drm/xe/pf: Allow bulk change all VFs priority using sysfs

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

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>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patch.msgid.link/20251030222348.186658-13-michal.wajdeczko@intel.com

diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_sysfs.c b/drivers/gpu/drm/xe/xe_sriov_pf_sysfs.c
index 0430ffaa746a8f3232bead4eb181ca736b8c066c..19724a28fb33b1b131b398bcef315d793002ed51 100644 (file)
--- 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
 };