Re: [PATCH 4/4] drm/xe/pf: Allow to restore auto-provisioning mode

["Piotr Piórkowski" <piotr.piorkowski@intel.com>]

Michal Wajdeczko <michal.wajdeczko@intel.com> wrote on śro [2025-paź-15 11:12:09 +0200]:
> After doing tweaks to the VFs provisioning we may want to restore
> back the auto-provisioning mode. Allow that unless VFs are still
> enabled. This can be also used to release all VFs resources.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c   | 63 ++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_sriov_pf_helpers.h   | 11 ++++
>  drivers/gpu/drm/xe/xe_sriov_pf_provision.c | 18 +++++++
>  3 files changed, 92 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
> index 97636ed86fb8..a81aa05c5532 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
> @@ -13,6 +13,7 @@
>  #include "xe_sriov_pf_control.h"
>  #include "xe_sriov_pf_debugfs.h"
>  #include "xe_sriov_pf_helpers.h"
> +#include "xe_sriov_pf_provision.h"
>  #include "xe_sriov_pf_service.h"
>  #include "xe_sriov_printk.h"
>  #include "xe_tile_sriov_pf_debugfs.h"
> @@ -43,6 +44,66 @@ static unsigned int extract_vfid(struct dentry *d)
>  	return p == extract_xe(d) ? PFID : (uintptr_t)p;
>  }
>  
> +/*
> + *      /sys/kernel/debug/dri/BDF/
> + *      ├── sriov
> + *      │   ├── restore_auto_provisioning
> + *      │   :
> + *      │   ├── pf/
> + *      │   ├── vf1
> + *      │   │   ├── ...
> + */
> +
> +static ssize_t from_file_write_to_xe_call(struct file *file, const char __user *userbuf,
> +					  size_t count, loff_t *ppos,
> +					  int (*call)(struct xe_device *))
> +{
> +	struct dentry *dent = file_dentry(file);
> +	struct xe_device *xe = extract_xe(dent);
> +	bool yes;
> +	int ret;
> +
> +	if (*ppos)
> +		return -EINVAL;
> +	ret = kstrtobool_from_user(userbuf, count, &yes);
> +	if (ret < 0)
> +		return ret;
> +	if (yes) {
> +		xe_pm_runtime_get(xe);
> +		ret = call(xe);
> +		xe_pm_runtime_put(xe);
> +	}
> +	if (ret < 0)
> +		return ret;
> +	return count;
> +}
> +
> +#define DEFINE_SRIOV_ATTRIBUTE(OP)						\
> +static int OP##_show(struct seq_file *s, void *unused)				\
> +{										\
> +	return 0;								\
> +}										\
> +static ssize_t OP##_write(struct file *file, const char __user *userbuf,	\
> +			  size_t count, loff_t *ppos)				\
> +{										\
> +	return from_file_write_to_xe_call(file, userbuf, count, ppos,		\
> +					  xe_sriov_pf_##OP);			\
> +}										\
> +DEFINE_SHOW_STORE_ATTRIBUTE(OP)
> +
> +static inline int xe_sriov_pf_restore_auto_provisioning(struct xe_device *xe)
> +{
> +	return xe_sriov_pf_provision_set_mode(xe, XE_SRIOV_PROVISIONING_MODE_AUTO);
> +}
> +
> +DEFINE_SRIOV_ATTRIBUTE(restore_auto_provisioning);
> +
> +static void pf_populate_root(struct xe_device *xe, struct dentry *dent)
> +{
> +	debugfs_create_file("restore_auto_provisioning", 0200, dent, xe,
> +			    &restore_auto_provisioning_fops);
> +}
> +
>  static int simple_show(struct seq_file *m, void *data)
>  {
>  	struct drm_printer p = drm_seq_file_printer(m);
> @@ -167,6 +228,8 @@ void xe_sriov_pf_debugfs_register(struct xe_device *xe, struct dentry *root)
>  		return;
>  	dent->d_inode->i_private = xe;
>  
> +	pf_populate_root(xe, dent);
> +
>  	/*
>  	 *      /sys/kernel/debug/dri/BDF/
>  	 *      ├── sriov		# d_inode->i_private = (xe_device*)
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
> index dd1df950b021..4a4340fb633a 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
> @@ -37,6 +37,17 @@ static inline int xe_sriov_pf_get_totalvfs(struct xe_device *xe)
>  	return xe->sriov.pf.driver_max_vfs;
>  }
>  
> +/**
> + * xe_sriov_pf_num_vfs() - Number of enabled VFs on the PF.
> + * @xe: the PF &xe_device
> + *
> + * Return: Number of enabled VFs on the PF.
> + */
> +static inline unsigned int xe_sriov_pf_num_vfs(const struct xe_device *xe)
> +{
> +	return pci_num_vf(to_pci_dev(xe->drm.dev));
> +}
> +
>  static inline struct mutex *xe_sriov_pf_master_mutex(struct xe_device *xe)
>  {
>  	xe_assert(xe, IS_SRIOV_PF(xe));
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_provision.c b/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> index 7e74175db972..32c281c1dc5d 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
> @@ -70,6 +70,11 @@ static void pf_unprovision_vfs(struct xe_device *xe, unsigned int num_vfs)
>  			xe_gt_sriov_pf_config_release(gt, n, true);
>  }
>  
> +static void pf_unprovision_all_vfs(struct xe_device *xe)
> +{
> +	pf_unprovision_vfs(xe, xe_sriov_pf_get_totalvfs(xe));
> +}
> +
>  /**
>   * xe_sriov_pf_provision_vfs() - Provision VFs in auto-mode.
>   * @xe: the PF &xe_device
> @@ -117,6 +122,10 @@ int xe_sriov_pf_unprovision_vfs(struct xe_device *xe, unsigned int num_vfs)
>   * When changing from AUTO to CUSTOM mode, any already allocated VFs resources
>   * will remain allocated and will not be released upon VFs disabling.
>   *
> + * When changing back to AUTO mode, if VFs are not enabled, already allocated
> + * VFs resources will be immediately released. If VFs are still enabled, such
> + * mode change is rejected.
> + *
>   * This function can only be called on PF.
>   *
>   * Return: 0 on success or a negative error code on failure.
> @@ -128,6 +137,15 @@ int xe_sriov_pf_provision_set_mode(struct xe_device *xe, enum xe_sriov_provision
>  	if (mode == xe->sriov.pf.provision.mode)
>  		return 0;
>  
> +	if (mode == XE_SRIOV_PROVISIONING_MODE_AUTO) {
> +		if (xe_sriov_pf_num_vfs(xe)) {
> +			xe_sriov_dbg(xe, "can't restore %s: VFs must be disabled!\n",
> +				     mode_to_string(mode));
NIT: I would consider a higher level of logging here.
> +			return -EBUSY;
> +		}
> +		pf_unprovision_all_vfs(xe);
> +	}
> +
>  	xe_sriov_dbg(xe, "mode %s changed to %s by %ps\n",
>  		     mode_to_string(xe->sriov.pf.provision.mode),
>  		     mode_to_string(mode), __builtin_return_address(0));

LGTM:
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>

> -- 
> 2.47.1
> 

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