Re: [PATCH 08/26] drm/i915/guc: Add multi-lrc context registration

On 10/4/2021 15:06, Matthew Brost wrote:

Add multi-lrc context registration H2G. In addition a workqueue and process descriptor are setup during multi-lrc context registration as these data structures are needed for multi-lrc submission.

v2: (John Harrison)

• Move GuC specific fields into sub-struct
• Clean up WQ defines
• Add comment explaining math to derive WQ / PD address

Signed-off-by: Matthew Brost matthew.brost@intel.com

drivers/gpu/drm/i915/gt/intel_context_types.h | 12 ++ drivers/gpu/drm/i915/gt/intel_lrc.c | 5 + .../gpu/drm/i915/gt/uc/abi/guc_actions_abi.h | 1 + drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h | 2 - .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 114 +++++++++++++++++- 5 files changed, 131 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h index 76dfca57cb45..48decb5ee954 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_types.h +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h @@ -239,6 +239,18 @@ struct intel_context { struct intel_context *parent; /** @number_children: number of children if parent */ u8 number_children;

• /** @guc: GuC specific members for parallel submission */
  

• struct {
  

• 	/** @wqi_head: head pointer in work queue */
  

• 	u16 wqi_head;
  

• 	/** @wqi_tail: tail pointer in work queue */
  

• 	u16 wqi_tail;
  

• 	/**
  

• 	 * @parent_page: page in context state (ce->state) used
  

• 	 * by parent for work queue, process descriptor
  

• 	 */
  

• 	u8 parent_page;
  

• } guc;
  

  } parallel;

  #ifdef CONFIG_DRM_I915_SELFTEST

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 3ef9eaf8c50e..57339d5c1fc8 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -942,6 +942,11 @@ __lrc_alloc_state(struct intel_context *ce, struct intel_engine_cs *engine) context_size += PAGE_SIZE; }

• if (intel_context_is_parent(ce) && intel_engine_uses_guc(engine)) {

• ce->parallel.guc.parent_page = context_size / PAGE_SIZE;
  

• context_size += PAGE_SIZE;
  

• }
• obj = i915_gem_object_create_lmem(engine->i915, context_size, I915_BO_ALLOC_PM_VOLATILE); if (IS_ERR(obj))

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 8ff582222aff..ba10bd374cee 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 @@ -142,6 +142,7 @@ enum intel_guc_action { 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_RESET_CLIENT = 0x5507, INTEL_GUC_ACTION_LIMIT };

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 fa4be13c8854..0eeb2a9feeed 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h @@ -52,8 +52,6 @@

#define GUC_DOORBELL_INVALID 256

-#define GUC_WQ_SIZE (PAGE_SIZE * 2)

• /* Work queue item header definitions */ #define WQ_STATUS_ACTIVE 1 #define WQ_STATUS_SUSPENDED 2

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 451d9ae861a6..ab6d7fc1b0b1 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -344,6 +344,45 @@ static inline struct i915_priolist *to_priolist(struct rb_node *rb) return rb_entry(rb, struct i915_priolist, node); }

+/*

• • When using multi-lrc submission an extra page in the context state is
• • reserved for the process descriptor and work queue.
• • The layout of this page is below:
• • 0 guc_process_desc
• • ... unused
• • PAGE_SIZE / 2 work queue start
• • ... work queue
• • PAGE_SIZE - 1 work queue end
• */

+#define WQ_SIZE (PAGE_SIZE / 2) +#define WQ_OFFSET (PAGE_SIZE - WQ_SIZE)

I thought you were going with '#define PARENT_SCRATCH SIZE PAGE_SIZE' and then using that everywhere else? Unless there is a fundamental reason why the above must be exactly a page in size then I think the size should be defined once and re-used rather than assumed in multiple places (including in the description comment).

+static u32 __get_process_desc_offset(struct intel_context *ce) +{

• GEM_BUG_ON(!ce->parallel.guc.parent_page);
• return ce->parallel.guc.parent_page * PAGE_SIZE;

+}

+static u32 __get_wq_offset(struct intel_context *ce) +{

• return __get_process_desc_offset(ce) + WQ_OFFSET;

+}

+static struct guc_process_desc * +__get_process_desc(struct intel_context *ce) +{

• /*

• * Need to subtract LRC_STATE_OFFSET here as the
  

• * parallel.guc.parent_page is the offset into ce->state while
  

• * ce->lrc_reg_reg is ce->state + LRC_STATE_OFFSET.
  

• */
  

• return (struct guc_process_desc *)

• (ce->lrc_reg_state +
  

•  ((__get_process_desc_offset(ce) -
  

•    LRC_STATE_OFFSET) / sizeof(u32)));
  

+}

• static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, u32 index) { struct guc_lrc_desc *base = guc->lrc_desc_pool_vaddr;

@@ -1365,6 +1404,30 @@ static void unpin_guc_id(struct intel_guc *guc, struct intel_context *ce) spin_unlock_irqrestore(&guc->submission_state.lock, flags); }

+static int __guc_action_register_multi_lrc(struct intel_guc *guc,

• 			   struct intel_context *ce,
  

• 			   u32 guc_id,
  

• 			   u32 offset,
  

• 			   bool loop)
  

+{

• struct intel_context *child;
• u32 action[4 + MAX_ENGINE_INSTANCE];
• int len = 0;
• GEM_BUG_ON(ce->parallel.number_children > MAX_ENGINE_INSTANCE);
• action[len++] = INTEL_GUC_ACTION_REGISTER_CONTEXT_MULTI_LRC;
• action[len++] = guc_id;
• action[len++] = ce->parallel.number_children + 1;
• action[len++] = offset;
• for_each_child(ce, child) {

• offset += sizeof(struct guc_lrc_desc);
  

• action[len++] = offset;
  

• }
• return guc_submission_send_busy_loop(guc, action, len, 0, loop);

+}

• static int __guc_action_register_context(struct intel_guc *guc, u32 guc_id, u32 offset,

@@ -1387,9 +1450,15 @@ static int register_context(struct intel_context *ce, bool loop) ce->guc_id.id * sizeof(struct guc_lrc_desc); int ret;

• GEM_BUG_ON(intel_context_is_child(ce)); trace_intel_context_register(ce);

• ret = __guc_action_register_context(guc, ce->guc_id.id, offset, loop);

• if (intel_context_is_parent(ce))

• ret = __guc_action_register_multi_lrc(guc, ce, ce->guc_id.id,
  

• 				      offset, loop);
  

• else

• ret = __guc_action_register_context(guc, ce->guc_id.id, offset,
  

• 				    loop);
  

  if (likely(!ret)) { unsigned long flags;

@@ -1418,6 +1487,7 @@ static int deregister_context(struct intel_context *ce, u32 guc_id) { struct intel_guc *guc = ce_to_guc(ce);

• GEM_BUG_ON(intel_context_is_child(ce)); trace_intel_context_deregister(ce);

  return __guc_action_deregister_context(guc, guc_id);

@@ -1445,6 +1515,7 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop) struct guc_lrc_desc *desc; bool context_registered; intel_wakeref_t wakeref;

• struct intel_context *child; int ret = 0;

  GEM_BUG_ON(!engine->mask);

@@ -1470,6 +1541,41 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop) desc->context_flags = CONTEXT_REGISTRATION_FLAG_KMD; guc_context_policy_init(engine, desc);

• /*

• * Context is a parent, we need to register a process descriptor
  

• * describing a work queue and register all child contexts.
  

• */
  

This was now meant to say 'If the context is a parent...'?

John.

• if (intel_context_is_parent(ce)) {

• struct guc_process_desc *pdesc;
  

• ce->parallel.guc.wqi_tail = 0;
  

• ce->parallel.guc.wqi_head = 0;
  

• desc->process_desc = i915_ggtt_offset(ce->state) +
  

• 	__get_process_desc_offset(ce);
  

• desc->wq_addr = i915_ggtt_offset(ce->state) +
  

• 	__get_wq_offset(ce);
  

• desc->wq_size = WQ_SIZE;
  

• pdesc = __get_process_desc(ce);
  

• memset(pdesc, 0, sizeof(*(pdesc)));
  

• pdesc->stage_id = ce->guc_id.id;
  

• pdesc->wq_base_addr = desc->wq_addr;
  

• pdesc->wq_size_bytes = desc->wq_size;
  

• pdesc->wq_status = WQ_STATUS_ACTIVE;
  

• for_each_child(ce, child) {
  

• 	desc = __get_lrc_desc(guc, child->guc_id.id);
  

• 	desc->engine_class =
  

• 		engine_class_to_guc_class(engine->class);
  

• 	desc->hw_context_desc = child->lrc.lrca;
  

• 	desc->priority = ce->guc_state.prio;
  

• 	desc->context_flags = CONTEXT_REGISTRATION_FLAG_KMD;
  

• 	guc_context_policy_init(engine, desc);
  

• }
  

• }
• /*
  • The context_lookup xarray is used to determine if the hardware
  • context is currently registered. There are two cases in which it

@@ -2804,6 +2910,12 @@ g2h_context_lookup(struct intel_guc *guc, u32 desc_idx) 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);
  

• return NULL;
  

• }
• return ce; }