[RFC] How implement Secure Data Path ?

[Enrico Weigelt, metux IT consult]

Am 08.05.2015 um 10:37 schrieb Daniel Vetter:

> dma-buf user handles are fds, which means anything allocated can be passed
> around nicely already. The question really is whether we'll have one ioctl
> on top of a special dev node or a syscall. I thought that in these cases
> where the dev node is only ever used to allocate the real thing, a syscall
> is the preferred way to go.

I'd generally prefer a /dev node instead of syscall, as they can be
dynamically allocated (loaded as module, etc), which in turn offers more
finer control (eg. for containers, etc). One could easily replace the
it with its own implementation (w/o patching the kernel directly and
reboot it).

Actually, I'm a bit unhappy with the syscall inflation, in fact I'm
not even a big friend of ioctl's - I'd really prefer the Plan9 way :p

>> I guess the same kind of logic as with GEM (except preferably without
>> the DoS security holes) applies as to why its useful to have handles to
>> the DMA buffers.
>
> We have handles (well file descriptors) to dma-bufs already, I'm a bit
> confused what you mean?

Just curious (as I'm pretty new to this area): how to GEM objects and
dma-bufs relate to each other ? Is it possible to directly exchange
buffers between GPUs, VPUs, IPUs, FBs, etc ?


cu
--
Enrico Weigelt, metux IT consult
+49-151-27565287
MELAG Medizintechnik oHG Sitz Berlin Registergericht AG Charlottenburg HRA 21333 B

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