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From dc5ac599ebd166f7541f8cfaad2b664e1c81b5e7 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 16 Dec 2019 14:24:09 +0000
Subject: drm/i915/gt: Tidy up full-ppgtt on Ivybridge
Git-commit: 902eb748e5c3d32ad955eef439e0911905758166
Patch-mainline: v5.6-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

With a couple more memory barriers dotted around the place we can
significantly reduce the MTBF on Ivybridge. Still doesn't really help
Haswell though.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191216142409.2605211-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 .../gpu/drm/i915/gt/intel_ring_submission.c   | 138 ++++++------------
 drivers/gpu/drm/i915/i915_gem_gtt.c           |   2 +
 2 files changed, 43 insertions(+), 97 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
index 77f78906f612..1b21a513521b 100644
--- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
@@ -362,6 +362,12 @@ gen7_render_ring_flush(struct i915_request *rq, u32 mode)
 	 */
 	flags |= PIPE_CONTROL_CS_STALL;
 
+	/*
+	 * CS_STALL suggests at least a post-sync write.
+	 */
+	flags |= PIPE_CONTROL_QW_WRITE;
+	flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
+
 	/* Just flush everything.  Experiments have shown that reducing the
 	 * number of bits based on the write domains has little performance
 	 * impact.
@@ -380,13 +386,6 @@ gen7_render_ring_flush(struct i915_request *rq, u32 mode)
 		flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
 		flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
 		flags |= PIPE_CONTROL_MEDIA_STATE_CLEAR;
-		/*
-		 * TLB invalidate requires a post-sync write.
-		 */
-		flags |= PIPE_CONTROL_QW_WRITE;
-		flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
-
-		flags |= PIPE_CONTROL_STALL_AT_SCOREBOARD;
 
 		/* Workaround: we must issue a pipe_control with CS-stall bit
 		 * set before a pipe_control command that has the state cache
@@ -1371,50 +1370,26 @@ static int load_pd_dir(struct i915_request *rq,
 	const struct intel_engine_cs * const engine = rq->engine;
 	u32 *cs;
 
-	cs = intel_ring_begin(rq, 12);
+	cs = intel_ring_begin(rq, 10);
 	if (IS_ERR(cs))
 		return PTR_ERR(cs);
 
-	*cs++ = MI_LOAD_REGISTER_IMM(1);
+	*cs++ = MI_LOAD_REGISTER_IMM(3);
 	*cs++ = i915_mmio_reg_offset(RING_PP_DIR_DCLV(engine->mmio_base));
 	*cs++ = valid;
-
-	*cs++ = MI_STORE_REGISTER_MEM | MI_SRM_LRM_GLOBAL_GTT;
-	*cs++ = i915_mmio_reg_offset(RING_PP_DIR_DCLV(engine->mmio_base));
-	*cs++ = intel_gt_scratch_offset(rq->engine->gt,
-					INTEL_GT_SCRATCH_FIELD_DEFAULT);
-
-	*cs++ = MI_LOAD_REGISTER_IMM(1);
 	*cs++ = i915_mmio_reg_offset(RING_PP_DIR_BASE(engine->mmio_base));
 	*cs++ = px_base(ppgtt->pd)->ggtt_offset << 10;
+	*cs++ = i915_mmio_reg_offset(RING_INSTPM(engine->mmio_base));
+	*cs++ = _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE);
 
 	/* Stall until the page table load is complete? */
 	*cs++ = MI_STORE_REGISTER_MEM | MI_SRM_LRM_GLOBAL_GTT;
 	*cs++ = i915_mmio_reg_offset(RING_PP_DIR_BASE(engine->mmio_base));
-	*cs++ = intel_gt_scratch_offset(rq->engine->gt,
+	*cs++ = intel_gt_scratch_offset(engine->gt,
 					INTEL_GT_SCRATCH_FIELD_DEFAULT);
 
 	intel_ring_advance(rq, cs);
 
-	return rq->engine->emit_flush(rq, EMIT_FLUSH);
-}
-
-static int flush_tlb(struct i915_request *rq)
-{
-	const struct intel_engine_cs * const engine = rq->engine;
-	u32 *cs;
-
-	cs = intel_ring_begin(rq, 4);
-	if (IS_ERR(cs))
-		return PTR_ERR(cs);
-
-	*cs++ = MI_LOAD_REGISTER_IMM(1);
-	*cs++ = i915_mmio_reg_offset(RING_INSTPM(engine->mmio_base));
-	*cs++ = _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE);
-
-	*cs++ = MI_NOOP;
-	intel_ring_advance(rq, cs);
-
 	return 0;
 }
 
@@ -1582,20 +1557,42 @@ static int remap_l3(struct i915_request *rq)
 	return 0;
 }
 
+static int switch_mm(struct i915_request *rq, struct i915_address_space *vm)
+{
+	int ret;
+
+	if (!vm)
+		return 0;
+
+	ret = rq->engine->emit_flush(rq, EMIT_FLUSH);
+	if (ret)
+		return ret;
+
+	/*
+	 * Not only do we need a full barrier (post-sync write) after
+	 * invalidating the TLBs, but we need to wait a little bit
+	 * longer. Whether this is merely delaying us, or the
+	 * subsequent flush is a key part of serialising with the
+	 * post-sync op, this extra pass appears vital before a
+	 * mm switch!
+	 */
+	ret = load_pd_dir(rq, i915_vm_to_ppgtt(vm), PP_DIR_DCLV_2G);
+	if (ret)
+		return ret;
+
+	return rq->engine->emit_flush(rq, EMIT_FLUSH);
+}
+
 static int switch_context(struct i915_request *rq)
 {
 	struct intel_context *ce = rq->hw_context;
-	struct i915_address_space *vm = vm_alias(ce);
-	u32 hw_flags = 0;
 	int ret;
 
 	GEM_BUG_ON(HAS_EXECLISTS(rq->i915));
 
-	if (vm) {
-		ret = load_pd_dir(rq, i915_vm_to_ppgtt(vm));
-		if (ret)
-			return ret;
-	}
+	ret = switch_mm(rq, vm_alias(ce));
+	if (ret)
+		return ret;
 
 	if (ce->state) {
 		u32 flags;
@@ -1607,65 +1604,12 @@ static int switch_context(struct i915_request *rq)
 		BUILD_BUG_ON(HSW_MI_RS_RESTORE_STATE_EN != MI_RESTORE_EXT_STATE_EN);
 
 		flags = MI_SAVE_EXT_STATE_EN | MI_MM_SPACE_GTT;
-		if (!rq->engine->default_state)
+		if (test_bit(CONTEXT_VALID_BIT, &ce->flags))
 			flags |= MI_RESTORE_EXT_STATE_EN;
 		else
 			flags |= MI_RESTORE_INHIBIT;
 
 		ret = mi_set_context(rq, flags);
-
-		ret = load_pd_dir(rq, i915_vm_to_ppgtt(vm));
-		if (ret)
-			return ret;
-
-		ret = engine->emit_flush(rq, EMIT_INVALIDATE);
-		if (ret)
-			return ret;
-
-		ret = flush_pd_dir(rq);
-		if (ret)
-			return ret;
-
-		/*
-		 * Not only do we need a full barrier (post-sync write) after
-		 * invalidating the TLBs, but we need to wait a little bit
-		 * longer. Whether this is merely delaying us, or the
-		 * subsequent flush is a key part of serialising with the
-		 * post-sync op, this extra pass appears vital before a
-		 * mm switch!
-		 */
-		ret = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
-		if (ret)
-			return ret;
-
-		ret = flush_tlb(rq);
-		if (ret)
-			return ret;
-
-		ret = load_pd_dir(rq, i915_vm_to_ppgtt(vm), 0);
-		if (ret)
-			return ret;
-
-		ret = load_pd_dir(rq, i915_vm_to_ppgtt(vm), PP_DIR_DCLV_2G);
-		if (ret)
-			return ret;
-
-		ret = flush_tlb(rq);
-		if (ret)
-			return ret;
-
-		ret = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
-		if (ret)
-			return ret;
-	}
-
-	if (ce->state) {
-		GEM_BUG_ON(rq->engine->id != RCS0);
-
-		if (!test_bit(CONTEXT_VALID_BIT, &ce->flags))
-			hw_flags = MI_RESTORE_INHIBIT;
-
-		ret = mi_set_context(rq, hw_flags);
 		if (ret)
 			return ret;
 	}
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 24de86cc29ca..2c706cf7bdc7 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1711,8 +1711,10 @@ static void gen6_flush_pd(struct gen6_ppgtt *ppgtt, u64 start, u64 end)
 	gen6_for_each_pde(pt, pd, start, end, pde)
 		gen6_write_pde(ppgtt, pde, pt);
 
+	mb();
 	ioread32(ppgtt->pd_addr + pde - 1);
 	gen6_ggtt_invalidate(ppgtt->base.vm.gt->ggtt);
+	mb();
 
 	mutex_unlock(&ppgtt->flush);
 }
-- 
2.28.0