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

[Zhang, Roy Fan]

Hi Akhil,

You are right, the new API will process the crypto workload, no heavy enqueue
Dequeue operations required. 

Cryptodev tends to support multiple crypto devices, including HW and SW. 
The 3-cache line access, iova address computation and assignment, simulation
of async enqueue/dequeue operations, allocate and free crypto ops, even the
mbuf linked-list for scatter-gather buffers are too heavy for SW crypto PMDs.

To create this new synchronous API in cryptodev cannot avoid the problem
listed above:  first the API shall not serve only to part of the crypto (SW) PMDs -
as you know, it is Cryptodev. The users can expect some PMD only support part
of the overall algorithms, but not the workload processing API. 

Another reason is, there is assumption made, first when creating a crypto op
we have to allocate the memory to hold crypto op + sym op + iv, - we cannot
simply declare an array of crypto ops in the run-time and discard it when processing
is done. Also we need to fill aad and digest HW address, which is not required for
SW at all. 

Bottom line: using crypto op will still have 3 cache-line access performance problem.

So if we to create the new API in Cryptodev instead of rte_security, we need to
create new crypto op structure only for the SW PMDs, carefully document them
to not confuse with existing cryptodev APIs, make new device feature flags to
indicate the API is not supported by some PMDs, and again carefully document
them of these device feature flags.

So, to push these changes to rte_security instead the above problem can be resolved,
and the performance improvement because of this change is big for smaller packets
- I attached a performance test app in the patchset.

For rte_security, we already have inline-crypto type that works quite close to the this
new API, the only difference is that it is processed by the CPU cycles. As you may
have already seen the ipsec-library has wrapped these changes, and ipsec-secgw
has only minimum updates to adopt this change too. So to the end user, if they 
use IPSec this patchset can seamlessly enabled with just commandline update when
creating an SA.

Regards,
Fan
 

> -----Original Message-----
> From: Akhil Goyal [mailto:akhil.goyal at nxp.com]
> Sent: Friday, September 6, 2019 10:01 AM
> To: Zhang, Roy Fan <roy.fan.zhang at intel.com>; dev at dpdk.org
> Cc: Ananyev, Konstantin <konstantin.ananyev at intel.com>; Doherty, Declan
> <declan.doherty at intel.com>; De Lara Guarch, Pablo
> <pablo.de.lara.guarch at intel.com>
> Subject: RE: [RFC PATCH 1/9] security: introduce CPU Crypto action type and
> API
> 
> 
> Hi Fan,
> >
> > 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.
> It would be a new API something like process_packets and it will have the
> crypto processed packets while returning from the API?
> 
> 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.
> 
> >
> > 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 at nxp.com]
> > > Sent: Wednesday, September 4, 2019 11:33 AM
> > > To: Zhang, Roy Fan <roy.fan.zhang at intel.com>; dev at dpdk.org
> > > Cc: Ananyev, Konstantin <konstantin.ananyev at intel.com>; Doherty,
> > > Declan <declan.doherty at intel.com>; De Lara Guarch, Pablo
> > > <pablo.de.lara.guarch at 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