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

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

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?

> 
> 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
>