Re: [PATCH v3 1/6] drm/i915/pxp: Make gt and pxp init/fini aware of PXP-owning-GT

["Ceraolo Spurio, Daniele" <daniele.ceraolospurio@xxxxxxxxx>]

On 10/21/2022 10:39 AM, Alan Previn wrote:
> In preparation for future MTL-PXP feature support, PXP control
> context should only valid on the correct gt tile. Depending on the
> device-info this depends on which tile owns the VEBOX and KCR.
> PXP is still a global feature though (despite its control-context
> located in the owning GT structure). Additionally, we find
> that the HAS_PXP macro is only used within the pxp module,
>
> That said, lets drop that HAS_PXP macro altogether and replace it
> with a more fitting named intel_gtpxp_is_supported and helpers
> so that PXP init/fini can use to verify if the referenced gt supports
> PXP or teelink.
>
> Add TODO for Meteorlake that will come in future series.
>
> Signed-off-by: Alan Previn <alan.previn.teres.alexis@xxxxxxxxx>
> ---
>   drivers/gpu/drm/i915/i915_drv.h              |  4 ---
>   drivers/gpu/drm/i915/pxp/intel_pxp.c         | 35 ++++++++++++++++----
>   drivers/gpu/drm/i915/pxp/intel_pxp.h         |  2 ++
>   drivers/gpu/drm/i915/pxp/intel_pxp_debugfs.c |  2 +-
>   4 files changed, 32 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 7c64f8a17493..0921d1107825 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -923,10 +923,6 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
>   
>   #define HAS_GLOBAL_MOCS_REGISTERS(dev_priv)	(INTEL_INFO(dev_priv)->has_global_mocs)
>   
> -#define HAS_PXP(dev_priv)  ((IS_ENABLED(CONFIG_DRM_I915_PXP) && \
> -			    INTEL_INFO(dev_priv)->has_pxp) && \
> -			    VDBOX_MASK(to_gt(dev_priv)))
> -
>   #define HAS_GMCH(dev_priv) (INTEL_INFO(dev_priv)->display.has_gmch)
>   
>   #define HAS_GMD_ID(i915)	(INTEL_INFO(i915)->has_gmd_id)
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> index 5efe61f67546..545c075bf1aa 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> @@ -44,6 +44,30 @@ struct intel_gt *pxp_to_gt(const struct intel_pxp *pxp)
>   	return container_of(pxp, struct intel_gt, pxp);
>   }
>   
> +static bool _gt_needs_teelink(struct intel_gt *gt)
> +{
> +	/* TODO: MTL won't rely on CONFIG_INTEL_MEI_PXP but on GSC engine */
> +	return (IS_ENABLED(CONFIG_INTEL_MEI_PXP) && intel_huc_is_loaded_by_gsc(&gt->uc.huc) &&
> +		intel_uc_uses_huc(&gt->uc));
> +}
> +
> +static bool _gt_supports_pxp(struct intel_gt *gt)
> +{
> +	/* TODO: MTL won't rely on CONFIG_INTEL_MEI_PXP but on GSC engine */
> +	return (IS_ENABLED(CONFIG_INTEL_MEI_PXP) && IS_ENABLED(CONFIG_DRM_I915_PXP) &&
> +		INTEL_INFO((gt)->i915)->has_pxp && VDBOX_MASK(gt));
> +}
> +
> +bool intel_gtpxp_is_supported(struct intel_pxp *pxp)
> +{
> +	struct intel_gt *gt = pxp_to_gt(pxp);
> +
> +	if (_gt_needs_teelink(gt) || _gt_supports_pxp(gt))
> +		return true;
> +
> +	return false;
> +}
> +
>   bool intel_pxp_is_enabled(const struct intel_pxp *pxp)
>   {
>   	return pxp->ce;
> @@ -142,22 +166,21 @@ void intel_pxp_init(struct intel_pxp *pxp)
>   {
>   	struct intel_gt *gt = pxp_to_gt(pxp);
>   
> -	/* we rely on the mei PXP module */
> -	if (!IS_ENABLED(CONFIG_INTEL_MEI_PXP))
> -		return;
> -
>   	/*
>   	 * If HuC is loaded by GSC but PXP is disabled, we can skip the init of
>   	 * the full PXP session/object management and just init the tee channel.
>   	 */
> -	if (HAS_PXP(gt->i915))
> +	if (_gt_supports_pxp(gt))
>   		pxp_init_full(pxp);
> -	else if (intel_huc_is_loaded_by_gsc(&gt->uc.huc) && intel_uc_uses_huc(&gt->uc))
> +	else if (_gt_needs_teelink(gt))
>   		intel_pxp_tee_component_init(pxp);
>   }
>   
>   void intel_pxp_fini(struct intel_pxp *pxp)
>   {
> +	if (!intel_gtpxp_is_supported(pxp))
> +		return;

Why do you need this? the fini below should already be smart enough to 
only cleanup when needed.

> +
>   	pxp->arb_is_valid = false;
>   
>   	intel_pxp_tee_component_fini(pxp);
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.h b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> index 2da309088c6d..c12e4d419c78 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> @@ -13,6 +13,8 @@ struct intel_pxp;
>   struct drm_i915_gem_object;
>   
>   struct intel_gt *pxp_to_gt(const struct intel_pxp *pxp);
> +bool intel_gtpxp_is_supported(struct intel_pxp *pxp);
> +
>   bool intel_pxp_is_enabled(const struct intel_pxp *pxp);
>   bool intel_pxp_is_active(const struct intel_pxp *pxp);
>   
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_debugfs.c b/drivers/gpu/drm/i915/pxp/intel_pxp_debugfs.c
> index 4359e8be4101..124663cf0047 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_debugfs.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_debugfs.c
> @@ -70,7 +70,7 @@ void intel_pxp_debugfs_register(struct intel_pxp *pxp, struct dentry *gt_root)
>   	if (!gt_root)
>   		return;
>   
> -	if (!HAS_PXP((pxp_to_gt(pxp)->i915)))
> +	if (!intel_gtpxp_is_supported(pxp))
>   		return;
>   

This now returns true for DG2, but  we don't want to register the PXP 
debugfs there as we don't support PXP aside from HuC loading. IMO a 
better approach would be to have intel_gtpxp_is_supported be what you 
currently have as _gt_supports_pxp().

Also, intel_gtpxp_is_supported is a bit confusing because of the new 
"gtpxp" prefix. Why not use just intel_pxp_is_supported? We already have 
per-gt checkers that refer only to the subcomponent, like 
intel_huc_is_supported(), which for MTL is false on the primary GT and 
true on the media one. I don't see why we can't do the same for PXP.

Daniele

>   	root = debugfs_create_dir("pxp", gt_root);