drm/xe: Make bind engines safe

We currently have a race between bind engines which can result in
corrupted page tables leading to faults.

A simple example:
bind A 0x0000-0x1000, engine A, has unsatisfied in-fence
bind B 0x1000-0x2000, engine B, no in-fences
exec A uses 0x1000-0x2000

Bind B will pass bind A and exec A will fault. This occurs as bind A
programs the root of the page table in a bind job which is held up by an
in-fence. Bind B in this case just programs a leaf entry of the
structure.

To fix use range-fence utility to track cross bind engine conflicts. In
the above example bind A would insert an dependency into the range-fence
tree with a key of 0x0-0x7fffffffff, bind B would find that dependency
and its bind job would scheduled behind the unsatisfied in-fence and
bind A's job.

Reviewed-by: Maarten Lankhorst<maarten.lankhorst@linux.intel.com>
Co-developed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_migrate.h b/drivers/gpu/drm/xe/xe_migrate.h
index 204337ea3b4e..0d62aff6421c 100644
--- a/drivers/gpu/drm/xe/xe_migrate.h
+++ b/drivers/gpu/drm/xe/xe_migrate.h
@@ -69,6 +69,14 @@ struct xe_migrate_pt_update {
 	const struct xe_migrate_pt_update_ops *ops;
 	/** @vma: The vma we're updating the pagetable for. */
 	struct xe_vma *vma;
+	/** @job: The job if a GPU page-table update. NULL otherwise */
+	struct xe_sched_job *job;
+	/** @start: Start of update for the range fence */
+	u64 start;
+	/** @last: Last of update for the range fence */
+	u64 last;
+	/** @tile_id: Tile ID of the update */
+	u8 tile_id;
 };
 
 struct xe_migrate *xe_migrate_init(struct xe_tile *tile);