[RFC 1/2] drm/i915/dgfx: Release mmap on rpm suspend

[Anshuman Gupta <anshuman.gupta@xxxxxxxxx>]

Release all mmap mapping for all lmem objects which are associated
with userfault such that, while pcie function in D3hot, any access
to memory mappings will raise a userfault.

Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c  | 4 ++++
 drivers/gpu/drm/i915/gt/intel_gt.c       | 1 +
 drivers/gpu/drm/i915/gt/intel_gt_types.h | 2 ++
 drivers/gpu/drm/i915/i915_gem.c          | 6 ++++++
 4 files changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 5a5cf332d8a5..b49823d599e7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -1073,6 +1073,10 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
 	} else {
 		ret = ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot);
 	}
+
+	if (i915_gem_object_is_lmem(obj))
+		list_add(&obj->userfault_link, &to_gt(to_i915(obj->base.dev))->lmem_userfault_list);
+
 	if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
 		return ret;
 
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index e4bac2431e41..f0d641c3153c 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -39,6 +39,7 @@ static void __intel_gt_init_early(struct intel_gt *gt)
 {
 	spin_lock_init(&gt->irq_lock);
 
+	INIT_LIST_HEAD(&gt->lmem_userfault_list);
 	INIT_LIST_HEAD(&gt->closed_vma);
 	spin_lock_init(&gt->closed_lock);
 
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_types.h b/drivers/gpu/drm/i915/gt/intel_gt_types.h
index 4d56f7d5a3be..3e915df255f3 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_types.h
@@ -132,6 +132,8 @@ struct intel_gt {
 	struct intel_wakeref wakeref;
 	atomic_t user_wakeref;
 
+	struct list_head lmem_userfault_list;
+
 	struct list_head closed_vma;
 	spinlock_t closed_lock; /* guards the list of closed_vma */
 
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 702e5b89be22..1e6ce6d06c11 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -842,6 +842,12 @@ void i915_gem_runtime_suspend(struct drm_i915_private *i915)
 				 &to_gt(i915)->ggtt->userfault_list, userfault_link)
 		__i915_gem_object_release_mmap_gtt(obj);
 
+	list_for_each_entry_safe(obj, on,
+				 &to_gt(i915)->lmem_userfault_list, userfault_link) {
+		i915_gem_object_release_mmap_offset(obj);
+		list_del(&obj->userfault_link);
+	}
+
 	/*
 	 * The fence will be lost when the device powers down. If any were
 	 * in use by hardware (i.e. they are pinned), we should not be powering
-- 
2.26.2