[Intel-gfx] [PATCH 13/27] drm/i915/guc: Ensure GuC schedule operations do not operate on child contexts

Matthew Brost
2021-08-20T22:51:15Z

In GuC parent-child contexts the parent context controls the scheduling,
ensure only the parent does the scheduling operations.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 24 ++++++++++++++-----
1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index dbcb9ab28a9a..00d54bb00bfb 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -320,6 +320,12 @@ static void decr_context_committed_requests(struct intel_context *ce)
GEM_BUG_ON(ce->guc_state.number_committed_requests < 0);
}

+static struct intel_context *
+request_to_scheduling_context(struct i915_request *rq)
+{
+ return intel_context_to_parent(rq->context);
+}
+
static bool context_guc_id_invalid(struct intel_context *ce)
{
return ce->guc_id.id == GUC_INVALID_LRC_ID;
@@ -1684,6 +1690,7 @@ static void __guc_context_sched_disable(struct intel_guc *guc,

GEM_BUG_ON(guc_id == GUC_INVALID_LRC_ID);

+ GEM_BUG_ON(intel_context_is_child(ce));
trace_intel_context_sched_disable(ce);

guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action),
@@ -1898,6 +1905,8 @@ static void guc_context_sched_disable(struct intel_context *ce)
u16 guc_id;
bool enabled;

+ GEM_BUG_ON(intel_context_is_child(ce));
+
if (submission_disabled(guc) || context_guc_id_invalid(ce) ||
!lrc_desc_registered(guc, ce->guc_id.id)) {
spin_lock_irqsave(&ce->guc_state.lock, flags);
@@ -2286,6 +2295,8 @@ static void guc_signal_context_fence(struct intel_context *ce)
{
unsigned long flags;

+ GEM_BUG_ON(intel_context_is_child(ce));
+
spin_lock_irqsave(&ce->guc_state.lock, flags);
clr_context_wait_for_deregister_to_register(ce);
__guc_signal_context_fence(ce);
@@ -2315,7 +2326,7 @@ static void guc_context_init(struct intel_context *ce)

static int guc_request_alloc(struct i915_request *rq)
{
- struct intel_context *ce = rq->context;
+ struct intel_context *ce = request_to_scheduling_context(rq);
struct intel_guc *guc = ce_to_guc(ce);
unsigned long flags;
int ret;
@@ -2358,11 +2369,12 @@ static int guc_request_alloc(struct i915_request *rq)
* exhausted and return -EAGAIN to the user indicating that they can try
* again in the future.
*
- * There is no need for a lock here as the timeline mutex ensures at
- * most one context can be executing this code path at once. The
- * guc_id_ref is incremented once for every request in flight and
- * decremented on each retire. When it is zero, a lock around the
- * increment (in pin_guc_id) is needed to seal a race with unpin_guc_id.
+ * There is no need for a lock here as the timeline mutex (or
+ * parallel_submit mutex in the case of multi-lrc) ensures at most one
+ * context can be executing this code path at once. The guc_id_ref is
+ * incremented once for every request in flight and decremented on each
+ * retire. When it is zero, a lock around the increment (in pin_guc_id)
+ * is needed to seal a race with unpin_guc_id.
*/
if (atomic_add_unless(&ce->guc_id.ref, 1, 0))
goto out;
--
2.32.0