Re: [PATCH v12 3/4] drm/xe/guc: Introduce enum with offsets for context register H2Gs

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 18.04.2025 16:10, Tomasz Lis wrote:
> Some GuC messages are constructed with incrementing dword counter
> rather than referencing specific DWORDs, as described in GuC interface
> specification.
> 
> This change introduces the definitions of DWORD numbers for parameters
> which will need to be referenced in a CTB parser to be added in a
> following patch. To ensure correctness of these DWORDs, verification
> in form of asserts was added to the message construction code.
> 
> v2: Renamed enum members, added ones for single context registration,
>   modified asserts to check values rather than indexes.
> v3: Reordered assert args to take less lines
> v4: Added lengths
> 
> Signed-off-by: Tomasz Lis <tomasz.lis@intel.com>
> Suggested-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com> (v3)
> ---
>  drivers/gpu/drm/xe/abi/guc_actions_abi.h | 31 ++++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_guc_submit.c       | 17 +++++++++++++
>  2 files changed, 48 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/abi/guc_actions_abi.h b/drivers/gpu/drm/xe/abi/guc_actions_abi.h
> index 448afb86e05c..3c2808fabc6a 100644
> --- a/drivers/gpu/drm/xe/abi/guc_actions_abi.h
> +++ b/drivers/gpu/drm/xe/abi/guc_actions_abi.h
> @@ -161,6 +161,37 @@ enum xe_guc_preempt_options {
>  	XE_GUC_PREEMPT_OPTION_DROP_SUBMIT_Q = 0x8,
>  };
>  
> +enum xe_guc_register_context_param_offsets {
> +	XE_GUC_REGISTER_CONTEXT_DATA_0_MBZ = 0,
> +	XE_GUC_REGISTER_CONTEXT_DATA_1_FLAGS,
> +	XE_GUC_REGISTER_CONTEXT_DATA_2_CONTEXT_INDEX,
> +	XE_GUC_REGISTER_CONTEXT_DATA_3_ENGINE_CLASS,
> +	XE_GUC_REGISTER_CONTEXT_DATA_4_ENGINE_SUBMIT_MASK,
> +	XE_GUC_REGISTER_CONTEXT_DATA_5_WQ_DESC_ADDR_LOWER,
> +	XE_GUC_REGISTER_CONTEXT_DATA_6_WQ_DESC_ADDR_UPPER,
> +	XE_GUC_REGISTER_CONTEXT_DATA_7_WQ_BUF_BASE_LOWER,
> +	XE_GUC_REGISTER_CONTEXT_DATA_8_WQ_BUF_BASE_UPPER,
> +	XE_GUC_REGISTER_CONTEXT_DATA_9_WQ_BUF_SIZE,
> +	XE_GUC_REGISTER_CONTEXT_DATA_10_HW_LRC_ADDR,
> +	XE_GUC_REGISTER_CONTEXT_MSG_LEN,

didn't notice this earlier...

this enum, as it's name says, was about param offsets, so adding here
MSG_LEN is not the best fit, likely should be a separate #define, unless
we want to say that this enum is just a placeholder for random defines
related to this H2G action ... it's just sad that we don't have (and
don't want) unified way how to describe GuC ABI messages consts

> +};
> +
> +enum xe_guc_register_context_multi_lrc_param_offsets {
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_0_MBZ = 0,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_1_FLAGS,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_2_PARENT_CONTEXT,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_3_ENGINE_CLASS,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_4_ENGINE_SUBMIT_MASK,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_5_WQ_DESC_ADDR_LOWER,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_6_WQ_DESC_ADDR_UPPER,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_7_WQ_BUF_BASE_LOWER,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_8_WQ_BUF_BASE_UPPER,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_9_WQ_BUF_SIZE,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_10_NUM_CTXS,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_11_HW_LRC_ADDR,
> +	XE_GUC_REGISTER_CONTEXT_MULTI_LRC_MSG_LEN = 11,

same here and also this one should be named, as already suggested, as
"MSG_MIN_LEN" since this message has a flexible length and we can be
only sure about its min size (or max if we consider max CTB msg len)

> +};
> +
>  enum xe_guc_report_status {
>  	XE_GUC_REPORT_STATUS_UNKNOWN = 0x0,
>  	XE_GUC_REPORT_STATUS_ACKED = 0x1,
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 813c3c0bb250..cfc65f21b2f7 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -487,6 +487,15 @@ static void __register_mlrc_exec_queue(struct xe_guc *guc,
>  		action[len++] = upper_32_bits(xe_lrc_descriptor(lrc));
>  	}
>  
> +	/* explicitly checks some fields that we might fixup later */
> +	xe_gt_assert(guc_to_gt(guc), info->wq_desc_lo ==
> +		     action[XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_5_WQ_DESC_ADDR_LOWER]);
> +	xe_gt_assert(guc_to_gt(guc), info->wq_base_lo ==
> +		     action[XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_7_WQ_BUF_BASE_LOWER]);
> +	xe_gt_assert(guc_to_gt(guc), q->width ==
> +		     action[XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_10_NUM_CTXS]);
> +	xe_gt_assert(guc_to_gt(guc), info->hwlrca_lo ==
> +		     action[XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_11_HW_LRC_ADDR]);
>  	xe_gt_assert(guc_to_gt(guc), len <= MAX_MLRC_REG_SIZE);
>  #undef MAX_MLRC_REG_SIZE
>  
> @@ -511,6 +520,14 @@ static void __register_exec_queue(struct xe_guc *guc,
>  		info->hwlrca_hi,
>  	};

nit: since v4 we also have MSG_LEN so we can use it in action[]

>  
> +	/* explicitly checks some fields that we might fixup later */
> +	xe_gt_assert(guc_to_gt(guc), info->wq_desc_lo ==
> +		     action[XE_GUC_REGISTER_CONTEXT_DATA_5_WQ_DESC_ADDR_LOWER]);
> +	xe_gt_assert(guc_to_gt(guc), info->wq_base_lo ==
> +		     action[XE_GUC_REGISTER_CONTEXT_DATA_7_WQ_BUF_BASE_LOWER]);
> +	xe_gt_assert(guc_to_gt(guc), info->hwlrca_lo ==
> +		     action[XE_GUC_REGISTER_CONTEXT_DATA_10_HW_LRC_ADDR]);
> +
>  	xe_guc_ct_send(&guc->ct, action, ARRAY_SIZE(action), 0, 0);
>  }
>  

as above comments are just about enum names, which could be updated once
we decide on how to unify all GuC ABI definitions, this is not worth
blocking the whole series, so let it be,

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>