Re: [dpdk-dev] [dpdk-dev v10 2/4] cryptodev: add raw crypto data-path APIs

["Zhang, Roy Fan" <roy.fan.zhang@intel.com>]

Hi, Good idea. Will do.

> -----Original Message-----
> From: Akhil Goyal <akhil.goyal@nxp.com>
> Sent: Thursday, October 8, 2020 5:08 PM
> To: Zhang, Roy Fan <roy.fan.zhang@intel.com>; dev@dpdk.org
> Cc: Trahe, Fiona <fiona.trahe@intel.com>; Kusztal, ArkadiuszX
> <arkadiuszx.kusztal@intel.com>; Dybkowski, AdamX
> <adamx.dybkowski@intel.com>; anoobj@marvell.com; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; Bronowski, PiotrX
> <piotrx.bronowski@intel.com>
> Subject: RE: [dpdk-dev v10 2/4] cryptodev: add raw crypto data-path APIs
> 
> > > > +During the enqueue, the cryptodev driver only sets the enqueued
> > > descriptors
> > > > +into the device queue but not initiates the device to start processing
> them.
> > > > +The temporary queue pair data changes in relation to the enqueued
> > > descriptors
> > > > +may be recorded in the ``struct rte_crypto_raw_dp_ctx`` buffer as the
> > > > reference
> > > > +to the next enqueue function call. When
> > > ``rte_cryptodev_raw_enqueue_done``
> > > > is
> > > > +called, the driver will initiate the processing of all enqueued
> descriptors
> > > and
> > > > +merge the temporary queue pair data changes into the driver's private
> > > queue
> > > > +pair data. Calling ``rte_cryptodev_raw_configure_dp_context`` twice
> > > without
> > > > +``rte_cryptodev_dp_enqueue_done`` call in between will invalidate
> the
> > > > temporary
> > > > +data stored in ``struct rte_crypto_raw_dp_ctx`` buffer. This feature is
> > > useful
> > > > +when the user wants to abandon partially enqueued data for a failed
> > > enqueue
> > > > +burst operation and try enqueuing in a whole later.
> > >
> > > This feature may not be supported by all the HW PMDs, Can there be a
> way
> > > to bypass
> > > this done API?
> >
> > We can add another feature flag
> > "RTE_CRYPTODEV_FF_SYM_HW_RAW_DP_ALLOW_CACHE". The PMDs
> who
> > do not support this feature can simply return "- ENOTSUP" when calling
> > enqueue_done and dequeue_done function. What do you think?
> 
> Can the enqueue/dequeue API return a flag which decide whether
> to call done API or not?
> Returning ENOTSUP will break the execution.
> 
> 
> > > > +int
> > > > +rte_cryptodev_raw_configure_dp_context(uint8_t dev_id, uint16_t
> > > qp_id,
> > > > +	struct rte_crypto_raw_dp_ctx *ctx)
> > >
> > > rte_cryptodev_configure_raw_dp_ctx
> > >
> > > > +{
> > > > +	struct rte_cryptodev *dev;
> > > > +	union rte_cryptodev_session_ctx sess_ctx = {NULL};
> > > > +
> > > > +	if (!rte_cryptodev_get_qp_status(dev_id, qp_id))
> > > > +		return -EINVAL;
> > > > +
> > > > +	dev = rte_cryptodev_pmd_get_dev(dev_id);
> > > > +	if (!(dev->feature_flags & RTE_CRYPTODEV_FF_SYM_HW_RAW_DP)
> > > > +			|| dev->dev_ops->configure_dp_ctx == NULL)
> > > > +		return -ENOTSUP;
> > > > +
> > > > +	return (*dev->dev_ops->configure_dp_ctx)(dev, qp_id,
> > > > +			RTE_CRYPTO_OP_WITH_SESSION, sess_ctx, ctx);
> > > > +}
> > > > +
> > > > +int
> > > > +rte_cryptodev_raw_attach_session(uint8_t dev_id, uint16_t qp_id,
> > > > +	struct rte_crypto_raw_dp_ctx *ctx,
> > > > +	enum rte_crypto_op_sess_type sess_type,
> > > > +	union rte_cryptodev_session_ctx session_ctx)
> > > > +{
> > > > +	struct rte_cryptodev *dev;
> > > > +
> > > > +	if (!rte_cryptodev_get_qp_status(dev_id, qp_id))
> > > > +		return -EINVAL;
> > > > +
> > > > +	dev = rte_cryptodev_pmd_get_dev(dev_id);
> > > > +	if (!(dev->feature_flags & RTE_CRYPTODEV_FF_SYM_HW_RAW_DP)
> > > > +			|| dev->dev_ops->configure_dp_ctx == NULL)
> > > > +		return -ENOTSUP;
> > > > +	return (*dev->dev_ops->configure_dp_ctx)(dev, qp_id, sess_type,
> > > > +			session_ctx, ctx);
> > >
> > > What is the difference between
> rte_cryptodev_raw_configure_dp_context
> > > and
> > > rte_cryptodev_raw_attach_session?
> > > And if at all it is needed, then it should be
> > > rte_cryptodev_attach_raw_dp_session.
> > > IMO attach is not needed, I am not clear about it.
> > >
> > > You are calling the same dev_ops for both - one with explicit session time
> > > and other
> > > From an argument.
> >
> > rte_cryptodev_raw_configure_dp_context creates a shadow copy of the
> queue
> > pair data with in ctx, where rte_cryptodev_raw_attach_session sets the
> function
> > handler based on the session data. Using of the same PMD callback
> function is
> > to
> > save one function pointer stored in the dev_ops. If you don't like it I can
> create
> > 2 callback functions no problem.
> 
> I don't like the idea of having 2 APIs.
> 
> Why do you need to create a shadow copy of the queue data? Why it can't
> be
> Done in the attach API by the driver? In v9 it was doing that, why is it changed?
>