[Intel-gfx] [PATCH] drm/i915: avoid concurrent writes to aux_inv
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Mon Mar 28 08:37:10 UTC 2022
On 28/03/2022 04:16, fei.yang at intel.com wrote:
> From: Fei Yang <fei.yang at intel.com>
>
> GPU hangs have been observed when multiple engines write to the
> same aux_inv register at the same time. To avoid this each engine
> should only invalidate its own auxiliary table. The function
> gen12_emit_flush_xcs() currently invalidate the auxiliary table for
> all engines because the rq->engine is not necessarily the engine
> eventually carrying out the request, and potentially the engine
> could even be a virtual one (with engine->instance being -1).
> With the MMIO remap feature, we can actually set bit 17 of MI_LRI
> instruction and let the hardware to figure out the local aux_inv
> register at runtime to avoid invalidating auxiliary table for all
> engines.
>
> Bspec: 45728
>
> v2: Invalidate AUX table for indirect context as well.
>
> Cc: Stuart Summers <stuart.summers at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Signed-off-by: Chris Wilson <chris.p.wilson at intel.com>
> Signed-off-by: Fei Yang <fei.yang at intel.com>
> ---
> drivers/gpu/drm/i915/gt/gen8_engine_cs.c | 48 ++++----------------
> drivers/gpu/drm/i915/gt/gen8_engine_cs.h | 4 +-
> drivers/gpu/drm/i915/gt/intel_gpu_commands.h | 1 +
> drivers/gpu/drm/i915/gt/intel_lrc.c | 12 +++++
> 4 files changed, 26 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> index 36148887c699..8178be083b42 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> @@ -6,7 +6,6 @@
> #include "gen8_engine_cs.h"
> #include "i915_drv.h"
> #include "intel_gpu_commands.h"
> -#include "intel_gt_regs.h"
> #include "intel_lrc.h"
> #include "intel_ring.h"
>
> @@ -165,33 +164,9 @@ static u32 preparser_disable(bool state)
> return MI_ARB_CHECK | 1 << 8 | state;
> }
>
> -static i915_reg_t aux_inv_reg(const struct intel_engine_cs *engine)
> +u32 *gen12_emit_aux_table_inv(const i915_reg_t inv_reg, u32 *cs)
I think all helpers which emit to ring take cs as the first argument so
it would be good to make this consistent.
> {
> - static const i915_reg_t vd[] = {
> - GEN12_VD0_AUX_NV,
> - GEN12_VD1_AUX_NV,
> - GEN12_VD2_AUX_NV,
> - GEN12_VD3_AUX_NV,
> - };
> -
> - static const i915_reg_t ve[] = {
> - GEN12_VE0_AUX_NV,
> - GEN12_VE1_AUX_NV,
> - };
> -
> - if (engine->class == VIDEO_DECODE_CLASS)
> - return vd[engine->instance];
> -
> - if (engine->class == VIDEO_ENHANCEMENT_CLASS)
> - return ve[engine->instance];
> -
> - GEM_BUG_ON("unknown aux_inv reg\n");
> - return INVALID_MMIO_REG;
> -}
> -
> -static u32 *gen12_emit_aux_table_inv(const i915_reg_t inv_reg, u32 *cs)
> -{
> - *cs++ = MI_LOAD_REGISTER_IMM(1);
> + *cs++ = MI_LOAD_REGISTER_IMM(1) | MI_LRI_MMIO_REMAP_EN;
> *cs++ = i915_mmio_reg_offset(inv_reg);
> *cs++ = AUX_INV;
> *cs++ = MI_NOOP;
> @@ -293,10 +268,12 @@ int gen12_emit_flush_xcs(struct i915_request *rq, u32 mode)
> if (mode & EMIT_INVALIDATE) {
> cmd += 2;
>
> - if (!HAS_FLAT_CCS(rq->engine->i915)) {
> + if (!HAS_FLAT_CCS(rq->engine->i915) &&
> + (rq->engine->class == VIDEO_DECODE_CLASS ||
> + rq->engine->class == VIDEO_ENHANCEMENT_CLASS)) {
> aux_inv = rq->engine->mask & ~BIT(BCS0);
> if (aux_inv)
> - cmd += 2 * hweight32(aux_inv) + 2;
> + cmd += 4;
> }
> }
>
> @@ -329,15 +306,10 @@ int gen12_emit_flush_xcs(struct i915_request *rq, u32 mode)
> *cs++ = 0; /* value */
>
> if (aux_inv) { /* hsdes: 1809175790 */
> - struct intel_engine_cs *engine;
> - unsigned int tmp;
> -
> - *cs++ = MI_LOAD_REGISTER_IMM(hweight32(aux_inv));
> - for_each_engine_masked(engine, rq->engine->gt, aux_inv, tmp) {
> - *cs++ = i915_mmio_reg_offset(aux_inv_reg(engine));
> - *cs++ = AUX_INV;
> - }
> - *cs++ = MI_NOOP;
> + if (rq->engine->class == VIDEO_DECODE_CLASS)
> + cs = gen12_emit_aux_table_inv(GEN12_VD0_AUX_NV, cs);
> + else
> + cs = gen12_emit_aux_table_inv(GEN12_VE0_AUX_NV, cs);
Not sure if, here and below, it would be worth to put register in a
local and then have a single function call - up to you.
> }
>
> if (mode & EMIT_INVALIDATE)
> diff --git a/drivers/gpu/drm/i915/gt/gen8_engine_cs.h b/drivers/gpu/drm/i915/gt/gen8_engine_cs.h
> index cc6e21d3662a..94f589e73d10 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_engine_cs.h
> +++ b/drivers/gpu/drm/i915/gt/gen8_engine_cs.h
> @@ -10,7 +10,7 @@
> #include <linux/types.h>
>
> #include "i915_gem.h" /* GEM_BUG_ON */
> -
> +#include "intel_gt_regs.h"
> #include "intel_gpu_commands.h"
>
> struct i915_request;
> @@ -38,6 +38,8 @@ u32 *gen8_emit_fini_breadcrumb_rcs(struct i915_request *rq, u32 *cs);
> u32 *gen11_emit_fini_breadcrumb_rcs(struct i915_request *rq, u32 *cs);
> u32 *gen12_emit_fini_breadcrumb_rcs(struct i915_request *rq, u32 *cs);
>
> +u32 *gen12_emit_aux_table_inv(const i915_reg_t inv_reg, u32 *cs);
> +
> static inline u32 *
> __gen8_emit_pipe_control(u32 *batch, u32 flags0, u32 flags1, u32 offset)
> {
> diff --git a/drivers/gpu/drm/i915/gt/intel_gpu_commands.h b/drivers/gpu/drm/i915/gt/intel_gpu_commands.h
> index d112ffd56418..4243be030bc1 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gpu_commands.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gpu_commands.h
> @@ -144,6 +144,7 @@
> #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_LRM_CS_MMIO REG_BIT(19)
> +#define MI_LRI_MMIO_REMAP_EN REG_BIT(17)
> #define MI_LRI_FORCE_POSTED (1<<12)
> #define MI_LOAD_REGISTER_IMM_MAX_REGS (126)
> #define MI_STORE_REGISTER_MEM MI_INSTR(0x24, 1)
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 07bef7128fdb..7581ef9e2cce 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -1208,6 +1208,10 @@ gen12_emit_indirect_ctx_rcs(const struct intel_context *ce, u32 *cs)
> IS_DG2_G11(ce->engine->i915))
> cs = gen8_emit_pipe_control(cs, PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE, 0);
>
> + /* hsdes: 1809175790 */
> + if (!HAS_FLAT_CCS(ce->engine->i915))
> + cs = gen12_emit_aux_table_inv(GEN12_GFX_CCS_AUX_NV, cs);
> +
> return cs;
> }
>
> @@ -1225,6 +1229,14 @@ gen12_emit_indirect_ctx_xcs(const struct intel_context *ce, u32 *cs)
> PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE,
> 0);
>
> + /* hsdes: 1809175790 */
> + if (!HAS_FLAT_CCS(ce->engine->i915)) {
> + if (ce->engine->class == VIDEO_DECODE_CLASS)
> + cs = gen12_emit_aux_table_inv(GEN12_VD0_AUX_NV, cs);
> + else if (ce->engine->class == VIDEO_ENHANCEMENT_CLASS)
> + cs = gen12_emit_aux_table_inv(GEN12_VE0_AUX_NV, cs);
> + }
> +
> return cs;
> }
>
Apart from the cs re-order looks good to me.
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Regards,
Tvrtko
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