Re: [PATCH] drm/amdgpu:Added support for MV packet

[James Zhu <jamesz-5C7GfCeVMHo@public.gmane.org>]

Hi Christian,

Thanks for correction.

Since MV dump is not normal encoding, its size is HxW/8. So the 2nd 
buffer size if  1/12 of the 1st one.

Thanks and Best Regards!

James Zhu


On 2018-04-03 05:11 AM, Christian König wrote:
> Am 02.04.2018 um 22:27 schrieb James Zhu:
>>
>>
>> On 2018-03-31 01:51 PM, Christian König wrote:
>>> Am 29.03.2018 um 23:02 schrieb James Zhu:
>>>> Motion vector packet needs support in physic mode.
>>>>
>>>> Signed-off-by: James Zhu <James.Zhu@amd.com>
>>>> ---
>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c | 24 
>>>> ++++++++++++++++++++++++
>>>>   1 file changed, 24 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c 
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
>>>> index 4dfa868..ef6b780 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c
>>>> @@ -767,6 +767,18 @@ int amdgpu_vce_ring_parse_cs(struct 
>>>> amdgpu_cs_parser *p, uint32_t ib_idx)
>>>>               if (r)
>>>>                   goto out;
>>>>               break;
>>>> +
>>>> +        case 0x0500000d: /* MV buffer */
>>>> +            r = amdgpu_vce_validate_bo(p, ib_idx, idx + 3,
>>>> +                            idx + 2, 0, 0);
>>>> +            if (r)
>>>> +                goto out;
>>>> +
>>>> +            r = amdgpu_vce_validate_bo(p, ib_idx, idx + 8,
>>>> +                            idx + 7, 0, 0);
>>>> +            if (r)
>>>> +                goto out;
>>>> +            break;
>>>
>>> You need to specify a size here or otherwise userspace could 
>>> allocate only a 4kb buffer and hope that VCE write over the end of 
>>> the buffer.
>>>
>>> Since the MVs are easily controllable userspace can hope to hit and 
>>> fill a page table with this. That would be a security hole you can 
>>> push an elephant through, taking over the whole system with that is 
>>> just a typing exercise.
>>>
>>> Regards,
>>> Christian.
>>>
>> Hi Christian,
>>
>> The first buffer is for input frame, I saw encode doesn't specify the 
>> size.
>
> Good point, that makes this far less problematic, but I still think 
> correct size handling would be nice to have.
>
> Take a look at the second pass for the encode command, size handling 
> is there:
>>                 case 0x03000001: /* encode */
>>                         r = amdgpu_vce_cs_reloc(p, ib_idx, idx + 10, 
>> idx + 9,
>>                                                 *size, 0);
>>                         if (r)
>>                                 goto out;
>
> If I'm not completely mistake you just need to specify "*size" and 
> "*size / 3" as parameters for your call to amdgpu_vce_cs_reloc as well.
>
>> The 2nd buffer is for mv dump buffer, the size should be fixed with 
>> ALIGN(enc.width, 16) * ALIGN(enc.height, 16) / 8 which is less than 
>> 4k. Since IB doesn't pass down this value. how to specify the size 
>> for this case?
>
> Why do you think that ALIGN(enc.width, 16) * ALIGN(enc.height, 16) / 8 
> is less than 4k? If I do the math correctly for a 1920x1088 input 
> picture that should be around 255k.
>
> *size should be size of the input picture in bytes (luma+chroma), so 
> something like "*ALIGN(size * 3 / 2 / 8, 256) / 8" should do it.
>
> Regards,
> Christian.
>
>>
>> Best Regards!
>> James Zhu
>>>>           }
>>>>             idx += len / 4;
>>>> @@ -884,6 +896,18 @@ int amdgpu_vce_ring_parse_cs(struct 
>>>> amdgpu_cs_parser *p, uint32_t ib_idx)
>>>>                   goto out;
>>>>               break;
>>>>   +        case 0x0500000d: /* MV buffer */
>>>> +            r = amdgpu_vce_cs_reloc(p, ib_idx, idx + 3,
>>>> +                            idx + 2, 0, 0);
>>>> +            if (r)
>>>> +                goto out;
>>>> +
>>>> +            r = amdgpu_vce_cs_reloc(p, ib_idx, idx + 8,
>>>> +                            idx + 7, 0, 0);
>>>> +            if (r)
>>>> +                goto out;
>>>> +            break;
>>>> +
>>>>           default:
>>>>               DRM_ERROR("invalid VCE command (0x%x)!\n", cmd);
>>>>               r = -EINVAL;
>>>
>>
>

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