Re: [RFC v8 1/1] drm/xe/pf: Restrict device query responses in admin-only PF mode

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

On 4/2/2026 3:19 PM, Satyanarayana K V P wrote:
> When a PF is configured in admin-only mode, it is intended for management
> only and must not expose workload-facing capabilities to userspace.
> 
> Limit the exposed ioctl set in admin-only PF mode to XE_DEVICE_QUERY and
> XE_OBSERVATION, and suppress capability-bearing query payloads so that
> the userspace cannot discover execution-related device details in this
> mode.
> 
> Enable admin-only mode with:
> echo <B:D:F> | sudo tee /sys/bus/pci/drivers/xe/unbind
> sudo mkdir /sys/kernel/config/xe/<B:D:F>
> echo yes | sudo tee /sys/kernel/config/xe/<B:D:F>/sriov/admin_only_pf
> echo <B:D:F> | sudo tee /sys/bus/pci/drivers/xe/bind
> 
> 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: Ashutosh Dixit <ashutosh.dixit@intel.com>
> Cc: dri-devel@lists.freedesktop.org
> Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Acked-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> 
> ---
> V7 -> V8:
> - Fixed issues reported by CI.Hooks
> - Updated commit message (Ashutosh)
> - Removed gem_prime_import from admin_only_driver structure (Michal)
> 
> V6 -> V7:
> - Allowed xe_observation_ioctl as well with admin-only PF (Ashutosh,
> Michal).
> - Updated commit message with steps to enable admin-only mode (Rodrigo).
> 
> V5 -> V6:
> - Updated commit message.
> - Return number of engines and memory regions as zero instead of
> returning query size as zero (Michal Wajdeczko).
> - Allow all other query IOCTLs excepts query_engines and
> query_mem_regions (Michal Wajdeczko).
> 
> V4 -> V5:
> - Updated commit message (Matt B).
> - Introduced new driver_admin_only_pf structure (Michal Wajdeczko).
> - Updated all query configs (Michal Wajdeczko).
> - Renamed xe_device_is_admin_only() to xe_device_is_admin_only_pf()
> - Fixed other review comments (Michal Wajdeczko).
> 
> 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    | 60 ++++++++++++++++++++++++++++---
>  drivers/gpu/drm/xe/xe_device.h    |  1 +
>  drivers/gpu/drm/xe/xe_hw_engine.c |  3 ++
>  drivers/gpu/drm/xe/xe_query.c     | 10 +++++-
>  4 files changed, 69 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
> index cbce1d0ffe48..eba2fa6dc7d3 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"
> @@ -216,6 +217,11 @@ static const struct drm_ioctl_desc xe_ioctls[] = {
>  			  DRM_RENDER_ALLOW),
>  };
>  
> +static const struct drm_ioctl_desc xe_ioctls_admin_only[] = {
> +	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;
> @@ -390,7 +396,7 @@ bool xe_is_xe_file(const struct file *file)
>  	return file->f_op == &xe_driver_fops;
>  }
>  
> -static struct drm_driver driver = {
> +static struct drm_driver regular_driver = {
>  	.driver_features =
>  	    DRIVER_GEM |
>  	    DRIVER_RENDER | DRIVER_SYNCOBJ |
> @@ -415,6 +421,38 @@ static struct drm_driver driver = {
>  	.patchlevel = DRIVER_PATCHLEVEL,
>  };
>  
> +static struct drm_driver admin_only_driver = {
> +	.driver_features =
> +	    DRIVER_GEM | DRIVER_RENDER | DRIVER_GEM_GPUVA,
> +	.open = xe_file_open,
> +	.postclose = xe_file_close,
> +
> +	.dumb_create = xe_bo_dumb_create,
> +	.dumb_map_offset = drm_gem_ttm_dumb_map_offset,
> +#ifdef CONFIG_PROC_FS
> +	.show_fdinfo = xe_drm_client_fdinfo,

do we want to expose memory or engines details here?

> +#endif
> +	.ioctls = xe_ioctls_admin_only,
> +	.num_ioctls = ARRAY_SIZE(xe_ioctls_admin_only),
> +	.fops = &xe_driver_fops,
> +	.name = DRIVER_NAME,
> +	.desc = DRIVER_DESC,
> +	.major = DRIVER_MAJOR,
> +	.minor = DRIVER_MINOR,
> +	.patchlevel = DRIVER_PATCHLEVEL,
> +};
> +
> +/**
> + * xe_device_is_admin_only() - Check whether device is admin only or not.
> + * @xe: the &xe_device to check
> + *
> + * Return: true if the device is admin only, false otherwise.
> + */
> +bool xe_device_is_admin_only(const struct xe_device *xe)
> +{
> +	return xe->drm.driver == &admin_only_driver;
> +}

I'm still looking for patch #2 which would update xe_sriov_pf_admin_only()

> +
>  static void xe_device_destroy(struct drm_device *dev, void *dummy)
>  {
>  	struct xe_device *xe = to_xe_device(dev);
> @@ -439,16 +477,25 @@ static void xe_device_destroy(struct drm_device *dev, void *dummy)
>  struct xe_device *xe_device_create(struct pci_dev *pdev,
>  				   const struct pci_device_id *ent)
>  {
> +	struct drm_driver *driver = &regular_driver;
>  	struct xe_device *xe;
>  	int err;
>  
> -	xe_display_driver_set_hooks(&driver);
> +#ifdef CONFIG_PCI_IOV

maybe use if (IS_ENABLED()) to avoid complains about unused static in PCI_IOV=n ?

> +	/*
> +	 * Since XE device is not initialized yet, read from configfs
> +	 * directly to decide whether we are in admin-only PF mode or not.
> +	 */
> +	if (xe_configfs_admin_only_pf(pdev))
> +		driver = &admin_only_driver;
> +#endif

nit: add empty line here

> +	xe_display_driver_set_hooks(driver);
>  
> -	err = aperture_remove_conflicting_pci_devices(pdev, driver.name);
> +	err = aperture_remove_conflicting_pci_devices(pdev, driver->name);
>  	if (err)
>  		return ERR_PTR(err);
>  
> -	xe = devm_drm_dev_alloc(&pdev->dev, &driver, struct xe_device, drm);
> +	xe = devm_drm_dev_alloc(&pdev->dev, driver, struct xe_device, drm);
>  	if (IS_ERR(xe))
>  		return xe;
>  
> @@ -708,6 +755,11 @@ int xe_device_probe_early(struct xe_device *xe)
>  
>  	xe_sriov_probe_early(xe);
>  
> +	if (xe_device_is_admin_only(xe) && !IS_SRIOV_PF(xe)) {
> +		xe_err(xe, "Can't run Admin-only mode without SR-IOV PF mode!\n");
> +		return -ENODEV;
> +	}
> +
>  	if (IS_SRIOV_VF(xe))
>  		vf_update_device_info(xe);
>  
> diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
> index e4b9de8d8e95..c220f2f1352f 100644
> --- a/drivers/gpu/drm/xe/xe_device.h
> +++ b/drivers/gpu/drm/xe/xe_device.h
> @@ -43,6 +43,7 @@ static inline struct xe_device *ttm_to_xe_device(struct ttm_device *ttm)
>  	return container_of(ttm, struct xe_device, ttm);
>  }
>  
> +bool xe_device_is_admin_only(const struct xe_device *xe);
>  struct xe_device *xe_device_create(struct pci_dev *pdev,
>  				   const struct pci_device_id *ent);
>  int xe_device_probe_early(struct xe_device *xe);
> diff --git a/drivers/gpu/drm/xe/xe_hw_engine.c b/drivers/gpu/drm/xe/xe_hw_engine.c
> index 337baf0a6e87..2c324acb1dd0 100644
> --- a/drivers/gpu/drm/xe/xe_hw_engine.c
> +++ b/drivers/gpu/drm/xe/xe_hw_engine.c
> @@ -1027,6 +1027,9 @@ bool xe_hw_engine_is_reserved(struct xe_hw_engine *hwe)
>  	struct xe_gt *gt = hwe->gt;
>  	struct xe_device *xe = gt_to_xe(gt);
>  
> +	if (xe_device_is_admin_only(xe))
> +		return true;
> +
>  	if (hwe->class == XE_ENGINE_CLASS_OTHER)
>  		return true;
>  
> diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
> index d84d6a422c45..b10a281c6ae0 100644
> --- a/drivers/gpu/drm/xe/xe_query.c
> +++ b/drivers/gpu/drm/xe/xe_query.c
> @@ -231,10 +231,13 @@ static size_t calc_mem_regions_size(struct xe_device *xe)
>  	u32 num_managers = 1;
>  	int i;
>  
> +	if (xe_device_is_admin_only(xe))
> +		goto out;

or maybe just:
		return sizeof(drm_xe_query_mem_regions);

> +
>  	for (i = XE_PL_VRAM0; i <= XE_PL_VRAM1; ++i)
>  		if (ttm_manager_type(&xe->ttm, i))
>  			num_managers++;
> -
> +out:
>  	return offsetof(struct drm_xe_query_mem_regions, mem_regions[num_managers]);
>  }
>  
> @@ -273,6 +276,8 @@ static int query_mem_regions(struct xe_device *xe,
>  	mem_regions->num_mem_regions = 1;

IMO we shouldn't attempt to fill region0 here, and then memset it
but just jump to ...

>  
>  	for (i = XE_PL_VRAM0; i <= XE_PL_VRAM1; ++i) {
> +		if (xe_device_is_admin_only(xe))
> +			break;
>  		man = ttm_manager_type(&xe->ttm, i);
>  		if (man) {
>  			mem_regions->mem_regions[mem_regions->num_mem_regions].mem_class =
> @@ -297,6 +302,9 @@ static int query_mem_regions(struct xe_device *xe,
>  		}
>  	}
>  
> +	if (xe_device_is_admin_only(xe))
> +		memset(mem_regions, 0, size);
> +

... here

>  	if (!copy_to_user(query_ptr, mem_regions, size))
>  		ret = 0;
>  	else