[dpdk-dev] [PATCH v1] lib/bpf: add event callback for bpf

[dpdk-dev] [PATCH v1] lib/bpf: add event callback for bpf

[Vipin Varghese]

The patch series adds bpf load-unload to event pre-enqueue and
post-dequeue stages.

Signed-off-by: Vipin Varghese <vipin.varghese@intel.com>
---
 lib/librte_bpf/bpf_event.c         | 432 +++++++++++++++++++++++++++++
 lib/librte_bpf/rte_bpf_eventdev.h  | 117 ++++++++
 lib/librte_bpf/rte_bpf_version.map |   4 +
 3 files changed, 553 insertions(+)
 create mode 100644 lib/librte_bpf/bpf_event.c
 create mode 100644 lib/librte_bpf/rte_bpf_eventdev.h

diff --git a/lib/librte_bpf/bpf_event.c b/lib/librte_bpf/bpf_event.c
new file mode 100644
index 000000000..7cabfd1f5
--- /dev/null
+++ b/lib/librte_bpf/bpf_event.c
@@ -0,0 +1,432 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018 Intel Corporation
+ */
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <inttypes.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/queue.h>
+
+#include <rte_common.h>
+#include <rte_byteorder.h>
+#include <rte_malloc.h>
+#include <rte_log.h>
+#include <rte_debug.h>
+#include <rte_cycles.h>
+#include <rte_eal.h>
+#include <rte_per_lcore.h>
+#include <rte_lcore.h>
+#include <rte_atomic.h>
+#include <rte_eventdev.h>
+
+#include <rte_bpf_eventdev.h>
+#include "bpf_impl.h"
+
+/*
+ * information about installed BPF enq/deq callback
+ */
+
+struct bpf_event_cbi {
+	/* used by both data & control path */
+	uint32_t use;    /*usage counter */
+	struct rte_eventdev_callback *cb;  /* callback handle */
+	struct rte_bpf *bpf;
+	struct rte_bpf_jit jit;
+	/* used by control path only */
+	LIST_ENTRY(bpf_event_cbi) link;
+	uint16_t deviceid;
+} __rte_cache_aligned;
+
+/*
+ * Odd number means that callback is used by datapath.
+ * Even number means that callback is not used by datapath.
+ */
+#define BPF_EVENT_CBI_INUSE  1
+
+/*
+ * List to manage RX/TX installed callbacks.
+ */
+LIST_HEAD(bpf_event_cbi_list, bpf_event_cbi);
+
+enum {
+	BPF_EVENT_ENQ,
+	BPF_EVENT_DEQ,
+	BPF_EVENT_NUM,
+};
+
+/*
+ * information about all installed BPF rx/tx callbacks
+ */
+struct bpf_event_cbh {
+	rte_spinlock_t lock;
+	struct bpf_event_cbi_list list;
+	uint32_t type;
+};
+
+static struct bpf_event_cbh event_enq_cbh = {
+	.lock = RTE_SPINLOCK_INITIALIZER,
+	.list = LIST_HEAD_INITIALIZER(list),
+	.type = BPF_EVENT_ENQ,
+};
+
+static struct bpf_event_cbh event_deq_cbh = {
+	.lock = RTE_SPINLOCK_INITIALIZER,
+	.list = LIST_HEAD_INITIALIZER(list),
+	.type = BPF_EVENT_DEQ,
+};
+/*
+ * Marks given callback as used by datapath.
+ */
+
+/*
+ * Marks given callback list as not used by datapath.
+ */
+
+/*
+ * Waits till datapath finished using given callback.
+ */
+
+/*
+ * BPF packet processing routinies.
+ */
+
+static void
+bpf_event_cbi_wait(const struct bpf_event_cbi *cbi)
+{
+	uint32_t nuse, puse;
+
+	/* make sure all previous loads and stores are completed */
+	rte_smp_mb();
+
+	puse = cbi->use;
+
+	/* in use, busy wait till current RX/TX iteration is finished */
+	if ((puse & BPF_EVENT_CBI_INUSE) != 0) {
+		do {
+			rte_pause();
+			rte_compiler_barrier();
+			nuse = cbi->use;
+		} while (nuse == puse);
+	}
+}
+
+static inline uint32_t
+apply_event_filter(struct rte_event *ev,
+		const uint64_t rc[], uint32_t num)
+{
+	uint32_t i, j, k;
+	struct rte_event *dr[num];
+
+	for (i = 0, j = 0, k = 0; i != num; i++) {
+		/* filter matches */
+		if (rc[i] != 0)
+			ev[j++] = ev[i];
+		/* no match */
+		else
+			dr[k++] = &ev[i];
+	}
+
+	for (i = 0; i != k; i++)
+		ev[j + i] = *dr[i];
+
+	return j;
+}
+
+static inline uint32_t
+event_filter_jit(const struct rte_bpf_jit *jit, struct rte_event *ev,
+		uint16_t num)
+{
+	uint32_t i, n;
+	uint64_t rc[num];
+
+	n = 0;
+	for (i = 0; i != num; i++) {
+		rc[i] = jit->func((void *) &ev[i]);
+		n += (rc[i] == 0);
+	}
+
+	if (n != 0)
+		num = apply_event_filter(ev, rc, num);
+
+	return num;
+}
+
+static __rte_always_inline void
+bpf_event_cbi_inuse(struct bpf_event_cbi *cbi)
+{
+	cbi->use++;
+	/* make sure no store/load reordering could happen */
+	rte_smp_mb();
+}
+
+static __rte_always_inline void
+bpf_event_cbi_unuse(struct bpf_event_cbi *cbi)
+{
+	/* make sure all previous loads are completed */
+	rte_smp_rmb();
+	cbi->use++;
+}
+
+static uint16_t
+bpf_event_enq_jit(__rte_unused uint16_t deviceid,
+		__rte_unused uint16_t port,
+		struct rte_event *ev, uint16_t nb_events, void *user_param)
+{
+	struct bpf_event_cbi *cbi;
+	uint16_t rc;
+
+	cbi = user_param;
+	bpf_event_cbi_inuse(cbi);
+	rc = (cbi->cb != NULL) ?
+			event_filter_jit(&cbi->jit, ev, nb_events) :
+			nb_events;
+	bpf_event_cbi_unuse(cbi);
+
+	return rc;
+}
+
+static uint16_t
+bpf_event_deq_jit(__rte_unused uint16_t deviceid,
+		__rte_unused uint16_t port,
+		struct rte_event *ev, uint16_t nb_events, void *user_param)
+{
+	struct bpf_event_cbi *cbi;
+	uint16_t rc;
+
+	cbi = user_param;
+	bpf_event_cbi_inuse(cbi);
+	rc = (cbi->cb != NULL) ?
+			event_filter_jit(&cbi->jit, ev, nb_events) :
+			nb_events;
+	bpf_event_cbi_unuse(cbi);
+
+	return rc;
+}
+
+static void
+bpf_event_cbi_cleanup(struct bpf_event_cbi *bc)
+{
+	bc->bpf = NULL;
+	memset(&bc->jit, 0, sizeof(bc->jit));
+}
+
+static struct bpf_event_cbi *
+bpf_event_cbh_find(struct bpf_event_cbh *cbh, uint16_t deviceid)
+{
+	struct bpf_event_cbi *cbi;
+
+	LIST_FOREACH(cbi, &cbh->list, link) {
+		if (cbi->deviceid == deviceid)
+			break;
+	}
+	return cbi;
+}
+
+static struct bpf_event_cbi *
+bpf_event_cbh_add(struct bpf_event_cbh *cbh, uint16_t deviceid)
+{
+	struct bpf_event_cbi *cbi;
+
+	/* return an existing one */
+	cbi = bpf_event_cbh_find(cbh, deviceid);
+	if (cbi != NULL)
+		return cbi;
+
+	cbi = rte_zmalloc(NULL, sizeof(*cbi), RTE_CACHE_LINE_SIZE);
+	if (cbi != NULL) {
+		cbi->deviceid = deviceid;
+		LIST_INSERT_HEAD(&cbh->list, cbi, link);
+	}
+	return cbi;
+}
+
+static void
+bpf_event_cbi_unload(struct bpf_event_cbi *bc)
+{
+	/* mark this cbi as empty */
+	bc->cb = NULL;
+	rte_smp_mb();
+
+	/* make sure datapath doesn't use bpf anymore, then destroy bpf */
+	bpf_event_cbi_wait(bc);
+	rte_bpf_destroy(bc->bpf);
+	bpf_event_cbi_cleanup(bc);
+}
+static void
+bpf_event_unload(struct bpf_event_cbh *cbh, uint16_t deviceid)
+{
+	struct bpf_event_cbi *bc;
+	struct rte_eventdev_callback *cb;
+
+	bc = bpf_event_cbh_find(cbh, deviceid);
+	if (bc == NULL || bc->cb == NULL)
+		return;
+
+	cb = bc->cb;
+
+	if (cbh->type == BPF_EVENT_ENQ)
+		rte_eventdev_preenq_callback_unregister(deviceid, 0,
+			cb->cb_fn, cb->cb_arg);
+	else
+		rte_eventdev_pstdeq_callback_unregister(deviceid, 0,
+			cb->cb_fn, cb->cb_arg);
+
+	bpf_event_cbi_unload(bc);
+}
+
+__rte_experimental void
+rte_bpf_event_enq_unload(uint8_t device, __rte_unused uint8_t port)
+{
+	struct bpf_event_cbh *cbh;
+
+	cbh = &event_enq_cbh;
+	rte_spinlock_lock(&cbh->lock);
+	bpf_event_unload(cbh, device);
+	rte_spinlock_unlock(&cbh->lock);
+}
+
+__rte_experimental void
+rte_bpf_event_deq_unload(uint8_t device, __rte_unused uint8_t port)
+{
+	struct bpf_event_cbh *cbh;
+
+	cbh = &event_deq_cbh;
+	rte_spinlock_lock(&cbh->lock);
+	bpf_event_unload(cbh, device);
+	rte_spinlock_unlock(&cbh->lock);
+}
+
+
+static rte_eventdev_cb_fn
+select_event_enq_callback(enum rte_bpf_arg_type type, uint32_t flags)
+{
+	if (flags & RTE_BPF_EVENT_F_JIT) {
+		if (type == RTE_BPF_ARG_PTR)
+			return (rte_eventdev_cb_fn) bpf_event_enq_jit;
+	}
+
+	return NULL;
+}
+
+static rte_eventdev_cb_fn
+select_event_deq_callback(enum rte_bpf_arg_type type, uint32_t flags)
+{
+	if (flags & RTE_BPF_EVENT_F_JIT) {
+		if (type == RTE_BPF_ARG_PTR)
+			return (rte_eventdev_cb_fn) bpf_event_deq_jit;
+	}
+
+	return NULL;
+}
+
+
+static int
+bpf_event_elf_load(struct bpf_event_cbh *cbh, uint16_t deviceid, uint16_t port,
+	const struct rte_bpf_prm *prm, const char *fname, const char *sname,
+	uint32_t flags)
+{
+	int32_t rc;
+	struct bpf_event_cbi *bc;
+	struct rte_bpf *bpf;
+	rte_eventdev_cb_fn fenq;
+	rte_eventdev_cb_fn fdeq;
+	struct rte_bpf_jit jit;
+
+	fenq = NULL;
+	fdeq = NULL;
+
+	if (prm == NULL || rte_event_dev_socket_id(deviceid) == -EINVAL)
+		return -EINVAL;
+
+	if (cbh->type == BPF_EVENT_ENQ)
+		fenq = select_event_enq_callback(prm->prog_arg.type, flags);
+	else if (cbh->type == BPF_EVENT_DEQ)
+		fdeq = select_event_deq_callback(prm->prog_arg.type, flags);
+	else
+		return -EINVAL;
+
+	if (fenq == NULL && fdeq == NULL) {
+		RTE_BPF_LOG(ERR, "%s(%u): no callback selected;\n",
+			__func__, deviceid);
+		return -EINVAL;
+	}
+
+	bpf = rte_bpf_elf_load(prm, fname, sname);
+	if (bpf == NULL)
+		return -rte_errno;
+
+	rte_bpf_get_jit(bpf, &jit);
+
+	if ((flags & RTE_BPF_EVENT_F_JIT) != 0 && jit.func == NULL) {
+		RTE_BPF_LOG(ERR, "%s(%u): no JIT generated;\n",
+			__func__, deviceid);
+		rte_bpf_destroy(bpf);
+		return -ENOTSUP;
+	}
+
+	/* setup/update global callback info */
+	bc = bpf_event_cbh_add(cbh, deviceid);
+	if (bc == NULL)
+		return -ENOMEM;
+
+	/* remove old one, if any */
+	if (bc->cb != NULL)
+		bpf_event_unload(cbh, deviceid);
+
+	bc->bpf = bpf;
+	bc->jit = jit;
+
+	if (cbh->type == BPF_EVENT_ENQ)
+		bc->cb = rte_event_add_preenq(deviceid, port, fenq, bc);
+	else if (cbh->type == BPF_EVENT_DEQ)
+		bc->cb = rte_event_add_pstdeq(deviceid, port, fdeq, bc);
+
+	if (bc->cb == NULL) {
+		rc = -rte_errno;
+		rte_bpf_destroy(bpf);
+		bpf_event_cbi_cleanup(bc);
+	} else
+		rc = 0;
+
+	return rc;
+}
+
+__rte_experimental int
+rte_bpf_event_enq_elf_load(uint8_t deviceid, uint8_t port,
+	const struct rte_bpf_prm *prm, const char *fname, const char *sname,
+	uint32_t flags)
+{
+	int32_t rc;
+	struct bpf_event_cbh *cbh;
+
+	cbh = &event_enq_cbh;
+	rte_spinlock_lock(&cbh->lock);
+	rc = bpf_event_elf_load(cbh, deviceid, port, prm, fname, sname, flags);
+	rte_spinlock_unlock(&cbh->lock);
+
+	return rc;
+}
+
+__rte_experimental int
+rte_bpf_event_deq_elf_load(uint8_t deviceid, uint8_t port,
+	const struct rte_bpf_prm *prm, const char *fname, const char *sname,
+	uint32_t flags)
+{
+	int32_t rc;
+	struct bpf_event_cbh *cbh;
+
+	cbh = &event_deq_cbh;
+	rte_spinlock_lock(&cbh->lock);
+	rc = bpf_event_elf_load(cbh, deviceid, port, prm, fname, sname, flags);
+	rte_spinlock_unlock(&cbh->lock);
+
+	return rc;
+}
diff --git a/lib/librte_bpf/rte_bpf_eventdev.h b/lib/librte_bpf/rte_bpf_eventdev.h
new file mode 100644
index 000000000..2db65c93c
--- /dev/null
+++ b/lib/librte_bpf/rte_bpf_eventdev.h
@@ -0,0 +1,117 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018 Intel Corporation
+ */
+
+#ifndef _RTE_BPF_EVENTDEV_H_
+#define _RTE_BPF_EVENTDEV_H_
+
+/**
+ * @file rte_bpf_eventdev.h
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * API to install BPF filter as Enqueue/Dequeue callbacks for event devices.
+ * Note that right now:
+ * - it is not MT safe, i.e. it is not allowed to do load/unload for the
+ *   same device from different threads in parallel.
+ * - though it allows to do load/unload at runtime
+ *   (while Enqueue/Dequeue is ongoing on given device).
+ * - allows only one BPF program per device,
+ * i.e. new load will replace previously loaded for that device BPF program.
+ * Filter behaviour - if BPF program returns zero value for a given event,
+ * then it will be dropped inside callback and no further processing
+ *   on Enqueue - it will be dropped inside callback and no further processing
+ *   for that event will happen.
+ *   on Dequeue - packet will remain unsent, and it is responsibility of the
+ *   user to handle such situation (drop, try to send again, etc.).
+ */
+
+#include <rte_bpf.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum {
+	RTE_BPF_EVENT_F_NONE = 0,
+	RTE_BPF_EVENT_F_JIT  = 0x1, /*< use compiled into native ISA code */
+};
+
+/**
+ * Unload previously loaded BPF program (if any) from given event-port
+ * and remove appropriate pre-enqueue event-port callback.
+ *
+ * @param device
+ *  The identifier of the event device
+ * @param port
+ *  The identifier of the port for event device
+ */
+void __rte_experimental
+rte_bpf_event_enq_unload(uint8_t device, uint8_t port);
+
+/**
+ * Unload previously loaded BPF program (if any) from given event-port
+ * and remove appropriate post-dequeue event-port callback.
+ *
+ * @param device
+ *  The identifier of the event device
+ * @param port
+ *  The identifier of the port for event device
+ */
+void __rte_experimental
+rte_bpf_event_deq_unload(uint8_t device, uint8_t port);
+
+/**
+ * Load BPF program from the ELF file and install callback to execute it
+ * on given event device-port for pre-enqueue.
+ *
+ * @param device
+ *  The identifier of the event device
+ * @param port
+ *  The identifier of the event-port
+ * @param prm
+ *  Parameters used to create and initialise the BPF exeution context.
+ * @param fname
+ *  Pathname for a ELF file.
+ * @param sname
+ *  Name of the executable section within the file to load.
+ * @param flags
+ *  Flags that define expected behavior of the loaded filter
+ *  (i.e. jited/non-jited version to use).
+ * @return
+ *   Zero on successful completion or negative error code otherwise.
+ */
+int __rte_experimental
+rte_bpf_event_enq_elf_load(uint8_t device, uint8_t port,
+	const struct rte_bpf_prm *prm, const char *fname, const char *sname,
+	uint32_t flags);
+
+/**
+ * Load BPF program from the ELF file and install callback to execute it
+ * on given device-port for post-dequeue.
+ *
+ * @param device
+ *  The identifier of the event device.
+ * @param port
+ *  The identifier of the event-port
+ * @param prm
+ *  Parameters used to create and initialise the BPF exeution context.
+ * @param fname
+ *  Pathname for a ELF file.
+ * @param sname
+ *  Name of the executable section within the file to load.
+ * @param flags
+ *  Flags that define expected expected behavior of the loaded filter
+ *  (i.e. jited/non-jited version to use).
+ * @return
+ *   Zero on successful completion or negative error code otherwise.
+ */
+int __rte_experimental
+rte_bpf_event_deq_elf_load(uint8_t device, uint8_t port,
+	const struct rte_bpf_prm *prm, const char *fname, const char *sname,
+	uint32_t flags);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_BPF_EVENTDEV_H_ */
diff --git a/lib/librte_bpf/rte_bpf_version.map b/lib/librte_bpf/rte_bpf_version.map
index a203e088e..09a9d9131 100644
--- a/lib/librte_bpf/rte_bpf_version.map
+++ b/lib/librte_bpf/rte_bpf_version.map
@@ -7,6 +7,10 @@ EXPERIMENTAL {
 	rte_bpf_eth_rx_unload;
 	rte_bpf_eth_tx_elf_load;
 	rte_bpf_eth_tx_unload;
+	rte_bpf_event_deq_load;
+	rte_bpf_event_deq_unload;
+	rte_bpf_event_enq_load;
+	rte_bpf_event_enq_unload;
 	rte_bpf_exec;
 	rte_bpf_exec_burst;
 	rte_bpf_get_jit;
-- 
2.17.1