Re: [PATCH 03/13] drm/xe/pf: Force new VFs prorities only once

["Piotr Piórkowski" <piotr.piorkowski@intel.com>]

Michal Wajdeczko <michal.wajdeczko@intel.com> wrote on pon [2026-mar-30 22:40:34 +0200]:
> We should force change of VFs scheduling priorities only after
> initial change of the SCHED_IF_IDLE policy. Doing that also during
> any later policy reprovisioning will overwrite changes done on the
> individual per-VF scheduling priorities (currently only for PF).
> 
> While around also move priority change code to the _config component
> to maintain a proper isolation. Also document our expectation about
> the GuC version where the new meaning of the policy KLV is present.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c | 28 ++++++++++++++
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_config.h |  1 +
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.c | 44 ++++++++++------------
>  3 files changed, 48 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
> index 658e9b048751..e1c028176eb8 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
> @@ -2550,6 +2550,34 @@ u32 xe_gt_sriov_pf_config_get_sched_priority(struct xe_gt *gt, unsigned int vfid
>  	return priority;
>  }
>  
> +/**
> + * xe_gt_sriov_pf_config_force_sched_priority_locked() - Force update scheduling priority.
> + * @gt: the &xe_gt
> + * @priority: new scheduling priority to set
> + *
> + * This function allows to update cached values of the scheduling priorities of all
> + * VFs (and PF) as result of applying the `GUC_KLV_VGT_POLICY_SCHED_IF_IDLE`_ policy.
> + *
> + * This function can only be called on PF.
> + */
> +void xe_gt_sriov_pf_config_force_sched_priority_locked(struct xe_gt *gt, u32 priority)
> +{
> +	unsigned int total_vfs = 1 + xe_gt_sriov_pf_get_totalvfs(gt);
> +	struct xe_gt_sriov_config *config;
> +	unsigned int n;
> +
> +	xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
I will add:
lockdep_assert_held(xe_gt_sriov_pf_master_mutex(gt));

> +
> +	for (n = 0; n < total_vfs; n++) {
> +		config = pf_pick_vf_config(gt, VFID(n));
> +		config->sched_priority = priority;
> +	}
> +
> +	pf_config_bulk_set_u32_done(gt, PFID, 1 + total_vfs, priority,
> +				    pf_get_sched_priority, "scheduling priority",
> +				    sched_priority_unit, n, 0);
> +}
> +
>  static void pf_reset_config_sched(struct xe_gt *gt, struct xe_gt_sriov_config *config)
>  {
>  	int i;
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.h b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.h
> index 4a004ecd6140..e9314f0a9b4e 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.h
> @@ -71,6 +71,7 @@ int xe_gt_sriov_pf_config_set_groups_preempt_timeouts(struct xe_gt *gt, unsigned
>  
>  u32 xe_gt_sriov_pf_config_get_sched_priority(struct xe_gt *gt, unsigned int vfid);
>  int xe_gt_sriov_pf_config_set_sched_priority(struct xe_gt *gt, unsigned int vfid, u32 priority);
> +void xe_gt_sriov_pf_config_force_sched_priority_locked(struct xe_gt *gt, u32 priority);
>  
>  u32 xe_gt_sriov_pf_config_get_threshold(struct xe_gt *gt, unsigned int vfid,
>  					enum xe_guc_klv_threshold_index index);
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.c
> index 848e24926ecd..6ab02e96e46c 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.c
> @@ -8,6 +8,7 @@
>  #include "abi/guc_actions_sriov_abi.h"
>  
>  #include "xe_gt.h"
> +#include "xe_gt_sriov_pf_config.h"
>  #include "xe_gt_sriov_pf_helpers.h"
>  #include "xe_gt_sriov_pf_policy.h"
>  #include "xe_gt_sriov_printk.h"
> @@ -153,33 +154,14 @@ static int pf_update_policy_u32(struct xe_gt *gt, u16 key, u32 *policy, u32 valu
>  	return 0;
>  }
>  
> -static void pf_bulk_reset_sched_priority(struct xe_gt *gt, u32 priority)
> -{
> -	unsigned int total_vfs = 1 + xe_gt_sriov_pf_get_totalvfs(gt);
> -	unsigned int n;
> -
> -	xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
> -	lockdep_assert_held(xe_gt_sriov_pf_master_mutex(gt));
> -
> -	for (n = 0; n < total_vfs; n++)
> -		gt->sriov.pf.vfs[n].config.sched_priority = priority;
> -}
> -
>  static int pf_provision_sched_if_idle(struct xe_gt *gt, bool enable)
>  {
> -	int err;
> -
>  	xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
>  	lockdep_assert_held(xe_gt_sriov_pf_master_mutex(gt));
>  
> -	err = pf_update_policy_bool(gt, GUC_KLV_VGT_POLICY_SCHED_IF_IDLE_KEY,
> -				    &gt->sriov.pf.policy.guc.sched_if_idle,
> -				    enable);
> -
> -	if (!err)
> -		pf_bulk_reset_sched_priority(gt, enable ? GUC_SCHED_PRIORITY_NORMAL :
> -					     GUC_SCHED_PRIORITY_LOW);
> -	return err;
> +	return pf_update_policy_bool(gt, GUC_KLV_VGT_POLICY_SCHED_IF_IDLE_KEY,
> +				     &gt->sriov.pf.policy.guc.sched_if_idle,
> +				     enable);
>  }
>  
>  static int pf_reprovision_sched_if_idle(struct xe_gt *gt)
> @@ -209,13 +191,25 @@ static void pf_sanitize_sched_if_idle(struct xe_gt *gt)
>   */
>  int xe_gt_sriov_pf_policy_set_sched_if_idle(struct xe_gt *gt, bool enable)
>  {
> +	u32 priority;
>  	int err;
>  
> -	mutex_lock(xe_gt_sriov_pf_master_mutex(gt));
> +	guard(mutex)(xe_gt_sriov_pf_master_mutex(gt));
> +
>  	err = pf_provision_sched_if_idle(gt, enable);
> -	mutex_unlock(xe_gt_sriov_pf_master_mutex(gt));
> +	if (err)
> +		return err;
>  
> -	return err;
> +	/*
> +	 * As of GuC 70.12 a change of this policy impacts individual configs
> +	 * of all VFs. See `GUC_KLV_VGT_POLICY_SCHED_IF_IDLE`_ for details.
> +	 */
> +	xe_gt_assert(gt, GUC_FIRMWARE_VER_AT_LEAST(&gt->uc.guc, 70, 12));
> +
> +	priority = enable ? GUC_SCHED_PRIORITY_NORMAL : GUC_SCHED_PRIORITY_LOW;
> +	xe_gt_sriov_pf_config_force_sched_priority_locked(gt, priority);
> +
> +	return 0;
>  }
>  

LGTM:
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>


>  /**
> -- 
> 2.47.1
> 

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