As soon as we re-enable the various functions within the HW, they may go
off and read data via a GGTT offset. Hence, if we have not yet restored
the GGTT PTE before then, they may read and even *write* random locations
in memory.

Detected by DMAR faults during resume.

Signed-off-by: Chris Wilson <[email protected]>
Cc: Mika Kuoppala <[email protected]>
Cc: Martin Peres <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: [email protected]
---
I assumed the selftest had struct_mutex already, it did not.
---
 drivers/gpu/drm/i915/gem/i915_gem_pm.c    | 3 ---
 drivers/gpu/drm/i915/i915_drv.c           | 5 +++++
 drivers/gpu/drm/i915/selftests/i915_gem.c | 6 ++++++
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pm.c 
b/drivers/gpu/drm/i915/gem/i915_gem_pm.c
index b3993d24b83d..9b1129aaacfe 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pm.c
@@ -242,9 +242,6 @@ void i915_gem_resume(struct drm_i915_private *i915)
        mutex_lock(&i915->drm.struct_mutex);
        intel_uncore_forcewake_get(&i915->uncore, FORCEWAKE_ALL);
 
-       i915_gem_restore_gtt_mappings(i915);
-       i915_gem_restore_fences(i915);
-
        if (i915_gem_init_hw(i915))
                goto err_wedged;
 
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 7b2c81a8bbaa..1af4eba968c0 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1877,6 +1877,11 @@ static int i915_drm_resume(struct drm_device *dev)
        if (ret)
                DRM_ERROR("failed to re-enable GGTT\n");
 
+       mutex_lock(&dev_priv->drm.struct_mutex);
+       i915_gem_restore_gtt_mappings(dev_priv);
+       i915_gem_restore_fences(dev_priv);
+       mutex_unlock(&dev_priv->drm.struct_mutex);
+
        intel_csr_ucode_resume(dev_priv);
 
        i915_restore_state(dev_priv);
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem.c 
b/drivers/gpu/drm/i915/selftests/i915_gem.c
index bb6dd54a6ff3..37593831b539 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem.c
@@ -118,6 +118,12 @@ static void pm_resume(struct drm_i915_private *i915)
        with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
                intel_gt_sanitize(&i915->gt, false);
                i915_gem_sanitize(i915);
+
+               mutex_lock(&i915->drm.struct_mutex);
+               i915_gem_restore_gtt_mappings(i915);
+               i915_gem_restore_fences(i915);
+               mutex_unlock(&i915->drm.struct_mutex);
+
                i915_gem_resume(i915);
        }
 }
-- 
2.23.0

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