Re: [PATCH net-next 6/6] tools: virtio: introduce vhost_net_test

From: Jason Wang
Date: Thu Dec 07 2023 - 01:02:13 EST

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In reply to: Yunsheng Lin: "[PATCH net-next 6/6] tools: virtio: introduce vhost_net_test"
Next in thread: Yunsheng Lin: "Re: [PATCH net-next 6/6] tools: virtio: introduce vhost_net_test"
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On Tue, Dec 5, 2023 at 7:35 PM Yunsheng Lin <linyunsheng@xxxxxxxxxx> wrote:
>
> introduce vhost_net_test basing on virtio_test to test
> vhost_net changing in the kernel.
>
> Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
> ---
> tools/virtio/Makefile | 8 +-
> tools/virtio/vhost_net_test.c | 441 ++++++++++++++++++++++++++++++++++
> 2 files changed, 446 insertions(+), 3 deletions(-)
> create mode 100644 tools/virtio/vhost_net_test.c
>
> diff --git a/tools/virtio/Makefile b/tools/virtio/Makefile
> index d128925980e0..e25e99c1c3b7 100644
> --- a/tools/virtio/Makefile
> +++ b/tools/virtio/Makefile
> @@ -1,8 +1,9 @@
> # SPDX-License-Identifier: GPL-2.0
> all: test mod
> -test: virtio_test vringh_test
> +test: virtio_test vringh_test vhost_net_test
> virtio_test: virtio_ring.o virtio_test.o
> vringh_test: vringh_test.o vringh.o virtio_ring.o
> +vhost_net_test: virtio_ring.o vhost_net_test.o
>
> try-run = $(shell set -e; \
> if ($(1)) >/dev/null 2>&1; \
> @@ -49,6 +50,7 @@ oot-clean: OOT_BUILD+=clean
>
> .PHONY: all test mod clean vhost oot oot-clean oot-build
> clean:
> - ${RM} *.o vringh_test virtio_test vhost_test/*.o vhost_test/.*.cmd \
> - vhost_test/Module.symvers vhost_test/modules.order *.d
> + ${RM} *.o vringh_test virtio_test vhost_net_test vhost_test/*.o \
> + vhost_test/.*.cmd vhost_test/Module.symvers \
> + vhost_test/modules.order *.d
> -include *.d
> diff --git a/tools/virtio/vhost_net_test.c b/tools/virtio/vhost_net_test.c
> new file mode 100644
> index 000000000000..7e7b7aba3668
> --- /dev/null
> +++ b/tools/virtio/vhost_net_test.c
> @@ -0,0 +1,441 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#define _GNU_SOURCE
> +#include <getopt.h>
> +#include <limits.h>
> +#include <string.h>
> +#include <poll.h>
> +#include <sys/eventfd.h>
> +#include <stdlib.h>
> +#include <assert.h>
> +#include <unistd.h>
> +#include <sys/ioctl.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <fcntl.h>
> +#include <stdbool.h>
> +#include <linux/virtio_types.h>
> +#include <linux/vhost.h>
> +#include <linux/virtio.h>
> +#include <linux/virtio_ring.h>
> +#include <linux/if.h>
> +#include <linux/if_tun.h>
> +
> +#define RANDOM_BATCH -1
> +
> +static int tun_alloc(void)
> +{
> + struct ifreq ifr;
> + int fd, e;
> +
> + fd = open("/dev/net/tun", O_RDWR);
> + if (fd < 0) {
> + perror("Cannot open /dev/net/tun");
> + return fd;
> + }
> +
> + memset(&ifr, 0, sizeof(ifr));
> +
> + ifr.ifr_flags = IFF_TUN | IFF_NO_PI;

Why did you use IFF_TUN but not IFF_TAP here?

> + strncpy(ifr.ifr_name, "tun0", IFNAMSIZ);

tun0 is pretty common if there's a VPN. Do we need some randomized name here?

> +
> + e = ioctl(fd, TUNSETIFF, (void *) &ifr);
> + if (e < 0) {
> + perror("ioctl[TUNSETIFF]");
> + close(fd);
> + return e;
> + }
> +
> + return fd;
> +}
> +
> +/* Unused */
> +void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end;

Why do we need trick like these here?

> +
> +struct vq_info {
> + int kick;
> + int call;
> + int num;
> + int idx;
> + void *ring;
> + /* copy used for control */
> + struct vring vring;
> + struct virtqueue *vq;
> +};
> +
> +struct vdev_info {
> + struct virtio_device vdev;
> + int control;
> + struct pollfd fds[1];
> + struct vq_info vqs[1];
> + int nvqs;
> + void *buf;
> + size_t buf_size;
> + struct vhost_memory *mem;
> +};
> +
> +static struct vhost_vring_file no_backend = { .index = 1, .fd = -1 },
> + backend = { .index = 1, .fd = 1 };

A magic number like fd = 1 is pretty confusing.

And I don't see why we need global variables here.

> +static const struct vhost_vring_state null_state = {};
> +
> +bool vq_notify(struct virtqueue *vq)
> +{
> + struct vq_info *info = vq->priv;
> + unsigned long long v = 1;
> + int r;
> + r = write(info->kick, &v, sizeof v);
> + assert(r == sizeof v);
> + return true;
> +}
> +
> +void vq_callback(struct virtqueue *vq)
> +{
> +}
> +
> +
> +void vhost_vq_setup(struct vdev_info *dev, struct vq_info *info)
> +{
> + struct vhost_vring_state state = { .index = info->idx };
> + struct vhost_vring_file file = { .index = info->idx };
> + unsigned long long features = dev->vdev.features;
> + struct vhost_vring_addr addr = {
> + .index = info->idx,
> + .desc_user_addr = (uint64_t)(unsigned long)info->vring.desc,
> + .avail_user_addr = (uint64_t)(unsigned long)info->vring.avail,
> + .used_user_addr = (uint64_t)(unsigned long)info->vring.used,
> + };
> + int r;
> + r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
> + assert(r >= 0);
> + state.num = info->vring.num;
> + r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state);
> + assert(r >= 0);
> + state.num = 0;
> + r = ioctl(dev->control, VHOST_SET_VRING_BASE, &state);
> + assert(r >= 0);
> + r = ioctl(dev->control, VHOST_SET_VRING_ADDR, &addr);
> + assert(r >= 0);
> + file.fd = info->kick;
> + r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file);
> + assert(r >= 0);
> + file.fd = info->call;
> + r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file);
> + assert(r >= 0);
> +}
> +
> +static void vq_reset(struct vq_info *info, int num, struct virtio_device *vdev)
> +{
> + if (info->vq)
> + vring_del_virtqueue(info->vq);
> +
> + memset(info->ring, 0, vring_size(num, 4096));
> + vring_init(&info->vring, num, info->ring, 4096);
> + info->vq = vring_new_virtqueue(info->idx, num, 4096, vdev, true, false,
> + info->ring, vq_notify, vq_callback, "test");
> + assert(info->vq);
> + info->vq->priv = info;
> +}
> +
> +static void vq_info_add(struct vdev_info *dev, int num)
> +{
> + struct vq_info *info = &dev->vqs[dev->nvqs];
> + int r;
> +
> + /* use VHOST_NET_VQ_TX for testing */
> + info->idx = 1;
> + info->kick = eventfd(0, EFD_NONBLOCK);
> + info->call = eventfd(0, EFD_NONBLOCK);
> + r = posix_memalign(&info->ring, 4096, vring_size(num, 4096));
> + assert(r >= 0);
> + vq_reset(info, num, &dev->vdev);
> + vhost_vq_setup(dev, info);
> + dev->fds[0].fd = info->call;
> + dev->fds[0].events = POLLIN;
> + dev->nvqs++;
> +}
> +
> +static void vdev_info_init(struct vdev_info* dev, unsigned long long features)
> +{
> + int r;
> + memset(dev, 0, sizeof *dev);
> + dev->vdev.features = features;
> + INIT_LIST_HEAD(&dev->vdev.vqs);
> + spin_lock_init(&dev->vdev.vqs_list_lock);
> + dev->buf_size = 1024;
> + dev->buf = malloc(dev->buf_size);
> + assert(dev->buf);
> + dev->control = open("/dev/vhost-net", O_RDWR);
> + assert(dev->control >= 0);
> + r = ioctl(dev->control, VHOST_SET_OWNER, NULL);
> + assert(r >= 0);
> + dev->mem = malloc(offsetof(struct vhost_memory, regions) +
> + sizeof dev->mem->regions[0]);
> + assert(dev->mem);
> + memset(dev->mem, 0, offsetof(struct vhost_memory, regions) +
> + sizeof dev->mem->regions[0]);
> + dev->mem->nregions = 1;
> + dev->mem->regions[0].guest_phys_addr = (long)dev->buf;
> + dev->mem->regions[0].userspace_addr = (long)dev->buf;
> + dev->mem->regions[0].memory_size = dev->buf_size;
> + r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
> + assert(r >= 0);
> +}
> +
> +/* TODO: this is pretty bad: we get a cache line bounce
> + * for the wait queue on poll and another one on read,
> + * plus the read which is there just to clear the
> + * current state. */
> +static void wait_for_interrupt(struct vdev_info *dev)
> +{
> + int i;
> + unsigned long long val;
> + poll(dev->fds, dev->nvqs, -1);
> + for (i = 0; i < dev->nvqs; ++i)
> + if (dev->fds[i].revents & POLLIN) {
> + read(dev->fds[i].fd, &val, sizeof val);
> + }
> +}
> +
> +static void run_test(struct vdev_info *dev, struct vq_info *vq,
> + bool delayed, int batch, int reset_n, int bufs)
> +{
> + struct scatterlist sl;
> + long started = 0, completed = 0, next_reset = reset_n;
> + long completed_before, started_before;
> + int r;
> + unsigned int len;
> + long long spurious = 0;
> + const bool random_batch = batch == RANDOM_BATCH;
> +
> + r = ioctl(dev->control, VHOST_NET_SET_BACKEND, &backend);
> + assert(!r);
> +
> + if (!reset_n) {
> + next_reset = INT_MAX;
> + }
> +
> + for (;;) {
> + virtqueue_disable_cb(vq->vq);
> + completed_before = completed;
> + started_before = started;
> + do {
> + const bool reset = completed > next_reset;
> + if (random_batch)
> + batch = (random() % vq->vring.num) + 1;
> +
> + while (started < bufs &&
> + (started - completed) < batch) {
> + sg_init_one(&sl, dev->buf, dev->buf_size);
> + r = virtqueue_add_outbuf(vq->vq, &sl, 1,
> + dev->buf + started,
> + GFP_ATOMIC);
> + if (unlikely(r != 0)) {
> + if (r == -ENOSPC &&
> + started > started_before)
> + r = 0;
> + else
> + r = -1;
> + break;
> + }
> +
> + ++started;
> +
> + if (unlikely(!virtqueue_kick(vq->vq))) {
> + r = -1;
> + break;
> + }
> + }
> +
> + if (started >= bufs)
> + r = -1;
> +
> + if (reset) {
> + r = ioctl(dev->control, VHOST_NET_SET_BACKEND,
> + &no_backend);
> + assert(!r);
> + }
> +
> + /* Flush out completed bufs if any */
> + while (virtqueue_get_buf(vq->vq, &len)) {
> + ++completed;
> + r = 0;
> + }
> +
> + if (reset) {
> + struct vhost_vring_state s = { .index = 0 };
> +
> + vq_reset(vq, vq->vring.num, &dev->vdev);
> +
> + r = ioctl(dev->control, VHOST_GET_VRING_BASE,
> + &s);
> + assert(!r);
> +
> + s.num = 0;
> + r = ioctl(dev->control, VHOST_SET_VRING_BASE,
> + &null_state);
> + assert(!r);
> +
> + r = ioctl(dev->control, VHOST_NET_SET_BACKEND,
> + &backend);
> + assert(!r);
> +
> + started = completed;
> + while (completed > next_reset)
> + next_reset += completed;
> + }
> + } while (r == 0);
> + if (completed == completed_before && started == started_before)
> + ++spurious;
> + assert(completed <= bufs);
> + assert(started <= bufs);
> + if (completed == bufs)
> + break;
> + if (delayed) {
> + if (virtqueue_enable_cb_delayed(vq->vq))
> + wait_for_interrupt(dev);
> + } else {
> + if (virtqueue_enable_cb(vq->vq))
> + wait_for_interrupt(dev);
> + }
> + }
> + fprintf(stderr,
> + "spurious wakeups: 0x%llx started=0x%lx completed=0x%lx\n",
> + spurious, started, completed);
> +}
> +
> +const char optstring[] = "h";
> +const struct option longopts[] = {
> + {
> + .name = "help",
> + .val = 'h',
> + },
> + {
> + .name = "event-idx",
> + .val = 'E',
> + },
> + {
> + .name = "no-event-idx",
> + .val = 'e',
> + },
> + {
> + .name = "indirect",
> + .val = 'I',
> + },
> + {
> + .name = "no-indirect",
> + .val = 'i',
> + },
> + {
> + .name = "virtio-1",
> + .val = '1',
> + },
> + {
> + .name = "no-virtio-1",
> + .val = '0',
> + },
> + {
> + .name = "delayed-interrupt",
> + .val = 'D',
> + },
> + {
> + .name = "no-delayed-interrupt",
> + .val = 'd',
> + },
> + {
> + .name = "buf-num",
> + .val = 'n',
> + .has_arg = required_argument,
> + },
> + {
> + .name = "batch",
> + .val = 'b',
> + .has_arg = required_argument,
> + },
> + {
> + .name = "reset",
> + .val = 'r',
> + .has_arg = optional_argument,
> + },
> + {
> + }
> +};
> +
> +static void help(int status)
> +{
> + fprintf(stderr, "Usage: virtio_test [--help]"
> + " [--no-indirect]"
> + " [--no-event-idx]"
> + " [--no-virtio-1]"
> + " [--delayed-interrupt]"
> + " [--batch=random/N]"
> + " [--reset=N]"
> + "\n");
> +
> + exit(status);
> +}
> +
> +int main(int argc, char **argv)
> +{
> + struct vdev_info dev;
> + unsigned long long features = (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> + (1ULL << VIRTIO_RING_F_EVENT_IDX) | (1ULL << VIRTIO_F_VERSION_1);
> + long batch = 1, reset = 0, nbufs = 0x100000;
> + int o;
> + bool delayed = false;
> +
> + for (;;) {
> + o = getopt_long(argc, argv, optstring, longopts, NULL);
> + switch (o) {
> + case -1:
> + goto done;
> + case '?':
> + help(2);
> + case 'e':
> + features &= ~(1ULL << VIRTIO_RING_F_EVENT_IDX);
> + break;
> + case 'h':
> + help(0);
> + case 'i':
> + features &= ~(1ULL << VIRTIO_RING_F_INDIRECT_DESC);
> + break;
> + case '0':
> + features &= ~(1ULL << VIRTIO_F_VERSION_1);
> + break;
> + case 'D':
> + delayed = true;
> + break;
> + case 'b':
> + if (0 == strcmp(optarg, "random")) {
> + batch = RANDOM_BATCH;
> + } else {
> + batch = strtol(optarg, NULL, 10);
> + assert(batch > 0);
> + assert(batch < (long)INT_MAX + 1);
> + }
> + break;
> + case 'r':
> + if (!optarg) {
> + reset = 1;
> + } else {
> + reset = strtol(optarg, NULL, 10);
> + assert(reset > 0);
> + assert(reset < (long)INT_MAX + 1);
> + }
> + break;
> + case 'n':
> + nbufs = strtol(optarg, NULL, 10);
> + assert(nbufs > 0);
> + break;
> + default:
> + assert(0);
> + break;
> + }
> + }
> +
> +done:
> + backend.fd = tun_alloc();
> + assert(backend.fd >= 0);
> + vdev_info_init(&dev, features);
> + vq_info_add(&dev, 256);
> + run_test(&dev, &dev.vqs[0], delayed, batch, reset, nbufs);

I'd expect we are testing some basic traffic here. E.g can we use a
packet socket then we can test both tx and rx?

Thanks

> + return 0;
> +}
> --
> 2.33.0
>

Next message: Tony Lu: "Re: [PATCH net] net/smc: fix missing byte order conversion in CLC handshake"
Previous message: Aboorva Devarajan: "Re: [PATCH v3 0/7] sched: Implement shared runqueue in CFS"
In reply to: Yunsheng Lin: "[PATCH net-next 6/6] tools: virtio: introduce vhost_net_test"
Next in thread: Yunsheng Lin: "Re: [PATCH net-next 6/6] tools: virtio: introduce vhost_net_test"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]