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 Sun, Feb 22, 2026 at 11:02:25AM +0530, Aravind Iddamsetty wrote:
> 
> On 20-02-2026 20:22, Vivi, Rodrigo wrote:
> > On Fri, 2026-02-20 at 16:48 +0530, Aravind Iddamsetty wrote:
> >> 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..,
> > No, the motivation is not to move everything there.
> > I was thinking on the lines of avoiding sysfs. But well, it is only
> > one sysfs and I don't believe we would need any notification upon
> > new pages marked as bad, or do we?
> 
> I do not see a requirement to have any additional notification, as there
> would already be a notification for an uncorrectable error.

Fair enough then

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

on continuing with this sysfs entry for this case.

> 
> Thanks,
> Aravind.
> >
> > If we need notifications then sysfs is bad choice and netlink could
> > provide info and notification in a single place.
> >
> >> 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
> >>>>