From 85e97b1dd5d29b66a249406624734843b71c0a0c Mon Sep 17 00:00:00 2001 From: Matthew Brost Date: Wed, 19 Jan 2022 13:06:39 -0800 Subject: [PATCH] drm/i915/guc: Ensure multi-lrc fini breadcrumb math is correct Realized that the GuC multi-lrc fini breadcrumb emit code is very delicate as the math this code does relies on functions it calls to emit a certain number of DWs. Add a few GEM_BUG_ONs to assert the math is correct. v2: - Rebase + resend for CI (Checkpatch) - Fix blank line warning Signed-off-by: Matthew Brost Reviewed-by: John Harrison Signed-off-by: John Harrison Link: https://patchwork.freedesktop.org/patch/msgid/20220119210639.33053-1-matthew.brost@intel.com --- .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 33 +++++++++++++++---- 1 file changed, 27 insertions(+), 6 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 343bd4804e73f..422353a70d5db 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -4441,27 +4441,31 @@ static inline bool skip_handshake(struct i915_request *rq) return test_bit(I915_FENCE_FLAG_SKIP_PARALLEL, &rq->fence.flags); } +#define NON_SKIP_LEN 6 static u32 * emit_fini_breadcrumb_parent_no_preempt_mid_batch(struct i915_request *rq, u32 *cs) { struct intel_context *ce = rq->context; + __maybe_unused u32 *before_fini_breadcrumb_user_interrupt_cs; + __maybe_unused u32 *start_fini_breadcrumb_cs = cs; GEM_BUG_ON(!intel_context_is_parent(ce)); if (unlikely(skip_handshake(rq))) { /* * NOP everything in __emit_fini_breadcrumb_parent_no_preempt_mid_batch, - * the -6 comes from the length of the emits below. + * the NON_SKIP_LEN comes from the length of the emits below. */ memset(cs, 0, sizeof(u32) * - (ce->engine->emit_fini_breadcrumb_dw - 6)); - cs += ce->engine->emit_fini_breadcrumb_dw - 6; + (ce->engine->emit_fini_breadcrumb_dw - NON_SKIP_LEN)); + cs += ce->engine->emit_fini_breadcrumb_dw - NON_SKIP_LEN; } else { cs = __emit_fini_breadcrumb_parent_no_preempt_mid_batch(rq, cs); } /* Emit fini breadcrumb */ + before_fini_breadcrumb_user_interrupt_cs = cs; cs = gen8_emit_ggtt_write(cs, rq->fence.seqno, i915_request_active_timeline(rq)->hwsp_offset, @@ -4471,6 +4475,12 @@ emit_fini_breadcrumb_parent_no_preempt_mid_batch(struct i915_request *rq, *cs++ = MI_USER_INTERRUPT; *cs++ = MI_NOOP; + /* Ensure our math for skip + emit is correct */ + GEM_BUG_ON(before_fini_breadcrumb_user_interrupt_cs + NON_SKIP_LEN != + cs); + GEM_BUG_ON(start_fini_breadcrumb_cs + + ce->engine->emit_fini_breadcrumb_dw != cs); + rq->tail = intel_ring_offset(rq, cs); return cs; @@ -4513,22 +4523,25 @@ emit_fini_breadcrumb_child_no_preempt_mid_batch(struct i915_request *rq, u32 *cs) { struct intel_context *ce = rq->context; + __maybe_unused u32 *before_fini_breadcrumb_user_interrupt_cs; + __maybe_unused u32 *start_fini_breadcrumb_cs = cs; GEM_BUG_ON(!intel_context_is_child(ce)); if (unlikely(skip_handshake(rq))) { /* * NOP everything in __emit_fini_breadcrumb_child_no_preempt_mid_batch, - * the -6 comes from the length of the emits below. + * the NON_SKIP_LEN comes from the length of the emits below. */ memset(cs, 0, sizeof(u32) * - (ce->engine->emit_fini_breadcrumb_dw - 6)); - cs += ce->engine->emit_fini_breadcrumb_dw - 6; + (ce->engine->emit_fini_breadcrumb_dw - NON_SKIP_LEN)); + cs += ce->engine->emit_fini_breadcrumb_dw - NON_SKIP_LEN; } else { cs = __emit_fini_breadcrumb_child_no_preempt_mid_batch(rq, cs); } /* Emit fini breadcrumb */ + before_fini_breadcrumb_user_interrupt_cs = cs; cs = gen8_emit_ggtt_write(cs, rq->fence.seqno, i915_request_active_timeline(rq)->hwsp_offset, @@ -4538,11 +4551,19 @@ emit_fini_breadcrumb_child_no_preempt_mid_batch(struct i915_request *rq, *cs++ = MI_USER_INTERRUPT; *cs++ = MI_NOOP; + /* Ensure our math for skip + emit is correct */ + GEM_BUG_ON(before_fini_breadcrumb_user_interrupt_cs + NON_SKIP_LEN != + cs); + GEM_BUG_ON(start_fini_breadcrumb_cs + + ce->engine->emit_fini_breadcrumb_dw != cs); + rq->tail = intel_ring_offset(rq, cs); return cs; } +#undef NON_SKIP_LEN + static struct intel_context * guc_create_virtual(struct intel_engine_cs **siblings, unsigned int count, unsigned long flags) -- 2.30.2