Re: [PATCH v3 05/12] drm/xe/sriov: Scheduler groups are incompatible with multi-lrc

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 12/11/2025 2:57 AM, Daniele Ceraolo Spurio wrote:
> Since engines in the same class can be divided across multiple groups,
> the GuC does not allow scheduler groups to be active if there are
> multi-lrc contexts. This means that:
> 
> 1) if a MLRC context is registered when we enable scheduler groups, the
>    GuC will silently ignore the configuration
> 2) if a MLRC context is registered after scheduler groups are enabled,
>    the GuC will disable the groups and generate an adverse event.
> 
> The expectation is that the admin will ensure that all apps that use
> MLRC on PF have been terminated before scheduler groups are created. A
> check on PF is added anyway to make sure we don't still have contexts
> waiting to be cleaned up laying around.
> On both PF and VF we block creation of new MLRC queues once scheduler
> groups have been enabled.
> 
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>

likely this patch could be easily split into PF-only and VF-only
with that,

	Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>

and one more nit below

> ---
> v2: move threshold handling to its own patch, move MLRC check to
>     guc_submit.c, hide SRIOV interals from exec_queue creation code,
>     better comments/docs (Michal)
> v3: s/query_vf/vf_query/ and move the function closer to the
>     caller (Michal)
> ---
>  drivers/gpu/drm/xe/abi/guc_klvs_abi.h      |  7 +++
>  drivers/gpu/drm/xe/xe_exec_queue.c         | 19 +++++++
>  drivers/gpu/drm/xe/xe_gt_sriov_pf.c        | 17 ++++++
>  drivers/gpu/drm/xe/xe_gt_sriov_pf.h        |  8 +++
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.c | 28 ++++++++++
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.h |  1 +
>  drivers/gpu/drm/xe/xe_gt_sriov_vf.c        | 61 ++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_gt_sriov_vf.h        |  1 +
>  drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h  |  2 +
>  drivers/gpu/drm/xe/xe_guc_klv_helpers.c    |  3 ++
>  drivers/gpu/drm/xe/xe_guc_submit.c         | 21 ++++++++
>  drivers/gpu/drm/xe/xe_guc_submit.h         |  2 +
>  12 files changed, 170 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/abi/guc_klvs_abi.h b/drivers/gpu/drm/xe/abi/guc_klvs_abi.h
> index f0a87a1cb12f..5f791237d0ab 100644
> --- a/drivers/gpu/drm/xe/abi/guc_klvs_abi.h
> +++ b/drivers/gpu/drm/xe/abi/guc_klvs_abi.h
> @@ -48,11 +48,18 @@
>   *      Refers to 32 bit architecture version as reported by the HW IP.
>   *      This key is supported on MTL+ platforms only.
>   *      Requires GuC ABI 1.2+.
> + *
> + * _`GUC_KLV_GLOBAL_CFG_GROUP_SCHEDULING_AVAILABLE` : 0x3001
> + *      Tells the driver whether scheduler groups are enabled or not.
> + *      Requires GuC ABI 1.26+
>   */
>  
>  #define GUC_KLV_GLOBAL_CFG_GMD_ID_KEY			0x3000u
>  #define GUC_KLV_GLOBAL_CFG_GMD_ID_LEN			1u
>  
> +#define GUC_KLV_GLOBAL_CFG_GROUP_SCHEDULING_AVAILABLE_KEY	0x3001u
> +#define GUC_KLV_GLOBAL_CFG_GROUP_SCHEDULING_AVAILABLE_LEN	1u
> +
>  /**
>   * DOC: GuC Self Config KLVs
>   *
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c b/drivers/gpu/drm/xe/xe_exec_queue.c
> index 226d07a3d852..df01c0664965 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue.c
> +++ b/drivers/gpu/drm/xe/xe_exec_queue.c
> @@ -16,6 +16,7 @@
>  #include "xe_dep_scheduler.h"
>  #include "xe_device.h"
>  #include "xe_gt.h"
> +#include "xe_gt_sriov_pf.h"
>  #include "xe_gt_sriov_vf.h"
>  #include "xe_hw_engine_class_sysfs.h"
>  #include "xe_hw_engine_group.h"
> @@ -718,6 +719,17 @@ static u32 calc_validate_logical_mask(struct xe_device *xe,
>  	return return_mask;
>  }
>  
> +static bool has_sched_groups(struct xe_gt *gt)
> +{
> +	if (IS_SRIOV_PF(gt_to_xe(gt)) && xe_gt_sriov_pf_sched_groups_enabled(gt))
> +		return true;
> +
> +	if (IS_SRIOV_VF(gt_to_xe(gt)) && xe_gt_sriov_vf_sched_groups_enabled(gt))
> +		return true;
> +
> +	return false;
> +}
> +
>  int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
>  			       struct drm_file *file)
>  {
> @@ -810,6 +822,13 @@ int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
>  			return -ENOENT;
>  		}
>  
> +		/* SRIOV sched groups are not compatible with multi-lrc */
> +		if (XE_IOCTL_DBG(xe, args->width > 1 && has_sched_groups(hwe->gt))) {
> +			up_read(&vm->lock);
> +			xe_vm_put(vm);
> +			return -EINVAL;
> +		}
> +
>  		q = xe_exec_queue_create(xe, vm, logical_mask,
>  					 args->width, hwe, flags,
>  					 args->extensions);
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
> index 0d97a823e702..fb5c9101e275 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf.c
> @@ -284,3 +284,20 @@ int xe_gt_sriov_pf_wait_ready(struct xe_gt *gt)
>  	pf_flush_restart(gt);
>  	return 0;
>  }
> +
> +/**
> + * xe_gt_sriov_pf_sched_groups_enabled - Check if multiple scheduler groups are
> + * enabled
> + * @gt: the &xe_gt
> + *
> + * This function is for PF use only.
> + *
> + * Return: true if shed groups were enabled, false otherwise.
> + */
> +bool xe_gt_sriov_pf_sched_groups_enabled(struct xe_gt *gt)
> +{
> +	xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
> +
> +	return xe_gt_sriov_pf_policy_sched_groups_enabled(gt);
> +}
> +
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf.h b/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
> index e7fde3f9937a..1ccfc7137b98 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf.h
> @@ -6,6 +6,8 @@
>  #ifndef _XE_GT_SRIOV_PF_H_
>  #define _XE_GT_SRIOV_PF_H_
>  
> +#include <linux/types.h>
> +
>  struct xe_gt;
>  
>  #ifdef CONFIG_PCI_IOV
> @@ -16,6 +18,7 @@ void xe_gt_sriov_pf_init_hw(struct xe_gt *gt);
>  void xe_gt_sriov_pf_sanitize_hw(struct xe_gt *gt, unsigned int vfid);
>  void xe_gt_sriov_pf_stop_prepare(struct xe_gt *gt);
>  void xe_gt_sriov_pf_restart(struct xe_gt *gt);
> +bool xe_gt_sriov_pf_sched_groups_enabled(struct xe_gt *gt);
>  #else
>  static inline int xe_gt_sriov_pf_init_early(struct xe_gt *gt)
>  {
> @@ -38,6 +41,11 @@ static inline void xe_gt_sriov_pf_stop_prepare(struct xe_gt *gt)
>  static inline void xe_gt_sriov_pf_restart(struct xe_gt *gt)
>  {
>  }
> +
> +static inline bool xe_gt_sriov_pf_sched_groups_enabled(struct xe_gt *gt)
> +{
> +	return false;
> +}
>  #endif
>  
>  #endif
> 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 7738d515ea9e..7f8dc2b56719 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.c
> @@ -16,6 +16,7 @@
>  #include "xe_guc_buf.h"
>  #include "xe_guc_ct.h"
>  #include "xe_guc_klv_helpers.h"
> +#include "xe_guc_submit.h"
>  #include "xe_pm.h"
>  
>  /*
> @@ -583,6 +584,19 @@ static int pf_provision_sched_groups(struct xe_gt *gt, u32 mode)
>  	if (xe_sriov_pf_num_vfs(gt_to_xe(gt)))
>  		return -EBUSY;
>  
> +	/*
> +	 * The GuC silently ignores the setting if any MLRC contexts are
> +	 * registered. We expect the admin to make sure that all apps that use
> +	 * MLRC are terminated before scheduler groups are enabled, so this
> +	 * check is just to make sure that the exec_queue destruction has been
> +	 * completed.
> +	 */
> +	if (mode != XE_SRIOV_SCHED_GROUPS_DISABLED &&
> +	    xe_guc_has_registered_mlrc_queues(&gt->uc.guc)) {
> +		xe_gt_sriov_notice(gt, "can't enable sched groups with active MLRC queues\n");
> +		return -EPERM;
> +	}
> +
>  	err = __pf_provision_sched_groups(gt, mode);
>  	if (err)
>  		return err;
> @@ -630,6 +644,20 @@ int xe_gt_sriov_pf_policy_set_sched_groups_mode(struct xe_gt *gt, u32 value)
>  	return pf_provision_sched_groups(gt, value);
>  }
>  
> +/**
> + * xe_gt_sriov_pf_policy_sched_groups_enabled() - check whether the GT has
> + * multiple scheduler groups enabled
> + * @gt: the &xe_gt to check
> + *
> + * This function can only be called on PF.
> + *
> + * Return: true if the GT has multiple groups enabled, false otherwise.
> + */
> +bool xe_gt_sriov_pf_policy_sched_groups_enabled(struct xe_gt *gt)
> +{
> +	return gt->sriov.pf.policy.guc.sched_groups.current_mode != XE_SRIOV_SCHED_GROUPS_DISABLED;
> +}
> +
>  static void pf_sanitize_guc_policies(struct xe_gt *gt)
>  {
>  	pf_sanitize_sched_if_idle(gt);
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.h b/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.h
> index d1b1fa9f0a09..f5ea44dcaf82 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_policy.h
> @@ -21,6 +21,7 @@ bool xe_sriov_gt_pf_policy_has_sched_groups_support(struct xe_gt *gt);
>  bool xe_sriov_gt_pf_policy_has_multi_group_modes(struct xe_gt *gt);
>  bool xe_sriov_gt_pf_policy_has_sched_group_mode(struct xe_gt *gt, u32 mode);
>  int xe_gt_sriov_pf_policy_set_sched_groups_mode(struct xe_gt *gt, u32 value);
> +bool xe_gt_sriov_pf_policy_sched_groups_enabled(struct xe_gt *gt);
>  
>  void xe_gt_sriov_pf_policy_init(struct xe_gt *gt);
>  void xe_gt_sriov_pf_policy_sanitize(struct xe_gt *gt);
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> index 3c806c8e5f3e..e0ab1a7a76c4 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> @@ -612,6 +612,46 @@ static void vf_cache_gmdid(struct xe_gt *gt)
>  	gt->sriov.vf.runtime.gmdid = xe_gt_sriov_vf_gmdid(gt);
>  }
>  
> +static int vf_query_sched_groups(struct xe_gt *gt)
> +{
> +	struct xe_guc *guc = &gt->uc.guc;
> +	struct xe_uc_fw_version guc_version;
> +	u32 value = 0;
> +	int err;
> +
> +	xe_gt_sriov_vf_guc_versions(gt, NULL, &guc_version);
> +
> +	if (MAKE_GUC_VER_STRUCT(guc_version) < MAKE_GUC_VER(1, 26, 0))
> +		return 0;
> +
> +	err = guc_action_query_single_klv32(guc,
> +					    GUC_KLV_GLOBAL_CFG_GROUP_SCHEDULING_AVAILABLE_KEY,
> +					    &value);
> +	if (unlikely(err)) {
> +		xe_gt_sriov_err(gt, "Failed to obtain sched groups status (%pe)\n",
> +				ERR_PTR(err));
> +		return err;
> +	}

nit: maybe we should also fail with -EPROTO if GuC returns something different than 0/1 ?

> +
> +	xe_gt_sriov_dbg(gt, "sched groups %s\n", str_enabled_disabled(value));
> +	return value;
> +}
> +
> +static int vf_cache_sched_groups_status(struct xe_gt *gt)
> +{
> +	int ret;
> +
> +	xe_gt_assert(gt, IS_SRIOV_VF(gt_to_xe(gt)));
> +
> +	ret = vf_query_sched_groups(gt);
> +	if (ret < 0)
> +		return ret;
> +
> +	gt->sriov.vf.runtime.uses_sched_groups = ret;
> +
> +	return 0;
> +}
> +
>  /**
>   * xe_gt_sriov_vf_query_config - Query SR-IOV config data over MMIO.
>   * @gt: the &xe_gt
> @@ -641,12 +681,33 @@ int xe_gt_sriov_vf_query_config(struct xe_gt *gt)
>  	if (unlikely(err))
>  		return err;
>  
> +	err = vf_cache_sched_groups_status(gt);
> +	if (unlikely(err))
> +		return err;
> +
>  	if (has_gmdid(xe))
>  		vf_cache_gmdid(gt);
>  
>  	return 0;
>  }
>  
> +/**
> + * xe_gt_sriov_vf_sched_groups_enabled() - Check if PF has enabled multiple
> + * scheduler groups
> + * @gt: the &xe_gt
> + *
> + * This function is for VF use only.
> + *
> + * Return: true if shed groups were enabled, false otherwise.
> + */
> +bool xe_gt_sriov_vf_sched_groups_enabled(struct xe_gt *gt)
> +{
> +	xe_gt_assert(gt, IS_SRIOV_VF(gt_to_xe(gt)));
> +	xe_gt_assert(gt, gt->sriov.vf.guc_version.major);
> +
> +	return gt->sriov.vf.runtime.uses_sched_groups;
> +}
> +
>  /**
>   * xe_gt_sriov_vf_guc_ids - VF GuC context IDs configuration.
>   * @gt: the &xe_gt
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.h b/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
> index af40276790fa..7d97189c2d3d 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
> @@ -30,6 +30,7 @@ bool xe_gt_sriov_vf_recovery_pending(struct xe_gt *gt);
>  u32 xe_gt_sriov_vf_gmdid(struct xe_gt *gt);
>  u16 xe_gt_sriov_vf_guc_ids(struct xe_gt *gt);
>  u64 xe_gt_sriov_vf_lmem(struct xe_gt *gt);
> +bool xe_gt_sriov_vf_sched_groups_enabled(struct xe_gt *gt);
>  
>  u32 xe_gt_sriov_vf_read32(struct xe_gt *gt, struct xe_reg reg);
>  void xe_gt_sriov_vf_write32(struct xe_gt *gt, struct xe_reg reg, u32 val);
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h b/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
> index 510c33116fbd..9a6b5672d569 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
> @@ -27,6 +27,8 @@ struct xe_gt_sriov_vf_selfconfig {
>  struct xe_gt_sriov_vf_runtime {
>  	/** @gmdid: cached value of the GDMID register. */
>  	u32 gmdid;
> +	/** @uses_sched_groups: whether PF enabled sched groups or not. */
> +	bool uses_sched_groups;
>  	/** @regs_size: size of runtime register array. */
>  	u32 regs_size;
>  	/** @num_regs: number of runtime registers in the array. */
> diff --git a/drivers/gpu/drm/xe/xe_guc_klv_helpers.c b/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
> index 1b08b443606e..dd504b77cb17 100644
> --- a/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
> +++ b/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
> @@ -21,6 +21,9 @@
>  const char *xe_guc_klv_key_to_string(u16 key)
>  {
>  	switch (key) {
> +	/* GuC Global Config KLVs */
> +	case GUC_KLV_GLOBAL_CFG_GROUP_SCHEDULING_AVAILABLE_KEY:
> +		return "group_scheduling_available";
>  	/* VGT POLICY keys */
>  	case GUC_KLV_VGT_POLICY_SCHED_IF_IDLE_KEY:
>  		return "sched_if_idle";
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 0fd08d59b644..b983f5a7056f 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -3001,6 +3001,27 @@ void xe_guc_submit_print(struct xe_guc *guc, struct drm_printer *p)
>  	mutex_unlock(&guc->submission_state.lock);
>  }
>  
> +/**
> + * xe_guc_has_registered_mlrc_queues - check whether there are any MLRC queues
> + * registered with the GuC
> + * @guc: GuC.
> + *
> + * Return: true if any MLRC queue is registered with the GuC, false otherwise.
> + */
> +bool xe_guc_has_registered_mlrc_queues(struct xe_guc *guc)
> +{
> +	struct xe_exec_queue *q;
> +	unsigned long index;
> +
> +	guard(mutex)(&guc->submission_state.lock);
> +
> +	xa_for_each(&guc->submission_state.exec_queue_lookup, index, q)
> +		if (q->width > 1)
> +			return true;
> +
> +	return false;
> +}
> +
>  /**
>   * xe_guc_contexts_hwsp_rebase - Re-compute GGTT references within all
>   * exec queues registered to given GuC.
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.h b/drivers/gpu/drm/xe/xe_guc_submit.h
> index 100a7891b918..49e608500a4e 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.h
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.h
> @@ -49,6 +49,8 @@ xe_guc_exec_queue_snapshot_free(struct xe_guc_submit_exec_queue_snapshot *snapsh
>  void xe_guc_submit_print(struct xe_guc *guc, struct drm_printer *p);
>  void xe_guc_register_vf_exec_queue(struct xe_exec_queue *q, int ctx_type);
>  
> +bool xe_guc_has_registered_mlrc_queues(struct xe_guc *guc);
> +
>  int xe_guc_contexts_hwsp_rebase(struct xe_guc *guc, void *scratch);
>  
>  #endif