Re: [PATCH 03/10] drm/amdgpu: add gfx shadow CS IOCTL support

["Christian König" <christian.koenig@amd.com>]

Am 17.03.23 um 18:17 schrieb Alex Deucher:
> From: Christian König <christian.koenig@amd.com>
>
> Add support for submitting the shadow update packet
> when submitting an IB.  Needed for MCBP on GFX11.
>
> v2: update API for CSA (Alex)
> v3: fix ordering; SET_Q_PREEMPTION_MODE most come before COND_EXEC
>      Add missing check for AMDGPU_CHUNK_ID_CP_GFX_SHADOW in
>      amdgpu_cs_pass1()
>      Only initialize shadow on first use
>      (Alex)
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c   | 24 ++++++++++++++++++++++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h  |  1 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c   |  4 ++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_job.h  |  6 ++++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h |  2 ++
>   5 files changed, 37 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index f6144b378617..9bdda246b09c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -280,6 +280,7 @@ static int amdgpu_cs_pass1(struct amdgpu_cs_parser *p,
>   		case AMDGPU_CHUNK_ID_SCHEDULED_DEPENDENCIES:
>   		case AMDGPU_CHUNK_ID_SYNCOBJ_TIMELINE_WAIT:
>   		case AMDGPU_CHUNK_ID_SYNCOBJ_TIMELINE_SIGNAL:
> +		case AMDGPU_CHUNK_ID_CP_GFX_SHADOW:
>   			break;
>   
>   		default:
> @@ -587,6 +588,26 @@ static int amdgpu_cs_p2_syncobj_timeline_signal(struct amdgpu_cs_parser *p,
>   	return 0;
>   }
>   
> +static void amdgpu_cs_p2_shadow(struct amdgpu_cs_parser *p,
> +				struct amdgpu_cs_chunk *chunk)
> +{
> +	struct drm_amdgpu_cs_chunk_cp_gfx_shadow *shadow = chunk->kdata;
> +	bool shadow_initialized = false;
> +	int i;
> +
> +	for (i = 0; i < p->gang_size; ++i) {
> +		p->jobs[i]->shadow_va = shadow->shadow_va;
> +		p->jobs[i]->csa_va = shadow->csa_va;
> +		p->jobs[i]->gds_va = shadow->gds_va;

Do we really need all three VAs separately?

> +		if (!p->ctx->shadow_initialized) {
> +			p->jobs[i]->init_shadow = true;
> +			shadow_initialized = true;

> +		}
> +	}
> +	if (shadow_initialized)
> +		p->ctx->shadow_initialized = true;

This is a really bad idea since the IOCTL can be interrupted later on.

Why do we need that?

Regards,
Christian.


> +}
> +
>   static int amdgpu_cs_pass2(struct amdgpu_cs_parser *p)
>   {
>   	unsigned int ce_preempt = 0, de_preempt = 0;
> @@ -629,6 +650,9 @@ static int amdgpu_cs_pass2(struct amdgpu_cs_parser *p)
>   			if (r)
>   				return r;
>   			break;
> +		case AMDGPU_CHUNK_ID_CP_GFX_SHADOW:
> +			amdgpu_cs_p2_shadow(p, chunk);
> +			break;
>   		}
>   	}
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
> index 0fa0e56daf67..909d188c41f2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
> @@ -57,6 +57,7 @@ struct amdgpu_ctx {
>   	unsigned long			ras_counter_ce;
>   	unsigned long			ras_counter_ue;
>   	uint32_t			stable_pstate;
> +	bool				shadow_initialized;
>   };
>   
>   struct amdgpu_ctx_mgr {
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> index bcccc348dbe2..d88964b9407f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> @@ -212,6 +212,10 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
>   	}
>   
>   	amdgpu_ring_ib_begin(ring);
> +
> +	if (job && ring->funcs->emit_gfx_shadow)
> +		amdgpu_ring_emit_gfx_shadow(ring, job);
> +
>   	if (job && ring->funcs->init_cond_exec)
>   		patch_offset = amdgpu_ring_init_cond_exec(ring);
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> index 9790def34815..b470808fa40e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> @@ -68,6 +68,12 @@ struct amdgpu_job {
>   	uint64_t		uf_addr;
>   	uint64_t		uf_sequence;
>   
> +	/* virtual addresses for shadow/GDS/CSA */
> +	uint64_t		shadow_va;
> +	uint64_t		csa_va;
> +	uint64_t		gds_va;
> +	bool			init_shadow;
> +
>   	/* job_run_counter >= 1 means a resubmit job */
>   	uint32_t		job_run_counter;
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> index 3989e755a5b4..8643d4a92c27 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> @@ -212,6 +212,7 @@ struct amdgpu_ring_funcs {
>   	void (*end_use)(struct amdgpu_ring *ring);
>   	void (*emit_switch_buffer) (struct amdgpu_ring *ring);
>   	void (*emit_cntxcntl) (struct amdgpu_ring *ring, uint32_t flags);
> +	void (*emit_gfx_shadow)(struct amdgpu_ring *ring, struct amdgpu_job *job);
>   	void (*emit_rreg)(struct amdgpu_ring *ring, uint32_t reg,
>   			  uint32_t reg_val_offs);
>   	void (*emit_wreg)(struct amdgpu_ring *ring, uint32_t reg, uint32_t val);
> @@ -307,6 +308,7 @@ struct amdgpu_ring {
>   #define amdgpu_ring_emit_hdp_flush(r) (r)->funcs->emit_hdp_flush((r))
>   #define amdgpu_ring_emit_switch_buffer(r) (r)->funcs->emit_switch_buffer((r))
>   #define amdgpu_ring_emit_cntxcntl(r, d) (r)->funcs->emit_cntxcntl((r), (d))
> +#define amdgpu_ring_emit_gfx_shadow(r, j) (r)->funcs->emit_gfx_shadow((r), (j))
>   #define amdgpu_ring_emit_rreg(r, d, o) (r)->funcs->emit_rreg((r), (d), (o))
>   #define amdgpu_ring_emit_wreg(r, d, v) (r)->funcs->emit_wreg((r), (d), (v))
>   #define amdgpu_ring_emit_reg_wait(r, d, v, m) (r)->funcs->emit_reg_wait((r), (d), (v), (m))