drm/i915/gt: Discard stale context state from across idling

Before we idle, on parking, we switch to the kernel context such that we
have a scratch context loaded while the GPU idle, protecting any
precious user state. Be paranoid and assume that the idle state may have
been trashed, and reset the kernel_context image after idling.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200102131707.1463945-4-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index cd82f0b..1b9f739 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -20,6 +20,7 @@ static int __engine_unpark(struct intel_wakeref *wf)
 {
        struct intel_engine_cs *engine =
                container_of(wf, typeof(*engine), wakeref);
+       struct intel_context *ce;
        void *map;
 
        ENGINE_TRACE(engine, "\n");
@@ -34,6 +35,11 @@ static int __engine_unpark(struct intel_wakeref *wf)
        if (!IS_ERR_OR_NULL(map))
                engine->pinned_default_state = map;
 
+       /* Discard stale context state from across idling */
+       ce = engine->kernel_context;
+       if (ce)
+               ce->ops->reset(ce);
+
        if (engine->unpark)
                engine->unpark(engine);
 

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index 9b220c9..d1c2f03 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -213,16 +213,8 @@ int intel_gt_resume(struct intel_gt *gt)
        intel_llc_enable(&gt->llc);
 
        for_each_engine(engine, gt, id) {
-               struct intel_context *ce;
-
                intel_engine_pm_get(engine);
 
-               ce = engine->kernel_context;
-               if (ce) {
-                       GEM_BUG_ON(!intel_context_is_pinned(ce));
-                       ce->ops->reset(ce);
-               }
-
                engine->serial++; /* kernel context lost */
                err = engine->resume(engine);
 

diff --git a/drivers/gpu/drm/i915/gt/mock_engine.c b/drivers/gpu/drm/i915/gt/mock_engine.c
index 4e1eafa..d0e68ce 100644 (file)
--- a/drivers/gpu/drm/i915/gt/mock_engine.c
+++ b/drivers/gpu/drm/i915/gt/mock_engine.c
@@ -152,6 +152,10 @@ static int mock_context_pin(struct intel_context *ce)
        return intel_context_active_acquire(ce);
 }
 
+static void mock_context_reset(struct intel_context *ce)
+{
+}
+
 static const struct intel_context_ops mock_context_ops = {
        .alloc = mock_context_alloc,
 
@@ -161,6 +165,7 @@ static const struct intel_context_ops mock_context_ops = {
        .enter = intel_context_enter_engine,
        .exit = intel_context_exit_engine,
 
+       .reset = mock_context_reset,
        .destroy = mock_context_destroy,
 };