drm/xe: Implement VM snapshot support for BO's and userptr

Since we cannot immediately capture the BO's and userptr, perform it in
2 stages. The immediate stage takes a reference to each BO and userptr,
while a delayed worker captures the contents and then frees the
reference.

This is required because in signaling context, no locks can be taken, no
memory can be allocated, and no waits on userspace can be performed.

With the delayed worker, all of this can be performed very easily,
without having to resort to hacks.

Changes since v1:
- Fix crash on NULL captured vm.
- Use ascii85_encode to capture BO contents and save some space.
- Add length to coredump output for each captured area.
Changes since v2:
- Dump each mapping on their own line, to simplify tooling.
- Fix null pointer deref in xe_vm_snapshot_free.
Changes since v3:
- Don't add uninitialized value to snap->ofs. (Souza)
- Use kernel types for u32 and u64.
- Move snap_mutex destruction to final vm destruction. (Souza)
Changes since v4:
- Remove extra memset. (Souza)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240221133024.898315-6-maarten.lankhorst@linux.intel.com

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_devcoredump_types.h b/drivers/gpu/drm/xe/xe_devcoredump_types.h
index d259119b2c98..6f654b63c7f1 100644
--- a/drivers/gpu/drm/xe/xe_devcoredump_types.h
+++ b/drivers/gpu/drm/xe/xe_devcoredump_types.h
@@ -12,6 +12,7 @@
 #include "xe_hw_engine_types.h"
 
 struct xe_device;
+struct xe_gt;
 
 /**
  * struct xe_devcoredump_snapshot - Crash snapshot
@@ -26,6 +27,11 @@ struct xe_devcoredump_snapshot {
 	/** @boot_time:  Relative boot time so the uptime can be calculated. */
 	ktime_t boot_time;
 
+	/** @gt: Affected GT, used by forcewake for delayed capture */
+	struct xe_gt *gt;
+	/** @work: Workqueue for deferred capture outside of signaling context */
+	struct work_struct work;
+
 	/* GuC snapshots */
 	/** @ct: GuC CT snapshot */
 	struct xe_guc_ct_snapshot *ct;
@@ -36,6 +42,8 @@ struct xe_devcoredump_snapshot {
 	struct xe_hw_engine_snapshot *hwe[XE_NUM_HW_ENGINES];
 	/** @job: Snapshot of job state */
 	struct xe_sched_job_snapshot *job;
+	/** @vm: Snapshot of VM state */
+	struct xe_vm_snapshot *vm;
 };
 
 /**