[PATCH v2 03/13] drm/xe/pf: Force new VFs prorities only once

Michal Wajdeczko
2026-04-02T19:18:12Z

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>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
---
v2: add lockdep_assert_held (Piotr)
---
drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c | 29 ++++++++++++++
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, 49 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..c74745642a92 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 +2550,35 @@ 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)));
+ 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;
}

/**
--
2.47.1