Re: [PATCH 5/6] drm/amdkfd: Import DMABufs for interop through DRM

["Chen, Xiaogang" <xiaogang.chen@amd.com>]

On 11/8/2023 5:26 PM, Felix Kuehling wrote:
> On 2023-11-08 18:20, Chen, Xiaogang wrote:
>>
>> On 11/7/2023 10:58 AM, Felix Kuehling wrote:
>>> Use drm_gem_prime_fd_to_handle to import DMABufs for interop. This
>>> ensures that a GEM handle is created on import and that obj->dma_buf
>>> will be set and remain set as long as the object is imported into KFD.
>>>
>>> Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h    |  9 ++-
>>>   .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 64 
>>> +++++++++++++------
>>>   drivers/gpu/drm/amd/amdkfd/kfd_chardev.c      | 15 ++---
>>>   3 files changed, 52 insertions(+), 36 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
>>> index 4caf8cece028..88a0e0734270 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
>>> @@ -318,11 +318,10 @@ int 
>>> amdgpu_amdkfd_gpuvm_restore_process_bos(void *process_info,
>>>                           struct dma_fence **ef);
>>>   int amdgpu_amdkfd_gpuvm_get_vm_fault_info(struct amdgpu_device *adev,
>>>                             struct kfd_vm_fault_info *info);
>>> -int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
>>> -                      struct dma_buf *dmabuf,
>>> -                      uint64_t va, void *drm_priv,
>>> -                      struct kgd_mem **mem, uint64_t *size,
>>> -                      uint64_t *mmap_offset);
>>> +int amdgpu_amdkfd_gpuvm_import_dmabuf_fd(struct amdgpu_device 
>>> *adev, int fd,
>>> +                     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);
>>>   void amdgpu_amdkfd_debug_mem_fence(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 4bb8b5fd7598..1077de8bced2 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>> @@ -2006,8 +2006,7 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
>>>         /* Free the BO*/
>>> drm_vma_node_revoke(&mem->bo->tbo.base.vma_node, drm_priv);
>>> -    if (!mem->is_imported)
>>> -        drm_gem_handle_delete(adev->kfd.client.file, mem->gem_handle);
>>> +    drm_gem_handle_delete(adev->kfd.client.file, mem->gem_handle);
>>
>> A minor thing for this patch: I think this is a correction for last 
>> patch " Export DMABufs from KFD using GEM handles". mem->gem_handle 
>> is created unconditionally at 
>> amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu.  drm_gem_handle_delete 
>> should be put at the lat patch.
>
> This change was intentional. Without this patch, imported DMABufs 
> didn't get a GEM handle, so I didn't need to delete one. With this 
> patch, I now have a GEM handle for imported BOs, so I delete the GEM 
> handle unconditionally.
>
oh, imported mem->gem_handle is generated at 
amdgpu_amdkfd_gpuvm_import_dmabuf_fd. Need refresh my memory after a 
while.  This patch is:

Reviwed-by: Xiaogang.Chen <Xiaogang.Chen@amd.com>

> Regards,
>   Felix
>
>
>>
>> Regards
>>
>> Xiaogang
>>
>>>       if (mem->dmabuf) {
>>>           dma_buf_put(mem->dmabuf);
>>>           mem->dmabuf = NULL;
>>> @@ -2363,34 +2362,26 @@ int 
>>> amdgpu_amdkfd_gpuvm_get_vm_fault_info(struct amdgpu_device *adev,
>>>       return 0;
>>>   }
>>>   -int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
>>> -                      struct dma_buf *dma_buf,
>>> -                      uint64_t va, void *drm_priv,
>>> -                      struct kgd_mem **mem, uint64_t *size,
>>> -                      uint64_t *mmap_offset)
>>> +static int import_obj_create(struct amdgpu_device *adev,
>>> +                 struct dma_buf *dma_buf,
>>> +                 struct drm_gem_object *obj,
>>> +                 uint64_t va, void *drm_priv,
>>> +                 struct kgd_mem **mem, uint64_t *size,
>>> +                 uint64_t *mmap_offset)
>>>   {
>>>       struct amdgpu_vm *avm = drm_priv_to_vm(drm_priv);
>>> -    struct drm_gem_object *obj;
>>>       struct amdgpu_bo *bo;
>>>       int ret;
>>>   -    obj = amdgpu_gem_prime_import(adev_to_drm(adev), dma_buf);
>>> -    if (IS_ERR(obj))
>>> -        return PTR_ERR(obj);
>>> -
>>>       bo = gem_to_amdgpu_bo(obj);
>>>       if (!(bo->preferred_domains & (AMDGPU_GEM_DOMAIN_VRAM |
>>> -                    AMDGPU_GEM_DOMAIN_GTT))) {
>>> +                    AMDGPU_GEM_DOMAIN_GTT)))
>>>           /* Only VRAM and GTT BOs are supported */
>>> -        ret = -EINVAL;
>>> -        goto err_put_obj;
>>> -    }
>>> +        return -EINVAL;
>>>         *mem = kzalloc(sizeof(struct kgd_mem), GFP_KERNEL);
>>> -    if (!*mem) {
>>> -        ret = -ENOMEM;
>>> -        goto err_put_obj;
>>> -    }
>>> +    if (!*mem)
>>> +        return -ENOMEM;
>>>         ret = drm_vma_node_allow(&obj->vma_node, drm_priv);
>>>       if (ret)
>>> @@ -2440,8 +2431,41 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct 
>>> amdgpu_device *adev,
>>>       drm_vma_node_revoke(&obj->vma_node, drm_priv);
>>>   err_free_mem:
>>>       kfree(*mem);
>>> +    return ret;
>>> +}
>>> +
>>> +int amdgpu_amdkfd_gpuvm_import_dmabuf_fd(struct amdgpu_device 
>>> *adev, int fd,
>>> +                     uint64_t va, void *drm_priv,
>>> +                     struct kgd_mem **mem, uint64_t *size,
>>> +                     uint64_t *mmap_offset)
>>> +{
>>> +    struct drm_gem_object *obj;
>>> +    uint32_t handle;
>>> +    int ret;
>>> +
>>> +    ret = drm_gem_prime_fd_to_handle(&adev->ddev, 
>>> adev->kfd.client.file, fd,
>>> +                     &handle);
>>> +    if (ret)
>>> +        return ret;
>>> +    obj = drm_gem_object_lookup(adev->kfd.client.file, handle);
>>> +    if (!obj) {
>>> +        ret = -EINVAL;
>>> +        goto err_release_handle;
>>> +    }
>>> +
>>> +    ret = import_obj_create(adev, obj->dma_buf, obj, va, drm_priv, 
>>> mem, size,
>>> +                mmap_offset);
>>> +    if (ret)
>>> +        goto err_put_obj;
>>> +
>>> +    (*mem)->gem_handle = handle;
>>> +
>>> +    return 0;
>>> +
>>>   err_put_obj:
>>>       drm_gem_object_put(obj);
>>> +err_release_handle:
>>> +    drm_gem_handle_delete(adev->kfd.client.file, handle);
>>>       return ret;
>>>   }
>>>   diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c 
>>> b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>> index 4417a9863cd0..1a2e9f564b7f 100644
>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>> @@ -1564,16 +1564,11 @@ static int kfd_ioctl_import_dmabuf(struct 
>>> file *filep,
>>>   {
>>>       struct kfd_ioctl_import_dmabuf_args *args = data;
>>>       struct kfd_process_device *pdd;
>>> -    struct dma_buf *dmabuf;
>>>       int idr_handle;
>>>       uint64_t size;
>>>       void *mem;
>>>       int r;
>>>   -    dmabuf = dma_buf_get(args->dmabuf_fd);
>>> -    if (IS_ERR(dmabuf))
>>> -        return PTR_ERR(dmabuf);
>>> -
>>>       mutex_lock(&p->mutex);
>>>       pdd = kfd_process_device_data_by_id(p, args->gpu_id);
>>>       if (!pdd) {
>>> @@ -1587,10 +1582,10 @@ static int kfd_ioctl_import_dmabuf(struct 
>>> file *filep,
>>>           goto err_unlock;
>>>       }
>>>   -    r = amdgpu_amdkfd_gpuvm_import_dmabuf(pdd->dev->adev, dmabuf,
>>> -                          args->va_addr, pdd->drm_priv,
>>> -                          (struct kgd_mem **)&mem, &size,
>>> -                          NULL);
>>> +    r = amdgpu_amdkfd_gpuvm_import_dmabuf_fd(pdd->dev->adev, 
>>> args->dmabuf_fd,
>>> +                         args->va_addr, pdd->drm_priv,
>>> +                         (struct kgd_mem **)&mem, &size,
>>> +                         NULL);
>>>       if (r)
>>>           goto err_unlock;
>>>   @@ -1601,7 +1596,6 @@ static int kfd_ioctl_import_dmabuf(struct 
>>> file *filep,
>>>       }
>>>         mutex_unlock(&p->mutex);
>>> -    dma_buf_put(dmabuf);
>>>         args->handle = MAKE_HANDLE(args->gpu_id, idr_handle);
>>>   @@ -1612,7 +1606,6 @@ static int kfd_ioctl_import_dmabuf(struct 
>>> file *filep,
>>>                              pdd->drm_priv, NULL);
>>>   err_unlock:
>>>       mutex_unlock(&p->mutex);
>>> -    dma_buf_put(dmabuf);
>>>       return r;
>>>   }