Restoration of a previous timestamp can collide
with updating the timestamp, causing a value corruption.
Combat this issue by using indirect ctx bb to
modify the context image during restoring process.
For render engine, we can preload value into
scratch register. From which we then do the actual
write with LRR. LRR is faster and thus less error prone.
For other engines, no scratch is available so we
must do a more complex sequence of sync and async LRMs.
As the LRM is slower, the probablity of racy write
raises and thus we still see corruption sometimes.
v2: tidying (Chris)
References: HSDES#16010904313
Testcase: igt/i915_selftest/gt_lrc
Suggested-by: Joseph Koston <joseph.koston@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_context_types.h | 3 +
drivers/gpu/drm/i915/gt/intel_gpu_commands.h | 3 +-
drivers/gpu/drm/i915/gt/intel_lrc.c | 205 ++++++++++++++----
drivers/gpu/drm/i915/gt/intel_lrc_reg.h | 1 +
4 files changed, 174 insertions(+), 38 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index 07cb83a0d017..c7573d565f58 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -70,6 +70,9 @@ struct intel_context {
u32 *lrc_reg_state;
u64 lrc_desc;
+
+ u32 ctx_bb_offset;
+
u32 tag; /* cookie passed to HW to track this context on submission */
/* Time on GPU as tracked by the hw. */
diff --git a/drivers/gpu/drm/i915/gt/intel_gpu_commands.h b/drivers/gpu/drm/i915/gt/intel_gpu_commands.h
index f04214a54f75..0c2adb4078a7 100644
--- a/drivers/gpu/drm/i915/gt/intel_gpu_commands.h
+++ b/drivers/gpu/drm/i915/gt/intel_gpu_commands.h
@@ -138,7 +138,7 @@
*/
#define MI_LOAD_REGISTER_IMM(x) MI_INSTR(0x22, 2*(x)-1)
/* Gen11+. addr = base + (ctx_restore ? offset & GENMASK(12,2) : offset) */
-#define MI_LRI_CS_MMIO (1<<19)
+#define MI_LRI_LRM_CS_MMIO (1<<19)
#define MI_LRI_FORCE_POSTED (1<<12)
#define MI_LOAD_REGISTER_IMM_MAX_REGS (126)
#define MI_STORE_REGISTER_MEM MI_INSTR(0x24, 1)
@@ -155,6 +155,7 @@
#define MI_FLUSH_DW_USE_PPGTT (0<<2)
#define MI_LOAD_REGISTER_MEM MI_INSTR(0x29, 1)
#define MI_LOAD_REGISTER_MEM_GEN8 MI_INSTR(0x29, 2)
+#define MI_LRM_ASYNC (1<<21)
#define MI_LOAD_REGISTER_REG MI_INSTR(0x2A, 1)
#define MI_BATCH_BUFFER MI_INSTR(0x30, 1)
#define MI_BATCH_NON_SECURE (1)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 6a4fa7c6176a..cc4d1967d00b 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -234,7 +234,7 @@ static void execlists_init_reg_state(u32 *reg_state,
const struct intel_ring *ring,
bool close);
static void
-__execlists_update_reg_state(const struct intel_context *ce,
+__execlists_update_reg_state(struct intel_context *ce,
const struct intel_engine_cs *engine,
u32 head);
@@ -537,7 +537,7 @@ static void set_offsets(u32 *regs,
if (flags & POSTED)
*regs |= MI_LRI_FORCE_POSTED;
if (INTEL_GEN(engine->i915) >= 11)
- *regs |= MI_LRI_CS_MMIO;
+ *regs |= MI_LRI_LRM_CS_MMIO;
regs++;
GEM_BUG_ON(!count);
@@ -3142,8 +3142,161 @@ static void execlists_context_unpin(struct intel_context *ce)
i915_gem_object_unpin_map(ce->state->obj);
}
+static u32 intel_lr_indirect_ctx_offset(const struct intel_engine_cs *engine)
+{
+ u32 indirect_ctx_offset;
+
+ switch (INTEL_GEN(engine->i915)) {
+ default:
+ MISSING_CASE(INTEL_GEN(engine->i915));
+ fallthrough;
+ case 12:
+ indirect_ctx_offset =
+ GEN12_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
+ break;
+ case 11:
+ indirect_ctx_offset =
+ GEN11_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
+ break;
+ case 10:
+ indirect_ctx_offset =
+ GEN10_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
+ break;
+ case 9:
+ indirect_ctx_offset =
+ GEN9_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
+ break;
+ case 8:
+ indirect_ctx_offset =
+ GEN8_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
+ break;
+ }
+
+ return indirect_ctx_offset;
+}
+
+static u32 *
+gen12_emit_timestamp_wa_lrm(struct intel_context *ce, u32 *cs)
+{
+ const u32 lrc_offset = i915_ggtt_offset(ce->state) +
+ LRC_STATE_OFFSET;
+ const u32 lrm = MI_LOAD_REGISTER_MEM_GEN8 |
+ MI_SRM_LRM_GLOBAL_GTT | MI_LRI_LRM_CS_MMIO;
+
+ *cs++ = lrm;
+ *cs++ = i915_mmio_reg_offset(RING_CTX_TIMESTAMP(0));
+ *cs++ = lrc_offset + CTX_TIMESTAMP * sizeof(u32);
+ *cs++ = 0;
+
+ *cs++ = lrm | MI_LRM_ASYNC;
+ *cs++ = i915_mmio_reg_offset(RING_CTX_TIMESTAMP(0));
+ *cs++ = lrc_offset + CTX_TIMESTAMP * sizeof(u32);
+ *cs++ = 0;
+
+ *cs++ = lrm | MI_LRM_ASYNC;
+ *cs++ = i915_mmio_reg_offset(RING_CTX_TIMESTAMP(0));
+ *cs++ = lrc_offset + CTX_TIMESTAMP * sizeof(u32);
+ *cs++ = 0;
+
+ *cs++ = lrm;
+ *cs++ = i915_mmio_reg_offset(RING_CTX_TIMESTAMP(0));
+ *cs++ = lrc_offset + CTX_TIMESTAMP * sizeof(u32);
+ *cs++ = 0;
+
+ return cs;
+}
+
+static u32 *
+gen12_emit_timestamp_wa_lrr(struct intel_context *ce, u32 *cs)
+{
+ const u32 lrc_offset = i915_ggtt_offset(ce->state) +
+ LRC_STATE_OFFSET;
+ const u32 scratch_reg = 0x2198;
+
+ *cs++ = MI_LOAD_REGISTER_MEM_GEN8 |
+ MI_SRM_LRM_GLOBAL_GTT | MI_LRI_LRM_CS_MMIO;
+ *cs++ = scratch_reg;
+ *cs++ = lrc_offset + CTX_TIMESTAMP * sizeof(u32);
+ *cs++ = 0;
+
+ *cs++ = MI_LOAD_REGISTER_REG | MI_LRI_LRM_CS_MMIO;
+ *cs++ = scratch_reg;
+ *cs++ = i915_mmio_reg_offset(RING_CTX_TIMESTAMP(0));
+
+ *cs++ = MI_LOAD_REGISTER_REG | MI_LRI_LRM_CS_MMIO;
+ *cs++ = scratch_reg;
+ *cs++ = i915_mmio_reg_offset(RING_CTX_TIMESTAMP(0));
+
+ return cs;
+}
+
+static u32 *context_indirect_bb(struct intel_context *ce)
+{
+ void *ptr;
+
+ GEM_BUG_ON(!ce->ctx_bb_offset);
+
+ ptr = ce->lrc_reg_state;
+ ptr -= LRC_STATE_OFFSET; /* back to start of context image */
+ ptr += ce->ctx_bb_offset;
+
+ return ptr;
+}
+
+static u32 *
+execlists_emit_ctx_bb(struct intel_context *ce,
+ u32 *(*emit)(struct intel_context *, u32 *))
+{
+ u32 *cs = context_indirect_bb(ce);
+ const u32 * const batch_start = cs;
+
+ cs = emit(ce, cs);
+
+ GEM_DEBUG_BUG_ON(cs - batch_start >
+ (I915_GTT_PAGE_SIZE - 4)/sizeof(*cs));
+
+ return cs;
+}
+
static void
-__execlists_update_reg_state(const struct intel_context *ce,
+setup_indirect_ctx_bb(struct intel_context *ce,
+ u32 *(*emit)(struct intel_context *, u32 *))
+{
+ const u32 indirect_ptr_offset =
+ INTEL_GEN(ce->engine->i915) >= 12 ?
+ GEN12_CTX_BB_PER_CTX_PTR + 2 :
+ CTX_BB_PER_CTX_PTR + 2;
+ const u32 * const start = context_indirect_bb(ce);
+ u32 *cs;
+
+ cs = execlists_emit_ctx_bb(ce, emit);
+
+ while ((unsigned long)cs % CACHELINE_BYTES)
+ *cs++ = MI_NOOP;
+
+ ce->lrc_reg_state[indirect_ptr_offset] =
+ (i915_ggtt_offset(ce->state) + ce->ctx_bb_offset) |
+ (cs - start) * sizeof(*cs) /
+ CACHELINE_BYTES;
+
+ ce->lrc_reg_state[indirect_ptr_offset + 2] =
+ intel_lr_indirect_ctx_offset(ce->engine) << 6;
+}
+
+static void
+gen12_setup_timestamp_ctx_wa(struct intel_context *ce)
+{
+ u32 *(*fn)(struct intel_context *ce, u32 *cs);
+
+ fn = gen12_emit_timestamp_wa_lrm;
+ if (ce->engine->class == RENDER_CLASS)
+ fn = gen12_emit_timestamp_wa_lrr;
+
+ setup_indirect_ctx_bb(ce, fn);
+}
+
+static void
+__execlists_update_reg_state(struct intel_context *ce,
const struct intel_engine_cs *engine,
u32 head)
{
@@ -3164,6 +3317,13 @@ __execlists_update_reg_state(const struct intel_context *ce,
intel_sseu_make_rpcs(engine->i915, &ce->sseu);
i915_oa_init_reg_state(ce, engine);
+
+ }
+
+ if (ce->ctx_bb_offset) {
+ /* Mutually exclusive wrt to global indirect bb */
+ GEM_BUG_ON(engine->wa_ctx.indirect_ctx.size);
+ gen12_setup_timestamp_ctx_wa(ce);
}
}
@@ -4671,40 +4831,6 @@ int intel_execlists_submission_setup(struct intel_engine_cs *engine)
return 0;
}
-static u32 intel_lr_indirect_ctx_offset(const struct intel_engine_cs *engine)
-{
- u32 indirect_ctx_offset;
-
- switch (INTEL_GEN(engine->i915)) {
- default:
- MISSING_CASE(INTEL_GEN(engine->i915));
- /* fall through */
- case 12:
- indirect_ctx_offset =
- GEN12_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
- break;
- case 11:
- indirect_ctx_offset =
- GEN11_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
- break;
- case 10:
- indirect_ctx_offset =
- GEN10_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
- break;
- case 9:
- indirect_ctx_offset =
- GEN9_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
- break;
- case 8:
- indirect_ctx_offset =
- GEN8_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
- break;
- }
-
- return indirect_ctx_offset;
-}
-
-
static void init_common_reg_state(u32 * const regs,
const struct intel_engine_cs *engine,
const struct intel_ring *ring,
@@ -4871,6 +4997,11 @@ static int __execlists_context_alloc(struct intel_context *ce,
if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
context_size += I915_GTT_PAGE_SIZE; /* for redzone */
+ if (INTEL_GEN(engine->i915) == 12) {
+ ce->ctx_bb_offset = context_size;
+ context_size += PAGE_SIZE;
+ }
+
ctx_obj = i915_gem_object_create_shmem(engine->i915, context_size);
if (IS_ERR(ctx_obj))
return PTR_ERR(ctx_obj);
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc_reg.h b/drivers/gpu/drm/i915/gt/intel_lrc_reg.h
index d39b72590e40..bb444614f33b 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc_reg.h
+++ b/drivers/gpu/drm/i915/gt/intel_lrc_reg.h
@@ -32,6 +32,7 @@
/* GEN12+ Reg State Context */
#define GEN12_CTX_BB_PER_CTX_PTR (0x12 + 1)
+#define CTX_BB_PER_CTX_PTR_VALID BIT(0)
#define ASSIGN_CTX_PDP(ppgtt, reg_state, n) do { \
u32 *reg_state__ = (reg_state); \
--
2.17.1
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