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

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> 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.
> > >
> > > fill/read (+ alloc/free) is one of the main things that slowdown current crypto-op
> > > approach.
> > > That's why the general idea - have all data that wouldn't change from packet to
> > > packet
> > > included into the session and setup it once at session_init().
> >
> > I agree that you cannot use crypto-op.
> > You can have the new API in crypto.
> > As per the current patch, you only need cipher_offset which you can have it as a parameter until
> > You get it approved in the crypto xform. I believe it will be beneficial in case of other crypto cases as well.
> > We can have cipher offset at both places(crypto-op and cipher_xform). It will give flexibility to the user to
> > override it.
> 
> After having another thought on your proposal:
> Probably we can introduce new rte_crypto_sym_xform_types for CPU related stuff here?
> Let say we can have :
> num rte_crypto_sym_xform_type {
>         RTE_CRYPTO_SYM_XFORM_NOT_SPECIFIED = 0, /**< No xform specified */
>         RTE_CRYPTO_SYM_XFORM_AUTH,              /**< Authentication xform */
>         RTE_CRYPTO_SYM_XFORM_CIPHER,            /**< Cipher xform  */
>         RTE_CRYPTO_SYM_XFORM_AEAD               /**< AEAD xform  */
> +     RTE_CRYPTO_SYM_XFORM_CPU = INT32_MIN,
> +    RTE_CRYPTO_SYM_XFORM_CPU_AEAD = (RTE_CRYPTO_SYM_XFORM_CPU | RTE_CRYPTO_SYM_XFORM_CPU),
Meant
RTE_CRYPTO_SYM_XFORM_CPU_AEAD = (RTE_CRYPTO_SYM_XFORM_CPU | RTE_CRYPTO_SYM_XFORM_AEAD),
of course.

>       /* same for auth and crypto xforms */
> };
> 
> Then we either can re-define some values in struct rte_crypto_aead_xform (via unions),
> or even have new  struct rte_crypto_cpu_aead_xform (same for crypto and auth xforms).
> Then if PMD wants to support new sync API it would need to recognize new xform types
> and internally  it might end up with different session structure (one for sync, another for async mode).
> That I think should allow us to introduce cpu_crypto as part of crypto-dev API without ABI breakage.
> What do you think?
> Konstantin
> 
> >
> > >
> > > > If you intend not to use rte_crypto_op
> > > > You can pass this as an argument in the new cryptodev API.
> > >
> > > You mean extra parameter in rte_security_process_cpu_crypto_bulk()?
> > > It can be in theory, but that solution looks a bit ugly:
> > > 	why to pass for each call something that would be constant per session?
> > > 	Again having that value constant per session might allow some extra
> > > optimisations
> > > 	That would be hard to achieve for dynamic case.
> > > and not extendable:
> > > Suppose tomorrow will need to add something extra (some new algorithm
> > > support or so).
> > > With what you proposing will need to new parameter to the function,
> > > which means API breakage.
> > >
> > > > Something extra will also cause ABI breakage in security as well.
> > > > So it will be same.
> > >
> > > I don't think it would.
> > > AFAIK, right now this patch doesn't introduce any API/ABI breakage.
> > > Iinside struct rte_security_session_conf we have a union of xforms
> > > depending on session type.
> > > So as long as cpu_crypto_xform wouldn't exceed sizes of other xform -
> > > I believe no ABI breakage will appear.
> > Agreed, it will not break ABI in case of security till we do not exceed current size.
> >
> > Saving an ABI/API breakage is more important or placing the code at the correct place.
> > We need to find a tradeoff. Others can comment on this.
> > @Thomas Monjalon, @De Lara Guarch, Pablo Any comments?
> >
> > >
> > >
> > > >
> > > > > 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.
> > >
> > > Right now - just cipher_offset (see above).
> > > What else in future (if any) - don't know.
> > >
> > > > I don't think there is any.
> > > > I believe the same crypto session will be able to work synchronously as well.
> > >
> > > Exactly the same - problematically, see above.
> > >
> > > > 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.
> > >
> > > To add new API into crypto-dev would also require changes in the PMD,
> > > it wouldn't come totally free and I believe would require roughly the same
> > > amount of changes.
> >
> > It will be required only in the PMDs which support it and would be minimal.
> > You would need a feature flag, support  for that synchronous API. Session information will
> > already be there in the session. The changes wrt cipher_offset need to be added
> > but with some default value to identify override will be done or not.
> >
> > >
> > > >
> > > >
> > > > > 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.
> > >
> > > Various protocols and different types of sessions (and devices they belong to).
> > > Let say right now we have INLINE_CRYPTO, INLINE_PROTO, LOOKASIDE_PROTO,
> > > etc.
> > > Here we introduce new type of session.
> >
> > What is the new value add to the existing sessions. The changes that we are doing
> > here is just to avoid an API/ABI breakage. The synchronous processing can happen on both
> > crypto and security session. This would mean, only the processing API should be defined,
> > rest all should be already there in the sessions.
> > In All other cases, INLINE - eth device was not having any format to perform crypto op
> > LOOKASIDE - PROTO - add protocol specific sessions which is not available in crypto.
> >
> > >
> > > > 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.
> > >
> > > I am considering this new API as an alternative to existing ones, but as an
> > > extension.
> > > Existing crypto-op API has its own advantages (generic), and I think we should
> > > keep it supported by all crypto-devs.
> > > From other side rte_security is an extendable framework that suits the purpose:
> > > allows easily (and yes without ABI breakage) introduce new API for special type
> > > of crypto-dev (SW based).
> > >
> > >
> >
> > Adding a synchronous processing API is understandable and can be added in both
> > Crypto as well as Security, but a new action type for it is not required.
> > Now whether to support that, we have ABI/API breakage, that is a different issue.
> > And we may have to deal with it if no other option is there.
> >
> > >
> > >
> > >
> > > > 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