[v7,0/6] drm/xe/xe_vm: Implement xe_vm_get_faults_ioctl

Message

Cavitt, Jonathan March 10, 2025, 5:18 p.m. UTC

Add additional information to each VM so they can report up to the last
50 seen pagefaults.  Only failed pagefaults are saved this way, as
successful pagefaults should recover and not need to be reported to
userspace.

Additionally, add a new ioctl - xe_vm_get_faults_ioctl - that allows the
user to query these pagefaults

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)

Signed-off-by: Jonathan Cavitt <[e-mail]>
Suggested-by: Joonas Lahtinen <[e-mail]>
Suggested-by: Matthew Brost <[e-mail]>
CC: Zhang Jianxun <[e-mail]>
CC: Shuicheng Lin <[e-mail]>

Jonathan Cavitt (6):
  drm/xe/xe_gt_pagefault: Disallow writes to read-only VMAs
  drm/xe/xe_gt_pagefault: Migrate pagefault struct to header
  drm/xe/xe_vm: Add per VM pagefault info
  drm/xe/uapi: Define drm_xe_vm_get_faults
  drm/xe/xe_gt_pagefault: Add address_type field to pagefaults
  drm/xe/xe_vm: Implement xe_vm_get_faults_ioctl

 drivers/gpu/drm/xe/xe_device.c       |   3 +
 drivers/gpu/drm/xe/xe_gt_pagefault.c |  76 +++++++++--------
 drivers/gpu/drm/xe/xe_gt_pagefault.h |  29 +++++++
 drivers/gpu/drm/xe/xe_vm.c           | 119 +++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_vm.h           |   8 ++
 drivers/gpu/drm/xe/xe_vm_types.h     |  20 +++++
 include/uapi/drm/xe_drm.h            |  49 +++++++++++
 7 files changed, 271 insertions(+), 33 deletions(-)