[PATCH v9 02/18] drm/amdgpu: add SVM core header and VM integration

From: Honglei Huang <[email protected]>

Add amdgpu_svm.h with SVM data structures and public API:
- enum amdgpu_svm_xnack_mode: OFF, ON and DEFAULT mode
- struct amdgpu_svm: core context with drm_gpusvm, kref lifecycle,
  attribute tree, rw_semaphore, GC workqueue, xnack state.
- struct amdgpu_svm_gc: garbage collector with workqueue and work_struct
- Debug/trace macros: AMDGPU_SVM_TRACE, AMDGPU_SVM_WARN, AMDGPU_SVM_ERR
- Kmem cache helpers: AMDGPU_SVM_KMEM_CACHE_CREATE/DESTROY
- Locking helpers: amdgpu_svm_lock/unlock/assert_locked
- Public API declarations (including clean_queue, sync_work)

Signed-off-by: Honglei Huang <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_svm.h | 204 ++++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h  |   4 +
 2 files changed, 208 insertions(+)
 create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_svm.h

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_svm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_svm.h
new file mode 100644
index 0000000000000..f3b4f228405c2
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_svm.h
@@ -0,0 +1,204 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/*
+ * Copyright 2026 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __AMDGPU_SVM_H__
+#define __AMDGPU_SVM_H__
+
+#include <drm/amdgpu_drm.h>
+#include <drm/drm_gpusvm.h>
+#include <linux/atomic.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/printk.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+struct amdgpu_device;
+struct amdgpu_vm;
+struct amdgpu_svm_attr_tree;
+struct amdgpu_svm_attrs;
+struct drm_device;
+struct drm_file;
+
+enum amdgpu_svm_xnack_mode {
+	AMDGPU_SVM_XNACK_OFF,
+	AMDGPU_SVM_XNACK_ON,
+	AMDGPU_SVM_XNACK_DEFAULT,
+};
+
+#define AMDGPU_SVM_DBG(fmt, ...) \
+	pr_debug("%s: " fmt, __func__, ##__VA_ARGS__)
+
+#define AMDGPU_SVM_WARN(fmt, ...) \
+	pr_warn("%s: " fmt, __func__, ##__VA_ARGS__)
+
+#define AMDGPU_SVM_ERR(fmt, ...) \
+	pr_err("%s: " fmt, __func__, ##__VA_ARGS__)
+
+#define amdgpu_svm_assert_in_notifier(svm__) \
+	lockdep_assert_held_write(&(svm__)->gpusvm.notifier_lock)
+
+/**
+ * struct amdgpu_svm_gc - SVM range garbage collector used for unmapping
+ * SVM ranges in response to mmu_notifier events.
+ * @wq: Workqueue where @work runs on.
+ * @list: Ranges list in garbage collector. Protected by amdgpu_svm.work_lock.
+ * @work: Drains @list under amdgpu_svm.svm_lock.
+ */
+struct amdgpu_svm_gc {
+	struct workqueue_struct *wq;
+	struct list_head list;
+	struct work_struct work;
+};
+
+/**
+ * struct amdgpu_svm - shared virtual memory context
+ * @gpusvm: Embedded drm_gpusvm base, manages the range/notifier trees.
+ * @refcount: Reference count guarding the lifetime of this instance.
+ * @adev: The amdgpu device this SVM context belongs to.
+ * @vm: Back pointer to the owning amdgpu_vm.
+ * @attr_tree: Interval tree of SVM attributes.
+ * @svm_lock: The driver_svm_lock described in the GPU SVM locking section.
+ *            registered by drm_gpusvm_driver_set_lock().
+ * @work_lock: Protects the deferred work queues such as @gc.list.
+ * @gc: garbage collector for ranges queued for destruction.
+ * @exiting: Set once when the context starts tearing down.
+ * @checkpoint_ts: IH ring timestamp captured on unmap, used to drop stale
+ *                 faults.
+ * @default_granularity: Default range granularity.
+ * @xnack_enabled: Whether retry (XNACK) faults are enabled.
+ * @invalidate_ranges: Callback of the MMU notifier invalidate event.
+ */
+struct amdgpu_svm {
+	struct drm_gpusvm gpusvm;
+	struct kref refcount;
+	struct amdgpu_device *adev;
+	struct amdgpu_vm *vm;
+	struct amdgpu_svm_attr_tree *attr_tree;
+	struct rw_semaphore svm_lock;
+	spinlock_t work_lock;
+	struct amdgpu_svm_gc gc;
+	atomic_t exiting;
+	uint64_t checkpoint_ts;
+	u8 default_granularity;
+	bool xnack_enabled;
+	void (*invalidate_ranges)(struct amdgpu_svm *svm,
+				  struct drm_gpusvm_notifier *notifier,
+				  const struct mmu_notifier_range *mmu_range,
+				  struct drm_gpusvm_range *first,
+				  uint64_t adj_start, uint64_t adj_end);
+};
+
+static inline struct amdgpu_svm *to_amdgpu_svm(struct drm_gpusvm *gpusvm)
+{
+	return container_of(gpusvm, struct amdgpu_svm, gpusvm);
+}
+
+/*
+ * Helpers for amdgpu_svm.svm_lock, the driver_svm_lock registered with GPU SVM.
+ * Hold it in write mode around structural GPU SVM updates, including
+ * drm_gpusvm_range_find_or_insert() and drm_gpusvm_range_remove().
+ */
+static inline void amdgpu_svm_lock(struct amdgpu_svm *svm)
+{
+	down_write(&svm->svm_lock);
+}
+
+static inline void amdgpu_svm_unlock(struct amdgpu_svm *svm)
+{
+	up_write(&svm->svm_lock);
+}
+
+static inline void amdgpu_svm_assert_locked(struct amdgpu_svm *svm)
+{
+	lockdep_assert_held_write(&svm->svm_lock);
+}
+
+#if IS_ENABLED(CONFIG_DRM_AMDGPU_SVM)
+void amdgpu_svm_flush_tlb(struct amdgpu_svm *svm);
+
+int amdgpu_svm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm);
+void amdgpu_svm_close(struct amdgpu_vm *vm);
+void amdgpu_svm_fini(struct amdgpu_vm *vm);
+
+void amdgpu_svm_put(struct amdgpu_svm *svm);
+struct amdgpu_svm *amdgpu_svm_lookup_by_pasid(struct amdgpu_device *adev,
+					       uint32_t pasid);
+int amdgpu_svm_handle_fault(struct amdgpu_device *adev, uint32_t pasid,
+			    uint64_t fault_page, uint64_t ts,
+			    bool write_fault);
+bool amdgpu_svm_is_enabled(struct amdgpu_vm *vm);
+
+int amdgpu_gem_svm_ioctl(struct drm_device *dev, void *data,
+			 struct drm_file *filp);
+void amdgpu_svm_clean_queue(struct amdgpu_svm *svm,
+			    struct list_head *work_list);
+void amdgpu_svm_sync_work(struct amdgpu_svm *svm);
+int amdgpu_svm_garbage_collector(struct amdgpu_svm *svm);
+int amdgpu_svm_apply_attr_change(struct amdgpu_svm *svm,
+				 const struct amdgpu_svm_attrs *old_attrs,
+				 const struct amdgpu_svm_attrs *new_attrs,
+				 unsigned long start_page,
+				 unsigned long last_page);
+bool amdgpu_svm_devmem_possible(struct amdgpu_svm *svm);
+#else
+static inline int amdgpu_svm_init(struct amdgpu_device *adev,
+				  struct amdgpu_vm *vm)
+{
+	return 0;
+}
+
+static inline void amdgpu_svm_close(struct amdgpu_vm *vm)
+{
+}
+
+static inline void amdgpu_svm_fini(struct amdgpu_vm *vm)
+{
+}
+
+static inline int amdgpu_svm_handle_fault(struct amdgpu_device *adev,
+					  uint32_t pasid,
+					  uint64_t fault_page,
+					  uint64_t ts,
+					  bool write_fault)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline bool amdgpu_svm_is_enabled(struct amdgpu_vm *vm)
+{
+	return false;
+}
+
+static inline int amdgpu_gem_svm_ioctl(struct drm_device *dev, void *data,
+				       struct drm_file *filp)
+{
+	return -EOPNOTSUPP;
+}
+#endif /* CONFIG_DRM_AMDGPU_SVM */
+
+#endif /* __AMDGPU_SVM_H__ */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index ec1196d390bb7..30463a83e2e60 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -43,6 +43,7 @@ struct amdgpu_bo_va;
 struct amdgpu_job;
 struct amdgpu_bo_list_entry;
 struct amdgpu_bo_vm;
+struct amdgpu_svm;
 
 /*
  * GPUVM handling
@@ -373,6 +374,9 @@ struct amdgpu_vm {
 
 	/* cached fault info */
 	struct amdgpu_vm_fault_info fault_info;
+
+	/* SVM experimental implementation */
+	struct amdgpu_svm *svm;
 };
 
 struct amdgpu_vm_manager {
-- 
2.53.0