42. Event Crypto Adapter Library

The DPDK Eventdev library provides event driven programming model with features to schedule events. The Cryptodev library provides an interface to the crypto poll mode drivers which supports different crypto operations. The Event Crypto Adapter is one of the adapter which is intended to bridge between the event device and the crypto device.

The packet flow from crypto device to the event device can be accomplished using SW and HW based transfer mechanism. The Adapter queries an eventdev PMD to determine which mechanism to be used. The adapter uses an EAL service core function for SW based packet transfer and uses the eventdev PMD functions to configure HW based packet transfer between the crypto device and the event device. The crypto adapter uses a new event type called RTE_EVENT_TYPE_CRYPTODEV to indicate the event source.

The application can choose to submit a crypto operation directly to crypto device or send it to the crypto adapter via eventdev based on RTE_EVENT_CRYPTO_ADAPTER_CAP_INTERNAL_PORT_OP_FWD capability. The first mode is known as the event new(RTE_EVENT_CRYPTO_ADAPTER_OP_NEW) mode and the second as the event forward(RTE_EVENT_CRYPTO_ADAPTER_OP_FORWARD) mode. The choice of mode can be specified while creating the adapter. In the former mode, it is an application responsibility to enable ingress packet ordering. In the latter mode, it is the adapter responsibility to enable the ingress packet ordering.

42.1. Adapter Mode

42.1.1. RTE_EVENT_CRYPTO_ADAPTER_OP_NEW mode

In the RTE_EVENT_CRYPTO_ADAPTER_OP_NEW mode, application submits crypto operations directly to crypto device. The adapter then dequeues crypto completions from crypto device and enqueues them as events to the event device. This mode does not ensure ingress ordering, if the application directly enqueues to the cryptodev without going through crypto/atomic stage. In this mode, events dequeued from the adapter will be treated as new events. The application needs to specify event information (response information) which is needed to enqueue an event after the crypto operation is completed.

../_images/event_crypto_adapter_op_new.svg

Fig. 42.3 Working model of RTE_EVENT_CRYPTO_ADAPTER_OP_NEW mode

42.1.2. RTE_EVENT_CRYPTO_ADAPTER_OP_FORWARD mode

In the RTE_EVENT_CRYPTO_ADAPTER_OP_FORWARD mode, if HW supports RTE_EVENT_CRYPTO_ADAPTER_CAP_INTERNAL_PORT_OP_FWD capability the application can directly submit the crypto operations to the cryptodev. If not, application retrieves crypto adapter’s event port using rte_event_crypto_adapter_event_port_get() API. Then, links its event queue to this port and starts enqueuing crypto operations as events to the eventdev. The adapter then dequeues the events and submits the crypto operations to the cryptodev. After the crypto completions, the adapter enqueues events to the event device. Application can use this mode, when ingress packet ordering is needed. In this mode, events dequeued from the adapter will be treated as forwarded events. The application needs to specify the cryptodev ID and queue pair ID (request information) needed to enqueue a crypto operation in addition to the event information (response information) needed to enqueue an event after the crypto operation has completed.

../_images/event_crypto_adapter_op_forward.svg

Fig. 42.4 Working model of RTE_EVENT_CRYPTO_ADAPTER_OP_FORWARD mode

42.2. API Overview

This section has a brief introduction to the event crypto adapter APIs. The application is expected to create an adapter which is associated with a single eventdev, then add cryptodev and queue pair to the adapter instance.

42.2.1. Create an adapter instance

An adapter instance is created using rte_event_crypto_adapter_create(). This function is called with event device to be associated with the adapter and port configuration for the adapter to setup an event port(if the adapter needs to use a service function).

Adapter can be started in RTE_EVENT_CRYPTO_ADAPTER_OP_NEW or RTE_EVENT_CRYPTO_ADAPTER_OP_FORWARD mode.

int err;
uint8_t dev_id, id;
struct rte_event_dev_info dev_info;
struct rte_event_port_conf conf;
enum rte_event_crypto_adapter_mode mode;

err = rte_event_dev_info_get(id, &dev_info);

conf.new_event_threshold = dev_info.max_num_events;
conf.dequeue_depth = dev_info.max_event_port_dequeue_depth;
conf.enqueue_depth = dev_info.max_event_port_enqueue_depth;
mode = RTE_EVENT_CRYPTO_ADAPTER_OP_FORWARD;
err = rte_event_crypto_adapter_create(id, dev_id, &conf, mode);

If the application desires to have finer control of eventdev port allocation and setup, it can use the rte_event_crypto_adapter_create_ext() function. The rte_event_crypto_adapter_create_ext() function is passed as a callback function. The callback function is invoked if the adapter needs to use a service function and needs to create an event port for it. The callback is expected to fill the struct rte_event_crypto_adapter_conf structure passed to it.

For RTE_EVENT_CRYPTO_ADAPTER_OP_FORWARD mode, the event port created by adapter can be retrieved using rte_event_crypto_adapter_event_port_get() API. Application can use this event port to link with event queue on which it enqueues events towards the crypto adapter.

uint8_t id, evdev, crypto_ev_port_id, app_qid;
struct rte_event ev;
int ret;

ret = rte_event_crypto_adapter_event_port_get(id, &crypto_ev_port_id);
ret = rte_event_queue_setup(evdev, app_qid, NULL);
ret = rte_event_port_link(evdev, crypto_ev_port_id, &app_qid, NULL, 1);

// Fill in event info and update event_ptr with rte_crypto_op
memset(&ev, 0, sizeof(ev));
ev.queue_id = app_qid;
.
.
ev.event_ptr = op;
ret = rte_event_enqueue_burst(evdev, app_ev_port_id, ev, nb_events);

42.2.2. Querying adapter capabilities

The rte_event_crypto_adapter_caps_get() function allows the application to query the adapter capabilities for an eventdev and cryptodev combination. This API provides whether cryptodev and eventdev are connected using internal HW port or not.

rte_event_crypto_adapter_caps_get(dev_id, cdev_id, &cap);

42.2.3. Adding queue pair to the adapter instance

Cryptodev device id and queue pair are created using cryptodev APIs. For more information see here.

struct rte_cryptodev_config conf;
struct rte_cryptodev_qp_conf qp_conf;
uint8_t cdev_id = 0;
uint16_t qp_id = 0;

rte_cryptodev_configure(cdev_id, &conf);
rte_cryptodev_queue_pair_setup(cdev_id, qp_id, &qp_conf);

These cryptodev id and queue pair are added to the instance using the rte_event_crypto_adapter_queue_pair_add() API. The same is removed using rte_event_crypto_adapter_queue_pair_del() API. If HW supports RTE_EVENT_CRYPTO_ADAPTER_CAP_INTERNAL_PORT_QP_EV_BIND capability, event information must be passed to the add API.

uint32_t cap;
int ret;

ret = rte_event_crypto_adapter_caps_get(id, evdev, &cap);
if (cap & RTE_EVENT_CRYPTO_ADAPTER_CAP_INTERNAL_PORT_QP_EV_BIND) {
        struct rte_event event;

        // Fill in event information & pass it to add API
        rte_event_crypto_adapter_queue_pair_add(id, cdev_id, qp_id, &event);
} else
        rte_event_crypto_adapter_queue_pair_add(id, cdev_id, qp_id, NULL);

42.2.4. Configure the service function

If the adapter uses a service function, the application is required to assign a service core to the service function as show below.

uint32_t service_id;

if (rte_event_crypto_adapter_service_id_get(id, &service_id) == 0)
        rte_service_map_lcore_set(service_id, CORE_ID);

42.2.5. Set event request/response information

In the RTE_EVENT_CRYPTO_ADAPTER_OP_FORWARD mode, the application needs to specify the cryptodev ID and queue pair ID (request information) in addition to the event information (response information) needed to enqueue an event after the crypto operation has completed. The request and response information are specified in the struct rte_crypto_op private data or session’s private data.

In the RTE_EVENT_CRYPTO_ADAPTER_OP_NEW mode, the application is required to provide only the response information.

The SW adapter or HW PMD uses rte_crypto_op::sess_type to decide whether request/response data is located in the crypto session/ crypto security session or at an offset in the struct rte_crypto_op. The rte_crypto_op::private_data_offset is used to locate the request/ response in the rte_crypto_op.

For crypto session, rte_cryptodev_sym_session_set_user_data() API will be used to set request/response data. The same data will be obtained by rte_cryptodev_sym_session_get_user_data() API. The RTE_EVENT_CRYPTO_ADAPTER_CAP_SESSION_PRIVATE_DATA capability indicates whether HW or SW supports this feature.

For security session, rte_security_session_set_private_data() API will be used to set request/response data. The same data will be obtained by rte_security_session_get_private_data() API.

For session-less it is mandatory to place the request/response data with the rte_crypto_op.

union rte_event_crypto_metadata m_data;
struct rte_event ev;
struct rte_crypto_op *op;

/* Allocate & fill op structure */
op = rte_crypto_op_alloc();

memset(&m_data, 0, sizeof(m_data));
memset(&ev, 0, sizeof(ev));
/* Fill event information and update event_ptr to rte_crypto_op */
ev.event_ptr = op;

if (op->sess_type == RTE_CRYPTO_OP_WITH_SESSION) {
        /* Copy response information */
        rte_memcpy(&m_data.response_info, &ev, sizeof(ev));
        /* Copy request information */
        m_data.request_info.cdev_id = cdev_id;
        m_data.request_info.queue_pair_id = qp_id;
        /* Call set API to store private data information */
        rte_cryptodev_sym_session_set_user_data(
                op->sym->session,
                &m_data,
                sizeof(m_data));
} if (op->sess_type == RTE_CRYPTO_OP_SESSIONLESS) {
        uint32_t len = IV_OFFSET + MAXIMUM_IV_LENGTH +
                       (sizeof(struct rte_crypto_sym_xform) * 2);
        op->private_data_offset = len;
        /* Copy response information */
        rte_memcpy(&m_data.response_info, &ev, sizeof(ev));
        /* Copy request information */
        m_data.request_info.cdev_id = cdev_id;
        m_data.request_info.queue_pair_id = qp_id;
        /* Store private data information along with rte_crypto_op */
        rte_memcpy(op + len, &m_data, sizeof(m_data));
}

42.2.6. Start the adapter instance

The application calls rte_event_crypto_adapter_start() to start the adapter. This function calls the start callbacks of the eventdev PMDs for hardware based eventdev-cryptodev connections and rte_service_run_state_set() to enable the service function if one exists.

rte_event_crypto_adapter_start(id, mode);

Note

The eventdev to which the event_crypto_adapter is connected needs to be started before calling rte_event_crypto_adapter_start().

42.2.7. Get adapter statistics

The rte_event_crypto_adapter_stats_get() function reports counters defined in struct rte_event_crypto_adapter_stats. The received packet and enqueued event counts are a sum of the counts from the eventdev PMD callbacks if the callback is supported, and the counts maintained by the service function, if one exists.