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

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

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.
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?

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;
>

_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx