[PATCH 1/1] drm/amdkfd: Add IPC API

Felix Kuehling Felix.Kuehling at amd.com
Tue Jul 14 03:14:35 UTC 2020


This allows exporting and importing buffers. The API generates handles
that can be used with the HIP IPC API, i.e. big numbers rather than
file descriptors.

Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h    |   5 +
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  |  56 +++-
 drivers/gpu/drm/amd/amdkfd/Makefile           |   3 +-
 drivers/gpu/drm/amd/amdkfd/kfd_chardev.c      |  74 ++---
 drivers/gpu/drm/amd/amdkfd/kfd_ipc.c          | 263 ++++++++++++++++++
 drivers/gpu/drm/amd/amdkfd/kfd_ipc.h          |  55 ++++
 drivers/gpu/drm/amd/amdkfd/kfd_module.c       |   5 +
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h         |   5 +
 include/uapi/linux/kfd_ioctl.h                |  62 ++++-
 9 files changed, 488 insertions(+), 40 deletions(-)
 create mode 100644 drivers/gpu/drm/amd/amdkfd/kfd_ipc.c
 create mode 100644 drivers/gpu/drm/amd/amdkfd/kfd_ipc.h

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
index 3f2b695cf19e..0f8dc4c4f924 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -49,6 +49,7 @@ struct kfd_bo_va_list {
 struct kgd_mem {
 	struct mutex lock;
 	struct amdgpu_bo *bo;
+	struct kfd_ipc_obj *ipc_obj;
 	struct list_head bo_va_list;
 	/* protected by amdkfd_process_info.lock */
 	struct ttm_validate_buffer validate_list;
@@ -240,9 +241,13 @@ int amdgpu_amdkfd_gpuvm_get_vm_fault_info(struct kgd_dev *kgd,
 
 int amdgpu_amdkfd_gpuvm_import_dmabuf(struct kgd_dev *kgd,
 				      struct dma_buf *dmabuf,
+				      struct kfd_ipc_obj *ipc_obj,
 				      uint64_t va, void *vm,
 				      struct kgd_mem **mem, uint64_t *size,
 				      uint64_t *mmap_offset);
+int amdgpu_amdkfd_gpuvm_export_ipc_obj(struct kgd_dev *kgd, void *vm,
+				       struct kgd_mem *mem,
+				       struct kfd_ipc_obj **ipc_obj);
 
 void amdgpu_amdkfd_gpuvm_init_mem_limits(void);
 void amdgpu_amdkfd_unreserve_memory_limit(struct amdgpu_bo *bo);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index c408936e8f98..cd5f23c0c2ca 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -29,6 +29,7 @@
 #include "amdgpu_vm.h"
 #include "amdgpu_amdkfd.h"
 #include "amdgpu_dma_buf.h"
+#include "kfd_ipc.h"
 #include <uapi/linux/kfd_ioctl.h>
 
 /* BO flag to indicate a KFD userptr BO */
@@ -1353,6 +1354,9 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
 			*size = 0;
 	}
 
+	/* Unreference the ipc_obj if applicable */
+	kfd_ipc_obj_put(&mem->ipc_obj);
+
 	/* Free the BO*/
 	drm_gem_object_put_unlocked(&mem->bo->tbo.base);
 	mutex_destroy(&mem->lock);
@@ -1656,6 +1660,7 @@ int amdgpu_amdkfd_gpuvm_get_vm_fault_info(struct kgd_dev *kgd,
 
 int amdgpu_amdkfd_gpuvm_import_dmabuf(struct kgd_dev *kgd,
 				      struct dma_buf *dma_buf,
+				      struct kfd_ipc_obj *ipc_obj,
 				      uint64_t va, void *vm,
 				      struct kgd_mem **mem, uint64_t *size,
 				      uint64_t *mmap_offset)
@@ -1692,15 +1697,18 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct kgd_dev *kgd,
 
 	INIT_LIST_HEAD(&(*mem)->bo_va_list);
 	mutex_init(&(*mem)->lock);
-	
-	(*mem)->alloc_flags =
-		((bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM) ?
-		KFD_IOC_ALLOC_MEM_FLAGS_VRAM : KFD_IOC_ALLOC_MEM_FLAGS_GTT)
-		| KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE
-		| KFD_IOC_ALLOC_MEM_FLAGS_EXECUTABLE;
+	if (bo->kfd_bo)
+		(*mem)->alloc_flags = bo->kfd_bo->alloc_flags;
+	else
+		(*mem)->alloc_flags =
+			((bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM) ?
+			KFD_IOC_ALLOC_MEM_FLAGS_VRAM : KFD_IOC_ALLOC_MEM_FLAGS_GTT)
+			| KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE
+			| KFD_IOC_ALLOC_MEM_FLAGS_EXECUTABLE;
 
 	drm_gem_object_get(&bo->tbo.base);
 	(*mem)->bo = bo;
+	(*mem)->ipc_obj = ipc_obj;
 	(*mem)->va = va;
 	(*mem)->domain = (bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM) ?
 		AMDGPU_GEM_DOMAIN_VRAM : AMDGPU_GEM_DOMAIN_GTT;
@@ -1713,6 +1721,42 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct kgd_dev *kgd,
 	return 0;
 }
 
+int amdgpu_amdkfd_gpuvm_export_ipc_obj(struct kgd_dev *kgd, void *vm,
+				       struct kgd_mem *mem,
+				       struct kfd_ipc_obj **ipc_obj)
+{
+	struct amdgpu_device *adev = NULL;
+	struct dma_buf *dmabuf;
+	int r = 0;
+
+	if (!kgd || !vm || !mem)
+		return -EINVAL;
+
+	adev = get_amdgpu_device(kgd);
+	mutex_lock(&mem->lock);
+
+	if (mem->ipc_obj) {
+		*ipc_obj = mem->ipc_obj;
+		goto unlock_out;
+	}
+
+	dmabuf = amdgpu_gem_prime_export(&mem->bo->tbo.base, 0);
+	if (IS_ERR(dmabuf)) {
+		r = PTR_ERR(dmabuf);
+		goto unlock_out;
+	}
+
+	r = kfd_ipc_store_insert(dmabuf, &mem->ipc_obj);
+	if (r)
+		dma_buf_put(dmabuf);
+	else
+		*ipc_obj = mem->ipc_obj;
+
+unlock_out:
+	mutex_unlock(&mem->lock);
+	return r;
+}
+
 /* Evict a userptr BO by stopping the queues if necessary
  *
  * Runs in MMU notifier, may be in RECLAIM_FS context. This means it
diff --git a/drivers/gpu/drm/amd/amdkfd/Makefile b/drivers/gpu/drm/amd/amdkfd/Makefile
index e1e4115dcf78..815d9a9e7a3c 100644
--- a/drivers/gpu/drm/amd/amdkfd/Makefile
+++ b/drivers/gpu/drm/amd/amdkfd/Makefile
@@ -54,7 +54,8 @@ AMDKFD_FILES	:= $(AMDKFD_PATH)/kfd_module.o \
 		$(AMDKFD_PATH)/kfd_dbgdev.o \
 		$(AMDKFD_PATH)/kfd_dbgmgr.o \
 		$(AMDKFD_PATH)/kfd_smi_events.o \
-		$(AMDKFD_PATH)/kfd_crat.o
+		$(AMDKFD_PATH)/kfd_crat.o \
+		$(AMDKFD_PATH)/kfd_ipc.o
 
 ifneq ($(CONFIG_AMD_IOMMU_V2),)
 AMDKFD_FILES += $(AMDKFD_PATH)/kfd_iommu.o
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index e9b96ad3d9a5..e7d15fa02b5e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -38,6 +38,7 @@
 #include "kfd_priv.h"
 #include "kfd_device_queue_manager.h"
 #include "kfd_dbgmgr.h"
+#include "kfd_ipc.h"
 #include "amdgpu_amdkfd.h"
 #include "kfd_smi_events.h"
 
@@ -1691,53 +1692,58 @@ static int kfd_ioctl_import_dmabuf(struct file *filep,
 				   struct kfd_process *p, void *data)
 {
 	struct kfd_ioctl_import_dmabuf_args *args = data;
-	struct kfd_process_device *pdd;
-	struct dma_buf *dmabuf;
 	struct kfd_dev *dev;
-	int idr_handle;
-	uint64_t size;
-	void *mem;
 	int r;
 
 	dev = kfd_device_by_id(args->gpu_id);
 	if (!dev)
 		return -EINVAL;
 
-	dmabuf = dma_buf_get(args->dmabuf_fd);
-	if (IS_ERR(dmabuf))
-		return PTR_ERR(dmabuf);
+	r = kfd_ipc_import_dmabuf(dev, p, args->dmabuf_fd,
+				  args->va_addr, &args->handle, NULL);
+	if (r)
+		pr_err("Failed to import dmabuf\n");
 
-	mutex_lock(&p->mutex);
+	return r;
+}
 
-	pdd = kfd_bind_process_to_device(dev, p);
-	if (IS_ERR(pdd)) {
-		r = PTR_ERR(pdd);
-		goto err_unlock;
-	}
+static int kfd_ioctl_ipc_export_handle(struct file *filep,
+				       struct kfd_process *p,
+				       void *data)
+{
+	struct kfd_ioctl_ipc_export_handle_args *args = data;
+	struct kfd_dev *dev;
+	int r;
+
+	dev = kfd_device_by_id(args->gpu_id);
+	if (!dev)
+		return -EINVAL;
 
-	r = amdgpu_amdkfd_gpuvm_import_dmabuf(dev->kgd, dmabuf,
-					      args->va_addr, pdd->vm,
-					      (struct kgd_mem **)&mem, &size,
-					      NULL);
+	r = kfd_ipc_export_as_handle(dev, p, args->handle, args->share_handle);
 	if (r)
-		goto err_unlock;
+		pr_err("Failed to export IPC handle\n");
 
-	idr_handle = kfd_process_device_create_obj_handle(pdd, mem);
-	if (idr_handle < 0) {
-		r = -EFAULT;
-		goto err_free;
-	}
+	return r;
+}
 
-	mutex_unlock(&p->mutex);
+static int kfd_ioctl_ipc_import_handle(struct file *filep,
+				       struct kfd_process *p,
+				       void *data)
+{
+	struct kfd_ioctl_ipc_import_handle_args *args = data;
+	struct kfd_dev *dev = NULL;
+	int r;
 
-	args->handle = MAKE_HANDLE(args->gpu_id, idr_handle);
+	dev = kfd_device_by_id(args->gpu_id);
+	if (!dev)
+		return -EINVAL;
 
-	return 0;
+	r = kfd_ipc_import_handle(p, args->share_handle, args->va_addr,
+				  &args->handle, &args->gpu_id,
+				  &args->mmap_offset);
+	if (r)
+		pr_err("Failed to import IPC handle\n");
 
-err_free:
-	amdgpu_amdkfd_gpuvm_free_memory_of_gpu(dev->kgd, (struct kgd_mem *)mem, NULL);
-err_unlock:
-	mutex_unlock(&p->mutex);
 	return r;
 }
 
@@ -1853,6 +1859,12 @@ static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = {
 
 	AMDKFD_IOCTL_DEF(AMDKFD_IOC_SMI_EVENTS,
 			kfd_ioctl_smi_events, 0),
+
+	AMDKFD_IOCTL_DEF(AMDKFD_IOC_IPC_IMPORT_HANDLE,
+				kfd_ioctl_ipc_import_handle, 0),
+
+	AMDKFD_IOCTL_DEF(AMDKFD_IOC_IPC_EXPORT_HANDLE,
+				kfd_ioctl_ipc_export_handle, 0),
 };
 
 #define AMDKFD_CORE_IOCTL_COUNT	ARRAY_SIZE(amdkfd_ioctls)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_ipc.c b/drivers/gpu/drm/amd/amdkfd/kfd_ipc.c
new file mode 100644
index 000000000000..3de8d7826f07
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_ipc.c
@@ -0,0 +1,263 @@
+/*
+ * Copyright 2014 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.
+ */
+
+#include <linux/slab.h>
+#include <linux/random.h>
+
+#include "kfd_ipc.h"
+#include "kfd_priv.h"
+#include "amdgpu_amdkfd.h"
+
+#define KFD_IPC_HASH_TABLE_SIZE_SHIFT 4
+#define KFD_IPC_HASH_TABLE_SIZE_MASK ((1 << KFD_IPC_HASH_TABLE_SIZE_SHIFT) - 1)
+
+static struct kfd_ipc_handles {
+	DECLARE_HASHTABLE(handles, KFD_IPC_HASH_TABLE_SIZE_SHIFT);
+	struct mutex lock;
+} kfd_ipc_handles;
+
+/* Since, handles are random numbers, it can be used directly as hashing key.
+ * The least 4 bits of the handle are used as key. However, during import all
+ * 128 bits of the handle are checked to prevent handle snooping.
+ */
+#define HANDLE_TO_KEY(sh) ((*(uint64_t *)sh) & KFD_IPC_HASH_TABLE_SIZE_MASK)
+
+int kfd_ipc_store_insert(struct dma_buf *dmabuf, struct kfd_ipc_obj **ipc_obj)
+{
+	struct kfd_ipc_obj *obj;
+
+	obj = kmalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return -ENOMEM;
+
+	/* The initial ref belongs to the allocator process.
+	 * The IPC object store itself does not hold a ref since
+	 * there is no specific moment in time where that ref should
+	 * be dropped, except "when there are no more userspace processes
+	 * holding a ref to the object". Therefore the removal from IPC
+	 * storage happens at ipc_obj release time.
+	 */
+	kref_init(&obj->ref);
+	obj->dmabuf = dmabuf;
+	get_random_bytes(obj->share_handle, sizeof(obj->share_handle));
+
+	mutex_lock(&kfd_ipc_handles.lock);
+	hlist_add_head(&obj->node,
+		&kfd_ipc_handles.handles[HANDLE_TO_KEY(obj->share_handle)]);
+	mutex_unlock(&kfd_ipc_handles.lock);
+
+	if (ipc_obj)
+		*ipc_obj = obj;
+
+	return 0;
+}
+
+static void ipc_obj_release(struct kref *r)
+{
+	struct kfd_ipc_obj *obj;
+
+	obj = container_of(r, struct kfd_ipc_obj, ref);
+
+	mutex_lock(&kfd_ipc_handles.lock);
+	hash_del(&obj->node);
+	mutex_unlock(&kfd_ipc_handles.lock);
+
+	dma_buf_put(obj->dmabuf);
+	kfree(obj);
+}
+
+static struct kfd_ipc_obj *ipc_obj_get(struct kfd_ipc_obj *obj)
+{
+	if (kref_get_unless_zero(&obj->ref))
+		return obj;
+	return NULL;
+}
+
+void kfd_ipc_obj_put(struct kfd_ipc_obj **obj)
+{
+	if (*obj) {
+		kref_put(&(*obj)->ref, ipc_obj_release);
+		*obj = NULL;
+	}
+}
+
+int kfd_ipc_init(void)
+{
+	mutex_init(&kfd_ipc_handles.lock);
+	hash_init(kfd_ipc_handles.handles);
+	return 0;
+}
+
+static int kfd_import_dmabuf_create_kfd_bo(struct kfd_dev *dev,
+					   struct kfd_process *p,
+					   struct dma_buf *dmabuf,
+					   struct kfd_ipc_obj *ipc_obj,
+					   uint64_t va_addr, uint64_t *handle,
+					   uint64_t *mmap_offset)
+{
+	int r;
+	void *mem;
+	uint64_t size;
+	int idr_handle;
+	struct kfd_process_device *pdd = NULL;
+
+	if (!handle)
+		return -EINVAL;
+
+	if (!dev)
+		return -EINVAL;
+
+	mutex_lock(&p->mutex);
+
+	pdd = kfd_bind_process_to_device(dev, p);
+	if (IS_ERR(pdd)) {
+		r = PTR_ERR(pdd);
+		goto err_unlock;
+	}
+
+	r = amdgpu_amdkfd_gpuvm_import_dmabuf(dev->kgd, dmabuf, ipc_obj,
+					va_addr, pdd->vm,
+					(struct kgd_mem **)&mem, &size,
+					mmap_offset);
+	if (r)
+		goto err_unlock;
+
+	idr_handle = kfd_process_device_create_obj_handle(pdd, mem);
+	if (idr_handle < 0) {
+		r = -EFAULT;
+		goto err_free;
+	}
+
+	mutex_unlock(&p->mutex);
+
+	*handle = MAKE_HANDLE(dev->id, idr_handle);
+
+	return 0;
+
+err_free:
+	amdgpu_amdkfd_gpuvm_free_memory_of_gpu(dev->kgd, (struct kgd_mem *)mem,
+					       NULL);
+err_unlock:
+	mutex_unlock(&p->mutex);
+	return r;
+}
+
+int kfd_ipc_import_dmabuf(struct kfd_dev *dev, struct kfd_process *p,
+			  int dmabuf_fd, uint64_t va_addr,
+			  uint64_t *handle, uint64_t *mmap_offset)
+{
+	int r;
+	struct dma_buf *dmabuf = dma_buf_get(dmabuf_fd);
+
+	if (!dmabuf)
+		return -EINVAL;
+
+	r = kfd_import_dmabuf_create_kfd_bo(dev, p, dmabuf, NULL,
+					    va_addr, handle, mmap_offset);
+	dma_buf_put(dmabuf);
+	return r;
+}
+
+int kfd_ipc_import_handle(struct kfd_process *p,
+			  uint32_t *share_handle, uint64_t va_addr,
+			  uint64_t *handle, uint32_t *gpu_id,
+			  uint64_t *mmap_offset)
+{
+	struct kfd_dev *dev;
+	int r;
+	struct kfd_ipc_obj *entry, *found = NULL;
+
+	mutex_lock(&kfd_ipc_handles.lock);
+	/* Convert the user provided handle to hash key and search only in that
+	 * bucket
+	 */
+	hlist_for_each_entry(entry,
+		&kfd_ipc_handles.handles[HANDLE_TO_KEY(share_handle)], node) {
+		if (!memcmp(entry->share_handle, share_handle,
+			    sizeof(entry->share_handle))) {
+			found = ipc_obj_get(entry);
+			break;
+		}
+	}
+	mutex_unlock(&kfd_ipc_handles.lock);
+
+	if (!found)
+		return -EINVAL;
+
+	pr_debug("Found ipc_dma_buf: %p\n", found->dmabuf);
+
+	dev = kfd_device_by_id(found->gpu_id);
+	if (!dev)
+		return -ENODEV;
+
+	r = kfd_import_dmabuf_create_kfd_bo(dev, p, found->dmabuf, found,
+					    va_addr, handle, mmap_offset);
+	if (r)
+		goto error_unref;
+
+	*gpu_id = found->gpu_id;
+
+	return r;
+
+error_unref:
+	kfd_ipc_obj_put(&found);
+	return r;
+}
+
+int kfd_ipc_export_as_handle(struct kfd_dev *dev, struct kfd_process *p,
+			     uint64_t handle, uint32_t *ipc_handle)
+{
+	struct kfd_process_device *pdd = NULL;
+	struct kfd_ipc_obj *ipc_obj;
+	struct kgd_mem *mem;
+	int r;
+
+	if (!dev || !ipc_handle)
+		return -EINVAL;
+
+	mutex_lock(&p->mutex);
+	pdd = kfd_bind_process_to_device(dev, p);
+	if (IS_ERR(pdd)) {
+		mutex_unlock(&p->mutex);
+		pr_err("Failed to get pdd\n");
+		return PTR_ERR(pdd);
+	}
+
+	mem = kfd_process_device_translate_handle(pdd, GET_IDR_HANDLE(handle));
+	mutex_unlock(&p->mutex);
+
+	if (!mem) {
+		pr_err("Failed to get bo");
+		return -EINVAL;
+	}
+
+	r = amdgpu_amdkfd_gpuvm_export_ipc_obj(dev->kgd, pdd->vm, mem,
+					       &ipc_obj);
+	if (r)
+		return r;
+
+	ipc_obj->gpu_id = dev->id;
+	memcpy(ipc_handle, ipc_obj->share_handle,
+	       sizeof(ipc_obj->share_handle));
+
+	return r;
+}
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_ipc.h b/drivers/gpu/drm/amd/amdkfd/kfd_ipc.h
new file mode 100644
index 000000000000..9450a667918e
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_ipc.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2014 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 KFD_IPC_H_
+#define KFD_IPC_H_
+
+#include <linux/types.h>
+#include <linux/dma-buf.h>
+
+/* avoid including kfd_priv.h */
+struct kfd_dev;
+struct kfd_process;
+
+struct kfd_ipc_obj {
+	struct hlist_node node;
+	struct kref ref;
+	struct dma_buf *dmabuf;
+	uint32_t share_handle[4];
+	uint32_t gpu_id;
+};
+
+int kfd_ipc_import_handle(struct kfd_process *p,
+			  uint32_t *share_handle, uint64_t va_addr,
+			  uint64_t *handle, uint32_t *gpu_id,
+			  uint64_t *mmap_offset);
+int kfd_ipc_import_dmabuf(struct kfd_dev *kfd, struct kfd_process *p,
+			  int dmabuf_fd, uint64_t va_addr,
+			  uint64_t *handle, uint64_t *mmap_offset);
+int kfd_ipc_export_as_handle(struct kfd_dev *dev, struct kfd_process *p,
+			     uint64_t handle, uint32_t *ipc_handle);
+
+int kfd_ipc_store_insert(struct dma_buf *dmabuf, struct kfd_ipc_obj **ipc_obj);
+void kfd_ipc_obj_put(struct kfd_ipc_obj **obj);
+
+#endif /* KFD_IPC_H_ */
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_module.c b/drivers/gpu/drm/amd/amdkfd/kfd_module.c
index f4b7f7e6c40e..0946d5692692 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_module.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_module.c
@@ -52,6 +52,10 @@ static int kfd_init(void)
 	if (err < 0)
 		goto err_topology;
 
+	err = kfd_ipc_init();
+	if (err < 0)
+		goto err_ipc;
+
 	err = kfd_process_create_wq();
 	if (err < 0)
 		goto err_create_wq;
@@ -66,6 +70,7 @@ static int kfd_init(void)
 	return 0;
 
 err_create_wq:
+err_ipc:
 	kfd_topology_shutdown();
 err_topology:
 	kfd_chardev_exit();
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 51ba2020732e..1588b2b45a32 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -321,6 +321,8 @@ struct kfd_dev {
 	spinlock_t smi_lock;
 };
 
+struct kfd_ipc_obj;
+
 enum kfd_mempool {
 	KFD_MEMPOOL_SYSTEM_CACHEABLE = 1,
 	KFD_MEMPOOL_SYSTEM_WRITECOMBINE = 2,
@@ -1087,6 +1089,9 @@ int dbgdev_wave_reset_wavefronts(struct kfd_dev *dev, struct kfd_process *p);
 
 bool kfd_is_locked(void);
 
+/* IPC Support */
+int kfd_ipc_init(void);
+
 /* Compute profile */
 void kfd_inc_compute_active(struct kfd_dev *dev);
 void kfd_dec_compute_active(struct kfd_dev *dev);
diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
index f738c3b53f4e..90ff334e2b5b 100644
--- a/include/uapi/linux/kfd_ioctl.h
+++ b/include/uapi/linux/kfd_ioctl.h
@@ -29,9 +29,10 @@
 /*
  * - 1.1 - initial version
  * - 1.3 - Add SMI events support
+ * - 1.4 - Add IPC export/import
  */
 #define KFD_IOCTL_MAJOR_VERSION 1
-#define KFD_IOCTL_MINOR_VERSION 3
+#define KFD_IOCTL_MINOR_VERSION 4
 
 struct kfd_ioctl_get_version_args {
 	__u32 major_version;	/* from KFD */
@@ -464,6 +465,57 @@ enum kfd_mmio_remap {
 	KFD_MMIO_REMAP_HDP_REG_FLUSH_CNTL = 4,
 };
 
+/* Export IPC handle
+ *
+ * @handle[in]:         buffer handle of the BO to export
+ * @gpu_id[in]:         GPU ID where @handle was allocated
+ * @share_handle[out]:  share handle that can be used with
+ *                      @kfd_ioctl_ipc_import_handle_args
+ *
+ * @share_handle is a 128 bit random number generated with
+ * @get_random_bytes. This number should be very hard to guess.
+ * Knowledge of the @share_handle implies authorization to access
+ * the shared memory. User mode should treat it like a secret key.
+ * It can be used to import this BO in a different process context
+ * for IPC buffer sharing. The handle will be valid as long as the
+ * underlying BO exists. If the same BO is exported multiple times,
+ * the same handle will be returned.
+ *
+ * Return 0 on success, negative errno on errors.
+ */
+struct kfd_ioctl_ipc_export_handle_args {
+	__u64 handle;		/* to KFD */
+	__u32 share_handle[4];	/* from KFD */
+	__u32 gpu_id;		/* to KFD */
+	__u32 pad;
+};
+
+/* Import IPC handle
+ *
+ * @share_handle[in]:  share handle from @kfd_ioctl_ipc_export_handle_args
+ * @va_addr[in]:       virtual address at which to import the BO
+ * @handle[out]:       buffer handle of the imported BO
+ * @gpu_id[out]:       device in which the shared BO was created
+ * @mmap_offset[out]:  mmap offset for CPU-mapping the BO
+ *
+ * @handle represents a new reference to the shared BO. This reference
+ * must be released with kfd_ioctl_free_memory_of_gpu_args.
+ *
+ * The BO can be mapped for GPU access with @kfd_ioctl_map_memory_to_gpu_args.
+ *
+ * It can be mapped for CPU access using the @mmap_offset.
+ *
+ * Return 0 on success, negative errno on errors.
+ */
+struct kfd_ioctl_ipc_import_handle_args {
+	__u64 handle;		/* from KFD */
+	__u64 va_addr;		/* to KFD */
+	__u64 mmap_offset;	/* from KFD */
+	__u32 share_handle[4];	/* to KFD */
+	__u32 gpu_id;		/* from KFD */
+	__u32 pad;
+};
+
 #define AMDKFD_IOCTL_BASE 'K'
 #define AMDKFD_IO(nr)			_IO(AMDKFD_IOCTL_BASE, nr)
 #define AMDKFD_IOR(nr, type)		_IOR(AMDKFD_IOCTL_BASE, nr, type)
@@ -564,7 +616,13 @@ enum kfd_mmio_remap {
 #define AMDKFD_IOC_SMI_EVENTS			\
 		AMDKFD_IOWR(0x1F, struct kfd_ioctl_smi_events_args)
 
+#define AMDKFD_IOC_IPC_IMPORT_HANDLE                                    \
+		AMDKFD_IOWR(0x20, struct kfd_ioctl_ipc_import_handle_args)
+
+#define AMDKFD_IOC_IPC_EXPORT_HANDLE		\
+		AMDKFD_IOWR(0x21, struct kfd_ioctl_ipc_export_handle_args)
+
 #define AMDKFD_COMMAND_START		0x01
-#define AMDKFD_COMMAND_END		0x20
+#define AMDKFD_COMMAND_END		0x22
 
 #endif
-- 
2.27.0



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