Re: [PATCH v2 2/2] drm/xe/cri: Expose device UID through sysfs

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

On 9/10/2026 2:41 PM, Badal Nilawar wrote:
> Expose a read-only sysfs attribute, device_uid, that reports the
> GPU's unique hardware identifier.
> 

still no Bspec references

> Assisted-by: Claude:claude-opus-4.8
> Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
> ---
> v2:
>   - add has flag instead of platform check to determin uid support (Anshuman)
>   - Fix the DOC: section (Michal)
>   - %s/_uuid/uid (Joonas)
> ---
>  .../ABI/testing/sysfs-driver-intel-xe-gpu     | 10 ++++++
>  drivers/gpu/drm/xe/regs/xe_regs.h             |  2 ++
>  drivers/gpu/drm/xe/xe_device.c                |  4 +++
>  drivers/gpu/drm/xe/xe_device_sysfs.c          | 36 +++++++++++++++++++
>  drivers/gpu/drm/xe/xe_device_types.h          |  5 +++
>  drivers/gpu/drm/xe/xe_pci.c                   |  2 ++
>  drivers/gpu/drm/xe/xe_pci_types.h             |  1 +
>  7 files changed, 60 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-driver-intel-xe-gpu
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-xe-gpu b/Documentation/ABI/testing/sysfs-driver-intel-xe-gpu
> new file mode 100644
> index 000000000000..36182bbb1b54
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-intel-xe-gpu
> @@ -0,0 +1,10 @@
> +What:		/sys/bus/pci/drivers/xe/.../device_uid
> +Date:		September 2026
> +KernelVersion:	7.4
> +Contact:	intel-xe@lists.freedesktop.org
> +Description:
> +		RO. Unique 64-bit identifier of the GPU device, exposed as
> +		hexadecimal value.
> +
> +		This sysfs file is present only on Intel Xe platforms that
> +		provide a device UID. It is available to all users.
> diff --git a/drivers/gpu/drm/xe/regs/xe_regs.h b/drivers/gpu/drm/xe/regs/xe_regs.h
> index ef4746b7b5d3..437485b5a0af 100644
> --- a/drivers/gpu/drm/xe/regs/xe_regs.h
> +++ b/drivers/gpu/drm/xe/regs/xe_regs.h
> @@ -30,6 +30,8 @@
>  #define XEHP_MTCFG_ADDR				XE_REG(0x101800)
>  #define   TILE_COUNT				REG_GENMASK(15, 8)
>  
> +#define CRI_DEVICE_UID				XE_REG(0x102008)
> +
>  #define GGC					XE_REG(0x108040)
>  #define   GMS_MASK				REG_GENMASK(15, 8)
>  #define   GGMS_MASK				REG_GENMASK(7, 6)
> diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
> index 205cb4e7f9e8..99f6d4184b79 100644
> --- a/drivers/gpu/drm/xe/xe_device.c
> +++ b/drivers/gpu/drm/xe/xe_device.c
> @@ -671,6 +671,7 @@ static void vf_update_device_info(struct xe_device *xe)
>  	xe->info.skip_guc_pc = 1;
>  	xe->info.skip_pcode = 1;
>  	xe->info.has_drm_ras = false;
> +	xe->info.has_device_uid = false;
>  }
>  
>  static int xe_device_vram_alloc(struct xe_device *xe)
> @@ -878,6 +879,9 @@ int xe_device_probe(struct xe_device *xe)
>  	int err;
>  	u8 id;
>  
> +	if (xe->info.has_device_uid)
> +		xe->device_uid = xe_mmio_read64_2x32(xe_root_tile_mmio(xe), CRI_DEVICE_UID);

avoid low-level code in top level function, use some helper for this:

	xe_probe_uid(xe);

> +
>  	xe_pat_init_early(xe);
>  
>  	err = xe_sriov_init(xe);
> diff --git a/drivers/gpu/drm/xe/xe_device_sysfs.c b/drivers/gpu/drm/xe/xe_device_sysfs.c
> index a73e0e957cb0..657742c22d90 100644
> --- a/drivers/gpu/drm/xe/xe_device_sysfs.c
> +++ b/drivers/gpu/drm/xe/xe_device_sysfs.c
> @@ -8,6 +8,7 @@
>  #include <linux/pci.h>
>  #include <linux/sysfs.h>
>  
> +#include "regs/xe_regs.h"
>  #include "xe_device.h"
>  #include "xe_device_sysfs.h"
>  #include "xe_mmio.h"
> @@ -264,6 +265,35 @@ static const struct attribute_group auto_link_downgrade_attr_group = {
>  	.attrs = auto_link_downgrade_attrs,
>  };
>  
> +/**
> + * DOC: device_uid

	DOC: Device Unique ID

> + *
> + * On supported platforms, Xe devices expose a unique 64-bit GPU SOC
> + * identifier through the 'device_uid' sysfs entry.
> + *
> + * See Documentation/ABI/testing/sysfs-driver-intel-xe-gpu for the ABI
> + * specification.
> + */
> +
> +static ssize_t
> +device_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct xe_device *xe = pdev_to_xe_device(pdev);
> +
> +	return sysfs_emit(buf, "%016llx\n", xe->device_uid);

no 0x prefix?

> +}
> +static DEVICE_ATTR_RO(device_uid);
> +
> +static struct attribute *device_uid_attrs[] = {
> +	&dev_attr_device_uid.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group device_uid_attr_group = {
> +	.attrs = device_uid_attrs,
> +};
> +
>  int xe_device_sysfs_init(struct xe_device *xe)
>  {
>  	struct device *dev = xe->drm.dev;
> @@ -285,5 +315,11 @@ int xe_device_sysfs_init(struct xe_device *xe)
>  			return ret;
>  	}
>  
> +	if (xe->info.has_device_uid) {
> +		ret = devm_device_add_group(dev, &device_uid_attr_group);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index f88bacf63c83..65366e8173c9 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -174,6 +174,8 @@ struct xe_device {
>  		u8 has_cached_pt:1;
>  		/** @info.has_device_atomics_on_smem: Supports device atomics on SMEM */
>  		u8 has_device_atomics_on_smem:1;
> +		/** @info.has_device_uid: Device supports unique 64-bit GPU SOC ID */
> +		u8 has_device_uid:1;
>  		/** @info.has_drm_ras: Device supports drm_ras (Reliability, Availability, Serviceability) */
>  		u8 has_drm_ras:1;
>  		/** @info.has_fan_control: Device supports fan control */
> @@ -258,6 +260,9 @@ struct xe_device {
>  		bool oob_initialized;
>  	} wa_active;
>  
> +	/** @device_uid: unique 64-bit GPU SOC identifier */
> +	u64 device_uid;
> +
>  	/** @survivability: survivability information for device */
>  	struct xe_survivability survivability;
>  
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index ab4da1d9a9f1..2900f18c7b4c 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -471,6 +471,7 @@ static const struct xe_device_desc cri_desc = {
>  	PLATFORM(CRESCENTISLAND),
>  	.dma_mask_size = 52,
>  	.has_display = false,
> +	.has_device_uid = true,
>  	.has_drm_ras = true,
>  	.has_flat_ccs = false,
>  	.has_gsc_nvm = 1,
> @@ -793,6 +794,7 @@ static int xe_info_init_early(struct xe_device *xe,
>  
>  	xe->info.is_dgfx = desc->is_dgfx;
>  	xe->info.has_cached_pt = desc->has_cached_pt;
> +	xe->info.has_device_uid = desc->has_device_uid;
>  	xe->info.has_drm_ras = desc->has_drm_ras;
>  	xe->info.has_fan_control = desc->has_fan_control;
>  	/* runtime fusing may force flat_ccs to disabled later */
> diff --git a/drivers/gpu/drm/xe/xe_pci_types.h b/drivers/gpu/drm/xe/xe_pci_types.h
> index fed509ff601e..fe327323a0be 100644
> --- a/drivers/gpu/drm/xe/xe_pci_types.h
> +++ b/drivers/gpu/drm/xe/xe_pci_types.h
> @@ -40,6 +40,7 @@ struct xe_device_desc {
>  
>  	u8 has_cached_pt:1;
>  	u8 has_display:1;
> +	u8 has_device_uid:1;
>  	u8 has_drm_ras:1;
>  	u8 has_fan_control:1;
>  	u8 has_flat_ccs:1;