Re: [RFC v4 1/1] drm/xe/pf: Restrict device query responses in admin-only PF mode

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

On 2/26/2026 5:31 PM, Satyanarayana K V P wrote:
> When the PF is configured for admin‑only mode, it is restricted to
> management functions and should not allow users to run workloads.
> Suppress device capabilities to userspace in admin-only PF mode.
> 
> Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Cc: Michał Winiarski <michal.winiarski@intel.com>
> Cc: Dunajski Bartosz <bartosz.dunajski@intel.com>
> Cc: dri-devel@lists.freedesktop.org
> 
> ---
> V3 -> V4:
> - Suppressed device capabilities in admin-only PF mode. (Wajdeczko)
> 
> V2 -> V3:
> - Introduced new helper function xe_debugfs_create_files() to create
> debugfs entries based on admin_only_pf mode or normal mode.
> 
> V1 -> V2:
> - Rebased to latest drm-tip.
> - Update update_minor_dev() to debugfs_minor_dev().
> ---
>  drivers/gpu/drm/xe/xe_device.c | 14 ++++++++++++++
>  drivers/gpu/drm/xe/xe_query.c  | 11 ++++++++++-
>  drivers/gpu/drm/xe/xe_sriov.h  |  8 ++++++++
>  3 files changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
> index 3462645ca13c..7bf462eed917 100644
> --- a/drivers/gpu/drm/xe/xe_device.c
> +++ b/drivers/gpu/drm/xe/xe_device.c
> @@ -25,6 +25,7 @@
>  #include "regs/xe_regs.h"
>  #include "xe_bo.h"
>  #include "xe_bo_evict.h"
> +#include "xe_configfs.h"
>  #include "xe_debugfs.h"
>  #include "xe_defaults.h"
>  #include "xe_devcoredump.h"
> @@ -213,6 +214,11 @@ static const struct drm_ioctl_desc xe_ioctls[] = {
>  			  DRM_RENDER_ALLOW),
>  };
>  
> +static const struct drm_ioctl_desc xe_pf_admin_only_ioctls[] = {
> +	DRM_IOCTL_DEF_DRV(XE_DEVICE_QUERY, xe_query_ioctl, DRM_RENDER_ALLOW),
> +	DRM_IOCTL_DEF_DRV(XE_OBSERVATION, xe_observation_ioctl, DRM_RENDER_ALLOW),
> +};
> +
>  static long xe_drm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  {
>  	struct drm_file *file_priv = file->private_data;
> @@ -442,6 +448,14 @@ struct xe_device *xe_device_create(struct pci_dev *pdev,
>  	struct xe_device *xe;
>  	int err;
>  
> +	if (xe_configfs_admin_only_pf(pdev)) {

maybe we should add a note why we have to use configfs directly (and not 
a helper introduced below)

> +		driver.ioctls = xe_pf_admin_only_ioctls;
> +		driver.num_ioctls = ARRAY_SIZE(xe_pf_admin_only_ioctls);
> +	} else {
> +		driver.ioctls = xe_ioctls;
> +		driver.num_ioctls = ARRAY_SIZE(xe_ioctls);
> +	}

you shouldn't modify this singleton "driver" as its pointer will be passed
to devm_drm_dev_alloc() and will be referenced later by the drm code and
in case of multiple devices, above overwrite will mess things up.

as suggested before, define separate "driver_admin_only_pf" struct

> +
>  	xe_display_driver_set_hooks(&driver);
>  
>  	err = aperture_remove_conflicting_pci_devices(pdev, driver.name);
> diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
> index 34db266b723f..1416ab7be809 100644
> --- a/drivers/gpu/drm/xe/xe_query.c
> +++ b/drivers/gpu/drm/xe/xe_query.c
> @@ -215,7 +215,10 @@ static int query_engines(struct xe_device *xe,
>  			i++;
>  		}
>  
> -	engines->num_engines = i;
> +	if (xe_device_is_admin_only(xe))
> +		engines->num_engines = 0;
> +	else
> +		engines->num_engines = i;

shouldn't you also modify calc_hw_engine_info_size() and then skip
buffer setup?

>  
>  	if (copy_to_user(query_ptr, engines, size)) {
>  		kfree(engines);
> @@ -297,6 +300,9 @@ static int query_mem_regions(struct xe_device *xe,
>  		}
>  	}
>  
> +	if (xe_device_is_admin_only(xe)) 
> +		mem_regions->num_mem_regions = 0;
> +

same here

>  	if (!copy_to_user(query_ptr, mem_regions, size))
>  		ret = 0;
>  	else
> @@ -419,6 +425,9 @@ static int query_gt_list(struct xe_device *xe, struct drm_xe_device_query *query
>  		iter++;
>  	}
>  
> +	if (xe_device_is_admin_only(xe))
> +		gt_list->num_gt = 0;
> +

and here

>  	if (copy_to_user(query_ptr, gt_list, size)) {
>  		kfree(gt_list);
>  		return -EFAULT;

and what about query_config() ?

> diff --git a/drivers/gpu/drm/xe/xe_sriov.h b/drivers/gpu/drm/xe/xe_sriov.h
> index 72e55543c30e..be426afa90b1 100644
> --- a/drivers/gpu/drm/xe/xe_sriov.h
> +++ b/drivers/gpu/drm/xe/xe_sriov.h
> @@ -37,6 +37,14 @@ static inline bool xe_device_is_sriov_vf(const struct xe_device *xe)
>  	return xe_device_sriov_mode(xe) == XE_SRIOV_MODE_VF;
>  }
>  
> +static inline bool xe_device_is_admin_only(const struct xe_device *xe)

rather:

	xe_device_is_admin_only_pf()

> +{
> +	if (xe_device_is_sriov_pf(xe) && xe->sriov.pf.admin_only)
> +		return true;
> +	else
> +		return false;

just:
	return xe_device_is_sriov_pf(xe) && xe->sriov.pf.admin_only;

> +}
> +
>  #define IS_SRIOV_PF(xe) xe_device_is_sriov_pf(xe)
>  #define IS_SRIOV_VF(xe) xe_device_is_sriov_vf(xe)
>  

btw, we may also want to double check that setting from configfs was valid
(we are really running on the PF device) and abort probe if not