Re: [PATCH 09/14] drm/xe/pf: Allow bulk change all VFs priority using sysfs

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Oct 20, 2025 at 08:24:09PM +0200, Michal Wajdeczko wrote:
> It is expected to be a common practice to configure the same level
> of scheduling priority across all VFs and PF (at least as starting
> point). Due to current GuC FW limitations it is also the only way
> to change VFs priority.
> 
> Add write-only sysfs attribute that will apply required priority
> level to all VFs and PF at once.
> 
>   /sys/bus/pci/drivers/xe/BDF/
>   ├── sriov_admin/
>       ├── .bulk_profile
>       │   └── sched_priority		[WO] low, normal

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> 
> Writing "low" to this write-only attribute will change PF and
> VFs scheduling priority on all tiles/GTs to LOW (function will
> be scheduled only if it has work submitted). Similarly, writing
> "normal" will change functions priority to NORMAL (functions will
> be scheduled irrespective of whether there is a work or not).
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_sriov_pf_provision.c |  1 +
>  drivers/gpu/drm/xe/xe_sriov_pf_sysfs.c     | 42 +++++++++++++++++++++-
>  2 files changed, 42 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_provision.c b/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> index 3a3806055616..89b2feb43b77 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> @@ -6,6 +6,7 @@
>  #include "xe_assert.h"
>  #include "xe_device.h"
>  #include "xe_gt_sriov_pf_config.h"
> +#include "xe_gt_sriov_pf_policy.h"
>  #include "xe_sriov.h"
>  #include "xe_sriov_pf_helpers.h"
>  #include "xe_sriov_pf_provision.h"
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_sysfs.c b/drivers/gpu/drm/xe/xe_sriov_pf_sysfs.c
> index 5c445094e223..26ba9a2efec9 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_sysfs.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_sysfs.c
> @@ -24,7 +24,8 @@
>   *     ├── ...
>   *     ├── .bulk_profile
>   *     │   ├── exec_quantum_ms
> - *     │   └── preempt_timeout_us
> + *     │   ├── preempt_timeout_us
> + *     │   └── sched_priority
>   *     ├── pf/
>   *     │   ├── ...
>   *     │   └── profile
> @@ -108,9 +109,48 @@ static XE_SRIOV_DEV_ATTR_WO(NAME)
>  DEFINE_SIMPLE_BULK_PROVISIONING_SRIOV_DEV_ATTR_WO(exec_quantum_ms, eq, u32);
>  DEFINE_SIMPLE_BULK_PROVISIONING_SRIOV_DEV_ATTR_WO(preempt_timeout_us, pt, u32);
>  
> +static const char * const sched_priority_names[] = {
> +	[GUC_SCHED_PRIORITY_LOW] = "low",
> +	[GUC_SCHED_PRIORITY_NORMAL] = "normal",
> +	[GUC_SCHED_PRIORITY_HIGH] = "high",
> +};
> +
> +static bool sched_priority_high_allowed(unsigned int vfid)
> +{
> +	/* As of today GuC FW allows to select 'high' priority only for the PF. */
> +	return vfid == PFID;
> +}
> +
> +static bool sched_priority_bulk_high_allowed(struct xe_device *xe)
> +{
> +	/* all VFs are equal - it's sufficient to check VF1 only */
> +	return sched_priority_high_allowed(VFID(1));
> +}
> +
> +static ssize_t xe_sriov_dev_attr_sched_priority_store(struct xe_device *xe,
> +						      const char *buf, size_t count)
> +{
> +	size_t num_priorities = ARRAY_SIZE(sched_priority_names);
> +	int match;
> +	int err;
> +
> +	if (!sched_priority_bulk_high_allowed(xe))
> +		num_priorities--;
> +
> +	match = __sysfs_match_string(sched_priority_names, num_priorities, buf);
> +	if (match < 0)
> +		return -EINVAL;
> +
> +	err = xe_sriov_pf_provision_bulk_apply_priority(xe, match);
> +	return err ?: count;
> +}
> +
> +static XE_SRIOV_DEV_ATTR_WO(sched_priority);
> +
>  static struct attribute *bulk_profile_dev_attrs[] = {
>  	&xe_sriov_dev_attr_exec_quantum_ms.attr,
>  	&xe_sriov_dev_attr_preempt_timeout_us.attr,
> +	&xe_sriov_dev_attr_sched_priority.attr,
>  	NULL
>  };
>  
> -- 
> 2.47.1
>