ce)
>   	bool disabled;
>   
>   	GEM_BUG_ON(!intel_gt_pm_is_awake(gt));
> -	GEM_BUG_ON(!lrc_desc_registered(guc, ce->guc_id.id));
> +	GEM_BUG_ON(!ctx_id_mapped(guc, ce->guc_id.id));
>   	GEM_BUG_ON(ce != __get_context(guc, ce->guc_id.id));
>   	GEM_BUG_ON(context_enabled(ce));
>   
> @@ -2816,7 +2823,7 @@ static void guc_context_destroy(struct kref *kref)
>   	 */
>   	spin_lock_irqsave(&guc->submission_state.lock, flags);
>   	destroy = submission_disabled(guc) || context_guc_id_invalid(ce) ||
> -		!lrc_desc_registered(guc, ce->guc_id.id);
> +		!ctx_id_mapped(guc, ce->guc_id.id);
>   	if (likely(!destroy)) {
>   		if (!list_empty(&ce->guc_id.link))
>   			list_del_init(&ce->guc_id.link);
> @@ -3059,7 +3066,7 @@ static void guc_signal_context_fence(struct intel_context *ce)
>   static bool context_needs_register(struct intel_context *ce, bool new_guc_id)
>   {
>   	return (new_guc_id || test_bit(CONTEXT_LRCA_DIRTY, &ce->flags) ||
> -		!lrc_desc_registered(ce_to_guc(ce), ce->guc_id.id)) &&
> +		!ctx_id_mapped(ce_to_guc(ce), ce->guc_id.id)) &&
>   		!submission_disabled(ce_to_guc(ce));
>   }
>   

Re: [Intel-gfx] [PATCH 2/8] drm/i915/guc: Add an explicit 'submission_initialized' flag

[Ceraolo Spurio, Daniele]

On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The LRC descriptor pool is going away. So, stop using it as a check
> for whether submission has been initialised or not.
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>

grep confirmed those are the only places we use the pool that way, so:

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

> ---
>   drivers/gpu/drm/i915/gt/uc/intel_guc.h            | 2 ++
>   drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 8 +++++---
>   2 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> index 9d779de16613..568eb6352ef0 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> @@ -137,6 +137,8 @@ struct intel_guc {
>   	bool submission_supported;
>   	/** @submission_selected: tracks whether the user enabled GuC submission */
>   	bool submission_selected;
> +	/** @submission_initialized: tracks whether GuC submission has been initialised */
> +	bool submission_initialized;
>   	/**
>   	 * @rc_supported: tracks whether we support GuC rc on the current platform
>   	 */
> 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 7fb889e14995..11bf56b5a266 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -511,7 +511,7 @@ static void guc_lrc_desc_pool_destroy(struct intel_guc *guc)
>   
>   static inline bool guc_submission_initialized(struct intel_guc *guc)
>   {
> -	return !!guc->lrc_desc_pool_vaddr;
> +	return guc->submission_initialized;
>   }
>   
>   static inline void _reset_lrc_desc(struct intel_guc *guc, u32 id)
> @@ -1813,7 +1813,7 @@ int intel_guc_submission_init(struct intel_guc *guc)
>   	struct intel_gt *gt = guc_to_gt(guc);
>   	int ret;
>   
> -	if (guc->lrc_desc_pool)
> +	if (guc->submission_initialized)
>   		return 0;
>   
>   	ret = guc_lrc_desc_pool_create(guc);
> @@ -1845,19 +1845,21 @@ int intel_guc_submission_init(struct intel_guc *guc)
>   	INIT_DELAYED_WORK(&guc->timestamp.work, guc_timestamp_ping);
>   	guc->timestamp.ping_delay = (POLL_TIME_CLKS / gt->clock_frequency + 1) * HZ;
>   	guc->timestamp.shift = gpm_timestamp_shift(gt);
> +	guc->submission_initialized = true;
>   
>   	return 0;
>   }
>   
>   void intel_guc_submission_fini(struct intel_guc *guc)
>   {
> -	if (!guc->lrc_desc_pool)
> +	if (!guc->submission_initialized)
>   		return;
>   
>   	guc_flush_destroyed_contexts(guc);
>   	guc_lrc_desc_pool_destroy(guc);
>   	i915_sched_engine_put(guc->sched_engine);
>   	bitmap_free(guc->submission_state.guc_ids_bitmap);
> +	guc->submission_initialized = false;
>   }
>   
>   static inline void queue_request(struct i915_sched_engine *sched_engine,

Re: [PATCH 3/8] drm/i915/guc: Better name for context id limit

[Ceraolo Spurio, Daniele]

On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The LRC descriptor pool is going away. So, stop using it as the limit
> for how many context ids are available.

I think this could be slightly reworded to make it clear that the 
numbers are not changing. Maybe add something like "the desc pool is 
sized based on the maximum numbers of contexts supported by the GuC, so 
define that limit directly".

>
> While at it, also update a kzalloc(sizeof()*count) to be a
> kcalloc(count,size).
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

> ---
>   drivers/gpu/drm/i915/gt/intel_context.c          |  2 +-
>   drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h      |  4 ++--
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c    | 16 ++++++++--------
>   drivers/gpu/drm/i915/gt/uc/selftest_guc.c        |  2 +-
>   4 files changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
> index 5d0ec7c49b6a..d87145b8fca0 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context.c
> +++ b/drivers/gpu/drm/i915/gt/intel_context.c
> @@ -400,7 +400,7 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
>   	INIT_LIST_HEAD(&ce->guc_state.fences);
>   	INIT_LIST_HEAD(&ce->guc_state.requests);
>   
> -	ce->guc_id.id = GUC_INVALID_LRC_ID;
> +	ce->guc_id.id = GUC_INVALID_CONTEXT_ID;
>   	INIT_LIST_HEAD(&ce->guc_id.link);
>   
>   	INIT_LIST_HEAD(&ce->destroyed_link);
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
> index 6a4612a852e2..11099f0320ce 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h
> @@ -32,8 +32,8 @@
>   #define GUC_CLIENT_PRIORITY_NORMAL	3
>   #define GUC_CLIENT_PRIORITY_NUM		4
>   
> -#define GUC_MAX_LRC_DESCRIPTORS		65535
> -#define	GUC_INVALID_LRC_ID		GUC_MAX_LRC_DESCRIPTORS
> +#define GUC_MAX_CONTEXT_ID		65535
> +#define	GUC_INVALID_CONTEXT_ID		GUC_MAX_CONTEXT_ID
>   
>   #define GUC_RENDER_ENGINE		0
>   #define GUC_VIDEO_ENGINE		1
> 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 11bf56b5a266..ad784e8068c7 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -354,12 +354,12 @@ request_to_scheduling_context(struct i915_request *rq)
>   
>   static inline bool context_guc_id_invalid(struct intel_context *ce)
>   {
> -	return ce->guc_id.id == GUC_INVALID_LRC_ID;
> +	return ce->guc_id.id == GUC_INVALID_CONTEXT_ID;
>   }
>   
>   static inline void set_context_guc_id_invalid(struct intel_context *ce)
>   {
> -	ce->guc_id.id = GUC_INVALID_LRC_ID;
> +	ce->guc_id.id = GUC_INVALID_CONTEXT_ID;
>   }
>   
>   static inline struct intel_guc *ce_to_guc(struct intel_context *ce)
> @@ -474,7 +474,7 @@ static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, u32 index)
>   {
>   	struct guc_lrc_desc *base = guc->lrc_desc_pool_vaddr;
>   
> -	GEM_BUG_ON(index >= GUC_MAX_LRC_DESCRIPTORS);
> +	GEM_BUG_ON(index >= GUC_MAX_CONTEXT_ID);
>   
>   	return &base[index];
>   }
> @@ -483,7 +483,7 @@ static inline struct intel_context *__get_context(struct intel_guc *guc, u32 id)
>   {
>   	struct intel_context *ce = xa_load(&guc->context_lookup, id);
>   
> -	GEM_BUG_ON(id >= GUC_MAX_LRC_DESCRIPTORS);
> +	GEM_BUG_ON(id >= GUC_MAX_CONTEXT_ID);
>   
>   	return ce;
>   }
> @@ -494,7 +494,7 @@ static int guc_lrc_desc_pool_create(struct intel_guc *guc)
>   	int ret;
>   
>   	size = PAGE_ALIGN(sizeof(struct guc_lrc_desc) *
> -			  GUC_MAX_LRC_DESCRIPTORS);
> +			  GUC_MAX_CONTEXT_ID);
>   	ret = intel_guc_allocate_and_map_vma(guc, size, &guc->lrc_desc_pool,
>   					     (void **)&guc->lrc_desc_pool_vaddr);
>   	if (ret)
> @@ -2441,7 +2441,7 @@ static void __guc_context_sched_disable(struct intel_guc *guc,
>   		GUC_CONTEXT_DISABLE
>   	};
>   
> -	GEM_BUG_ON(guc_id == GUC_INVALID_LRC_ID);
> +	GEM_BUG_ON(guc_id == GUC_INVALID_CONTEXT_ID);
>   
>   	GEM_BUG_ON(intel_context_is_child(ce));
>   	trace_intel_context_sched_disable(ce);
> @@ -3840,7 +3840,7 @@ static bool __guc_submission_selected(struct intel_guc *guc)
>   
>   void intel_guc_submission_init_early(struct intel_guc *guc)
>   {
> -	guc->submission_state.num_guc_ids = GUC_MAX_LRC_DESCRIPTORS;
> +	guc->submission_state.num_guc_ids = GUC_MAX_CONTEXT_ID;
>   	guc->submission_supported = __guc_submission_supported(guc);
>   	guc->submission_selected = __guc_submission_selected(guc);
>   }
> @@ -3850,7 +3850,7 @@ g2h_context_lookup(struct intel_guc *guc, u32 desc_idx)
>   {
>   	struct intel_context *ce;
>   
> -	if (unlikely(desc_idx >= GUC_MAX_LRC_DESCRIPTORS)) {
> +	if (unlikely(desc_idx >= GUC_MAX_CONTEXT_ID)) {
>   		drm_err(&guc_to_gt(guc)->i915->drm,
>   			"Invalid desc_idx %u", desc_idx);
>   		return NULL;
> diff --git a/drivers/gpu/drm/i915/gt/uc/selftest_guc.c b/drivers/gpu/drm/i915/gt/uc/selftest_guc.c
> index a115894d5896..1df71d0796ae 100644
> --- a/drivers/gpu/drm/i915/gt/uc/selftest_guc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/selftest_guc.c
> @@ -148,7 +148,7 @@ static int intel_guc_steal_guc_ids(void *arg)
>   	struct i915_request *spin_rq = NULL, *rq, *last = NULL;
>   	int number_guc_id_stolen = guc->number_guc_id_stolen;
>   
> -	ce = kzalloc(sizeof(*ce) * GUC_MAX_LRC_DESCRIPTORS, GFP_KERNEL);
> +	ce = kcalloc(GUC_MAX_CONTEXT_ID, sizeof(*ce), GFP_KERNEL);
>   	if (!ce) {
>   		pr_err("Context array allocation failed\n");
>   		return -ENOMEM;

Re: [Intel-gfx] [PATCH 4/8] drm/i915/guc: Split guc_lrc_desc_pin apart

[Ceraolo Spurio, Daniele]

On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The LRC descriptor pool is going away. Further, the function that was
> populating it was also doing a bunch of logic about the context
> registration sequence. So, split that code apart into separate state
> setup and try to register functions. Note that some of those 'try to
> register' code paths actually undo the state setup and leave it to be
> redone again later (with potentially different values). This is
> inefficient. The next patch will correct this.
>
> Also, move a comment about ignoring return values to the place where
> the return values are actually ignored.
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

> ---
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 45 ++++++++++++-------
>   1 file changed, 28 insertions(+), 17 deletions(-)
>
> 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 ad784e8068c7..0ab2d1a24bf6 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -634,7 +634,7 @@ int intel_guc_wait_for_idle(struct intel_guc *guc, long timeout)
>   					      true, timeout);
>   }
>   
> -static int guc_lrc_desc_pin(struct intel_context *ce, bool loop);
> +static int try_context_registration(struct intel_context *ce, bool loop);
>   
>   static int __guc_add_request(struct intel_guc *guc, struct i915_request *rq)
>   {
> @@ -932,7 +932,7 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
>   
>   		if (unlikely(!ctx_id_mapped(guc, ce->guc_id.id) &&
>   			     !intel_context_is_banned(ce))) {
> -			ret = guc_lrc_desc_pin(ce, false);
> +			ret = try_context_registration(ce, false);
>   			if (unlikely(ret == -EPIPE)) {
>   				goto deadlk;
>   			} else if (ret == -EBUSY) {
> @@ -2237,17 +2237,13 @@ static void guc_context_policy_init(struct intel_engine_cs *engine,
>   	desc->preemption_timeout = engine->props.preempt_timeout_ms * 1000;
>   }
>   
> -static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
> +static void prepare_context_registration_info(struct intel_context *ce)
>   {
>   	struct intel_engine_cs *engine = ce->engine;
> -	struct intel_runtime_pm *runtime_pm = engine->uncore->rpm;
>   	struct intel_guc *guc = &engine->gt->uc.guc;
>   	u32 desc_idx = ce->guc_id.id;
>   	struct guc_lrc_desc *desc;
> -	bool context_registered;
> -	intel_wakeref_t wakeref;
>   	struct intel_context *child;
> -	int ret = 0;
>   
>   	GEM_BUG_ON(!engine->mask);
>   	GEM_BUG_ON(!sched_state_is_init(ce));
> @@ -2259,8 +2255,6 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
>   	GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) !=
>   		   i915_gem_object_is_lmem(ce->ring->vma->obj));
>   
> -	context_registered = ctx_id_mapped(guc, desc_idx);
> -
>   	clr_ctx_id_mapping(guc, desc_idx);
>   	set_ctx_id_mapping(guc, desc_idx, ce);
>   
> @@ -2308,6 +2302,21 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
>   
>   		clear_children_join_go_memory(ce);
>   	}
> +}
> +
> +static int try_context_registration(struct intel_context *ce, bool loop)
> +{
> +	struct intel_engine_cs *engine = ce->engine;
> +	struct intel_runtime_pm *runtime_pm = engine->uncore->rpm;
> +	struct intel_guc *guc = &engine->gt->uc.guc;
> +	intel_wakeref_t wakeref;
> +	u32 desc_idx = ce->guc_id.id;
> +	bool context_registered;
> +	int ret = 0;
> +
> +	context_registered = ctx_id_mapped(guc, desc_idx);
> +
> +	prepare_context_registration_info(ce);
>   
>   	/*
>   	 * The context_lookup xarray is used to determine if the hardware
> @@ -3145,7 +3154,7 @@ static int guc_request_alloc(struct i915_request *rq)
>   	if (unlikely(ret < 0))
>   		return ret;
>   	if (context_needs_register(ce, !!ret)) {
> -		ret = guc_lrc_desc_pin(ce, true);
> +		ret = try_context_registration(ce, true);
>   		if (unlikely(ret)) {	/* unwind */
>   			if (ret == -EPIPE) {
>   				disable_submission(guc);
> @@ -3633,9 +3642,17 @@ static void guc_set_default_submission(struct intel_engine_cs *engine)
>   static inline void guc_kernel_context_pin(struct intel_guc *guc,
>   					  struct intel_context *ce)
>   {
> +	/*
> +	 * Note: we purposefully do not check the returns below because
> +	 * the registration can only fail if a reset is just starting.
> +	 * This is called at the end of reset so presumably another reset
> +	 * isn't happening and even it did this code would be run again.
> +	 */
> +
>   	if (context_guc_id_invalid(ce))
>   		pin_guc_id(guc, ce);
> -	guc_lrc_desc_pin(ce, true);
> +
> +	try_context_registration(ce, true);
>   }
>   
>   static inline void guc_init_lrc_mapping(struct intel_guc *guc)
> @@ -3653,13 +3670,7 @@ static inline void guc_init_lrc_mapping(struct intel_guc *guc)
>   	 * Also, after a reset the of the GuC we want to make sure that the
>   	 * information shared with GuC is properly reset. The kernel LRCs are
>   	 * not attached to the gem_context, so they need to be added separately.
> -	 *
> -	 * Note: we purposefully do not check the return of guc_lrc_desc_pin,
> -	 * because that function can only fail if a reset is just starting. This
> -	 * is at the end of reset so presumably another reset isn't happening
> -	 * and even it did this code would be run again.
>   	 */
> -
>   	for_each_engine(engine, gt, id) {
>   		struct intel_context *ce;
>   

Re: [Intel-gfx] [PATCH 5/8] drm/i915/guc: Move lrc desc setup to where it is needed

[Ceraolo Spurio, Daniele]

On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The LRC descriptor was being initialised early on in the context
> registration sequence. It could then be determined that the actual
> registration needs to be delayed and the descriptor would be wiped
> out. This is inefficient, so move the setup to later in the process
> after the point of no return.
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
>   drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
>
> 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 0ab2d1a24bf6..aa74ec74194a 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -2153,6 +2153,8 @@ static int __guc_action_register_context(struct intel_guc *guc,
>   					     0, loop);
>   }
>   
> +static void prepare_context_registration_info(struct intel_context *ce);
> +
>   static int register_context(struct intel_context *ce, bool loop)
>   {
>   	struct intel_guc *guc = ce_to_guc(ce);
> @@ -2163,6 +2165,8 @@ static int register_context(struct intel_context *ce, bool loop)
>   	GEM_BUG_ON(intel_context_is_child(ce));
>   	trace_intel_context_register(ce);
>   
> +	prepare_context_registration_info(ce);
> +
>   	if (intel_context_is_parent(ce))
>   		ret = __guc_action_register_multi_lrc(guc, ce, ce->guc_id.id,
>   						      offset, loop);
> @@ -2246,7 +2250,6 @@ static void prepare_context_registration_info(struct intel_context *ce)
>   	struct intel_context *child;
>   
>   	GEM_BUG_ON(!engine->mask);
> -	GEM_BUG_ON(!sched_state_is_init(ce));
>   
>   	/*
>   	 * Ensure LRC + CT vmas are is same region as write barrier is done
> @@ -2314,9 +2317,13 @@ static int try_context_registration(struct intel_context *ce, bool loop)
>   	bool context_registered;
>   	int ret = 0;
>   
> +	GEM_BUG_ON(!sched_state_is_init(ce));
> +
>   	context_registered = ctx_id_mapped(guc, desc_idx);
>   
> -	prepare_context_registration_info(ce);
> +	if (context_registered)
> +		clr_ctx_id_mapping(guc, desc_idx);
> +	set_ctx_id_mapping(guc, desc_idx, ce);

I think we can do the clr unconditionally. Also, should we drop the 
clr/set pair in prepare_context_registration_info? it shouldn't be 
needed, unless I'm missing a path where we don;t pass through here.

Daniele

>   
>   	/*
>   	 * The context_lookup xarray is used to determine if the hardware

Re: [PATCH 6/8] drm/i915/guc: Rename desc_idx to ctx_id

[Ceraolo Spurio, Daniele]

On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The LRC descriptor pool is going away. So, stop naming context ids as
> descriptor pool indecies.
>
> While at it, add a bunch of missing line feeds to some error messages.
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

> ---
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 56 +++++++++----------
>   1 file changed, 28 insertions(+), 28 deletions(-)
>
> 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 aa74ec74194a..b70b1ff46418 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -2245,7 +2245,7 @@ static void prepare_context_registration_info(struct intel_context *ce)
>   {
>   	struct intel_engine_cs *engine = ce->engine;
>   	struct intel_guc *guc = &engine->gt->uc.guc;
> -	u32 desc_idx = ce->guc_id.id;
> +	u32 ctx_id = ce->guc_id.id;
>   	struct guc_lrc_desc *desc;
>   	struct intel_context *child;
>   
> @@ -2258,10 +2258,10 @@ static void prepare_context_registration_info(struct intel_context *ce)
>   	GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) !=
>   		   i915_gem_object_is_lmem(ce->ring->vma->obj));
>   
> -	clr_ctx_id_mapping(guc, desc_idx);
> -	set_ctx_id_mapping(guc, desc_idx, ce);
> +	clr_ctx_id_mapping(guc, ctx_id);
> +	set_ctx_id_mapping(guc, ctx_id, ce);
>   
> -	desc = __get_lrc_desc(guc, desc_idx);
> +	desc = __get_lrc_desc(guc, ctx_id);
>   	desc->engine_class = engine_class_to_guc_class(engine->class);
>   	desc->engine_submit_mask = engine->logical_mask;
>   	desc->hw_context_desc = ce->lrc.lrca;
> @@ -2313,17 +2313,17 @@ static int try_context_registration(struct intel_context *ce, bool loop)
>   	struct intel_runtime_pm *runtime_pm = engine->uncore->rpm;
>   	struct intel_guc *guc = &engine->gt->uc.guc;
>   	intel_wakeref_t wakeref;
> -	u32 desc_idx = ce->guc_id.id;
> +	u32 ctx_id = ce->guc_id.id;
>   	bool context_registered;
>   	int ret = 0;
>   
>   	GEM_BUG_ON(!sched_state_is_init(ce));
>   
> -	context_registered = ctx_id_mapped(guc, desc_idx);
> +	context_registered = ctx_id_mapped(guc, ctx_id);
>   
>   	if (context_registered)
> -		clr_ctx_id_mapping(guc, desc_idx);
> -	set_ctx_id_mapping(guc, desc_idx, ce);
> +		clr_ctx_id_mapping(guc, ctx_id);
> +	set_ctx_id_mapping(guc, ctx_id, ce);
>   
>   	/*
>   	 * The context_lookup xarray is used to determine if the hardware
> @@ -2349,7 +2349,7 @@ static int try_context_registration(struct intel_context *ce, bool loop)
>   		}
>   		spin_unlock_irqrestore(&ce->guc_state.lock, flags);
>   		if (unlikely(disabled)) {
> -			clr_ctx_id_mapping(guc, desc_idx);
> +			clr_ctx_id_mapping(guc, ctx_id);
>   			return 0;	/* Will get registered later */
>   		}
>   
> @@ -2365,9 +2365,9 @@ static int try_context_registration(struct intel_context *ce, bool loop)
>   		with_intel_runtime_pm(runtime_pm, wakeref)
>   			ret = register_context(ce, loop);
>   		if (unlikely(ret == -EBUSY)) {
> -			clr_ctx_id_mapping(guc, desc_idx);
> +			clr_ctx_id_mapping(guc, ctx_id);
>   		} else if (unlikely(ret == -ENODEV)) {
> -			clr_ctx_id_mapping(guc, desc_idx);
> +			clr_ctx_id_mapping(guc, ctx_id);
>   			ret = 0;	/* Will get registered later */
>   		}
>   	}
> @@ -3864,26 +3864,26 @@ void intel_guc_submission_init_early(struct intel_guc *guc)
>   }
>   
>   static inline struct intel_context *
> -g2h_context_lookup(struct intel_guc *guc, u32 desc_idx)
> +g2h_context_lookup(struct intel_guc *guc, u32 ctx_id)
>   {
>   	struct intel_context *ce;
>   
> -	if (unlikely(desc_idx >= GUC_MAX_CONTEXT_ID)) {
> +	if (unlikely(ctx_id >= GUC_MAX_CONTEXT_ID)) {
>   		drm_err(&guc_to_gt(guc)->i915->drm,
> -			"Invalid desc_idx %u", desc_idx);
> +			"Invalid ctx_id %u\n", ctx_id);
>   		return NULL;
>   	}
>   
> -	ce = __get_context(guc, desc_idx);
> +	ce = __get_context(guc, ctx_id);
>   	if (unlikely(!ce)) {
>   		drm_err(&guc_to_gt(guc)->i915->drm,
> -			"Context is NULL, desc_idx %u", desc_idx);
> +			"Context is NULL, ctx_id %u\n", ctx_id);
>   		return NULL;
>   	}
>   
>   	if (unlikely(intel_context_is_child(ce))) {
>   		drm_err(&guc_to_gt(guc)->i915->drm,
> -			"Context is child, desc_idx %u", desc_idx);
> +			"Context is child, ctx_id %u\n", ctx_id);
>   		return NULL;
>   	}
>   
> @@ -3895,14 +3895,14 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
>   					  u32 len)
>   {
>   	struct intel_context *ce;
> -	u32 desc_idx = msg[0];
> +	u32 ctx_id = msg[0];
>   
>   	if (unlikely(len < 1)) {
> -		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
> +		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u\n", len);
>   		return -EPROTO;
>   	}
>   
> -	ce = g2h_context_lookup(guc, desc_idx);
> +	ce = g2h_context_lookup(guc, ctx_id);
>   	if (unlikely(!ce))
>   		return -EPROTO;
>   
> @@ -3946,14 +3946,14 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
>   {
>   	struct intel_context *ce;
>   	unsigned long flags;
> -	u32 desc_idx = msg[0];
> +	u32 ctx_id = msg[0];
>   
>   	if (unlikely(len < 2)) {
> -		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
> +		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u\n", len);
>   		return -EPROTO;
>   	}
>   
> -	ce = g2h_context_lookup(guc, desc_idx);
> +	ce = g2h_context_lookup(guc, ctx_id);
>   	if (unlikely(!ce))
>   		return -EPROTO;
>   
> @@ -3961,8 +3961,8 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
>   		     (!context_pending_enable(ce) &&
>   		     !context_pending_disable(ce)))) {
>   		drm_err(&guc_to_gt(guc)->i915->drm,
> -			"Bad context sched_state 0x%x, desc_idx %u",
> -			ce->guc_state.sched_state, desc_idx);
> +			"Bad context sched_state 0x%x, ctx_id %u\n",
> +			ce->guc_state.sched_state, ctx_id);
>   		return -EPROTO;
>   	}
>   
> @@ -4061,14 +4061,14 @@ int intel_guc_context_reset_process_msg(struct intel_guc *guc,
>   {
>   	struct intel_context *ce;
>   	unsigned long flags;
> -	int desc_idx;
> +	int ctx_id;
>   
>   	if (unlikely(len != 1)) {
>   		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u", len);
>   		return -EPROTO;
>   	}
>   
> -	desc_idx = msg[0];
> +	ctx_id = msg[0];
>   
>   	/*
>   	 * The context lookup uses the xarray but lookups only require an RCU lock
> @@ -4077,7 +4077,7 @@ int intel_guc_context_reset_process_msg(struct intel_guc *guc,
>   	 * asynchronously until the reset is done.
>   	 */
>   	xa_lock_irqsave(&guc->context_lookup, flags);
> -	ce = g2h_context_lookup(guc, desc_idx);
> +	ce = g2h_context_lookup(guc, ctx_id);
>   	if (ce)
>   		intel_context_get(ce);
>   	xa_unlock_irqrestore(&guc->context_lookup, flags);

Re: [PATCH 7/8] drm/i915/guc: Drop obsolete H2G definitions

[Ceraolo Spurio, Daniele]

On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The CTB registration process changed significantly a while back using
> a single KLV based H2G. So drop the original and now obsolete H2G
> definitions.

The GuC specs has those defines marked as deprecated since v63 and 
they're being removed entirely in v70, so:

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
>   drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h | 2 --
>   1 file changed, 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
> index 7afdadc7656f..e77f955435ce 100644
> --- a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
> +++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_abi.h
> @@ -131,8 +131,6 @@ enum intel_guc_action {
>   	INTEL_GUC_ACTION_AUTHENTICATE_HUC = 0x4000,
>   	INTEL_GUC_ACTION_REGISTER_CONTEXT = 0x4502,
>   	INTEL_GUC_ACTION_DEREGISTER_CONTEXT = 0x4503,
> -	INTEL_GUC_ACTION_REGISTER_COMMAND_TRANSPORT_BUFFER = 0x4505,
> -	INTEL_GUC_ACTION_DEREGISTER_COMMAND_TRANSPORT_BUFFER = 0x4506,
>   	INTEL_GUC_ACTION_DEREGISTER_CONTEXT_DONE = 0x4600,
>   	INTEL_GUC_ACTION_REGISTER_CONTEXT_MULTI_LRC = 0x4601,
>   	INTEL_GUC_ACTION_CLIENT_SOFT_RESET = 0x5507,

Re: [PATCH 8/8] drm/i915/guc: Fix potential invalid pointer dereferences when decoding G2Hs

[Ceraolo Spurio, Daniele]

On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> Some G2H handlers were reading the context id field from the payload
> before checking the payload met the minimum length required.
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

While double-checking the other msg handler I noticed that we don't do 
any checks on len for intel_guc_log_handle_flush_event(). Not really 
relevant for this patch, just wondering out loud if we should add a 
check to make sure the message is not corrupted.

Daniele

> ---
>   drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> 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 b70b1ff46418..ea17dca68674 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -3895,12 +3895,13 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
>   					  u32 len)
>   {
>   	struct intel_context *ce;
> -	u32 ctx_id = msg[0];
> +	u32 ctx_id;
>   
>   	if (unlikely(len < 1)) {
>   		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u\n", len);
>   		return -EPROTO;
>   	}
> +	ctx_id = msg[0];
>   
>   	ce = g2h_context_lookup(guc, ctx_id);
>   	if (unlikely(!ce))
> @@ -3946,12 +3947,13 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
>   {
>   	struct intel_context *ce;
>   	unsigned long flags;
> -	u32 ctx_id = msg[0];
> +	u32 ctx_id;
>   
>   	if (unlikely(len < 2)) {
>   		drm_err(&guc_to_gt(guc)->i915->drm, "Invalid length %u\n", len);
>   		return -EPROTO;
>   	}
> +	ctx_id = msg[0];
>   
>   	ce = g2h_context_lookup(guc, ctx_id);
>   	if (unlikely(!ce))

Re: [Intel-gfx] [PATCH 5/8] drm/i915/guc: Move lrc desc setup to where it is needed

[John Harrison]

On 2/22/2022 17:12, Ceraolo Spurio, Daniele wrote:
> On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
>> From: John Harrison <John.C.Harrison@Intel.com>
>>
>> The LRC descriptor was being initialised early on in the context
>> registration sequence. It could then be determined that the actual
>> registration needs to be delayed and the descriptor would be wiped
>> out. This is inefficient, so move the setup to later in the process
>> after the point of no return.
>>
>> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
>> ---
>>   drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 11 +++++++++--
>>   1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> 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 0ab2d1a24bf6..aa74ec74194a 100644
>> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>> @@ -2153,6 +2153,8 @@ static int __guc_action_register_context(struct 
>> intel_guc *guc,
>>                            0, loop);
>>   }
>>   +static void prepare_context_registration_info(struct intel_context 
>> *ce);
>> +
>>   static int register_context(struct intel_context *ce, bool loop)
>>   {
>>       struct intel_guc *guc = ce_to_guc(ce);
>> @@ -2163,6 +2165,8 @@ static int register_context(struct 
>> intel_context *ce, bool loop)
>>       GEM_BUG_ON(intel_context_is_child(ce));
>>       trace_intel_context_register(ce);
>>   +    prepare_context_registration_info(ce);
>> +
>>       if (intel_context_is_parent(ce))
>>           ret = __guc_action_register_multi_lrc(guc, ce, ce->guc_id.id,
>>                                 offset, loop);
>> @@ -2246,7 +2250,6 @@ static void 
>> prepare_context_registration_info(struct intel_context *ce)
>>       struct intel_context *child;
>>         GEM_BUG_ON(!engine->mask);
>> -    GEM_BUG_ON(!sched_state_is_init(ce));
>>         /*
>>        * Ensure LRC + CT vmas are is same region as write barrier is 
>> done
>> @@ -2314,9 +2317,13 @@ static int try_context_registration(struct 
>> intel_context *ce, bool loop)
>>       bool context_registered;
>>       int ret = 0;
>>   +    GEM_BUG_ON(!sched_state_is_init(ce));
>> +
>>       context_registered = ctx_id_mapped(guc, desc_idx);
>>   -    prepare_context_registration_info(ce);
>> +    if (context_registered)
>> +        clr_ctx_id_mapping(guc, desc_idx);
>> +    set_ctx_id_mapping(guc, desc_idx, ce);
>
> I think we can do the clr unconditionally. Also, should we drop the 
> clr/set pair in prepare_context_registration_info? it shouldn't be 
> needed, unless I'm missing a path where we don;t pass through here.
>
> Daniele
I don't believe so.

The point is that the context id might have changed (it got stolen, 
re-used, etc. - all the state machine code below can cause aborts and 
retries and such like if something is pending and the register needs to 
be delayed). So we need to clear out the old mapping and add a new one 
to be safe. Also, I'm not sure if it is safe to do a xa_store to an 
already used entry as an update or if you are supposed to clear it 
first? But that's what the code did before and I'm trying to not change 
any actual behaviour here.

John.

>
>>         /*
>>        * The context_lookup xarray is used to determine if the hardware
>

Re: [Intel-gfx] [PATCH 5/8] drm/i915/guc: Move lrc desc setup to where it is needed

[Ceraolo Spurio, Daniele]

On 2/23/2022 12:23 PM, John Harrison wrote:
> On 2/22/2022 17:12, Ceraolo Spurio, Daniele wrote:
>> On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
>>> From: John Harrison <John.C.Harrison@Intel.com>
>>>
>>> The LRC descriptor was being initialised early on in the context
>>> registration sequence. It could then be determined that the actual
>>> registration needs to be delayed and the descriptor would be wiped
>>> out. This is inefficient, so move the setup to later in the process
>>> after the point of no return.
>>>
>>> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 11 +++++++++--
>>>   1 file changed, 9 insertions(+), 2 deletions(-)
>>>
>>> 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 0ab2d1a24bf6..aa74ec74194a 100644
>>> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>>> @@ -2153,6 +2153,8 @@ static int 
>>> __guc_action_register_context(struct intel_guc *guc,
>>>                            0, loop);
>>>   }
>>>   +static void prepare_context_registration_info(struct 
>>> intel_context *ce);
>>> +
>>>   static int register_context(struct intel_context *ce, bool loop)
>>>   {
>>>       struct intel_guc *guc = ce_to_guc(ce);
>>> @@ -2163,6 +2165,8 @@ static int register_context(struct 
>>> intel_context *ce, bool loop)
>>>       GEM_BUG_ON(intel_context_is_child(ce));
>>>       trace_intel_context_register(ce);
>>>   +    prepare_context_registration_info(ce);
>>> +
>>>       if (intel_context_is_parent(ce))
>>>           ret = __guc_action_register_multi_lrc(guc, ce, ce->guc_id.id,
>>>                                 offset, loop);
>>> @@ -2246,7 +2250,6 @@ static void 
>>> prepare_context_registration_info(struct intel_context *ce)
>>>       struct intel_context *child;
>>>         GEM_BUG_ON(!engine->mask);
>>> -    GEM_BUG_ON(!sched_state_is_init(ce));
>>>         /*
>>>        * Ensure LRC + CT vmas are is same region as write barrier is 
>>> done
>>> @@ -2314,9 +2317,13 @@ static int try_context_registration(struct 
>>> intel_context *ce, bool loop)
>>>       bool context_registered;
>>>       int ret = 0;
>>>   +    GEM_BUG_ON(!sched_state_is_init(ce));
>>> +
>>>       context_registered = ctx_id_mapped(guc, desc_idx);
>>>   -    prepare_context_registration_info(ce);
>>> +    if (context_registered)
>>> +        clr_ctx_id_mapping(guc, desc_idx);
>>> +    set_ctx_id_mapping(guc, desc_idx, ce);
>>
>> I think we can do the clr unconditionally. Also, should we drop the 
>> clr/set pair in prepare_context_registration_info? it shouldn't be 
>> needed, unless I'm missing a path where we don;t pass through here.
>>
>> Daniele
> I don't believe so.
>
> The point is that the context id might have changed (it got stolen, 
> re-used, etc. - all the state machine code below can cause aborts and 
> retries and such like if something is pending and the register needs 
> to be delayed). So we need to clear out the old mapping and add a new 
> one to be safe. Also, I'm not sure if it is safe to do a xa_store to 
> an already used entry as an update or if you are supposed to clear it 
> first? But that's what the code did before and I'm trying to not 
> change any actual behaviour here.

I was comparing with previous behavior. before this patch, we only do 
the setting of the ctx_id here (inside 
prepare_context_registration_info) and you're not changing any of the 
abort/retry behavior, so if it was enough before it should be enough now.

Regarding the xa ops, we did an unconditional clear before, so it should 
be ok to just do the same and have the clear and set back to back 
without checking if the context ID was already in use or not.

Daniele

>
> John.
>
>>
>>>         /*
>>>        * The context_lookup xarray is used to determine if the hardware
>>
>

Re: [Intel-gfx] [PATCH 5/8] drm/i915/guc: Move lrc desc setup to where it is needed

[John Harrison]

On 2/23/2022 18:03, Ceraolo Spurio, Daniele wrote:
> On 2/23/2022 12:23 PM, John Harrison wrote:
>> On 2/22/2022 17:12, Ceraolo Spurio, Daniele wrote:
>>> On 2/17/2022 3:52 PM, John.C.Harrison@Intel.com wrote:
>>>> From: John Harrison <John.C.Harrison@Intel.com>
>>>>
>>>> The LRC descriptor was being initialised early on in the context
>>>> registration sequence. It could then be determined that the actual
>>>> registration needs to be delayed and the descriptor would be wiped
>>>> out. This is inefficient, so move the setup to later in the process
>>>> after the point of no return.
>>>>
>>>> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
>>>> ---
>>>>   drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 11 +++++++++--
>>>>   1 file changed, 9 insertions(+), 2 deletions(-)
>>>>
>>>> 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 0ab2d1a24bf6..aa74ec74194a 100644
>>>> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>>>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>>>> @@ -2153,6 +2153,8 @@ static int 
>>>> __guc_action_register_context(struct intel_guc *guc,
>>>>                            0, loop);
>>>>   }
>>>>   +static void prepare_context_registration_info(struct 
>>>> intel_context *ce);
>>>> +
>>>>   static int register_context(struct intel_context *ce, bool loop)
>>>>   {
>>>>       struct intel_guc *guc = ce_to_guc(ce);
>>>> @@ -2163,6 +2165,8 @@ static int register_context(struct 
>>>> intel_context *ce, bool loop)
>>>>       GEM_BUG_ON(intel_context_is_child(ce));
>>>>       trace_intel_context_register(ce);
>>>>   +    prepare_context_registration_info(ce);
>>>> +
>>>>       if (intel_context_is_parent(ce))
>>>>           ret = __guc_action_register_multi_lrc(guc, ce, 
>>>> ce->guc_id.id,
>>>>                                 offset, loop);
>>>> @@ -2246,7 +2250,6 @@ static void 
>>>> prepare_context_registration_info(struct intel_context *ce)
>>>>       struct intel_context *child;
>>>>         GEM_BUG_ON(!engine->mask);
>>>> -    GEM_BUG_ON(!sched_state_is_init(ce));
>>>>         /*
>>>>        * Ensure LRC + CT vmas are is same region as write barrier 
>>>> is done
>>>> @@ -2314,9 +2317,13 @@ static int try_context_registration(struct 
>>>> intel_context *ce, bool loop)
>>>>       bool context_registered;
>>>>       int ret = 0;
>>>>   +    GEM_BUG_ON(!sched_state_is_init(ce));
>>>> +
>>>>       context_registered = ctx_id_mapped(guc, desc_idx);
>>>>   -    prepare_context_registration_info(ce);
>>>> +    if (context_registered)
>>>> +        clr_ctx_id_mapping(guc, desc_idx);
>>>> +    set_ctx_id_mapping(guc, desc_idx, ce);
>>>
>>> I think we can do the clr unconditionally. Also, should we drop the 
>>> clr/set pair in prepare_context_registration_info? it shouldn't be 
>>> needed, unless I'm missing a path where we don;t pass through here.
>>>
>>> Daniele
>> I don't believe so.
>>
>> The point is that the context id might have changed (it got stolen, 
>> re-used, etc. - all the state machine code below can cause aborts and 
>> retries and such like if something is pending and the register needs 
>> to be delayed). So we need to clear out the old mapping and add a new 
>> one to be safe. Also, I'm not sure if it is safe to do a xa_store to 
>> an already used entry as an update or if you are supposed to clear it 
>> first? But that's what the code did before and I'm trying to not 
>> change any actual behaviour here.
>
> I was comparing with previous behavior. before this patch, we only do 
> the setting of the ctx_id here (inside 
> prepare_context_registration_info) and you're not changing any of the 
> abort/retry behavior, so if it was enough before it should be enough now.
Hmm, I think I must have confused myself with the intermediate steps 
along the way. Yes, it looks like the clr/set in prepare is redundant by 
the end.

>
> Regarding the xa ops, we did an unconditional clear before, so it 
> should be ok to just do the same and have the clear and set back to 
> back without checking if the context ID was already in use or not.
Actually, I was thinking you meant to drop the clr completely rather 
than just drop the condition. Yeah, that sounds fine.

Will post an update.

John.

>
> Daniele
>
>>
>> John.
>>
>>>
>>>>         /*
>>>>        * The context_lookup xarray is used to determine if the 
>>>> hardware
>>>
>>
>