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 <[email protected]>
---
  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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