[PATCH i-g-t 0/4] xe: watch queue event support and VM restart recovery

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

This series adds IGT support for two new Xe kernel interfaces: the watch
queue event notification mechanism and the VM restart IOCTL.

The watch queue allows a userspace process to subscribe to device-scoped
events delivered through a pipe — notably VM errors caused by memory
pressure.  The VM restart IOCTL lets userspace synchronously trigger a
re-run of the preempt-rebind worker to recover a VM after such an error.

Together they enable a fault-tolerance loop: a listener thread receives
VM error events carrying an error code and VM id; when the error is
-ENOMEM or -ENOSPC the test can immediately attempt to restart the
affected VM rather than letting it stay faulted.

The xe_exec_compute_mode test is extended to demonstrate this: it
subscribes to file events at fixture time, logs all notifications, and
automatically calls VM restart on memory-pressure errors.

Thomas Hellström (4):
  lib/xe: add xe_vm_restart ioctl helper
  lib/xe: add xe_watch listener for watch queue events
  tests/intel/xe_exec_compute_mode: Add a listener for file events
  tests/intel/xe_exec_compute_mode: Restart VM on ENOMEM/ENOSPC errors

 include/drm-uapi/xe_drm.h          |  84 +++++++++++
 include/drm-uapi/xe_drm_events.h   |  71 +++++++++
 lib/meson.build                    |   1 +
 lib/xe/xe_ioctl.c                  |  44 ++++++
 lib/xe/xe_ioctl.h                  |   2 +
 lib/xe/xe_watch.c                  | 221 +++++++++++++++++++++++++++++
 lib/xe/xe_watch.h                  |  80 +++++++++++
 tests/intel/xe_exec_compute_mode.c |  92 +++++++++++-
 8 files changed, 591 insertions(+), 4 deletions(-)
 create mode 100644 include/drm-uapi/xe_drm_events.h
 create mode 100644 lib/xe/xe_watch.c
 create mode 100644 lib/xe/xe_watch.h

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2.54.0