Re: [Intel-gfx] [PATCH 33/51] drm/i915/guc: Provide mmio list to be saved/restored on engine reset

Matthew Brost
2021-07-22T04:47:18Z

On Fri, Jul 16, 2021 at 01:17:06PM -0700, Matthew Brost wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The driver must provide GuC with a list of mmio registers
> that should be saved/restored during a GuC-based engine reset.
> Unfortunately, the list must be dynamically allocated as its size is
> variable. That means the driver must generate the list twice - once to
> work out the size and a second time to actually save it.
>
> v2:
> (Alan / CI)
> - GEN7_GT_MODE -> GEN6_GT_MODE to fix WA selftest failure
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> Signed-off-by: Fernando Pacheco <fernando.pacheco@intel.com>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>

Everything looks structurally correct. Feel confident on my below RB but
W/A are not my area of expertise. If any one else wanted to give it a
look, I wouldn't mind.

With that:
Reviewed-by: Matthew Brost <matthew.brost@intel.com>

> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
> drivers/gpu/drm/i915/gt/intel_workarounds.c | 46 ++--
> .../gpu/drm/i915/gt/intel_workarounds_types.h | 1 +
> drivers/gpu/drm/i915/gt/uc/intel_guc.h | 1 +
> drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c | 199 +++++++++++++++++-
> drivers/gpu/drm/i915/i915_reg.h | 1 +
> 5 files changed, 222 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> index 72562c233ad2..34738ccab8bd 100644
> --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> @@ -150,13 +150,14 @@ static void _wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
> }
>
> static void wa_add(struct i915_wa_list *wal, i915_reg_t reg,
> - u32 clear, u32 set, u32 read_mask)
> + u32 clear, u32 set, u32 read_mask, bool masked_reg)
> {
> struct i915_wa wa = {
> .reg = reg,
> .clr = clear,
> .set = set,
> .read = read_mask,
> + .masked_reg = masked_reg,
> };
>
> _wa_add(wal, &wa);
> @@ -165,7 +166,7 @@ static void wa_add(struct i915_wa_list *wal, i915_reg_t reg,
> static void
> wa_write_clr_set(struct i915_wa_list *wal, i915_reg_t reg, u32 clear, u32 set)
> {
> - wa_add(wal, reg, clear, set, clear);
> + wa_add(wal, reg, clear, set, clear, false);
> }
>
> static void
> @@ -200,20 +201,20 @@ wa_write_clr(struct i915_wa_list *wal, i915_reg_t reg, u32 clr)
> static void
> wa_masked_en(struct i915_wa_list *wal, i915_reg_t reg, u32 val)
> {
> - wa_add(wal, reg, 0, _MASKED_BIT_ENABLE(val), val);
> + wa_add(wal, reg, 0, _MASKED_BIT_ENABLE(val), val, true);
> }
>
> static void
> wa_masked_dis(struct i915_wa_list *wal, i915_reg_t reg, u32 val)
> {
> - wa_add(wal, reg, 0, _MASKED_BIT_DISABLE(val), val);
> + wa_add(wal, reg, 0, _MASKED_BIT_DISABLE(val), val, true);
> }
>
> static void
> wa_masked_field_set(struct i915_wa_list *wal, i915_reg_t reg,
> u32 mask, u32 val)
> {
> - wa_add(wal, reg, 0, _MASKED_FIELD(mask, val), mask);
> + wa_add(wal, reg, 0, _MASKED_FIELD(mask, val), mask, true);
> }
>
> static void gen6_ctx_workarounds_init(struct intel_engine_cs *engine,
> @@ -583,10 +584,10 @@ static void icl_ctx_workarounds_init(struct intel_engine_cs *engine,
> GEN11_BLEND_EMB_FIX_DISABLE_IN_RCC);
>
> /* WaEnableFloatBlendOptimization:icl */
> - wa_write_clr_set(wal,
> - GEN10_CACHE_MODE_SS,
> - 0, /* write-only, so skip validation */
> - _MASKED_BIT_ENABLE(FLOAT_BLEND_OPTIMIZATION_ENABLE));
> + wa_add(wal, GEN10_CACHE_MODE_SS, 0,
> + _MASKED_BIT_ENABLE(FLOAT_BLEND_OPTIMIZATION_ENABLE),
> + 0 /* write-only, so skip validation */,
> + true);
>
> /* WaDisableGPGPUMidThreadPreemption:icl */
> wa_masked_field_set(wal, GEN8_CS_CHICKEN1,
> @@ -631,7 +632,7 @@ static void gen12_ctx_gt_tuning_init(struct intel_engine_cs *engine,
> FF_MODE2,
> FF_MODE2_TDS_TIMER_MASK,
> FF_MODE2_TDS_TIMER_128,
> - 0);
> + 0, false);
> }
>
> static void gen12_ctx_workarounds_init(struct intel_engine_cs *engine,
> @@ -669,7 +670,7 @@ static void gen12_ctx_workarounds_init(struct intel_engine_cs *engine,
> FF_MODE2,
> FF_MODE2_GS_TIMER_MASK,
> FF_MODE2_GS_TIMER_224,
> - 0);
> + 0, false);
>
> /*
> * Wa_14012131227:dg1
> @@ -847,7 +848,7 @@ hsw_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
> wa_add(wal,
> HSW_ROW_CHICKEN3, 0,
> _MASKED_BIT_ENABLE(HSW_ROW_CHICKEN3_L3_GLOBAL_ATOMICS_DISABLE),
> - 0 /* XXX does this reg exist? */);
> + 0 /* XXX does this reg exist? */, true);
>
> /* WaVSRefCountFullforceMissDisable:hsw */
> wa_write_clr(wal, GEN7_FF_THREAD_MODE, GEN7_FF_VS_REF_CNT_FFME);
> @@ -1937,10 +1938,10 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
> * disable bit, which we don't touch here, but it's good
> * to keep in mind (see 3DSTATE_PS and 3DSTATE_WM).
> */
> - wa_add(wal, GEN7_GT_MODE, 0,
> - _MASKED_FIELD(GEN6_WIZ_HASHING_MASK,
> - GEN6_WIZ_HASHING_16x4),
> - GEN6_WIZ_HASHING_16x4);
> + wa_masked_field_set(wal,
> + GEN7_GT_MODE,
> + GEN6_WIZ_HASHING_MASK,
> + GEN6_WIZ_HASHING_16x4);
> }
>
> if (IS_GRAPHICS_VER(i915, 6, 7))
> @@ -1990,10 +1991,10 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
> * disable bit, which we don't touch here, but it's good
> * to keep in mind (see 3DSTATE_PS and 3DSTATE_WM).
> */
> - wa_add(wal,
> - GEN6_GT_MODE, 0,
> - _MASKED_FIELD(GEN6_WIZ_HASHING_MASK, GEN6_WIZ_HASHING_16x4),
> - GEN6_WIZ_HASHING_16x4);
> + wa_masked_field_set(wal,
> + GEN6_GT_MODE,
> + GEN6_WIZ_HASHING_MASK,
> + GEN6_WIZ_HASHING_16x4);
>
> /* WaDisable_RenderCache_OperationalFlush:snb */
> wa_masked_dis(wal, CACHE_MODE_0, RC_OP_FLUSH_ENABLE);
> @@ -2014,7 +2015,7 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
> wa_add(wal, MI_MODE,
> 0, _MASKED_BIT_ENABLE(VS_TIMER_DISPATCH),
> /* XXX bit doesn't stick on Broadwater */
> - IS_I965G(i915) ? 0 : VS_TIMER_DISPATCH);
> + IS_I965G(i915) ? 0 : VS_TIMER_DISPATCH, true);
>
> if (GRAPHICS_VER(i915) == 4)
> /*
> @@ -2029,7 +2030,8 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
> */
> wa_add(wal, ECOSKPD,
> 0, _MASKED_BIT_ENABLE(ECO_CONSTANT_BUFFER_SR_DISABLE),
> - 0 /* XXX bit doesn't stick on Broadwater */);
> + 0 /* XXX bit doesn't stick on Broadwater */,
> + true);
> }
>
> static void
> diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds_types.h b/drivers/gpu/drm/i915/gt/intel_workarounds_types.h
> index c214111ea367..1e873681795d 100644
> --- a/drivers/gpu/drm/i915/gt/intel_workarounds_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_workarounds_types.h
> @@ -15,6 +15,7 @@ struct i915_wa {
> u32 clr;
> u32 set;
> u32 read;
> + bool masked_reg;
> };
>
> struct i915_wa_list {
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> index 7f14e1873010..3897abb59dba 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> @@ -59,6 +59,7 @@ struct intel_guc {
>
> struct i915_vma *ads_vma;
> struct __guc_ads_blob *ads_blob;
> + u32 ads_regset_size;
>
> struct i915_vma *lrc_desc_pool;
> void *lrc_desc_pool_vaddr;
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
> index b82145652d57..9fd3c911f5fb 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
> @@ -3,6 +3,8 @@
> * Copyright © 2014-2019 Intel Corporation
> */
>
> +#include <linux/bsearch.h>
> +
> #include "gt/intel_gt.h"
> #include "gt/intel_lrc.h"
> #include "intel_guc_ads.h"
> @@ -23,7 +25,12 @@
> * | guc_policies |
> * +---------------------------------------+
> * | guc_gt_system_info |
> - * +---------------------------------------+
> + * +---------------------------------------+ <== static
> + * | guc_mmio_reg[countA] (engine 0.0) |
> + * | guc_mmio_reg[countB] (engine 0.1) |
> + * | guc_mmio_reg[countC] (engine 1.0) |
> + * | ... |
> + * +---------------------------------------+ <== dynamic
> * | padding |
> * +---------------------------------------+ <== 4K aligned
> * | private data |
> @@ -35,16 +42,33 @@ struct __guc_ads_blob {
> struct guc_ads ads;
> struct guc_policies policies;
> struct guc_gt_system_info system_info;
> + /* From here on, location is dynamic! Refer to above diagram. */
> + struct guc_mmio_reg regset[0];
> } __packed;
>
> +static u32 guc_ads_regset_size(struct intel_guc *guc)
> +{
> + GEM_BUG_ON(!guc->ads_regset_size);
> + return guc->ads_regset_size;
> +}
> +
> static u32 guc_ads_private_data_size(struct intel_guc *guc)
> {
> return PAGE_ALIGN(guc->fw.private_data_size);
> }
>
> +static u32 guc_ads_regset_offset(struct intel_guc *guc)
> +{
> + return offsetof(struct __guc_ads_blob, regset);
> +}
> +
> static u32 guc_ads_private_data_offset(struct intel_guc *guc)
> {
> - return PAGE_ALIGN(sizeof(struct __guc_ads_blob));
> + u32 offset;
> +
> + offset = guc_ads_regset_offset(guc) +
> + guc_ads_regset_size(guc);
> + return PAGE_ALIGN(offset);
> }
>
> static u32 guc_ads_blob_size(struct intel_guc *guc)
> @@ -83,6 +107,165 @@ static void guc_mapping_table_init(struct intel_gt *gt,
> }
> }
>
> +/*
> + * The save/restore register list must be pre-calculated to a temporary
> + * buffer of driver defined size before it can be generated in place
> + * inside the ADS.
> + */
> +#define MAX_MMIO_REGS 128 /* Arbitrary size, increase as needed */
> +struct temp_regset {
> + struct guc_mmio_reg *registers;
> + u32 used;
> + u32 size;
> +};
> +
> +static int guc_mmio_reg_cmp(const void *a, const void *b)
> +{
> + const struct guc_mmio_reg *ra = a;
> + const struct guc_mmio_reg *rb = b;
> +
> + return (int)ra->offset - (int)rb->offset;
> +}
> +
> +static void guc_mmio_reg_add(struct temp_regset *regset,
> + u32 offset, u32 flags)
> +{
> + u32 count = regset->used;
> + struct guc_mmio_reg reg = {
> + .offset = offset,
> + .flags = flags,
> + };
> + struct guc_mmio_reg *slot;
> +
> + GEM_BUG_ON(count >= regset->size);
> +
> + /*
> + * The mmio list is built using separate lists within the driver.
> + * It's possible that at some point we may attempt to add the same
> + * register more than once. Do not consider this an error; silently
> + * move on if the register is already in the list.
> + */
> + if (bsearch(&reg, regset->registers, count,
> + sizeof(reg), guc_mmio_reg_cmp))
> + return;
> +
> + slot = &regset->registers[count];
> + regset->used++;
> + *slot = reg;
> +
> + while (slot-- > regset->registers) {
> + GEM_BUG_ON(slot[0].offset == slot[1].offset);
> + if (slot[1].offset > slot[0].offset)
> + break;
> +
> + swap(slot[1], slot[0]);
> + }
> +}
> +
> +#define GUC_MMIO_REG_ADD(regset, reg, masked) \
> + guc_mmio_reg_add(regset, \
> + i915_mmio_reg_offset((reg)), \
> + (masked) ? GUC_REGSET_MASKED : 0)
> +
> +static void guc_mmio_regset_init(struct temp_regset *regset,
> + struct intel_engine_cs *engine)
> +{
> + const u32 base = engine->mmio_base;
> + struct i915_wa_list *wal = &engine->wa_list;
> + struct i915_wa *wa;
> + unsigned int i;
> +
> + regset->used = 0;
> +
> + GUC_MMIO_REG_ADD(regset, RING_MODE_GEN7(base), true);
> + GUC_MMIO_REG_ADD(regset, RING_HWS_PGA(base), false);
> + GUC_MMIO_REG_ADD(regset, RING_IMR(base), false);
> +
> + for (i = 0, wa = wal->list; i < wal->count; i++, wa++)
> + GUC_MMIO_REG_ADD(regset, wa->reg, wa->masked_reg);
> +
> + /* Be extra paranoid and include all whitelist registers. */
> + for (i = 0; i < RING_MAX_NONPRIV_SLOTS; i++)
> + GUC_MMIO_REG_ADD(regset,
> + RING_FORCE_TO_NONPRIV(base, i),
> + false);
> +
> + /* add in local MOCS registers */
> + for (i = 0; i < GEN9_LNCFCMOCS_REG_COUNT; i++)
> + GUC_MMIO_REG_ADD(regset, GEN9_LNCFCMOCS(i), false);
> +}
> +
> +static int guc_mmio_reg_state_query(struct intel_guc *guc)
> +{
> + struct intel_gt *gt = guc_to_gt(guc);
> + struct intel_engine_cs *engine;
> + enum intel_engine_id id;
> + struct temp_regset temp_set;
> + u32 total;
> +
> + /*
> + * Need to actually build the list in order to filter out
> + * duplicates and other such data dependent constructions.
> + */
> + temp_set.size = MAX_MMIO_REGS;
> + temp_set.registers = kmalloc_array(temp_set.size,
> + sizeof(*temp_set.registers),
> + GFP_KERNEL);
> + if (!temp_set.registers)
> + return -ENOMEM;
> +
> + total = 0;
> + for_each_engine(engine, gt, id) {
> + guc_mmio_regset_init(&temp_set, engine);
> + total += temp_set.used;
> + }
> +
> + kfree(temp_set.registers);
> +
> + return total * sizeof(struct guc_mmio_reg);
> +}
> +
> +static void guc_mmio_reg_state_init(struct intel_guc *guc,
> + struct __guc_ads_blob *blob)
> +{
> + struct intel_gt *gt = guc_to_gt(guc);
> + struct intel_engine_cs *engine;
> + enum intel_engine_id id;
> + struct temp_regset temp_set;
> + struct guc_mmio_reg_set *ads_reg_set;
> + u32 addr_ggtt, offset;
> + u8 guc_class;
> +
> + offset = guc_ads_regset_offset(guc);
> + addr_ggtt = intel_guc_ggtt_offset(guc, guc->ads_vma) + offset;
> + temp_set.registers = (struct guc_mmio_reg *) (((u8 *) blob) + offset);
> + temp_set.size = guc->ads_regset_size / sizeof(temp_set.registers[0]);
> +
> + for_each_engine(engine, gt, id) {
> + /* Class index is checked in class converter */
> + GEM_BUG_ON(engine->instance >= GUC_MAX_INSTANCES_PER_CLASS);
> +
> + guc_class = engine_class_to_guc_class(engine->class);
> + ads_reg_set = &blob->ads.reg_state_list[guc_class][engine->instance];
> +
> + guc_mmio_regset_init(&temp_set, engine);
> + if (!temp_set.used) {
> + ads_reg_set->address = 0;
> + ads_reg_set->count = 0;
> + continue;
> + }
> +
> + ads_reg_set->address = addr_ggtt;
> + ads_reg_set->count = temp_set.used;
> +
> + temp_set.size -= temp_set.used;
> + temp_set.registers += temp_set.used;
> + addr_ggtt += temp_set.used * sizeof(struct guc_mmio_reg);
> + }
> +
> + GEM_BUG_ON(temp_set.size);
> +}
> +
> /*
> * The first 80 dwords of the register state context, containing the
> * execlists and ppgtt registers.
> @@ -121,8 +304,7 @@ static void __guc_ads_init(struct intel_guc *guc)
> */
> blob->ads.golden_context_lrca[guc_class] = 0;
> blob->ads.eng_state_size[guc_class] =
> - intel_engine_context_size(guc_to_gt(guc),
> - engine_class) -
> + intel_engine_context_size(gt, engine_class) -
> skipped_size;
> }
>
> @@ -153,6 +335,9 @@ static void __guc_ads_init(struct intel_guc *guc)
> blob->ads.scheduler_policies = base + ptr_offset(blob, policies);
> blob->ads.gt_system_info = base + ptr_offset(blob, system_info);
>
> + /* MMIO save/restore list */
> + guc_mmio_reg_state_init(guc, blob);
> +
> /* Private Data */
> blob->ads.private_data = base + guc_ads_private_data_offset(guc);
>
> @@ -173,6 +358,12 @@ int intel_guc_ads_create(struct intel_guc *guc)
>
> GEM_BUG_ON(guc->ads_vma);
>
> + /* Need to calculate the reg state size dynamically: */
> + ret = guc_mmio_reg_state_query(guc);
> + if (ret < 0)
> + return ret;
> + guc->ads_regset_size = ret;
> +
> size = guc_ads_blob_size(guc);
>
> ret = intel_guc_allocate_and_map_vma(guc, size, &guc->ads_vma,
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 204c95c39353..3584e4d03dc3 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -12309,6 +12309,7 @@ enum skl_power_gate {
>
> /* MOCS (Memory Object Control State) registers */
> #define GEN9_LNCFCMOCS(i) _MMIO(0xb020 + (i) * 4) /* L3 Cache Control */
> +#define GEN9_LNCFCMOCS_REG_COUNT 32
>
> #define __GEN9_RCS0_MOCS0 0xc800
> #define GEN9_GFX_MOCS(i) _MMIO(__GEN9_RCS0_MOCS0 + (i) * 4)
> --
> 2.28.0