[PATCH v2] drm/i915/gvt: Adding ppgtt to GVT GEM context after pin.

[Colin Xu]

Windows guest can't run after force-TDR with host log:
...
gvt: vgpu 1: workload shadow ppgtt isn't ready
gvt: vgpu 1: fail to dispatch workload, skip
...

The error is raised by set_context_ppgtt_from_shadow(), when it checks
and found the shadow_mm isn't marked as shadowed.

In work thread before each submission, a shadow_mm is set to shadowed in:
shadow_ppgtt_mm()
<-intel_vgpu_pin_mm()
<-prepare_workload()
<-dispatch_workload()
<-workload_thread()
However checking whether or not shadow_mm is shadowed is prior to it:
set_context_ppgtt_from_shadow()
<-dispatch_workload()
<-workload_thread()

In normal case, create workload will check the existence of shadow_mm,
if not it will create a new one and marked as shadowed. If already exist
it will reuse the old one. Since shadow_mm is reused, checking of shadowed
in set_context_ppgtt_from_shadow() actually always see the state set in
creation, but not the state set in intel_vgpu_pin_mm().

When force-TDR, all engines are reset, since it's not dmlr level, all
ppgtt_mm are invalidated but not destroyed. Invalidation will mark all
reused shadow_mm as not shadowed but still keeps in ppgtt_mm_list_head.
If workload submission phase those shadow_mm are reused with shadowed
not set, then set_context_ppgtt_from_shadow() will report error.

Fixes: 4f15665ccbba (drm/i915: Add ppgtt to GVT GEM context)

v2:
Move set_context_ppgtt_from_shadow() after prepare_workload(). (zhenyu)

Cc: stable at vger.kernel.org
Signed-off-by: Colin Xu <colin.xu at intel.com>
---
 drivers/gpu/drm/i915/gvt/scheduler.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 196b4155a309..100040209188 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -685,13 +685,6 @@ static int dispatch_workload(struct intel_vgpu_workload *workload)
 	mutex_lock(&vgpu->vgpu_lock);
 	mutex_lock(&dev_priv->drm.struct_mutex);
 
-	ret = set_context_ppgtt_from_shadow(workload,
-					    s->shadow[ring_id]->gem_context);
-	if (ret < 0) {
-		gvt_vgpu_err("workload shadow ppgtt isn't ready\n");
-		goto err_req;
-	}
-
 	ret = intel_gvt_workload_req_alloc(workload);
 	if (ret)
 		goto err_req;
@@ -707,6 +700,13 @@ static int dispatch_workload(struct intel_vgpu_workload *workload)
 	}
 
 	ret = prepare_workload(workload);
+	if (ret)
+		goto out;
+
+	ret = set_context_ppgtt_from_shadow(workload,
+					    s->shadow[ring_id]->gem_context);
+	if (ret)
+		gvt_vgpu_err("workload shadow ppgtt isn't ready\n");
 out:
 	if (ret) {
 		/* We might still need to add request with
-- 
2.22.0