Re: [PATCH v1 4/5] drm/xe/pf: Provision VFs under mutex

["Bernatowicz, Marcin" <marcin.bernatowicz@linux.intel.com>]

LGTM,

Reviewed-by: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>

On 10/27/2026 11:30 AM, Piórkowski, Piotr wrote:
> From: Piotr Piórkowski <piotr.piorkowski@intel.com>
>
> The provisioning mode is now changed under the master mutex, but it
> is still checked without any locking when VFs are being provisioned,
> so the mode could change between the check and the provisioning.
>
> Use the locked variants of the fair provisioning functions and hold
> the master mutex while checking the mode and provisioning the VFs.
>
> This was the last user of the unlocked fair provisioning functions,
> so remove them.
>
> Signed-off-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c | 34 ----------------------
>   drivers/gpu/drm/xe/xe_gt_sriov_pf_config.h |  2 --
>   drivers/gpu/drm/xe/xe_sriov_pf_provision.c |  8 +++--
>   3 files changed, 6 insertions(+), 38 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 c8ab4138f6a8..cca2f837e90b 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
> @@ -2142,24 +2142,6 @@ int xe_gt_sriov_pf_config_set_fair_locked(struct xe_gt *gt, unsigned int vfid,
>   	return result;
>   }
>   
> -/**
> - * xe_gt_sriov_pf_config_set_fair - Provision many VFs with fair resources.
> - * @gt: the &xe_gt
> - * @vfid: starting VF identifier (can't be 0)
> - * @num_vfs: number of VFs to provision (can't be 0)
> - *
> - * This function can only be called on PF.
> - *
> - * Return: 0 on success or a negative error code on failure.
> - */
> -int xe_gt_sriov_pf_config_set_fair(struct xe_gt *gt, unsigned int vfid,
> -				   unsigned int num_vfs)
> -{
> -	guard(mutex)(xe_gt_sriov_pf_master_mutex(gt));
> -
> -	return xe_gt_sriov_pf_config_set_fair_locked(gt, vfid, num_vfs);
> -}
> -
>   static const char *exec_quantum_unit(u32 exec_quantum)
>   {
>   	return exec_quantum ? "ms" : "(infinity)";
> @@ -2855,22 +2837,6 @@ int xe_gt_sriov_pf_config_set_fair_sched_locked(struct xe_gt *gt, unsigned int n
>   	return result;
>   }
>   
> -/**
> - * xe_gt_sriov_pf_config_set_fair_sched() - Provision PF and VFs with fair scheduling.
> - * @gt: the &xe_gt
> - * @num_vfs: number of VFs to provision (can't be 0)
> - *
> - * This function can only be called on PF.
> - *
> - * Return: 0 on success or a negative error code on failure.
> - */
> -int xe_gt_sriov_pf_config_set_fair_sched(struct xe_gt *gt, unsigned int num_vfs)
> -{
> -	guard(mutex)(xe_gt_sriov_pf_master_mutex(gt));
> -
> -	return xe_gt_sriov_pf_config_set_fair_sched_locked(gt, num_vfs);
> -}
> -
>   static int pf_provision_threshold(struct xe_gt *gt, unsigned int vfid,
>   				  enum xe_guc_klv_threshold_index index, u32 value)
>   {
> 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 69841b0fcddb..0d45dc9672e7 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.h
> @@ -89,9 +89,7 @@ u32 xe_gt_sriov_pf_config_get_threshold(struct xe_gt *gt, unsigned int vfid,
>   int xe_gt_sriov_pf_config_set_threshold(struct xe_gt *gt, unsigned int vfid,
>   					enum xe_guc_klv_threshold_index index, u32 value);
>   
> -int xe_gt_sriov_pf_config_set_fair_sched(struct xe_gt *gt, unsigned int num_vfs);
>   int xe_gt_sriov_pf_config_set_fair_sched_locked(struct xe_gt *gt, unsigned int num_vfs);
> -int xe_gt_sriov_pf_config_set_fair(struct xe_gt *gt, unsigned int vfid, unsigned int num_vfs);
>   int xe_gt_sriov_pf_config_set_fair_locked(struct xe_gt *gt, unsigned int vfid,
>   					  unsigned int num_vfs);
>   int xe_gt_sriov_pf_config_sanitize(struct xe_gt *gt, unsigned int vfid, long timeout);
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_provision.c b/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> index e713a24b8864..6ea2a24fef6e 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> @@ -40,10 +40,12 @@ static int pf_provision_vfs(struct xe_device *xe, unsigned int num_vfs)
>   	int result = 0;
>   	int err;
>   
> +	lockdep_assert_held(xe_sriov_pf_master_mutex(xe));
> +
>   	for_each_gt(gt, xe, id) {
> -		err = xe_gt_sriov_pf_config_set_fair_sched(gt, num_vfs);
> +		err = xe_gt_sriov_pf_config_set_fair_sched_locked(gt, num_vfs);
>   		result = result ?: err;
> -		err = xe_gt_sriov_pf_config_set_fair(gt, VFID(1), num_vfs);
> +		err = xe_gt_sriov_pf_config_set_fair_locked(gt, VFID(1), num_vfs);
>   		result = result ?: err;
>   	}
>   
> @@ -81,6 +83,8 @@ int xe_sriov_pf_provision_vfs(struct xe_device *xe, unsigned int num_vfs)
>   {
>   	xe_assert(xe, IS_SRIOV_PF(xe));
>   
> +	guard(mutex)(xe_sriov_pf_master_mutex(xe));
> +
>   	if (!pf_auto_provisioning_mode(xe))
>   		return 0;
>