Re: [RFC PATCH 6/6] [DO NOT REVIEW]]drm/xe/cri: Add sysfs interface for bad gpu vram pages

[Aravind Iddamsetty <aravind.iddamsetty@linux.intel.com>]

On 18-02-2026 06:07, Rodrigo Vivi wrote:
> On Fri, Feb 13, 2026 at 02:55:59PM +0530, Tejas Upadhyay wrote:
>> Starting CRI, Include a sysfs interface designed to expose information
>> about bad VRAM pages—those identified as having hardware faults
>> (e.g., ECC errors). This interface allows userspace tools and
>> administrators to monitor the health of the GPU's local memory and
>> track the status of page retirement.To get details on bad gpu vram
>> pages can be found under /sys/bus/pci/devices/bdf/vram_bad_pages.
>>
>> Where The format is, pfn : gpu page size : flags
>>
>> flags:
>> R: reserved, this gpu page is reserved.
>> P: pending for reserve, this gpu page is marked as bad, will be reserved in next window of page_reserve.
>> F: unable to reserve. this gpu page can’t be reserved due to some reasons.
>>
>> For example if you read using cat /sys/bus/pci/devices/bdf/vram_bad_pages,
>> 0x00000000 : 0x00001000 : R
>> 0x00001234 : 0x00001000 : P
> Riana, Raag, Aravind, a good new use case for the drm-ras no?!
> Thoughts?

In general the feature can be supported via drm-ras framework, but is
the motivation to move all error related info to drm-ras, also any gpu
hang data, health etc..,

Thanks,
Aravind.
>
>> Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
>> ---
>>  drivers/gpu/drm/xe/xe_device_sysfs.c |  2 +
>>  drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 78 ++++++++++++++++++++++++++++
>>  drivers/gpu/drm/xe/xe_ttm_vram_mgr.h |  1 +
>>  3 files changed, 81 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_device_sysfs.c b/drivers/gpu/drm/xe/xe_device_sysfs.c
>> index a73e0e957cb0..e6a017601428 100644
>> --- a/drivers/gpu/drm/xe/xe_device_sysfs.c
>> +++ b/drivers/gpu/drm/xe/xe_device_sysfs.c
>> @@ -14,6 +14,7 @@
>>  #include "xe_pcode_api.h"
>>  #include "xe_pcode.h"
>>  #include "xe_pm.h"
>> +#include "xe_ttm_vram_mgr.h"
>>  
>>  /**
>>   * DOC: Xe device sysfs
>> @@ -284,6 +285,7 @@ int xe_device_sysfs_init(struct xe_device *xe)
>>  		if (ret)
>>  			return ret;
>>  	}
>> +	xe_ttm_vram_sysfs_init(xe);
>>  
>>  	return 0;
>>  }
>> diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
>> index cb3394000e83..c6a81ccaa9d2 100644
>> --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
>> +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
>> @@ -744,3 +744,81 @@ int xe_ttm_tbo_handle_addr_fault(struct xe_tile *tile, unsigned long addr)
>>  	return ret;
>>  }
>>  EXPORT_SYMBOL(xe_ttm_tbo_handle_addr_fault);
>> +
>> +static void xe_ttm_vram_dump_bad_pages_info(char *buf, struct xe_ttm_vram_mgr *mgr)
>> +{
>> +	const unsigned int element_size = sizeof("0xabcdabcd : 0x12345678 : R\n") - 1;
>> +	struct xe_ttm_offline_resource *pos, *n;
>> +	struct drm_buddy_block *block;
>> +	ssize_t s = 0;
>> +
>> +	mutex_lock(&mgr->lock);
>> +	list_for_each_entry_safe(pos, n, &mgr->offlined_pages, offlined_link) {
>> +		block = list_first_entry(&pos->blocks,
>> +					 struct drm_buddy_block,
>> +					 link);
>> +		s += scnprintf(&buf[s], element_size + 1,
>> +			       "0x%08llx : 0x%08llx : %1s\n",
>> +			       drm_buddy_block_offset(block) >> PAGE_SHIFT,
>> +			       drm_buddy_block_size(&mgr->mm, block),
>> +			       "R");
>> +	}
>> +	list_for_each_entry_safe(pos, n, &mgr->queued_pages, queued_link) {
>> +		block = list_first_entry(&pos->blocks,
>> +					 struct drm_buddy_block,
>> +					 link);
>> +		s += scnprintf(&buf[s], element_size + 1,
>> +			       "0x%08llx : 0x%08llx : %1s\n",
>> +			       drm_buddy_block_offset(block) >> PAGE_SHIFT,
>> +			       drm_buddy_block_size(&mgr->mm, block),
>> +			       "P");
>> +	}
>> +	mutex_unlock(&mgr->lock);
>> +}
>> +
>> +static ssize_t vram_bad_pages_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);
>> +	struct ttm_resource_manager *man;
>> +	u8 mem_type = XE_PL_VRAM1;
>> +
>> +	do {
>> +		man = ttm_manager_type(&xe->ttm, mem_type);
>> +		struct xe_ttm_vram_mgr *mgr = to_xe_ttm_vram_mgr(man);
>> +
>> +		if (man)
>> +			xe_ttm_vram_dump_bad_pages_info(buf, mgr);
>> +		--mem_type;
>> +	} while (mem_type >= XE_PL_VRAM0);
>> +
>> +	return sysfs_emit(buf, "%s\n", buf);
>> +}
>> +static DEVICE_ATTR_RO(vram_bad_pages);
>> +
>> +static void xe_ttm_vram_sysfs_fini(void *arg)
>> +{
>> +	struct xe_device *xe = arg;
>> +
>> +	device_remove_file(xe->drm.dev, &dev_attr_vram_bad_pages);
>> +}
>> +
>> +/**
>> + * xe_ttm_vram_sysfs_init - Initialize vram sysfs component
>> + * @tile: Xe Tile object
>> + *
>> + * It needs to be initialized after the main tile component is ready
>> + *
>> + * Returns: 0 on success, negative error code on error.
>> + */
>> +int xe_ttm_vram_sysfs_init(struct xe_device *xe)
>> +{
>> +	int err;
>> +
>> +	err = device_create_file(xe->drm.dev, &dev_attr_vram_bad_pages);
>> +	if (err)
>> +		return 0;
>> +
>> +	return devm_add_action_or_reset(xe->drm.dev, xe_ttm_vram_sysfs_fini, xe);
>> +}
>> +EXPORT_SYMBOL(xe_ttm_vram_sysfs_init);
>> diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
>> index 5872e8b48779..6e69140c0be8 100644
>> --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
>> +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
>> @@ -34,6 +34,7 @@ void xe_ttm_vram_get_used(struct ttm_resource_manager *man,
>>  int xe_ttm_tbo_handle_addr_fault(struct xe_tile *tile, unsigned long addr);
>>  void xe_ttm_vram_dump_allocated_blocks(struct drm_device *dev, struct drm_buddy *mm,
>>  				       struct drm_printer *p);
>> +int xe_ttm_vram_sysfs_init(struct xe_device *xe);
>>  static inline struct xe_ttm_vram_mgr_resource *
>>  to_xe_ttm_vram_mgr_resource(struct ttm_resource *res)
>>  {
>> -- 
>> 2.52.0
>>