[PATCH libdrm 3/4] amdgpu: add a function to find bo by cpu mapping

[Christian König]

Am 07.08.2018 um 10:28 schrieb Zhang, Jerry (Junwei):
> On 08/07/2018 04:20 PM, Christian König wrote:
>> Well NAK, that wasn't the intention of putting all BOs into the 
>> handle table.
>>
>> You should still use the kernel implementation.
>
> I thought we have discussed that in below mail thread. any gap?
>
> [PATCH 1/2] drm/amdgpu: return bo itself if userptr is cpu addr of bo 
> (v3)
> {{{
> >> Well we could just completely drop the kernel implementation and use
> >> an userspace implementation.
> >
> > Do you mean to implement finding bo by cpu address in libdrm 
> completely?
>
> Yes, exactly.
> }}}

Ok, well that is a misunderstanding. I was just speculating about that.

On the other hand if searching all BOs for the right one is not to much 
overhead for that workaround I'm fine with it.

Just drop patch #2 in this series. All unused entries should be 
initialized to zero and walking the extra 512 isn't that much overhead.

Regards,
Christian.

>
> Regards,
> Jerry
>
>>
>> Christian.
>>
>> Am 07.08.2018 um 09:26 schrieb Junwei Zhang:
>>> Userspace needs to know if the user memory is from BO or malloc.
>>>
>>> Signed-off-by: Junwei Zhang <Jerry.Zhang at amd.com>
>>> ---
>>>   amdgpu/amdgpu.h    | 23 +++++++++++++++++++++++
>>>   amdgpu/amdgpu_bo.c | 34 ++++++++++++++++++++++++++++++++++
>>>   2 files changed, 57 insertions(+)
>>>
>>> diff --git a/amdgpu/amdgpu.h b/amdgpu/amdgpu.h
>>> index be83b45..a8c353c 100644
>>> --- a/amdgpu/amdgpu.h
>>> +++ b/amdgpu/amdgpu.h
>>> @@ -678,6 +678,29 @@ int 
>>> amdgpu_create_bo_from_user_mem(amdgpu_device_handle dev,
>>>                       amdgpu_bo_handle *buf_handle);
>>>   /**
>>> + * Validate if the user memory comes from BO
>>> + *
>>> + * \param dev - [in] Device handle. See #amdgpu_device_initialize()
>>> + * \param cpu - [in] CPU address of user allocated memory which we
>>> + * want to map to GPU address space (make GPU accessible)
>>> + * (This address must be correctly aligned).
>>> + * \param size - [in] Size of allocation (must be correctly aligned)
>>> + * \param buf_handle - [out] Buffer handle for the userptr memory
>>> + * if the user memory is not from BO, the buf_handle will be NULL.
>>> + * \param offset_in_bo - [out] offset in this BO for this user memory
>>> + *
>>> + *
>>> + * \return   0 on success\n
>>> + *          <0 - Negative POSIX Error code
>>> + *
>>> +*/
>>> +int amdgpu_find_bo_by_cpu_mapping(amdgpu_device_handle dev,
>>> +                  void *cpu,
>>> +                  uint64_t size,
>>> +                  amdgpu_bo_handle *buf_handle,
>>> +                  uint64_t *offset_in_bo);
>>> +
>>> +/**
>>>    * Free previosuly allocated memory
>>>    *
>>>    * \param   dev           - \c [in] Device handle. See 
>>> #amdgpu_device_initialize()
>>> diff --git a/amdgpu/amdgpu_bo.c b/amdgpu/amdgpu_bo.c
>>> index b24e698..a631050 100644
>>> --- a/amdgpu/amdgpu_bo.c
>>> +++ b/amdgpu/amdgpu_bo.c
>>> @@ -529,6 +529,40 @@ int amdgpu_bo_wait_for_idle(amdgpu_bo_handle bo,
>>>       }
>>>   }
>>> +int amdgpu_find_bo_by_cpu_mapping(amdgpu_device_handle dev,
>>> +                  void *cpu,
>>> +                  uint64_t size,
>>> +                  amdgpu_bo_handle *buf_handle,
>>> +                  uint64_t *offset_in_bo)
>>> +{
>>> +    int i;
>>> +    struct amdgpu_bo *bo;
>>> +
>>> +    if (cpu == NULL || size == 0)
>>> +        return -EINVAL;
>>> +
>>> +    pthread_mutex_lock(&dev->bo_table_mutex);
>>> +    for (i = 0; i <= dev->bo_handles.max_key; i++) {
>>> +        bo = handle_table_lookup(&dev->bo_handles, i);
>>> +        if (!bo || !bo->cpu_ptr || size > bo->alloc_size)
>>> +            continue;
>>> +        if (cpu >= bo->cpu_ptr && cpu < (bo->cpu_ptr + 
>>> bo->alloc_size))
>>> +            break;
>>> +    }
>>> +    pthread_mutex_unlock(&dev->bo_table_mutex);
>>> +
>>> +    if (i <= dev->bo_handles.max_key) {
>>> +        atomic_inc(&bo->refcount);
>>> +        *buf_handle = bo;
>>> +        *offset_in_bo = cpu - bo->cpu_ptr;
>>> +    } else {
>>> +        *buf_handle = NULL;
>>> +        *offset_in_bo = 0;
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>>   int amdgpu_create_bo_from_user_mem(amdgpu_device_handle dev,
>>>                       void *cpu,
>>>                       uint64_t size,
>>
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