Exports a DMA buf fd of a given KFD buffer handle. This is intended for the new upstreamable RDMA solution coming to UCX and libfabric.
The corresponding user mode change (Thunk API and kfdtest) is here: https://github.com/RadeonOpenCompute/ROCT-Thunk-Interface/commits/fxkamd/dmabuf Signed-off-by: Felix Kuehling <felix.kuehl...@amd.com> --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 2 + .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 45 +++++++++++---- drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 55 +++++++++++++++++++ include/uapi/linux/kfd_ioctl.h | 14 ++++- 4 files changed, 104 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h index fcbc8a9c9e06..840de82460a3 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h @@ -294,6 +294,8 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev, uint64_t va, void *drm_priv, struct kgd_mem **mem, uint64_t *size, uint64_t *mmap_offset); +int amdgpu_amdkfd_gpuvm_export_dmabuf(struct kgd_mem *mem, + struct dma_buf **dmabuf); int amdgpu_amdkfd_get_tile_config(struct amdgpu_device *adev, struct tile_config *config); void amdgpu_amdkfd_ras_poison_consumption_handler(struct amdgpu_device *adev); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index d53d19b9d6dc..9f57e5091fa8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -641,6 +641,21 @@ kfd_mem_attach_userptr(struct amdgpu_device *adev, struct kgd_mem *mem, return 0; } +static int kfd_mem_export_dmabuf(struct kgd_mem *mem) +{ + if (!mem->dmabuf) { + struct dma_buf *ret = amdgpu_gem_prime_export( + &mem->bo->tbo.base, + mem->alloc_flags & KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE ? + DRM_RDWR : 0); + if (IS_ERR(ret)) + return PTR_ERR(ret); + mem->dmabuf = ret; + } + + return 0; +} + static int kfd_mem_attach_dmabuf(struct amdgpu_device *adev, struct kgd_mem *mem, struct amdgpu_bo **bo) @@ -648,16 +663,9 @@ kfd_mem_attach_dmabuf(struct amdgpu_device *adev, struct kgd_mem *mem, struct drm_gem_object *gobj; int ret; - if (!mem->dmabuf) { - mem->dmabuf = amdgpu_gem_prime_export(&mem->bo->tbo.base, - mem->alloc_flags & KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE ? - DRM_RDWR : 0); - if (IS_ERR(mem->dmabuf)) { - ret = PTR_ERR(mem->dmabuf); - mem->dmabuf = NULL; - return ret; - } - } + ret = kfd_mem_export_dmabuf(mem); + if (ret) + return ret; gobj = amdgpu_gem_prime_import(adev_to_drm(adev), mem->dmabuf); if (IS_ERR(gobj)) @@ -2065,6 +2073,23 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev, return ret; } +int amdgpu_amdkfd_gpuvm_export_dmabuf(struct kgd_mem *mem, + struct dma_buf **dma_buf) +{ + int ret; + + mutex_lock(&mem->lock); + ret = kfd_mem_export_dmabuf(mem); + if (ret) + goto out; + + get_dma_buf(mem->dmabuf); + *dma_buf = mem->dmabuf; +out: + mutex_unlock(&mem->lock); + return ret; +} + /* 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/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c index 4bfc0c8ab764..ddbc28951ac1 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c @@ -1787,6 +1787,58 @@ static int kfd_ioctl_import_dmabuf(struct file *filep, return r; } +static int kfd_ioctl_export_dmabuf(struct file *filep, + struct kfd_process *p, void *data) +{ + struct kfd_ioctl_export_dmabuf_args *args = data; + struct kfd_process_device *pdd; + struct dma_buf *dmabuf; + struct kfd_dev *dev; + void *mem; + int ret = 0; + + dev = kfd_device_by_id(GET_GPU_ID(args->handle)); + if (!dev) + return -EINVAL; + + mutex_lock(&p->mutex); + + pdd = kfd_get_process_device_data(dev, p); + if (!pdd) { + ret = -EINVAL; + goto err_unlock; + } + + mem = kfd_process_device_translate_handle(pdd, + GET_IDR_HANDLE(args->handle)); + if (!mem) { + ret = -EINVAL; + goto err_unlock; + } + + ret = amdgpu_amdkfd_gpuvm_export_dmabuf(mem, &dmabuf); + mutex_unlock(&p->mutex); + if (ret) + goto err_out; + + ret = dma_buf_fd(dmabuf, args->flags); + if (ret < 0) { + dma_buf_put(dmabuf); + goto err_out; + } + /* dma_buf_fd assigns the reference count to the fd, no need to + * put the reference here. + */ + args->dmabuf_fd = ret; + + return 0; + +err_unlock: + mutex_unlock(&p->mutex); +err_out: + return ret; +} + /* Handle requests for watching SMI events */ static int kfd_ioctl_smi_events(struct file *filep, struct kfd_process *p, void *data) @@ -1959,6 +2011,9 @@ static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = { AMDKFD_IOCTL_DEF(AMDKFD_IOC_SET_XNACK_MODE, kfd_ioctl_set_xnack_mode, 0), + + AMDKFD_IOCTL_DEF(AMDKFD_IOC_EXPORT_DMABUF, + kfd_ioctl_export_dmabuf, 0), }; #define AMDKFD_CORE_IOCTL_COUNT ARRAY_SIZE(amdkfd_ioctls) diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h index af96af174dc4..3b80af5f5bdf 100644 --- a/include/uapi/linux/kfd_ioctl.h +++ b/include/uapi/linux/kfd_ioctl.h @@ -32,9 +32,10 @@ * - 1.4 - Indicate new SRAM EDC bit in device properties * - 1.5 - Add SVM API * - 1.6 - Query clear flags in SVM get_attr API + * - 1.7 - Add DMA buf export ioctl */ #define KFD_IOCTL_MAJOR_VERSION 1 -#define KFD_IOCTL_MINOR_VERSION 6 +#define KFD_IOCTL_MINOR_VERSION 7 struct kfd_ioctl_get_version_args { __u32 major_version; /* from KFD */ @@ -450,6 +451,12 @@ struct kfd_ioctl_import_dmabuf_args { __u32 dmabuf_fd; /* to KFD */ }; +struct kfd_ioctl_export_dmabuf_args { + __u64 handle; /* to KFD */ + __u32 flags; /* to KFD */ + __u32 dmabuf_fd; /* from KFD */ +}; + /* * KFD SMI(System Management Interface) events */ @@ -742,7 +749,10 @@ struct kfd_ioctl_set_xnack_mode_args { #define AMDKFD_IOC_SET_XNACK_MODE \ AMDKFD_IOWR(0x21, struct kfd_ioctl_set_xnack_mode_args) +#define AMDKFD_IOC_EXPORT_DMABUF \ + AMDKFD_IOWR(0x22, struct kfd_ioctl_export_dmabuf_args) + #define AMDKFD_COMMAND_START 0x01 -#define AMDKFD_COMMAND_END 0x22 +#define AMDKFD_COMMAND_END 0x23 #endif -- 2.32.0
