drm/xe: Rework rebinding in preparation for same-vm eviction

We are not allowing eviction / shrinking of completely unbound local objects during exec and rebind worker.
Since unbinding is the UMD primary means of
freeing up memory on local VM overcommit situations, this needs to be addressed.

Such funtionality will also open up the possibility to evict purgeable local objects with upcoming changes.

To make this work properly, rebinding needs to be moved to the while-not-all-locked drm-exec loop, since rebinding may allocate gpu page table bos and thus cause evictions which forces us to re-run validation.

This is done in patch 4, but when crafting that patch, a number couple of rebinding flaws were discovered.

1) When saving the rebinding fence we always presumed the rebinding fences were ordered. That is not true, and is fixed in patch 2, where we attach the rebind fences as kernel fences to the vm's resv.
2) In fact, TLB invalidation fences may currently not be assumed to be ordered at all. This is fixed in patch 3.
3) The combination of fixes for 1) and 2) makes the rebind of each vma wait for the TLB invalidation of the previous rebind, which is unnecessary and would incur unneeded latency. This is fixed in patch 1 where we move rebind TLB invalidation to the ring ops.

v2:
- Simplify if-statements around the tlb_flush_seqno. (Matthew Brost)
- Add some comments and asserts.
- Remove a leftover call to xe_vm_rebind() (Matt Brost)
- Add a helper function xe_vm_validate_rebind() (Matt Brost)
- Rebasing
v3:
- Only include the patches that reworks rebinding and includes it in the drm_exec locking loop, since the patches that dealt with same-vm eviction allowed page-table allocation to evict the object being bound, and while this was addressed properly during exec and rebind worker, it was not during the VM_BIND ioctl.
- Squash the patches moving fence reservation and moving rebinding into the locking loop since the code was not properly working in between those patches. (Matt Brost)
- Add code comments (Matt Brost)

Thomas Hellström (4):
drm/xe: Use ring ops TLB invalidation for rebinds drm/xe: Rework rebinding
drm/xe: Make TLB invalidation fences unordered drm/xe: Move vma rebinding to the drm_exec locking loop

 drivers/gpu/drm/xe/xe_exec.c                |  79 ++------------
 drivers/gpu/drm/xe/xe_exec_queue_types.h    |   5 +
 drivers/gpu/drm/xe/xe_gt_pagefault.c        |   3 +-
 drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c |   1 -
 drivers/gpu/drm/xe/xe_gt_types.h            |   7 --
 drivers/gpu/drm/xe/xe_pt.c                  |  25 ++++-
 drivers/gpu/drm/xe/xe_ring_ops.c            |  11 +-
 drivers/gpu/drm/xe/xe_sched_job.c           |  10 ++
 drivers/gpu/drm/xe/xe_sched_job_types.h     |   2 +
 drivers/gpu/drm/xe/xe_vm.c                  | 110 ++++++++++++--------
 drivers/gpu/drm/xe/xe_vm.h                  |   8 +-
 drivers/gpu/drm/xe/xe_vm_types.h            |   8 +-
 12 files changed, 126 insertions(+), 143 deletions(-)

2.44.0