On Wed, Apr 13, 2022 at 12:27:29PM -0700, Umesh Nerlige Ramappa wrote: > From: Matthew Brost <matthew.br...@intel.com> > > There is bug in DG2 where if the CCS contexts switches out while the RCS > is running it can cause memory corruption. To workaround this add an > atomic to a memory address with a value 1 and semaphore wait to the same > address for a value of 0. The GuC firmware is responsible for writing 0 > to the memory address when it is safe for the context to switch out. > > v2: Add atomic GPU instructions > v3: Add w/a number (JohnH) > v4: Set DW length to 9 atomic GPU instruction with inline data > v5: Rebase (Umesh) > v6: Split MI_ATOMIC definition into 2 (Daniele) > v7: (Daniele) > - For non-inline MI_ATOMIC, len should be 1 > - Make INLINE flag part of MI_ATOMIC_INLINE definition >
The internal version log should be dropped before posting upstream. Matt > Signed-off-by: Matthew Brost <matthew.br...@intel.com> > --- > drivers/gpu/drm/i915/gt/gen8_engine_cs.c | 41 +++++++++++++++++++ > drivers/gpu/drm/i915/gt/intel_engine_types.h | 8 ++++ > drivers/gpu/drm/i915/gt/intel_gpu_commands.h | 7 ++++ > drivers/gpu/drm/i915/gt/uc/intel_guc.c | 4 ++ > drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h | 1 + > .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 4 ++ > 6 files changed, 65 insertions(+) > > diff --git a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c > b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c > index 047b5a710149..9529c5455bc3 100644 > --- a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c > +++ b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c > @@ -583,6 +583,43 @@ static u32 *gen12_emit_preempt_busywait(struct > i915_request *rq, u32 *cs) > return cs; > } > > +/* Wa_14014475959:dg2 */ > +#define CCS_SEMAPHORE_PPHWSP_OFFSET 0x540 > +static u32 ccs_semaphore_offset(struct i915_request *rq) > +{ > + return i915_ggtt_offset(rq->context->state) + > + (LRC_PPHWSP_PN * PAGE_SIZE) + CCS_SEMAPHORE_PPHWSP_OFFSET; > +} > + > +/* Wa_14014475959:dg2 */ > +static u32 *ccs_emit_wa_busywait(struct i915_request *rq, u32 *cs) > +{ > + int i; > + > + *cs++ = MI_ATOMIC_INLINE | MI_ATOMIC_GLOBAL_GTT | MI_ATOMIC_CS_STALL | > + MI_ATOMIC_MOVE; > + *cs++ = ccs_semaphore_offset(rq); > + *cs++ = 0; > + *cs++ = 1; > + > + /* > + * When MI_ATOMIC_INLINE_DATA set this command must be 11 DW + (1 NOP) > + * to align. 4 DWs above + 8 filler DWs here. > + */ > + for (i = 0; i < 8; ++i) > + *cs++ = 0; > + > + *cs++ = MI_SEMAPHORE_WAIT | > + MI_SEMAPHORE_GLOBAL_GTT | > + MI_SEMAPHORE_POLL | > + MI_SEMAPHORE_SAD_EQ_SDD; > + *cs++ = 0; > + *cs++ = ccs_semaphore_offset(rq); > + *cs++ = 0; > + > + return cs; > +} > + > static __always_inline u32* > gen12_emit_fini_breadcrumb_tail(struct i915_request *rq, u32 *cs) > { > @@ -593,6 +630,10 @@ gen12_emit_fini_breadcrumb_tail(struct i915_request *rq, > u32 *cs) > !intel_uc_uses_guc_submission(&rq->engine->gt->uc)) > cs = gen12_emit_preempt_busywait(rq, cs); > > + /* Wa_14014475959:dg2 */ > + if (intel_engine_uses_wa_hold_ccs_switchout(rq->engine)) > + cs = ccs_emit_wa_busywait(rq, cs); > + > rq->tail = intel_ring_offset(rq, cs); > assert_ring_tail_valid(rq->ring, rq->tail); > > diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h > b/drivers/gpu/drm/i915/gt/intel_engine_types.h > index eac20112709c..298f2cc7a879 100644 > --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h > +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h > @@ -529,6 +529,7 @@ struct intel_engine_cs { > #define I915_ENGINE_HAS_RCS_REG_STATE BIT(9) > #define I915_ENGINE_HAS_EU_PRIORITY BIT(10) > #define I915_ENGINE_FIRST_RENDER_COMPUTE BIT(11) > +#define I915_ENGINE_USES_WA_HOLD_CCS_SWITCHOUT BIT(12) > unsigned int flags; > > /* > @@ -629,6 +630,13 @@ intel_engine_has_relative_mmio(const struct > intel_engine_cs * const engine) > return engine->flags & I915_ENGINE_HAS_RELATIVE_MMIO; > } > > +/* Wa_14014475959:dg2 */ > +static inline bool > +intel_engine_uses_wa_hold_ccs_switchout(struct intel_engine_cs *engine) > +{ > + return engine->flags & I915_ENGINE_USES_WA_HOLD_CCS_SWITCHOUT; > +} > + > #define instdone_has_slice(dev_priv___, sseu___, slice___) \ > ((GRAPHICS_VER(dev_priv___) == 7 ? 1 : ((sseu___)->slice_mask)) & > BIT(slice___)) > > diff --git a/drivers/gpu/drm/i915/gt/intel_gpu_commands.h > b/drivers/gpu/drm/i915/gt/intel_gpu_commands.h > index 4243be030bc1..f3fe7d4c3234 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gpu_commands.h > +++ b/drivers/gpu/drm/i915/gt/intel_gpu_commands.h > @@ -134,6 +134,13 @@ > #define MI_MEM_VIRTUAL (1 << 22) /* 945,g33,965 */ > #define MI_USE_GGTT (1 << 22) /* g4x+ */ > #define MI_STORE_DWORD_INDEX MI_INSTR(0x21, 1) > +#define MI_ATOMIC MI_INSTR(0x2f, 1) > +#define MI_ATOMIC_INLINE (MI_INSTR(0x2f, 9) | MI_ATOMIC_INLINE_DATA) > +#define MI_ATOMIC_GLOBAL_GTT (1 << 22) > +#define MI_ATOMIC_INLINE_DATA (1 << 18) > +#define MI_ATOMIC_CS_STALL (1 << 17) > +#define MI_ATOMIC_MOVE (0x4 << 8) > + > /* > * Official intel docs are somewhat sloppy concerning MI_LOAD_REGISTER_IMM: > * - Always issue a MI_NOOP _before_ the MI_LOAD_REGISTER_IMM - otherwise hw > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.c > b/drivers/gpu/drm/i915/gt/uc/intel_guc.c > index 830889349756..228070e31ef0 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.c > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.c > @@ -296,6 +296,10 @@ static u32 guc_ctl_wa_flags(struct intel_guc *guc) > if (IS_DG2_GRAPHICS_STEP(gt->i915, G10, STEP_A0, STEP_B0)) > flags |= GUC_WA_GAM_CREDITS; > > + /* Wa_14014475959:dg2 */ > + if (IS_DG2(gt->i915)) > + flags |= GUC_WA_HOLD_CCS_SWITCHOUT; > + > /* > * Wa_14012197797:dg2_g10:a0,dg2_g11:a0 > * Wa_22011391025:dg2_g10,dg2_g11,dg2_g12 > 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 126e67ea1619..e389a3a041a2 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h > @@ -102,6 +102,7 @@ > #define GUC_WA_DUAL_QUEUE BIT(11) > #define GUC_WA_RCS_RESET_BEFORE_RC6 BIT(13) > #define GUC_WA_PRE_PARSER BIT(14) > +#define GUC_WA_HOLD_CCS_SWITCHOUT BIT(17) > #define GUC_WA_POLLCS BIT(18) > > #define GUC_CTL_FEATURE 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 38ba9f783312..1cb88e99b040 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > @@ -3897,6 +3897,10 @@ static void guc_default_vfuncs(struct intel_engine_cs > *engine) > engine->flags |= I915_ENGINE_HAS_PREEMPTION; > engine->flags |= I915_ENGINE_HAS_TIMESLICES; > > + /* Wa_14014475959:dg2 */ > + if (IS_DG2(engine->i915) && engine->class == COMPUTE_CLASS) > + engine->flags |= I915_ENGINE_USES_WA_HOLD_CCS_SWITCHOUT; > + > /* > * TODO: GuC supports timeslicing and semaphores as well, but they're > * handled by the firmware so some minor tweaks are required before > -- > 2.35.1 >