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

["Nilawar, Badal" <badal.nilawar@intel.com>]

On 04-09-2026 22:07, Michal Wajdeczko wrote:
>
> On 9/4/2026 6:06 PM, Badal Nilawar wrote:
>> Expose a read-only sysfs attribute, device_uuid, that reports the
>> GPU's unique hardware identifier.
>>
> Bspec: 53048,53049
Sure
>
>> Assisted-by: Claude:claude-opus-4.8
>> Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
>> ---
>>   .../ABI/testing/sysfs-driver-intel-xe-gpu     | 10 ++++++
>>   drivers/gpu/drm/xe/regs/xe_regs.h             |  2 ++
>>   drivers/gpu/drm/xe/xe_device.c                |  3 ++
>>   drivers/gpu/drm/xe/xe_device_sysfs.c          | 36 +++++++++++++++++++
>>   drivers/gpu/drm/xe/xe_device_types.h          |  3 ++
>>   5 files changed, 54 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..1a4bdfbad8d7
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-driver-intel-xe-gpu
>> @@ -0,0 +1,10 @@
>> +What:		/sys/bus/pci/drivers/xe/.../device_uuid
>> +Date:		September 2026
>> +KernelVersion:	7.4
>> +Contact:	intel-xe@lists.freedesktop.org
>> +Description:	RO. Unique 64-bit identifier of the device instance, read from
>> +		the device's CRI_DEVICE_UUID register and printed as a
> hmm, maybe in the user facing documentation we should refer to this register as
>
> 	DEVICE_UUID(102008)
>
> instead of the meaningless macro name?
I will drop "read from ..." statement.
>
>> +		zero-padded 16-digit hexadecimal string.
> if this is UUID, shouldn't we print it in UUID format? see %pU
I this is not UUID, i will rename the node as device_uid.
>
>> +
>> +		This sysfs file is present only on Intel Xe platforms that
>> +		provide a device UUID. 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..68226fe0b659 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_UUID				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 8583b2e9ecf4..e8db8871990b 100644
>> --- a/drivers/gpu/drm/xe/xe_device.c
>> +++ b/drivers/gpu/drm/xe/xe_device.c
>> @@ -801,6 +801,9 @@ int xe_device_probe_early(struct xe_device *xe)
>>   	if (IS_SRIOV_VF(xe))
>>   		vf_update_device_info(xe);
>>   
>> +	if (xe->info.platform == XE_CRESCENTISLAND)
>> +		xe->device_uuid = xe_mmio_read64_2x32(xe_root_tile_mmio(xe), CRI_DEVICE_UUID);
>> +
>>   	/*
>>   	 * Check for pcode uncore_init status to confirm if the SoC
>>   	 * initialization is complete. Until done, any MMIO or lmem access from
>> diff --git a/drivers/gpu/drm/xe/xe_device_sysfs.c b/drivers/gpu/drm/xe/xe_device_sysfs.c
>> index a73e0e957cb0..a4d326159dce 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_uuid
> do we need this?
> you already described that in Documentation/ABI
I think I will drop the Documentation/ABI and keep DOC: section.
>
>> + *
>> + * Each Xe device exposes a 64-bit UUID that uniquely identifies the SoC.
>> + * The value is read from the CRI_DEVICE_UUID register and can be
>> + * read back through the ``device_uuid`` sysfs entry.
>> + *
>> + *    $ cat /sys/bus/pci/devices/<bdf>/device_uuid
>> + */
>> +
>> +static ssize_t
>> +device_uuid_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_uuid);
> %pU ?
Not needed.
>
>> +}
>> +static DEVICE_ATTR_RO(device_uuid);
>> +
>> +static struct attribute *device_uuid_attrs[] = {
>> +	&dev_attr_device_uuid.attr,
>> +	NULL
>> +};
>> +
>> +static const struct attribute_group device_uuid_attr_group = {
>> +	.attrs = device_uuid_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.platform == XE_CRESCENTISLAND) {
> use .is_visible instead

Will add has flag.

Thanks,
Badal

>
>> +		ret = devm_device_add_group(dev, &device_uuid_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 180d450a6deb..6fdd16eac906 100644
>> --- a/drivers/gpu/drm/xe/xe_device_types.h
>> +++ b/drivers/gpu/drm/xe/xe_device_types.h
>> @@ -257,6 +257,9 @@ struct xe_device {
>>   		bool oob_initialized;
>>   	} wa_active;
>>   
>> +	/** @device_uuid: unique 64-bit identifier read from CRI_DEVICE_UUID */
>> +	u64 device_uuid;
>> +
>>   	/** @survivability: survivability information for device */
>>   	struct xe_survivability survivability;
>>