Re: [PATCH v29 0/5] drm/xe/xe_vm: Implement xe_vm_get_property_ioctl

[Matthew Brost <matthew.brost@intel.com>]

On Tue, Dec 02, 2025 at 06:46:37PM +0000, Jonathan Cavitt wrote:
> Add additional information to each VM so they can report up to the first
> 50 seen faults.  Only pagefaults are saved this way currently, though in
> the future, all faults should be tracked by the VM for future reporting.
> 
> Additionally, of the pagefaults reported, only failed pagefaults are
> saved this way, as successful pagefaults should recover silently and not
> need to be reported to userspace.
> 
> To allow userspace to access these faults, a new ioctl -
> xe_vm_get_property_ioct - was created.
> 

Do we have a Mesa PR for this series? We will need one before merging +
Mesa ack for the uAPI patch. If any other UMD plan on using this, we
will an ack from them too.

Matt

> v2: (Matt Brost)
> - Break full ban list request into a separate property.
> - Reformat drm_xe_vm_get_property struct.
> - Remove need for drm_xe_faults helper struct.
> - Separate data pointer and scalar return value in ioctl.
> - Get address type on pagefault report and save it to the pagefault.
> - Correctly reject writes to read-only VMAs.
> - Miscellaneous formatting fixes.
> 
> v3: (Matt Brost)
> - Only allow querying of failed pagefaults
> 
> v4:
> - Remove unnecessary size parameter from helper function, as it
>   is a property of the arguments. (jcavitt)
> - Remove unnecessary copy_from_user (Jainxun)
> - Set address_precision to 1 (Jainxun)
> - Report max size instead of dynamic size for memory allocation
>   purposes.  Total memory usage is reported separately.
> 
> v5:
> - Return int from xe_vm_get_property_size (Shuicheng)
> - Fix memory leak (Shuicheng)
> - Remove unnecessary size variable (jcavitt)
> 
> v6:
> - Free vm after use (Shuicheng)
> - Compress pf copy logic (Shuicheng)
> - Update fault_unsuccessful before storing (Shuicheng)
> - Fix old struct name in comments (Shuicheng)
> - Keep first 50 pagefaults instead of last 50 (Jianxun)
> - Rename ioctl to xe_vm_get_faults_ioctl (jcavitt)
> 
> v7:
> - Avoid unnecessary execution by checking MAX_PFS earlier (jcavitt)
> - Fix double-locking error (jcavitt)
> - Assert kmemdump is successful (Shuicheng)
> - Repair and move fill_faults break condition (Dan Carpenter)
> - Free vm after use (jcavitt)
> - Combine assertions (jcavitt)
> - Expand size check in xe_vm_get_faults_ioctl (jcavitt)
> - Remove return mask from fill_faults, as return is already -EFAULT or 0
>   (jcavitt)
> 
> v8:
> - Revert back to using drm_xe_vm_get_property_ioctl
> - s/Migrate/Move (Michal)
> - s/xe_pagefault/xe_gt_pagefault (Michal)
> - Create new header file, xe_gt_pagefault_types.h (Michal)
> - Add and fix kernel docs (Michal)
> - Rename xe_vm.pfs to xe_vm.faults (jcavitt)
> - Store fault data and not pagefault in xe_vm faults list (jcavitt)
> - Store address, address type, and address precision per fault (jcavitt)
> - Store engine class and instance data per fault (Jianxun)
> - Properly handle kzalloc error (Michal W)
> - s/MAX_PFS/MAX_FAULTS_SAVED_PER_VM (Michal W)
> - Store fault level per fault (Micahl M)
> - Apply better copy_to_user logic (jcavitt)
> 
> v9:
> - More kernel doc fixes (Michal W, Jianxun)
> - Better error handling (jcavitt)
> 
> v10:
> - Convert enums to defines in regs folder (Michal W)
> - Move xe_guc_pagefault_desc to regs folder (Michal W)
> - Future-proof size logic for zero-size properties (jcavitt)
> - Replace address type extern with access type (Jianxun)
> - Add fault type to xe_drm_fault (Jianxun)
> 
> v11:
> - Remove unnecessary switch case logic (Raag)
> - Compress size get, size validation, and property fill functions into a
>   single helper function (jcavitt)
> - Assert valid size (jcavitt)
> - Store pagefaults in non-fault-mode VMs as well (Jianxun)
> 
> v12:
> - Remove unnecessary else condition
> - Correct backwards helper function size logic (jcavitt)
> - Fix kernel docs and comments (Michal W)
> 
> v13:
> - Move xe and user engine class mapping arrays to header (John H)
> 
> v14:
> - Fix double locking issue (Jianxun)
> - Use size_t instead of int (Raag)
> - Remove unnecessary includes (jcavitt)
> 
> v15:
> - Do not report faults from reserved engines (Jianxun)
> 
> v16:
> - Remove engine class and instance (Ivan)
> 
> v17:
> - Map access type, fault type, and fault level to user macros (Matt
>   Brost, Ivan)
> 
> v18:
> - Add uAPI merge request to this cover letter
> 
> v19:
> - Perform kzalloc outside of lock (Auld)
> 
> v20:
> - Fix inconsistent use of whitespace in defines
> 
> v21:
> - Remove unnecessary size assertion (jcavitt)
> 
> v22:
> - Fix xe_vm_fault_entry kernel docs (Shuicheng)
> 
> v23:
> - Nit fixes (Matt Brost)
> 
> v24:
> - s/xe_pagefault_desc.h/xe_guc_pagefault_desc.h (Dafna)
> - Move PF_MSG_LEN_DW to regs folder (Dafna)
> 
> v25:
> - Revert changes from last revision (John H)
> - Add missing bspec (Michal W)
> 
> v26:
> - Rebase and refactor on top of latest change to xe_pagefault layer
>   (jcavitt)
> 
> v27:
> - Apply max line length (Matt Brost)
> - Correctly ignore fault mode in save_pagefault_to_vm (jcavitt)
> 
> v28:
> - Do not copy_to_user in critical section (Matt Brost)
> - Assert args->size is multiple of sizeof(struct xe_vm_fault) (Matt
>   Brost)
> - s/save_pagefault_to_vm/xe_pagefault_save_to_vm (Matt Brost)
> - Use guard instead of spin_lock/unlock (Matt Brost)
> - GT was added to xe_pagefault struct.  Use xe_gt_hw_engine
>   instead of creating a new helper function (Matt Brost)
> 
> v29:
> - Track address precision separately and report it accurately (Matt
>   Brost)
> - Remove unnecessary memset (Matt Brost)
> 
> uAPI: TBD
> Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
> Suggested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Suggested-by: Matthew Brost <matthew.brost@intel.com>
> Cc: Zhang Jianxun <jianxun.zhang@intel.com>
> Cc: Shuicheng Lin <shuicheng.lin@intel.com>
> Cc: Michal Wajdeczko <Michal.Wajdeczko@intel.com>
> Cc: Michal Mrozek <michal.mrozek@intel.com>
> Cc: Raag Jadav <raag.jadav@intel.com>
> Cc: John Harrison <john.c.harrison@intel.com>
> Cc: Ivan Briano <ivan.briano@intel.com>
> Cc: Matthew Auld <matthew.auld@intel.com>
> Cc: Dafna Hirschfeld <dafna.hirschfeld@intel.com>
> 
> Jonathan Cavitt (5):
>   drm/xe/xe_pagefault: Disallow writes to read-only VMAs
>   drm/xe/xe_pagefault: Track address precision per pagefault
>   drm/xe/uapi: Define drm_xe_vm_get_property
>   drm/xe/xe_vm: Add per VM fault info
>   drm/xe/xe_vm: Implement xe_vm_get_property_ioctl
> 
>  drivers/gpu/drm/xe/xe_device.c          |   2 +
>  drivers/gpu/drm/xe/xe_guc_pagefault.c   |   1 +
>  drivers/gpu/drm/xe/xe_pagefault.c       |  34 +++++
>  drivers/gpu/drm/xe/xe_pagefault_types.h |   8 +-
>  drivers/gpu/drm/xe/xe_vm.c              | 184 ++++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_vm.h              |  12 ++
>  drivers/gpu/drm/xe/xe_vm_types.h        |  29 ++++
>  include/uapi/drm/xe_drm.h               |  86 +++++++++++
>  8 files changed, 355 insertions(+), 1 deletion(-)
> 
> -- 
> 2.43.0
>