Re: [dpdk-dev] [RFC PATCH 1/9] security: introduce CPU Crypto action type and API

[Akhil Goyal <akhil.goyal@nxp.com>]

Hi Konstantin,
> 
> Hi Akhil,
> 
> > > This action type allows the burst of symmetric crypto workload using the
> same
> > > algorithm, key, and direction being processed by CPU cycles synchronously.
> > > This flexible action type does not require external hardware involvement,
> > > having the crypto workload processed synchronously, and is more
> performant
> > > than Cryptodev SW PMD due to the saved cycles on removed "async mode
> > > simulation" as well as 3 cacheline access of the crypto ops.
> >
> > Does that mean application will not call the cryptodev_enqueue_burst and
> corresponding dequeue burst.
> 
> Yes, instead it just call rte_security_process_cpu_crypto_bulk(...)
> 
> > It would be a new API something like process_packets and it will have the
> crypto processed packets while returning from the API?
> 
> Yes, though the plan is that API will operate on raw data buffers, not mbufs.
> 
> >
> > I still do not understand why we cannot do with the conventional crypto lib
> only.
> > As far as I can understand, you are not doing any protocol processing or any
> value add
> > To the crypto processing. IMO, you just need a synchronous crypto processing
> API which
> > Can be defined in cryptodev, you don't need to re-create a crypto session in
> the name of
> > Security session in the driver just to do a synchronous processing.
> 
> I suppose your question is why not to have
> rte_crypot_process_cpu_crypto_bulk(...) instead?
> The main reason is that would require disruptive changes in existing cryptodev
> API
> (would cause ABI/API breakage).
> Session for  RTE_SECURITY_ACTION_TYPE_CPU_CRYPTO need some extra
> information
> that normal crypto_sym_xform doesn't contain
> (cipher offset from the start of the buffer, might be something extra in future).

Cipher offset will be part of rte_crypto_op. If you intend not to use rte_crypto_op
You can pass this as an argument in the new cryptodev API.
Something extra will also cause ABI breakage in security as well.
So it will be same.

> Also right now there is no way to add new type of crypto_sym_session without
> either breaking existing crypto-dev ABI/API or introducing new structure
> (rte_crypto_sym_cpu_session or so) for that.

What extra info is required in rte_cryptodev_sym_session to get the rte_crypto_sym_cpu_session.
I don't think there is any.
I believe the same crypto session will be able to work synchronously as well. We would only need
a new API to perform synchronous actions. That will reduce the duplication code significantly
in the driver to support 2 different kind of APIs with similar code inside. 
Please correct me in case I am missing something.


> While rte_security is designed in a way that we can add new session types and
> related parameters without causing API/ABI breakage.

Yes the intent is to add new sessions based on various protocols that can be supported by the driver.
It is not that we should find it as an alternative to cryptodev and using it just because it will not cause
ABI/API breakage. IMO the code should be placed where its intent is.

> 
> BTW, what is your concern with proposed approach (via rte_security)?
> From my perspective it is a lightweight change and it is totally optional
> for the crypto PMDs to support it or not.
> Konstantin
> 
> > >
> > > AESNI-GCM and AESNI-MB PMDs are updated with this support. There is a
> small
> > > performance test app under app/test/security_aesni_gcm(mb)_perftest to
> > > prove.
> > >
> > > For the new API
> > > The packet is sent to the crypto device for symmetric crypto
> > > processing. The device will encrypt or decrypt the buffer based on the
> session
> > > data specified and preprocessed in the security session. Different
> > > than the inline or lookaside modes, when the function exits, the user will
> > > expect the buffers are either processed successfully, or having the error
> number
> > > assigned to the appropriate index of the status array.
> > >
> > > Will update the program's guide in the v1 patch.
> > >
> > > Regards,
> > > Fan
> > >
> > > > -----Original Message-----
> > > > From: Akhil Goyal [mailto:akhil.goyal@nxp.com]
> > > > Sent: Wednesday, September 4, 2019 11:33 AM
> > > > To: Zhang, Roy Fan <roy.fan.zhang@intel.com>; dev@dpdk.org
> > > > Cc: Ananyev, Konstantin <konstantin.ananyev@intel.com>; Doherty,
> Declan
> > > > <declan.doherty@intel.com>; De Lara Guarch, Pablo
> > > > <pablo.de.lara.guarch@intel.com>
> > > > Subject: RE: [RFC PATCH 1/9] security: introduce CPU Crypto action type
> and
> > > > API
> > > >
> > > > Hi Fan,
> > > >
> > > > >
> > > > > This patch introduce new RTE_SECURITY_ACTION_TYPE_CPU_CRYPTO
> > > > action
> > > > > type to security library. The type represents performing crypto
> > > > > operation with CPU cycles. The patch also includes a new API to
> > > > > process crypto operations in bulk and the function pointers for PMDs.
> > > > >
> > > > I am not able to get the flow of execution for this action type. Could you
> > > > please elaborate the flow in the documentation. If not in documentation
> > > > right now, then please elaborate the flow in cover letter.
> > > > Also I see that there are new APIs for processing crypto operations in bulk.
> > > > What does that mean. How are they different from the existing APIs which
> > > > are also handling bulk crypto ops depending on the budget.
> > > >
> > > >
> > > > -Akhil