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examples/vhost: demonstrate the new generic APIs

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Now DPDK vhost lib has been generic enough, that it can be used to
implement any vhost-user drivers.

For example, this patch implements a very simple vhost-user net driver,
mainly for demonstrating how to use those generic vhost APIs.

And when the --builtin-net-driver option is used, the example virtio-net
driver code will be invoked, instead of the one provided from the vhost
library.

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
This commit is contained in:
Yuanhan Liu 2017-04-01 15:23:00 +08:00
parent 27052cd63f
commit ca059fa5e2
4 changed files with 463 additions and 7 deletions
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2
examples/vhost/Makefile
View File

@ -48,7 +48,7 @@ else
APP = vhost-switch
# all source are stored in SRCS-y
SRCS-y := main.c
SRCS-y := main.c virtio_net.c
CFLAGS += -O2 -D_FILE_OFFSET_BITS=64
CFLAGS += $(WERROR_FLAGS)

37
examples/vhost/main.c
View File

@ -1,7 +1,7 @@
/*-
* BSD LICENSE
*
* Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
* Copyright(c) 2010-2017 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -65,7 +65,6 @@
#define MBUF_CACHE_SIZE 128
#define MBUF_DATA_SIZE RTE_MBUF_DEFAULT_BUF_SIZE
#define MAX_PKT_BURST 32 /* Max burst size for RX/TX */
#define BURST_TX_DRAIN_US 100 /* TX drain every ~100us */
#define BURST_RX_WAIT_US 15 /* Defines how long we wait between retries on RX */
@ -129,6 +128,8 @@ static uint32_t enable_tso;
static int client_mode;
static int dequeue_zero_copy;
static int builtin_net_driver;
/* Specify timeout (in useconds) between retries on RX. */
static uint32_t burst_rx_delay_time = BURST_RX_WAIT_US;
/* Specify the number of retries on RX. */
@ -499,6 +500,7 @@ us_vhost_parse_args(int argc, char **argv)
{"tso", required_argument, NULL, 0},
{"client", no_argument, &client_mode, 1},
{"dequeue-zero-copy", no_argument, &dequeue_zero_copy, 1},
{"builtin-net-driver", no_argument, &builtin_net_driver, 1},
{NULL, 0, 0, 0},
};
@ -795,7 +797,12 @@ virtio_xmit(struct vhost_dev *dst_vdev, struct vhost_dev *src_vdev,
{
uint16_t ret;
ret = rte_vhost_enqueue_burst(dst_vdev->vid, VIRTIO_RXQ, &m, 1);
if (builtin_net_driver) {
ret = vs_enqueue_pkts(dst_vdev, VIRTIO_RXQ, &m, 1);
} else {
ret = rte_vhost_enqueue_burst(dst_vdev->vid, VIRTIO_RXQ, &m, 1);
}
if (enable_stats) {
rte_atomic64_inc(&dst_vdev->stats.rx_total_atomic);
rte_atomic64_add(&dst_vdev->stats.rx_atomic, ret);
@ -1066,8 +1073,13 @@ drain_eth_rx(struct vhost_dev *vdev)
}
}
enqueue_count = rte_vhost_enqueue_burst(vdev->vid, VIRTIO_RXQ,
if (builtin_net_driver) {
enqueue_count = vs_enqueue_pkts(vdev, VIRTIO_RXQ,
pkts, rx_count);
} else {
enqueue_count = rte_vhost_enqueue_burst(vdev->vid, VIRTIO_RXQ,
pkts, rx_count);
}
if (enable_stats) {
rte_atomic64_add(&vdev->stats.rx_total_atomic, rx_count);
rte_atomic64_add(&vdev->stats.rx_atomic, enqueue_count);
@ -1083,8 +1095,13 @@ drain_virtio_tx(struct vhost_dev *vdev)
uint16_t count;
uint16_t i;
count = rte_vhost_dequeue_burst(vdev->vid, VIRTIO_TXQ, mbuf_pool,
if (builtin_net_driver) {
count = vs_dequeue_pkts(vdev, VIRTIO_TXQ, mbuf_pool,
pkts, MAX_PKT_BURST);
} else {
count = rte_vhost_dequeue_burst(vdev->vid, VIRTIO_TXQ,
mbuf_pool, pkts, MAX_PKT_BURST);
}
/* setup VMDq for the first packet */
if (unlikely(vdev->ready == DEVICE_MAC_LEARNING) && count) {
@ -1187,6 +1204,9 @@ destroy_device(int vid)
rte_pause();
}
if (builtin_net_driver)
vs_vhost_net_remove(vdev);
TAILQ_REMOVE(&lcore_info[vdev->coreid].vdev_list, vdev,
lcore_vdev_entry);
TAILQ_REMOVE(&vhost_dev_list, vdev, global_vdev_entry);
@ -1235,6 +1255,9 @@ new_device(int vid)
}
vdev->vid = vid;
if (builtin_net_driver)
vs_vhost_net_setup(vdev);
TAILQ_INSERT_TAIL(&vhost_dev_list, vdev, global_vdev_entry);
vdev->vmdq_rx_q = vid * queues_per_pool + vmdq_queue_base;
@ -1513,6 +1536,10 @@ main(int argc, char *argv[])
rte_exit(EXIT_FAILURE,
"vhost driver register failure.\n");
}
if (builtin_net_driver)
rte_vhost_driver_set_features(file, VIRTIO_NET_FEATURES);
if (mergeable == 0) {
rte_vhost_driver_disable_features(file,
1ULL << VIRTIO_NET_F_MRG_RXBUF);

28
examples/vhost/main.h
View File

@ -1,7 +1,7 @@
/*-
* BSD LICENSE
*
* Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
* Copyright(c) 2010-2017 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -45,6 +45,8 @@
enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
#define MAX_PKT_BURST 32 /* Max burst size for RX/TX */
struct device_statistics {
uint64_t tx;
uint64_t tx_total;
@ -52,6 +54,12 @@ struct device_statistics {
rte_atomic64_t rx_total_atomic;
};
struct vhost_queue {
struct rte_vhost_vring vr;
uint16_t last_avail_idx;
uint16_t last_used_idx;
};
struct vhost_dev {
/**< Number of memory regions for gpa to hpa translation. */
uint32_t nregions_hpa;
@ -69,9 +77,16 @@ struct vhost_dev {
volatile uint8_t remove;
int vid;
uint64_t features;
size_t hdr_len;
uint16_t nr_vrings;
struct rte_vhost_memory *mem;
struct device_statistics stats;
TAILQ_ENTRY(vhost_dev) global_vdev_entry;
TAILQ_ENTRY(vhost_dev) lcore_vdev_entry;
#define MAX_QUEUE_PAIRS 4
struct vhost_queue queues[MAX_QUEUE_PAIRS * 2];
} __rte_cache_aligned;
TAILQ_HEAD(vhost_dev_tailq_list, vhost_dev);
@ -92,4 +107,15 @@ struct lcore_info {
struct vhost_dev_tailq_list vdev_list;
};
/* we implement non-extra virtio net features */
#define VIRTIO_NET_FEATURES 0
void vs_vhost_net_setup(struct vhost_dev *dev);
void vs_vhost_net_remove(struct vhost_dev *dev);
uint16_t vs_enqueue_pkts(struct vhost_dev *dev, uint16_t queue_id,
struct rte_mbuf **pkts, uint32_t count);
uint16_t vs_dequeue_pkts(struct vhost_dev *dev, uint16_t queue_id,
struct rte_mempool *mbuf_pool,
struct rte_mbuf **pkts, uint16_t count);
#endif /* _MAIN_H_ */

403
examples/vhost/virtio_net.c Normal file
View File

@ -0,0 +1,403 @@
/*-
* BSD LICENSE
*
* Copyright(c) 2010-2017 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdint.h>
#include <stdbool.h>
#include <linux/virtio_net.h>
#include <rte_mbuf.h>
#include <rte_memcpy.h>
#include <rte_vhost.h>
#include "main.h"
/*
* A very simple vhost-user net driver implementation, without
* any extra features being enabled, such as TSO and mrg-Rx.
*/
void
vs_vhost_net_setup(struct vhost_dev *dev)
{
uint16_t i;
int vid = dev->vid;
struct vhost_queue *queue;
RTE_LOG(INFO, VHOST_CONFIG,
"setting builtin vhost-user net driver\n");
rte_vhost_get_negotiated_features(vid, &dev->features);
if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
dev->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
else
dev->hdr_len = sizeof(struct virtio_net_hdr);
rte_vhost_get_mem_table(vid, &dev->mem);
dev->nr_vrings = rte_vhost_get_vring_num(vid);
for (i = 0; i < dev->nr_vrings; i++) {
queue = &dev->queues[i];
queue->last_used_idx = 0;
queue->last_avail_idx = 0;
rte_vhost_get_vhost_vring(vid, i, &queue->vr);
}
}
void
vs_vhost_net_remove(struct vhost_dev *dev)
{
free(dev->mem);
}
static inline int __attribute__((always_inline))
enqueue_pkt(struct vhost_dev *dev, struct rte_vhost_vring *vr,
struct rte_mbuf *m, uint16_t desc_idx)
{
uint32_t desc_avail, desc_offset;
uint32_t mbuf_avail, mbuf_offset;
uint32_t cpy_len;
struct vring_desc *desc;
uint64_t desc_addr;
struct virtio_net_hdr virtio_hdr = {0, 0, 0, 0, 0, 0};
/* A counter to avoid desc dead loop chain */
uint16_t nr_desc = 1;
desc = &vr->desc[desc_idx];
desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
/*
* Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
* performance issue with some versions of gcc (4.8.4 and 5.3.0) which
* otherwise stores offset on the stack instead of in a register.
*/
if (unlikely(desc->len < dev->hdr_len) || !desc_addr)
return -1;
rte_prefetch0((void *)(uintptr_t)desc_addr);
/* write virtio-net header */
*(struct virtio_net_hdr *)(uintptr_t)desc_addr = virtio_hdr;
desc_offset = dev->hdr_len;
desc_avail = desc->len - dev->hdr_len;
mbuf_avail = rte_pktmbuf_data_len(m);
mbuf_offset = 0;
while (mbuf_avail != 0 || m->next != NULL) {
/* done with current mbuf, fetch next */
if (mbuf_avail == 0) {
m = m->next;
mbuf_offset = 0;
mbuf_avail = rte_pktmbuf_data_len(m);
}
/* done with current desc buf, fetch next */
if (desc_avail == 0) {
if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
/* Room in vring buffer is not enough */
return -1;
}
if (unlikely(desc->next >= vr->size ||
++nr_desc > vr->size))
return -1;
desc = &vr->desc[desc->next];
desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
if (unlikely(!desc_addr))
return -1;
desc_offset = 0;
desc_avail = desc->len;
}
cpy_len = RTE_MIN(desc_avail, mbuf_avail);
rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
cpy_len);
mbuf_avail -= cpy_len;
mbuf_offset += cpy_len;
desc_avail -= cpy_len;
desc_offset += cpy_len;
}
return 0;
}
uint16_t
vs_enqueue_pkts(struct vhost_dev *dev, uint16_t queue_id,
struct rte_mbuf **pkts, uint32_t count)
{
struct vhost_queue *queue;
struct rte_vhost_vring *vr;
uint16_t avail_idx, free_entries, start_idx;
uint16_t desc_indexes[MAX_PKT_BURST];
uint16_t used_idx;
uint32_t i;
queue = &dev->queues[queue_id];
vr = &queue->vr;
avail_idx = *((volatile uint16_t *)&vr->avail->idx);
start_idx = queue->last_used_idx;
free_entries = avail_idx - start_idx;
count = RTE_MIN(count, free_entries);
count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
if (count == 0)
return 0;
/* Retrieve all of the desc indexes first to avoid caching issues. */
rte_prefetch0(&vr->avail->ring[start_idx & (vr->size - 1)]);
for (i = 0; i < count; i++) {
used_idx = (start_idx + i) & (vr->size - 1);
desc_indexes[i] = vr->avail->ring[used_idx];
vr->used->ring[used_idx].id = desc_indexes[i];
vr->used->ring[used_idx].len = pkts[i]->pkt_len +
dev->hdr_len;
}
rte_prefetch0(&vr->desc[desc_indexes[0]]);
for (i = 0; i < count; i++) {
uint16_t desc_idx = desc_indexes[i];
int err;
err = enqueue_pkt(dev, vr, pkts[i], desc_idx);
if (unlikely(err)) {
used_idx = (start_idx + i) & (vr->size - 1);
vr->used->ring[used_idx].len = dev->hdr_len;
}
if (i + 1 < count)
rte_prefetch0(&vr->desc[desc_indexes[i+1]]);
}
rte_smp_wmb();
*(volatile uint16_t *)&vr->used->idx += count;
queue->last_used_idx += count;
/* flush used->idx update before we read avail->flags. */
rte_mb();
/* Kick the guest if necessary. */
if (!(vr->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
&& (vr->callfd >= 0))
eventfd_write(vr->callfd, (eventfd_t)1);
return count;
}
static inline int __attribute__((always_inline))
dequeue_pkt(struct vhost_dev *dev, struct rte_vhost_vring *vr,
struct rte_mbuf *m, uint16_t desc_idx,
struct rte_mempool *mbuf_pool)
{
struct vring_desc *desc;
uint64_t desc_addr;
uint32_t desc_avail, desc_offset;
uint32_t mbuf_avail, mbuf_offset;
uint32_t cpy_len;
struct rte_mbuf *cur = m, *prev = m;
/* A counter to avoid desc dead loop chain */
uint32_t nr_desc = 1;
desc = &vr->desc[desc_idx];
if (unlikely((desc->len < dev->hdr_len)) ||
(desc->flags & VRING_DESC_F_INDIRECT))
return -1;
desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
if (unlikely(!desc_addr))
return -1;
/*
* We don't support ANY_LAYOUT, neither VERSION_1, meaning
* a Tx packet from guest must have 2 desc buffers at least:
* the first for storing the header and the others for
* storing the data.
*
* And since we don't support TSO, we could simply skip the
* header.
*/
desc = &vr->desc[desc->next];
desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
if (unlikely(!desc_addr))
return -1;
rte_prefetch0((void *)(uintptr_t)desc_addr);
desc_offset = 0;
desc_avail = desc->len;
nr_desc += 1;
mbuf_offset = 0;
mbuf_avail = m->buf_len - RTE_PKTMBUF_HEADROOM;
while (1) {
cpy_len = RTE_MIN(desc_avail, mbuf_avail);
rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
mbuf_offset),
(void *)((uintptr_t)(desc_addr + desc_offset)),
cpy_len);
mbuf_avail -= cpy_len;
mbuf_offset += cpy_len;
desc_avail -= cpy_len;
desc_offset += cpy_len;
/* This desc reaches to its end, get the next one */
if (desc_avail == 0) {
if ((desc->flags & VRING_DESC_F_NEXT) == 0)
break;
if (unlikely(desc->next >= vr->size ||
++nr_desc > vr->size))
return -1;
desc = &vr->desc[desc->next];
desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
if (unlikely(!desc_addr))
return -1;
rte_prefetch0((void *)(uintptr_t)desc_addr);
desc_offset = 0;
desc_avail = desc->len;
}
/*
* This mbuf reaches to its end, get a new one
* to hold more data.
*/
if (mbuf_avail == 0) {
cur = rte_pktmbuf_alloc(mbuf_pool);
if (unlikely(cur == NULL)) {
RTE_LOG(ERR, VHOST_DATA, "Failed to "
"allocate memory for mbuf.\n");
return -1;
}
prev->next = cur;
prev->data_len = mbuf_offset;
m->nb_segs += 1;
m->pkt_len += mbuf_offset;
prev = cur;
mbuf_offset = 0;
mbuf_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
}
}
prev->data_len = mbuf_offset;
m->pkt_len += mbuf_offset;
return 0;
}
uint16_t
vs_dequeue_pkts(struct vhost_dev *dev, uint16_t queue_id,
struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
{
struct vhost_queue *queue;
struct rte_vhost_vring *vr;
uint32_t desc_indexes[MAX_PKT_BURST];
uint32_t used_idx;
uint32_t i = 0;
uint16_t free_entries;
uint16_t avail_idx;
queue = &dev->queues[queue_id];
vr = &queue->vr;
free_entries = *((volatile uint16_t *)&vr->avail->idx) -
queue->last_avail_idx;
if (free_entries == 0)
return 0;
/* Prefetch available and used ring */
avail_idx = queue->last_avail_idx & (vr->size - 1);
used_idx = queue->last_used_idx & (vr->size - 1);
rte_prefetch0(&vr->avail->ring[avail_idx]);
rte_prefetch0(&vr->used->ring[used_idx]);
count = RTE_MIN(count, MAX_PKT_BURST);
count = RTE_MIN(count, free_entries);
/*
* Retrieve all of the head indexes first and pre-update used entries
* to avoid caching issues.
*/
for (i = 0; i < count; i++) {
avail_idx = (queue->last_avail_idx + i) & (vr->size - 1);
used_idx = (queue->last_used_idx + i) & (vr->size - 1);
desc_indexes[i] = vr->avail->ring[avail_idx];
vr->used->ring[used_idx].id = desc_indexes[i];
vr->used->ring[used_idx].len = 0;
}
/* Prefetch descriptor index. */
rte_prefetch0(&vr->desc[desc_indexes[0]]);
for (i = 0; i < count; i++) {
int err;
if (likely(i + 1 < count))
rte_prefetch0(&vr->desc[desc_indexes[i + 1]]);
pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
if (unlikely(pkts[i] == NULL)) {
RTE_LOG(ERR, VHOST_DATA,
"Failed to allocate memory for mbuf.\n");
break;
}
err = dequeue_pkt(dev, vr, pkts[i], desc_indexes[i], mbuf_pool);
if (unlikely(err)) {
rte_pktmbuf_free(pkts[i]);
break;
}
}
if (!i)
return 0;
queue->last_avail_idx += i;
queue->last_used_idx += i;
rte_smp_wmb();
rte_smp_rmb();
vr->used->idx += i;
if (!(vr->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
&& (vr->callfd >= 0))
eventfd_write(vr->callfd, (eventfd_t)1);
return i;
}