drm/xe: Force wedged state and block GT reset upon any GPU hang

In many validation situations when debugging GPU Hangs,
it is useful to preserve the GT situation from the moment
that the timeout occurred.

This patch introduces a module parameter that could be used
on situations like this.

If xe.wedged module parameter is set to 2, Xe will be declared
wedged on every single execution timeout (a.k.a. GPU hang) right
after devcoredump snapshot capture and without attempting any
kind of GT reset and blocking entirely any kind of execution.

v2: Really block gt_reset from guc side. (Lucas)
    s/wedged/busted (Lucas)

v3: - s/busted/wedged
    - Really use global_flags (Dafna)
    - More robust timeout handling when wedging it.

v4: A really robust clean exit done by Matt Brost.
    No more kernel warns on unbind.

v5: Simplify error message (Lucas)

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Dafna Hirschfeld <dhirschfeld@habana.ai>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Cc: Himanshu Somaiya <himanshu.somaiya@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240423221817.1285081-3-rodrigo.vivi@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_exec_queue.h b/drivers/gpu/drm/xe/xe_exec_queue.h
index 02ce8d204622..48f6da53a292 100644
--- a/drivers/gpu/drm/xe/xe_exec_queue.h
+++ b/drivers/gpu/drm/xe/xe_exec_queue.h
@@ -26,6 +26,15 @@ void xe_exec_queue_fini(struct xe_exec_queue *q);
 void xe_exec_queue_destroy(struct kref *ref);
 void xe_exec_queue_assign_name(struct xe_exec_queue *q, u32 instance);
 
+static inline struct xe_exec_queue *
+xe_exec_queue_get_unless_zero(struct xe_exec_queue *q)
+{
+	if (kref_get_unless_zero(&q->refcount))
+		return q;
+
+	return NULL;
+}
+
 struct xe_exec_queue *xe_exec_queue_lookup(struct xe_file *xef, u32 id);
 
 static inline struct xe_exec_queue *xe_exec_queue_get(struct xe_exec_queue *q)