[dpdk-dev] [PATCH v3 0/4] add AESNI-MB rawdev for multi-function processing

[Thomas Monjalon]

14/04/2020 16:02, Trahe, Fiona:
> Hi Thomas,
> 
> From: Thomas Monjalon <thomas at monjalon.net>
> > 14/04/2020 15:04, Trahe, Fiona:
> > > > 14/04/2020 12:21, Ferruh Yigit:
> > > >
> > http://inbox.dpdk.org/dev/MN2PR11MB35507D4B96677A41E66440C5E3C30@MN2PR11MB3550.na
> > > > mprd11.prod.outlook.com/
> > > >
> > > > I am not convinced.
> > > > I don't like rawdev in general.
> > > > Rawdev is good only for hardware support which cannot be generic
> > > > like SoC, FPGA management or DMA engine.
> > >
> > > [Fiona] CRC and BIP are not crypto algorithms, they are error detection processes.
> > > So there is no class in DPDK that these readily fit into.
> > > There was resistance to adding another xxxddev, and even if one had been added
> > > for error_detection_dev, there would still have been another layer needed
> > > to couple this with cryptodev. Various proposals for this have been discussed on the ML
> > > in RFC and recent patches, there doesn't seem to be an appetite for this as a generic API.
> > > So it seems that only Intel has software and hardware engines that provide this
> > > specialised feature coupling. In that case rawdev seems like the most
> > > appropriate vehicle to expose this.
> > 
> > Adding some vendor-specific API is not a good answer.
> > It will work in some cases, but it won't make DPDK better.
> > What's the purpose of DPDK if it's not solving a common problem
> > for different hardware?
> 
> [Fiona] Based on that logic rawdev should be deprecated.
> But the community has agreed that it has a place.

No, as I said above, rawdev is good for SoC, FPGA management or DMA engine.

> And the common problem here is device exposure.
> With a specialised service on top.
> 
> 
> > > > Here the intent is to use rawdev because we don't find a good API.
> > > > API defeat is a no-go.
> > >
> > > [Fiona] It's not that we haven't found a good API, but that there doesn't seem
> > > to be a general requirement for such a specialised API
> > 
> > There is a requirement to combine features of different classes.
> 
> [Fiona] Can you point me to that requirement please?

Yes, rte_security is trying to address this exact issue.

> We suggested it, but did not get community engagement and have 
> dropped our generic API requirement, instead focussing on this specialised case.

I did not see such generic proposal, sorry.

> > In the past, rte_security was an "answer" to this issue with crypto and ethdev.
> > This is a real topic, please let's find a generic elegant solution.