Re: [PATCH v3 07/12] drm/xe/sriov: Add debugfs to enable scheduler groups

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

this is PF only patch, so

	drm/xe/pf: ...

On 12/11/2025 2:57 AM, Daniele Ceraolo Spurio wrote:
> Reading the debugfs file lists the available configurations by name.
> Writing the name of a configuration to the file will enable it.
> 
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>

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

with 2 nits below

> ---
> v2: don't print anything if the feature is unsupported (Michal), add
>     TODO for reworking init order to know if there are valid groups
>     when we register debugfs, check for basic feature support.
> v3: use drm_puts, list modes even if we only support the disabled
>     one (Michal)
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c | 120 ++++++++++++++++++++
>  1 file changed, 120 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
> index 7833a7118039..8ac5e0e01e36 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
> @@ -156,6 +156,125 @@ static void pf_add_policy_attrs(struct xe_gt *gt, struct dentry *parent)
>  	debugfs_create_file_unsafe("sample_period_ms", 0644, parent, parent, &sample_period_fops);
>  }
>  
> +/*
> + *      /sys/kernel/debug/dri/BDF/
> + *      ├── sriov
> + *      :   ├── pf
> + *          :   ├── tile0
> + *              :   ├── gt0
> + *                  :   ├── sched_groups_mode
> + */
> +
> +static const char *sched_group_mode_to_string(enum xe_sriov_sched_group_modes mode)
> +{
> +	switch (mode) {
> +	case XE_SRIOV_SCHED_GROUPS_DISABLED:
> +		return "disabled";
> +	case XE_SRIOV_SCHED_GROUPS_MEDIA_SLICES:
> +		return "media_slices";
> +	default:
> +		return "unknown";
> +	}
> +}
> +
> +static int sched_groups_info(struct seq_file *m, void *data)
> +{
> +	struct drm_printer p = drm_seq_file_printer(m);
> +	struct xe_gt *gt = extract_gt(m->private);
> +	u32 current_mode = gt->sriov.pf.policy.guc.sched_groups.current_mode;

nit: current_mode is enum, not u32

> +	int mode = 0;
> +
> +	for (mode = 0; mode < XE_SRIOV_SCHED_GROUPS_MODES_COUNT; mode++) {
> +		if (!xe_sriov_gt_pf_policy_has_sched_group_mode(gt, mode))
> +			continue;
> +
> +		if (mode)
> +			drm_puts(&p, " ");
> +
> +		if (mode == current_mode)
> +			drm_puts(&p, "[");
> +
> +		drm_printf(&p, "%s", sched_group_mode_to_string(mode));
> +
> +		if (mode == current_mode)
> +			drm_puts(&p, "]");

nit: wondering if using single drm_printf with complex format would generate smaller code

	drm_printf(&p, "%s%s%s%s",
		mode ? " " : "",
		mode == current_mode ? "[" : "",
		sched_group_mode_to_string(mode),
		mode == current_mode ? "[" : "");

> +	}
> +
> +	drm_puts(&p, "\n");
> +
> +	return 0;
> +}
> +
> +static int sched_groups_open(struct inode *inode, struct file *file)
> +{
> +	return single_open(file, sched_groups_info, inode->i_private);
> +}
> +
> +static ssize_t sched_groups_write(struct file *file, const char __user *ubuf,
> +				  size_t size, loff_t *pos)
> +{
> +	struct xe_gt *gt = extract_gt(file_inode(file)->i_private);
> +	char name[32];
> +	int ret;
> +	int m;
> +
> +	if (*pos)
> +		return -ESPIPE;
> +
> +	if (!size)
> +		return -ENODATA;
> +
> +	if (size > sizeof(name) - 1)
> +		return -EINVAL;
> +
> +	ret = simple_write_to_buffer(name, sizeof(name) - 1, pos, ubuf, size);
> +	if (ret < 0)
> +		return ret;
> +	name[ret] = '\0';
> +
> +	for (m = 0; m < XE_SRIOV_SCHED_GROUPS_MODES_COUNT; m++)
> +		if (sysfs_streq(name, sched_group_mode_to_string(m)))
> +			break;
> +
> +	if (m == XE_SRIOV_SCHED_GROUPS_MODES_COUNT)
> +		return -EINVAL;
> +
> +	guard(xe_pm_runtime)(gt_to_xe(gt));
> +	ret = xe_gt_sriov_pf_policy_set_sched_groups_mode(gt, m);
> +
> +	return ret < 0 ? ret : size;
> +}
> +
> +static const struct file_operations sched_groups_fops = {
> +	.owner = THIS_MODULE,
> +	.open = sched_groups_open,
> +	.read = seq_read,
> +	.write = sched_groups_write,
> +	.llseek = seq_lseek,
> +	.release = single_release,
> +};
> +
> +static void pf_add_sched_groups(struct xe_gt *gt, struct dentry *parent)
> +{
> +	xe_gt_assert(gt, gt == extract_gt(parent));
> +	xe_gt_assert(gt, PFID == extract_vfid(parent));
> +
> +	/*
> +	 * TODO: we currently call this function before we initialize scheduler
> +	 * groups, so at this point in time we don't know if there are any
> +	 * valid groups on the GT and we can't selectively register the debugfs
> +	 * only if there are any. Therefore, we always register the debugfs
> +	 * files if we're on a platform that has support for groups.
> +	 * We should rework the flow so that debugfs is registered after the
> +	 * policy init, so that we check if there are valid groups before
> +	 * adding the debugfs files.
> +	 */
> +	if (!xe_sriov_gt_pf_policy_has_sched_groups_support(gt))
> +		return;
> +
> +	debugfs_create_file("sched_groups_mode", 0644, parent, parent, &sched_groups_fops);
> +}
> +
>  /*
>   *      /sys/kernel/debug/dri/BDF/
>   *      ├── sriov
> @@ -531,6 +650,7 @@ static void pf_populate_gt(struct xe_gt *gt, struct dentry *dent, unsigned int v
>  	} else {
>  		pf_add_config_attrs(gt, dent, PFID);
>  		pf_add_policy_attrs(gt, dent);
> +		pf_add_sched_groups(gt, dent);
>  
>  		drm_debugfs_create_files(pf_info, ARRAY_SIZE(pf_info), dent, minor);
>  	}