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

Zhang, Jerry (Junwei) Jerry.Zhang at amd.com
Tue Aug 7 09:52:17 UTC 2018


On 08/07/2018 05:33 PM, Christian König wrote:
> 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.

Yes, reserve it locally for now.
May I get your RB?

Regards,
Jerry

>
> 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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