[net-next,v4,5/5] tools: virtio: introduce vhost_net_test

Message ID 20240130113710.34511-6-linyunsheng@huawei.com
State New
Headers
Series None |

Commit Message

Yunsheng Lin Jan. 30, 2024, 11:37 a.m. UTC
  introduce vhost_net_test basing on virtio_test to test
vhost_net changing in the kernel.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 tools/virtio/.gitignore       |   1 +
 tools/virtio/Makefile         |   8 +-
 tools/virtio/vhost_net_test.c | 576 ++++++++++++++++++++++++++++++++++
 3 files changed, 582 insertions(+), 3 deletions(-)
 create mode 100644 tools/virtio/vhost_net_test.c
  

Comments

Jason Wang Feb. 2, 2024, 4:05 a.m. UTC | #1
On Tue, Jan 30, 2024 at 7:38 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
>
> introduce vhost_net_test basing on virtio_test to test
> vhost_net changing in the kernel.

Let's describe what kind of test is being done and how it is done here.

>
> Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
> ---
>  tools/virtio/.gitignore       |   1 +
>  tools/virtio/Makefile         |   8 +-
>  tools/virtio/vhost_net_test.c | 576 ++++++++++++++++++++++++++++++++++
>  3 files changed, 582 insertions(+), 3 deletions(-)
>  create mode 100644 tools/virtio/vhost_net_test.c
>
> diff --git a/tools/virtio/.gitignore b/tools/virtio/.gitignore
> index 9934d48d9a55..7e47b281c442 100644
> --- a/tools/virtio/.gitignore
> +++ b/tools/virtio/.gitignore
> @@ -1,5 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  *.d
>  virtio_test
> +vhost_net_test
>  vringh_test
>  virtio-trace/trace-agent
> 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..e336792a0d77
> --- /dev/null
> +++ b/tools/virtio/vhost_net_test.c
> @@ -0,0 +1,576 @@
> +// 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>
> +#include <linux/in.h>
> +#include <linux/if_packet.h>
> +#include <netinet/ether.h>
> +
> +#define RANDOM_BATCH   -1
> +#define HDR_LEN                12
> +#define TEST_BUF_LEN   256
> +#define TEST_PTYPE     ETH_P_LOOPBACK
> +
> +/* Used by implementation of kmalloc() in tools/virtio/linux/kernel.h */
> +void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end;
> +
> +struct vq_info {
> +       int kick;
> +       int call;
> +       int idx;
> +       long started;
> +       long completed;
> +       struct pollfd fds;
> +       void *ring;
> +       /* copy used for control */
> +       struct vring vring;
> +       struct virtqueue *vq;
> +};
> +
> +struct vdev_info {
> +       struct virtio_device vdev;
> +       int control;
> +       struct vq_info vqs[2];
> +       int nvqs;
> +       void *buf;
> +       size_t buf_size;
> +       char *test_buf;
> +       char *res_buf;
> +       struct vhost_memory *mem;
> +       int sock;
> +       int ifindex;
> +       unsigned char mac[ETHER_ADDR_LEN];
> +};
> +
> +static int tun_alloc(struct vdev_info *dev)
> +{
> +       struct ifreq ifr;
> +       int len = HDR_LEN;

Any reason you can't just use the virtio_net uapi?

> +       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_TAP | IFF_NO_PI | IFF_VNET_HDR;
> +       snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
> +
> +       e = ioctl(fd, TUNSETIFF, &ifr);
> +       if (e < 0) {
> +               perror("ioctl[TUNSETIFF]");
> +               close(fd);
> +               return e;
> +       }
> +
> +       e = ioctl(fd, TUNSETVNETHDRSZ, &len);
> +       if (e < 0) {
> +               perror("ioctl[TUNSETVNETHDRSZ]");
> +               close(fd);
> +               return e;
> +       }
> +
> +       e = ioctl(fd, SIOCGIFHWADDR, &ifr);
> +       if (e < 0) {
> +               perror("ioctl[SIOCGIFHWADDR]");
> +               close(fd);
> +               return e;
> +       }
> +
> +       memcpy(dev->mac, &ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
> +       return fd;
> +}
> +
> +static void vdev_create_socket(struct vdev_info *dev)
> +{
> +       struct ifreq ifr;
> +
> +       dev->sock = socket(AF_PACKET, SOCK_RAW, htons(TEST_PTYPE));
> +       assert(dev->sock != -1);
> +
> +       snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());

Nit: it might be better to accept the device name instead of repeating
the snprintf trick here, this would facilitate the future changes.

> +       assert(ioctl(dev->sock, SIOCGIFINDEX, &ifr) >= 0);
> +
> +       dev->ifindex = ifr.ifr_ifindex;
> +
> +       /* Set the flags that bring the device up */
> +       assert(ioctl(dev->sock, SIOCGIFFLAGS, &ifr) >= 0);
> +       ifr.ifr_flags |= (IFF_UP | IFF_RUNNING);
> +       assert(ioctl(dev->sock, SIOCSIFFLAGS, &ifr) >= 0);
> +}
> +
> +static void vdev_send_packet(struct vdev_info *dev)
> +{
> +       char *sendbuf = dev->test_buf + HDR_LEN;
> +       struct sockaddr_ll saddrll = {0};
> +       int sockfd = dev->sock;
> +       int ret;
> +
> +       saddrll.sll_family = PF_PACKET;
> +       saddrll.sll_ifindex = dev->ifindex;
> +       saddrll.sll_halen = ETH_ALEN;
> +       saddrll.sll_protocol = htons(TEST_PTYPE);
> +
> +       ret = sendto(sockfd, sendbuf, TEST_BUF_LEN, 0,
> +                    (struct sockaddr *)&saddrll,
> +                    sizeof(struct sockaddr_ll));
> +       assert(ret >= 0);
> +}
> +
> +static 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;
> +}
> +
> +static void vq_callback(struct virtqueue *vq)
> +{
> +}
> +
> +static void vhost_vq_setup(struct vdev_info *dev, struct vq_info *info)
> +{
> +       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->vringavail,
> +               .used_user_addr = (uint64_t)(unsigned long)info->vring.used,
> +       };
> +       struct vhost_vring_state state = { .index = info->idx };
> +       struct vhost_vring_file file = { .index = info->idx };
> +       int r;
> +
> +       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 idx, int num, int fd)
> +{
> +       struct vhost_vring_file backend = { .index = idx, .fd = fd };
> +       struct vq_info *info = &dev->vqs[idx];
> +       int r;
> +
> +       info->idx = idx;
> +       info->kick = eventfd(0, EFD_NONBLOCK);
> +       info->call = eventfd(0, EFD_NONBLOCK);

If we don't care about the callback, let's just avoid to set the call here?

(As I see vq_callback is a NULL)

> +       r = posix_memalign(&info->ring, 4096, vring_size(num, 4096));
> +       assert(r >= 0);
> +       vq_reset(info, num, &dev->vdev);
> +       vhost_vq_setup(dev, info);
> +       info->fds.fd = info->call;
> +       info->fds.events = POLLIN;
> +
> +       r = ioctl(dev->control, VHOST_NET_SET_BACKEND, &backend);
> +       assert(!r);
> +}
> +
> +static void vdev_info_init(struct vdev_info *dev, unsigned long long features)
> +{
> +       struct ether_header *eh;
> +       int i, r;
> +
> +       dev->vdev.features = features;
> +       INIT_LIST_HEAD(&dev->vdev.vqs);
> +       spin_lock_init(&dev->vdev.vqs_list_lock);
> +
> +       dev->buf_size = (HDR_LEN + TEST_BUF_LEN) * 2;
> +       dev->buf = malloc(dev->buf_size);
> +       assert(dev->buf);
> +       dev->test_buf = dev->buf;
> +       dev->res_buf = dev->test_buf + HDR_LEN + TEST_BUF_LEN;
> +
> +       memset(dev->test_buf, 0, HDR_LEN + TEST_BUF_LEN);
> +       eh = (struct ether_header *)(dev->test_buf + HDR_LEN);
> +       eh->ether_type = htons(TEST_PTYPE);
> +       memcpy(eh->ether_dhost, dev->mac, ETHER_ADDR_LEN);
> +       memcpy(eh->ether_shost, dev->mac, ETHER_ADDR_LEN);
> +
> +       for (i = sizeof(*eh); i < TEST_BUF_LEN; i++)
> +               dev->test_buf[i + HDR_LEN] = (char)i;
> +
> +       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);
> +
> +       r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
> +       assert(r >= 0);
> +
> +       dev->nvqs = 2;
> +}
> +
> +static void wait_for_interrupt(struct vq_info *vq)
> +{
> +       unsigned long long val;
> +
> +       poll(&vq->fds, 1, -1);
> +
> +       if (vq->fds.revents & POLLIN)
> +               read(vq->fds.fd, &val, sizeof(val));
> +}
> +
> +static void verify_res_buf(char *res_buf)
> +{
> +       int i;
> +
> +       for (i = ETHER_HDR_LEN; i < TEST_BUF_LEN; i++)
> +               assert(res_buf[i] == (char)i);
> +}
> +
> +static void run_tx_test(struct vdev_info *dev, struct vq_info *vq,
> +                       bool delayed, int batch, int bufs)

It might be better to describe the test design briefly above as a
comment. Or we can start from simple test logic and add sophisticated
ones on top.

> +{
> +       const bool random_batch = batch == RANDOM_BATCH;
> +       long long spurious = 0;
> +       struct scatterlist sl;
> +       unsigned int len;
> +       int r;
> +
> +       for (;;) {
> +               long started_before = vq->started;
> +               long completed_before = vq->completed;
> +
> +               virtqueue_disable_cb(vq->vq);
> +               do {
> +                       if (random_batch)
> +                               batch = (random() % vq->vring.num) + 1;
> +
> +                       while (vq->started < bufs &&
> +                              (vq->started - vq->completed) < batch) {
> +                               sg_init_one(&sl, dev->test_buf, HDR_LEN + TEST_BUF_LEN);
> +                               r = virtqueue_add_outbuf(vq->vq, &sl, 1,
> +                                                        dev->test_buf + vq->started,
> +                                                        GFP_ATOMIC);
> +                               if (unlikely(r != 0)) {
> +                                       if (r == -ENOSPC &&
> +                                           vq->started > started_before)
> +                                               r = 0;
> +                                       else
> +                                               r = -1;
> +                                       break;
> +                               }
> +
> +                               ++vq->started;
> +
> +                               if (unlikely(!virtqueue_kick(vq->vq))) {
> +                                       r = -1;
> +                                       break;
> +                               }
> +                       }
> +
> +                       if (vq->started >= bufs)
> +                               r = -1;
> +
> +                       /* Flush out completed bufs if any */
> +                       while (virtqueue_get_buf(vq->vq, &len)) {
> +                               int n;
> +
> +                               n = recvfrom(dev->sock, dev->res_buf, TEST_BUF_LEN, 0, NULL, NULL);
> +                               assert(n == TEST_BUF_LEN);
> +                               verify_res_buf(dev->res_buf);
> +
> +                               ++vq->completed;
> +                               r = 0;
> +                       }
> +               } while (r == 0);
> +
> +               if (vq->completed == completed_before && vq->started == started_before)
> +                       ++spurious;
> +
> +               assert(vq->completed <= bufs);
> +               assert(vq->started <= bufs);
> +               if (vq->completed == bufs)
> +                       break;
> +
> +               if (delayed) {
> +                       if (virtqueue_enable_cb_delayed(vq->vq))
> +                               wait_for_interrupt(vq);
> +               } else {
> +                       if (virtqueue_enable_cb(vq->vq))
> +                               wait_for_interrupt(vq);
> +               }
> +       }
> +       printf("TX spurious wakeups: 0x%llx started=0x%lx completed=0x%lx\n",
> +              spurious, vq->started, vq->completed);
> +}
> +
> +static void run_rx_test(struct vdev_info *dev, struct vq_info *vq,
> +                       bool delayed, int batch, int bufs)
> +{
> +       const bool random_batch = batch == RANDOM_BATCH;
> +       long long spurious = 0;
> +       struct scatterlist sl;
> +       unsigned int len;
> +       int r;
> +
> +       for (;;) {
> +               long started_before = vq->started;
> +               long completed_before = vq->completed;
> +
> +               do {
> +                       if (random_batch)
> +                               batch = (random() % vq->vring.num) + 1;
> +
> +                       while (vq->started < bufs &&
> +                              (vq->started - vq->completed) < batch) {
> +                               sg_init_one(&sl, dev->res_buf, HDR_LEN + TEST_BUF_LEN);
> +
> +                               r = virtqueue_add_inbuf(vq->vq, &sl, 1,
> +                                                       dev->res_buf + vq->started,
> +                                                       GFP_ATOMIC);
> +                               if (unlikely(r != 0)) {
> +                                       if (r == -ENOSPC &&

Drivers usually maintain a #free_slots, this can help to avoid the
trick for checking ENOSPC?

> +                                           vq->started > started_before)
> +                                               r = 0;
> +                                       else
> +                                               r = -1;
> +                                       break;
> +                               }
> +
> +                               ++vq->started;
> +
> +                               vdev_send_packet(dev);
> +
> +                               if (unlikely(!virtqueue_kick(vq->vq))) {
> +                                       r = -1;
> +                                       break;
> +                               }
> +                       }
> +
> +                       if (vq->started >= bufs)
> +                               r = -1;
> +
> +                       /* Flush out completed bufs if any */
> +                       while (virtqueue_get_buf(vq->vq, &len)) {
> +                               struct ether_header *eh;
> +
> +                               eh = (struct ether_header *)(dev->res_buf + HDR_LEN);
> +
> +                               /* tun netdev is up and running, ignore the
> +                                * non-TEST_PTYPE packet.
> +                                */

I wonder if it's better to set up some kind of qdisc to avoid the
unexpected packet here, or is it too complicated?

Thanks
  
Yunsheng Lin Feb. 2, 2024, 12:24 p.m. UTC | #2
On 2024/2/2 12:05, Jason Wang wrote:
> On Tue, Jan 30, 2024 at 7:38 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
>>
>> introduce vhost_net_test basing on virtio_test to test
>> vhost_net changing in the kernel.
> 
> Let's describe what kind of test is being done and how it is done here.

How about something like below:

This patch introduces testing for both vhost_net tx and rx.
Steps for vhost_net tx testing:
1. Prepare a out buf
2. Kick the vhost_net to do tx processing
3. Do the receiving in the tun side
4. verify the data received by tun is correct

Steps for vhost_net rx testing::
1. Prepare a in buf
2. Do the sending in the tun side
3. Kick the vhost_net to do rx processing
4. verify the data received by vhost_net is correct


>> +
>> +static int tun_alloc(struct vdev_info *dev)
>> +{
>> +       struct ifreq ifr;
>> +       int len = HDR_LEN;
> 
> Any reason you can't just use the virtio_net uapi?

I didn't find a macro for that in include/uapi/linux/virtio_net.h.

Did you mean using something like below?
sizeof(struct virtio_net_hdr_mrg_rxbuf)

> 
>> +       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_TAP | IFF_NO_PI | IFF_VNET_HDR;
>> +       snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
>> +
>> +       e = ioctl(fd, TUNSETIFF, &ifr);
>> +       if (e < 0) {
>> +               perror("ioctl[TUNSETIFF]");
>> +               close(fd);
>> +               return e;
>> +       }
>> +
>> +       e = ioctl(fd, TUNSETVNETHDRSZ, &len);
>> +       if (e < 0) {
>> +               perror("ioctl[TUNSETVNETHDRSZ]");
>> +               close(fd);
>> +               return e;
>> +       }
>> +
>> +       e = ioctl(fd, SIOCGIFHWADDR, &ifr);
>> +       if (e < 0) {
>> +               perror("ioctl[SIOCGIFHWADDR]");
>> +               close(fd);
>> +               return e;
>> +       }
>> +
>> +       memcpy(dev->mac, &ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
>> +       return fd;
>> +}
>> +
>> +static void vdev_create_socket(struct vdev_info *dev)
>> +{
>> +       struct ifreq ifr;
>> +
>> +       dev->sock = socket(AF_PACKET, SOCK_RAW, htons(TEST_PTYPE));
>> +       assert(dev->sock != -1);
>> +
>> +       snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
> 
> Nit: it might be better to accept the device name instead of repeating
> the snprintf trick here, this would facilitate the future changes.

I am not sure I understand what did you mean by "accept the device name"
here.

The above is used to get ifindex of the tun netdevice created in
tun_alloc(), so that we can use it in vdev_send_packet() to send
a packet using the tun netdevice created in tun_alloc(). Is there
anything obvious I missed here?

> 
>> +       assert(ioctl(dev->sock, SIOCGIFINDEX, &ifr) >= 0);
>> +
>> +       dev->ifindex = ifr.ifr_ifindex;
>> +
>> +       /* Set the flags that bring the device up */
>> +       assert(ioctl(dev->sock, SIOCGIFFLAGS, &ifr) >= 0);
>> +       ifr.ifr_flags |= (IFF_UP | IFF_RUNNING);
>> +       assert(ioctl(dev->sock, SIOCSIFFLAGS, &ifr) >= 0);
>> +}
>> +
>> +static void vdev_send_packet(struct vdev_info *dev)
>> +{
>> +       char *sendbuf = dev->test_buf + HDR_LEN;
>> +       struct sockaddr_ll saddrll = {0};
>> +       int sockfd = dev->sock;
>> +       int ret;
>> +
>> +       saddrll.sll_family = PF_PACKET;
>> +       saddrll.sll_ifindex = dev->ifindex;
>> +       saddrll.sll_halen = ETH_ALEN;
>> +       saddrll.sll_protocol = htons(TEST_PTYPE);
>> +
>> +       ret = sendto(sockfd, sendbuf, TEST_BUF_LEN, 0,
>> +                    (struct sockaddr *)&saddrll,
>> +                    sizeof(struct sockaddr_ll));
>> +       assert(ret >= 0);
>> +}
>> +

..

>> +
>> +static void vq_info_add(struct vdev_info *dev, int idx, int num, int fd)
>> +{
>> +       struct vhost_vring_file backend = { .index = idx, .fd = fd };
>> +       struct vq_info *info = &dev->vqs[idx];
>> +       int r;
>> +
>> +       info->idx = idx;
>> +       info->kick = eventfd(0, EFD_NONBLOCK);
>> +       info->call = eventfd(0, EFD_NONBLOCK);
> 
> If we don't care about the callback, let's just avoid to set the call here?
> 
> (As I see vq_callback is a NULL)

Sure, will remove the vq_callback related code.

> 
>> +       r = posix_memalign(&info->ring, 4096, vring_size(num, 4096));
>> +       assert(r >= 0);
>> +       vq_reset(info, num, &dev->vdev);
>> +       vhost_vq_setup(dev, info);
>> +       info->fds.fd = info->call;
>> +       info->fds.events = POLLIN;
>> +
>> +       r = ioctl(dev->control, VHOST_NET_SET_BACKEND, &backend);
>> +       assert(!r);
>> +}
>> +
>> +static void vdev_info_init(struct vdev_info *dev, unsigned long long features)
>> +{
>> +       struct ether_header *eh;
>> +       int i, r;
>> +
>> +       dev->vdev.features = features;
>> +       INIT_LIST_HEAD(&dev->vdev.vqs);
>> +       spin_lock_init(&dev->vdev.vqs_list_lock);
>> +
>> +       dev->buf_size = (HDR_LEN + TEST_BUF_LEN) * 2;
>> +       dev->buf = malloc(dev->buf_size);
>> +       assert(dev->buf);
>> +       dev->test_buf = dev->buf;
>> +       dev->res_buf = dev->test_buf + HDR_LEN + TEST_BUF_LEN;
>> +
>> +       memset(dev->test_buf, 0, HDR_LEN + TEST_BUF_LEN);
>> +       eh = (struct ether_header *)(dev->test_buf + HDR_LEN);
>> +       eh->ether_type = htons(TEST_PTYPE);
>> +       memcpy(eh->ether_dhost, dev->mac, ETHER_ADDR_LEN);
>> +       memcpy(eh->ether_shost, dev->mac, ETHER_ADDR_LEN);
>> +
>> +       for (i = sizeof(*eh); i < TEST_BUF_LEN; i++)
>> +               dev->test_buf[i + HDR_LEN] = (char)i;
>> +
>> +       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);
>> +
>> +       r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
>> +       assert(r >= 0);
>> +
>> +       dev->nvqs = 2;
>> +}
>> +
>> +static void wait_for_interrupt(struct vq_info *vq)
>> +{
>> +       unsigned long long val;
>> +
>> +       poll(&vq->fds, 1, -1);
>> +
>> +       if (vq->fds.revents & POLLIN)
>> +               read(vq->fds.fd, &val, sizeof(val));
>> +}
>> +
>> +static void verify_res_buf(char *res_buf)
>> +{
>> +       int i;
>> +
>> +       for (i = ETHER_HDR_LEN; i < TEST_BUF_LEN; i++)
>> +               assert(res_buf[i] == (char)i);
>> +}
>> +
>> +static void run_tx_test(struct vdev_info *dev, struct vq_info *vq,
>> +                       bool delayed, int batch, int bufs)
> 
> It might be better to describe the test design briefly above as a
> comment. Or we can start from simple test logic and add sophisticated
> ones on top.

Does something described in the comment log as suggested by you make
sense to you?
Steps for vhost_net tx testing:
1. Prepare a out buf
2. Kick the vhost_net to do tx processing
3. Do the receiving in the tun side
4. verify the data received by tun is correct

> 
>> +{
>> +       const bool random_batch = batch == RANDOM_BATCH;
>> +       long long spurious = 0;
>> +       struct scatterlist sl;
>> +       unsigned int len;
>> +       int r;
>> +
>> +       for (;;) {
>> +               long started_before = vq->started;
>> +               long completed_before = vq->completed;
>> +
>> +               virtqueue_disable_cb(vq->vq);
>> +               do {
>> +                       if (random_batch)
>> +                               batch = (random() % vq->vring.num) + 1;
>> +
>> +                       while (vq->started < bufs &&
>> +                              (vq->started - vq->completed) < batch) {
>> +                               sg_init_one(&sl, dev->test_buf, HDR_LEN + TEST_BUF_LEN);
>> +                               r = virtqueue_add_outbuf(vq->vq, &sl, 1,
>> +                                                        dev->test_buf + vq->started,
>> +                                                        GFP_ATOMIC);
>> +                               if (unlikely(r != 0)) {
>> +                                       if (r == -ENOSPC &&
>> +                                           vq->started > started_before)
>> +                                               r = 0;
>> +                                       else
>> +                                               r = -1;
>> +                                       break;
>> +                               }
>> +
>> +                               ++vq->started;
>> +
>> +                               if (unlikely(!virtqueue_kick(vq->vq))) {
>> +                                       r = -1;
>> +                                       break;
>> +                               }
>> +                       }
>> +
>> +                       if (vq->started >= bufs)
>> +                               r = -1;
>> +
>> +                       /* Flush out completed bufs if any */
>> +                       while (virtqueue_get_buf(vq->vq, &len)) {
>> +                               int n;
>> +
>> +                               n = recvfrom(dev->sock, dev->res_buf, TEST_BUF_LEN, 0, NULL, NULL);
>> +                               assert(n == TEST_BUF_LEN);
>> +                               verify_res_buf(dev->res_buf);
>> +
>> +                               ++vq->completed;
>> +                               r = 0;
>> +                       }
>> +               } while (r == 0);
>> +
>> +               if (vq->completed == completed_before && vq->started == started_before)
>> +                       ++spurious;
>> +
>> +               assert(vq->completed <= bufs);
>> +               assert(vq->started <= bufs);
>> +               if (vq->completed == bufs)
>> +                       break;
>> +
>> +               if (delayed) {
>> +                       if (virtqueue_enable_cb_delayed(vq->vq))
>> +                               wait_for_interrupt(vq);
>> +               } else {
>> +                       if (virtqueue_enable_cb(vq->vq))
>> +                               wait_for_interrupt(vq);
>> +               }
>> +       }
>> +       printf("TX spurious wakeups: 0x%llx started=0x%lx completed=0x%lx\n",
>> +              spurious, vq->started, vq->completed);
>> +}
>> +
>> +static void run_rx_test(struct vdev_info *dev, struct vq_info *vq,
>> +                       bool delayed, int batch, int bufs)
>> +{
>> +       const bool random_batch = batch == RANDOM_BATCH;
>> +       long long spurious = 0;
>> +       struct scatterlist sl;
>> +       unsigned int len;
>> +       int r;
>> +
>> +       for (;;) {
>> +               long started_before = vq->started;
>> +               long completed_before = vq->completed;
>> +
>> +               do {
>> +                       if (random_batch)
>> +                               batch = (random() % vq->vring.num) + 1;
>> +
>> +                       while (vq->started < bufs &&
>> +                              (vq->started - vq->completed) < batch) {
>> +                               sg_init_one(&sl, dev->res_buf, HDR_LEN + TEST_BUF_LEN);
>> +
>> +                               r = virtqueue_add_inbuf(vq->vq, &sl, 1,
>> +                                                       dev->res_buf + vq->started,
>> +                                                       GFP_ATOMIC);
>> +                               if (unlikely(r != 0)) {
>> +                                       if (r == -ENOSPC &&
> 
> Drivers usually maintain a #free_slots, this can help to avoid the
> trick for checking ENOSPC?

The above "(vq->started - vq->completed) < batch" seems to ensure that
the 'r' can't be '-ENOSPC'? We just need to ensure the batch <= desc_num,
and the 'r == -ENOSPC' checking seems to be unnecessary.

> 
>> +                                           vq->started > started_before)
>> +                                               r = 0;
>> +                                       else
>> +                                               r = -1;
>> +                                       break;
>> +                               }
>> +
>> +                               ++vq->started;
>> +
>> +                               vdev_send_packet(dev);
>> +
>> +                               if (unlikely(!virtqueue_kick(vq->vq))) {
>> +                                       r = -1;
>> +                                       break;
>> +                               }
>> +                       }
>> +
>> +                       if (vq->started >= bufs)
>> +                               r = -1;
>> +
>> +                       /* Flush out completed bufs if any */
>> +                       while (virtqueue_get_buf(vq->vq, &len)) {
>> +                               struct ether_header *eh;
>> +
>> +                               eh = (struct ether_header *)(dev->res_buf + HDR_LEN);
>> +
>> +                               /* tun netdev is up and running, ignore the
>> +                                * non-TEST_PTYPE packet.
>> +                                */
> 
> I wonder if it's better to set up some kind of qdisc to avoid the
> unexpected packet here, or is it too complicated?

Yes, at least I don't know to do that yet.

> 
> Thanks
> 
> .
>
  
Jason Wang Feb. 4, 2024, 1:30 a.m. UTC | #3
On Fri, Feb 2, 2024 at 8:24 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
>
> On 2024/2/2 12:05, Jason Wang wrote:
> > On Tue, Jan 30, 2024 at 7:38 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
> >>
> >> introduce vhost_net_test basing on virtio_test to test
> >> vhost_net changing in the kernel.
> >
> > Let's describe what kind of test is being done and how it is done here.
>
> How about something like below:
>
> This patch introduces testing for both vhost_net tx and rx.
> Steps for vhost_net tx testing:
> 1. Prepare a out buf
> 2. Kick the vhost_net to do tx processing
> 3. Do the receiving in the tun side
> 4. verify the data received by tun is correct
>
> Steps for vhost_net rx testing::
> 1. Prepare a in buf
> 2. Do the sending in the tun side
> 3. Kick the vhost_net to do rx processing
> 4. verify the data received by vhost_net is correct

It looks like some important details were lost, e.g the logic for batching etc.

>
>
> >> +
> >> +static int tun_alloc(struct vdev_info *dev)
> >> +{
> >> +       struct ifreq ifr;
> >> +       int len = HDR_LEN;
> >
> > Any reason you can't just use the virtio_net uapi?
>
> I didn't find a macro for that in include/uapi/linux/virtio_net.h.
>
> Did you mean using something like below?
> sizeof(struct virtio_net_hdr_mrg_rxbuf)

Yes.

>
> >
> >> +       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_TAP | IFF_NO_PI | IFF_VNET_HDR;
> >> +       snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
> >> +
> >> +       e = ioctl(fd, TUNSETIFF, &ifr);
> >> +       if (e < 0) {
> >> +               perror("ioctl[TUNSETIFF]");
> >> +               close(fd);
> >> +               return e;
> >> +       }
> >> +
> >> +       e = ioctl(fd, TUNSETVNETHDRSZ, &len);
> >> +       if (e < 0) {
> >> +               perror("ioctl[TUNSETVNETHDRSZ]");
> >> +               close(fd);
> >> +               return e;
> >> +       }
> >> +
> >> +       e = ioctl(fd, SIOCGIFHWADDR, &ifr);
> >> +       if (e < 0) {
> >> +               perror("ioctl[SIOCGIFHWADDR]");
> >> +               close(fd);
> >> +               return e;
> >> +       }
> >> +
> >> +       memcpy(dev->mac, &ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
> >> +       return fd;
> >> +}
> >> +
> >> +static void vdev_create_socket(struct vdev_info *dev)
> >> +{
> >> +       struct ifreq ifr;
> >> +
> >> +       dev->sock = socket(AF_PACKET, SOCK_RAW, htons(TEST_PTYPE));
> >> +       assert(dev->sock != -1);
> >> +
> >> +       snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
> >
> > Nit: it might be better to accept the device name instead of repeating
> > the snprintf trick here, this would facilitate the future changes.
>
> I am not sure I understand what did you mean by "accept the device name"
> here.
>
> The above is used to get ifindex of the tun netdevice created in
> tun_alloc(), so that we can use it in vdev_send_packet() to send
> a packet using the tun netdevice created in tun_alloc(). Is there
> anything obvious I missed here?

I meant a const char *ifname for this function and let the caller to
pass the name.

>
> >
> >> +       assert(ioctl(dev->sock, SIOCGIFINDEX, &ifr) >= 0);
> >> +
> >> +       dev->ifindex = ifr.ifr_ifindex;
> >> +
> >> +       /* Set the flags that bring the device up */
> >> +       assert(ioctl(dev->sock, SIOCGIFFLAGS, &ifr) >= 0);
> >> +       ifr.ifr_flags |= (IFF_UP | IFF_RUNNING);
> >> +       assert(ioctl(dev->sock, SIOCSIFFLAGS, &ifr) >= 0);
> >> +}
> >> +
> >> +static void vdev_send_packet(struct vdev_info *dev)
> >> +{
> >> +       char *sendbuf = dev->test_buf + HDR_LEN;
> >> +       struct sockaddr_ll saddrll = {0};
> >> +       int sockfd = dev->sock;
> >> +       int ret;
> >> +
> >> +       saddrll.sll_family = PF_PACKET;
> >> +       saddrll.sll_ifindex = dev->ifindex;
> >> +       saddrll.sll_halen = ETH_ALEN;
> >> +       saddrll.sll_protocol = htons(TEST_PTYPE);
> >> +
> >> +       ret = sendto(sockfd, sendbuf, TEST_BUF_LEN, 0,
> >> +                    (struct sockaddr *)&saddrll,
> >> +                    sizeof(struct sockaddr_ll));
> >> +       assert(ret >= 0);
> >> +}
> >> +
>
> ...
>
> >> +
> >> +static void vq_info_add(struct vdev_info *dev, int idx, int num, int fd)
> >> +{
> >> +       struct vhost_vring_file backend = { .index = idx, .fd = fd };
> >> +       struct vq_info *info = &dev->vqs[idx];
> >> +       int r;
> >> +
> >> +       info->idx = idx;
> >> +       info->kick = eventfd(0, EFD_NONBLOCK);
> >> +       info->call = eventfd(0, EFD_NONBLOCK);
> >
> > If we don't care about the callback, let's just avoid to set the call here?
> >
> > (As I see vq_callback is a NULL)
>
> Sure, will remove the vq_callback related code.
>
> >
> >> +       r = posix_memalign(&info->ring, 4096, vring_size(num, 4096));
> >> +       assert(r >= 0);
> >> +       vq_reset(info, num, &dev->vdev);
> >> +       vhost_vq_setup(dev, info);
> >> +       info->fds.fd = info->call;
> >> +       info->fds.events = POLLIN;
> >> +
> >> +       r = ioctl(dev->control, VHOST_NET_SET_BACKEND, &backend);
> >> +       assert(!r);
> >> +}
> >> +
> >> +static void vdev_info_init(struct vdev_info *dev, unsigned long long features)
> >> +{
> >> +       struct ether_header *eh;
> >> +       int i, r;
> >> +
> >> +       dev->vdev.features = features;
> >> +       INIT_LIST_HEAD(&dev->vdev.vqs);
> >> +       spin_lock_init(&dev->vdev.vqs_list_lock);
> >> +
> >> +       dev->buf_size = (HDR_LEN + TEST_BUF_LEN) * 2;
> >> +       dev->buf = malloc(dev->buf_size);
> >> +       assert(dev->buf);
> >> +       dev->test_buf = dev->buf;
> >> +       dev->res_buf = dev->test_buf + HDR_LEN + TEST_BUF_LEN;
> >> +
> >> +       memset(dev->test_buf, 0, HDR_LEN + TEST_BUF_LEN);
> >> +       eh = (struct ether_header *)(dev->test_buf + HDR_LEN);
> >> +       eh->ether_type = htons(TEST_PTYPE);
> >> +       memcpy(eh->ether_dhost, dev->mac, ETHER_ADDR_LEN);
> >> +       memcpy(eh->ether_shost, dev->mac, ETHER_ADDR_LEN);
> >> +
> >> +       for (i = sizeof(*eh); i < TEST_BUF_LEN; i++)
> >> +               dev->test_buf[i + HDR_LEN] = (char)i;
> >> +
> >> +       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);
> >> +
> >> +       r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
> >> +       assert(r >= 0);
> >> +
> >> +       dev->nvqs = 2;
> >> +}
> >> +
> >> +static void wait_for_interrupt(struct vq_info *vq)
> >> +{
> >> +       unsigned long long val;
> >> +
> >> +       poll(&vq->fds, 1, -1);
> >> +
> >> +       if (vq->fds.revents & POLLIN)
> >> +               read(vq->fds.fd, &val, sizeof(val));
> >> +}
> >> +
> >> +static void verify_res_buf(char *res_buf)
> >> +{
> >> +       int i;
> >> +
> >> +       for (i = ETHER_HDR_LEN; i < TEST_BUF_LEN; i++)
> >> +               assert(res_buf[i] == (char)i);
> >> +}
> >> +
> >> +static void run_tx_test(struct vdev_info *dev, struct vq_info *vq,
> >> +                       bool delayed, int batch, int bufs)
> >
> > It might be better to describe the test design briefly above as a
> > comment. Or we can start from simple test logic and add sophisticated
> > ones on top.
>
> Does something described in the comment log as suggested by you make
> sense to you?
> Steps for vhost_net tx testing:
> 1. Prepare a out buf
> 2. Kick the vhost_net to do tx processing
> 3. Do the receiving in the tun side
> 4. verify the data received by tun is correct

See my reply above.

>
> >
> >> +{
> >> +       const bool random_batch = batch == RANDOM_BATCH;
> >> +       long long spurious = 0;
> >> +       struct scatterlist sl;
> >> +       unsigned int len;
> >> +       int r;
> >> +
> >> +       for (;;) {
> >> +               long started_before = vq->started;
> >> +               long completed_before = vq->completed;
> >> +
> >> +               virtqueue_disable_cb(vq->vq);
> >> +               do {
> >> +                       if (random_batch)
> >> +                               batch = (random() % vq->vring.num) + 1;
> >> +
> >> +                       while (vq->started < bufs &&
> >> +                              (vq->started - vq->completed) < batch) {
> >> +                               sg_init_one(&sl, dev->test_buf, HDR_LEN + TEST_BUF_LEN);
> >> +                               r = virtqueue_add_outbuf(vq->vq, &sl, 1,
> >> +                                                        dev->test_buf + vq->started,
> >> +                                                        GFP_ATOMIC);
> >> +                               if (unlikely(r != 0)) {
> >> +                                       if (r == -ENOSPC &&
> >> +                                           vq->started > started_before)
> >> +                                               r = 0;
> >> +                                       else
> >> +                                               r = -1;
> >> +                                       break;
> >> +                               }
> >> +
> >> +                               ++vq->started;
> >> +
> >> +                               if (unlikely(!virtqueue_kick(vq->vq))) {
> >> +                                       r = -1;
> >> +                                       break;
> >> +                               }
> >> +                       }
> >> +
> >> +                       if (vq->started >= bufs)
> >> +                               r = -1;
> >> +
> >> +                       /* Flush out completed bufs if any */
> >> +                       while (virtqueue_get_buf(vq->vq, &len)) {
> >> +                               int n;
> >> +
> >> +                               n = recvfrom(dev->sock, dev->res_buf, TEST_BUF_LEN, 0, NULL, NULL);
> >> +                               assert(n == TEST_BUF_LEN);
> >> +                               verify_res_buf(dev->res_buf);
> >> +
> >> +                               ++vq->completed;
> >> +                               r = 0;
> >> +                       }
> >> +               } while (r == 0);
> >> +
> >> +               if (vq->completed == completed_before && vq->started == started_before)
> >> +                       ++spurious;
> >> +
> >> +               assert(vq->completed <= bufs);
> >> +               assert(vq->started <= bufs);
> >> +               if (vq->completed == bufs)
> >> +                       break;
> >> +
> >> +               if (delayed) {
> >> +                       if (virtqueue_enable_cb_delayed(vq->vq))
> >> +                               wait_for_interrupt(vq);
> >> +               } else {
> >> +                       if (virtqueue_enable_cb(vq->vq))
> >> +                               wait_for_interrupt(vq);
> >> +               }
> >> +       }
> >> +       printf("TX spurious wakeups: 0x%llx started=0x%lx completed=0x%lx\n",
> >> +              spurious, vq->started, vq->completed);
> >> +}
> >> +
> >> +static void run_rx_test(struct vdev_info *dev, struct vq_info *vq,
> >> +                       bool delayed, int batch, int bufs)
> >> +{
> >> +       const bool random_batch = batch == RANDOM_BATCH;
> >> +       long long spurious = 0;
> >> +       struct scatterlist sl;
> >> +       unsigned int len;
> >> +       int r;
> >> +
> >> +       for (;;) {
> >> +               long started_before = vq->started;
> >> +               long completed_before = vq->completed;
> >> +
> >> +               do {
> >> +                       if (random_batch)
> >> +                               batch = (random() % vq->vring.num) + 1;
> >> +
> >> +                       while (vq->started < bufs &&
> >> +                              (vq->started - vq->completed) < batch) {
> >> +                               sg_init_one(&sl, dev->res_buf, HDR_LEN + TEST_BUF_LEN);
> >> +
> >> +                               r = virtqueue_add_inbuf(vq->vq, &sl, 1,
> >> +                                                       dev->res_buf + vq->started,
> >> +                                                       GFP_ATOMIC);
> >> +                               if (unlikely(r != 0)) {
> >> +                                       if (r == -ENOSPC &&
> >
> > Drivers usually maintain a #free_slots, this can help to avoid the
> > trick for checking ENOSPC?
>
> The above "(vq->started - vq->completed) < batch" seems to ensure that
> the 'r' can't be '-ENOSPC'?

Well, if this is true any reason we still check ENOSPEC here?

> We just need to ensure the batch <= desc_num,
> and the 'r == -ENOSPC' checking seems to be unnecessary.
>
> >
> >> +                                           vq->started > started_before)
> >> +                                               r = 0;
> >> +                                       else
> >> +                                               r = -1;
> >> +                                       break;
> >> +                               }
> >> +
> >> +                               ++vq->started;
> >> +
> >> +                               vdev_send_packet(dev);
> >> +
> >> +                               if (unlikely(!virtqueue_kick(vq->vq))) {
> >> +                                       r = -1;
> >> +                                       break;
> >> +                               }
> >> +                       }
> >> +
> >> +                       if (vq->started >= bufs)
> >> +                               r = -1;
> >> +
> >> +                       /* Flush out completed bufs if any */
> >> +                       while (virtqueue_get_buf(vq->vq, &len)) {
> >> +                               struct ether_header *eh;
> >> +
> >> +                               eh = (struct ether_header *)(dev->res_buf + HDR_LEN);
> >> +
> >> +                               /* tun netdev is up and running, ignore the
> >> +                                * non-TEST_PTYPE packet.
> >> +                                */
> >
> > I wonder if it's better to set up some kind of qdisc to avoid the
> > unexpected packet here, or is it too complicated?
>
> Yes, at least I don't know to do that yet.

For example, the blackhole qdisc?

Thanks
  
Yunsheng Lin Feb. 4, 2024, 3:50 a.m. UTC | #4
On 2024/2/4 9:30, Jason Wang wrote:
> On Fri, Feb 2, 2024 at 8:24 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
>>
>> On 2024/2/2 12:05, Jason Wang wrote:
>>> On Tue, Jan 30, 2024 at 7:38 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
>>>>
>>>> introduce vhost_net_test basing on virtio_test to test
>>>> vhost_net changing in the kernel.
>>>
>>> Let's describe what kind of test is being done and how it is done here.
>>
>> How about something like below:
>>
>> This patch introduces testing for both vhost_net tx and rx.
>> Steps for vhost_net tx testing:
>> 1. Prepare a out buf
>> 2. Kick the vhost_net to do tx processing
>> 3. Do the receiving in the tun side
>> 4. verify the data received by tun is correct
>>
>> Steps for vhost_net rx testing::
>> 1. Prepare a in buf
>> 2. Do the sending in the tun side
>> 3. Kick the vhost_net to do rx processing
>> 4. verify the data received by vhost_net is correct
> 
> It looks like some important details were lost, e.g the logic for batching etc.

I am supposeing you are referring to the virtio desc batch handling,
right?

It was a copy & paste code of virtio_test.c, I was thinking about removing
the virtio desc batch handling for now, as this patchset does not require
that to do the testing, it mainly depend on the "sock->sk->sk_sndbuf" to
be INT_MAX to call vhost_net_build_xdp(), which seems to be the default
case for vhost_net.

> 
>>

..

>>>> +static void vdev_create_socket(struct vdev_info *dev)
>>>> +{
>>>> +       struct ifreq ifr;
>>>> +
>>>> +       dev->sock = socket(AF_PACKET, SOCK_RAW, htons(TEST_PTYPE));
>>>> +       assert(dev->sock != -1);
>>>> +
>>>> +       snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
>>>
>>> Nit: it might be better to accept the device name instead of repeating
>>> the snprintf trick here, this would facilitate the future changes.
>>
>> I am not sure I understand what did you mean by "accept the device name"
>> here.
>>
>> The above is used to get ifindex of the tun netdevice created in
>> tun_alloc(), so that we can use it in vdev_send_packet() to send
>> a packet using the tun netdevice created in tun_alloc(). Is there
>> anything obvious I missed here?
> 
> I meant a const char *ifname for this function and let the caller to
> pass the name.

Sure.

> 
>>

>>>> +
>>>> +static void run_rx_test(struct vdev_info *dev, struct vq_info *vq,
>>>> +                       bool delayed, int batch, int bufs)
>>>> +{
>>>> +       const bool random_batch = batch == RANDOM_BATCH;
>>>> +       long long spurious = 0;
>>>> +       struct scatterlist sl;
>>>> +       unsigned int len;
>>>> +       int r;
>>>> +
>>>> +       for (;;) {
>>>> +               long started_before = vq->started;
>>>> +               long completed_before = vq->completed;
>>>> +
>>>> +               do {
>>>> +                       if (random_batch)
>>>> +                               batch = (random() % vq->vring.num) + 1;
>>>> +
>>>> +                       while (vq->started < bufs &&
>>>> +                              (vq->started - vq->completed) < batch) {
>>>> +                               sg_init_one(&sl, dev->res_buf, HDR_LEN + TEST_BUF_LEN);
>>>> +
>>>> +                               r = virtqueue_add_inbuf(vq->vq, &sl, 1,
>>>> +                                                       dev->res_buf + vq->started,
>>>> +                                                       GFP_ATOMIC);
>>>> +                               if (unlikely(r != 0)) {
>>>> +                                       if (r == -ENOSPC &&
>>>
>>> Drivers usually maintain a #free_slots, this can help to avoid the
>>> trick for checking ENOSPC?
>>
>> The above "(vq->started - vq->completed) < batch" seems to ensure that
>> the 'r' can't be '-ENOSPC'?
> 
> Well, if this is true any reason we still check ENOSPEC here?

As mentioned above, It was a copy & paste code of virtio_test.c.
Will remove 'r == -ENOSPC' checking.

> 
>> We just need to ensure the batch <= desc_num,
>> and the 'r == -ENOSPC' checking seems to be unnecessary.
>>
>>>
>>>> +                                           vq->started > started_before)
>>>> +                                               r = 0;
>>>> +                                       else
>>>> +                                               r = -1;
>>>> +                                       break;
>>>> +                               }
>>>> +
>>>> +                               ++vq->started;
>>>> +
>>>> +                               vdev_send_packet(dev);
>>>> +
>>>> +                               if (unlikely(!virtqueue_kick(vq->vq))) {
>>>> +                                       r = -1;
>>>> +                                       break;
>>>> +                               }
>>>> +                       }
>>>> +
>>>> +                       if (vq->started >= bufs)
>>>> +                               r = -1;
>>>> +
>>>> +                       /* Flush out completed bufs if any */
>>>> +                       while (virtqueue_get_buf(vq->vq, &len)) {
>>>> +                               struct ether_header *eh;
>>>> +
>>>> +                               eh = (struct ether_header *)(dev->res_buf + HDR_LEN);
>>>> +
>>>> +                               /* tun netdev is up and running, ignore the
>>>> +                                * non-TEST_PTYPE packet.
>>>> +                                */
>>>
>>> I wonder if it's better to set up some kind of qdisc to avoid the
>>> unexpected packet here, or is it too complicated?
>>
>> Yes, at least I don't know to do that yet.
> 
> For example, the blackhole qdisc?

It seems the blackhole_enqueue() just drop everything, which includes
the packet sent using the raw socket in vdev_send_packet()?

We may bypass qdisc for the raw socket in vdev_send_packet(),but it
means other caller may bypass qdisc, and even cook up a packet with
ethertype being ETH_P_LOOPBACK, there is part of the reason I added a
simple payload verification in verify_res_buf().

> 
> Thanks
> 
> .
>
  
Jason Wang Feb. 5, 2024, 1:43 a.m. UTC | #5
On Sun, Feb 4, 2024 at 11:50 AM Yunsheng Lin <linyunsheng@huawei.com> wrote:
>
> On 2024/2/4 9:30, Jason Wang wrote:
> > On Fri, Feb 2, 2024 at 8:24 PM Yunsheng Lin <linyunsheng@huaweicom> wrote:
> >>
> >> On 2024/2/2 12:05, Jason Wang wrote:
> >>> On Tue, Jan 30, 2024 at 7:38 PM Yunsheng Lin <linyunsheng@huawei.com> wrote:
> >>>>
> >>>> introduce vhost_net_test basing on virtio_test to test
> >>>> vhost_net changing in the kernel.
> >>>
> >>> Let's describe what kind of test is being done and how it is done here.
> >>
> >> How about something like below:
> >>
> >> This patch introduces testing for both vhost_net tx and rx.
> >> Steps for vhost_net tx testing:
> >> 1. Prepare a out buf
> >> 2. Kick the vhost_net to do tx processing
> >> 3. Do the receiving in the tun side
> >> 4. verify the data received by tun is correct
> >>
> >> Steps for vhost_net rx testing::
> >> 1. Prepare a in buf
> >> 2. Do the sending in the tun side
> >> 3. Kick the vhost_net to do rx processing
> >> 4. verify the data received by vhost_net is correct
> >
> > It looks like some important details were lost, e.g the logic for batching etc.
>
> I am supposeing you are referring to the virtio desc batch handling,
> right?

Yes.

>
> It was a copy & paste code of virtio_test.c, I was thinking about removing
> the virtio desc batch handling for now, as this patchset does not require
> that to do the testing, it mainly depend on the "sock->sk->sk_sndbuf" to
> be INT_MAX to call vhost_net_build_xdp(), which seems to be the default
> case for vhost_net.

Ok.

>
> >
> >>
>
> ...
>
> >>>> +static void vdev_create_socket(struct vdev_info *dev)
> >>>> +{
> >>>> +       struct ifreq ifr;
> >>>> +
> >>>> +       dev->sock = socket(AF_PACKET, SOCK_RAW, htons(TEST_PTYPE));
> >>>> +       assert(dev->sock != -1);
> >>>> +
> >>>> +       snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
> >>>
> >>> Nit: it might be better to accept the device name instead of repeating
> >>> the snprintf trick here, this would facilitate the future changes.
> >>
> >> I am not sure I understand what did you mean by "accept the device name"
> >> here.
> >>
> >> The above is used to get ifindex of the tun netdevice created in
> >> tun_alloc(), so that we can use it in vdev_send_packet() to send
> >> a packet using the tun netdevice created in tun_alloc(). Is there
> >> anything obvious I missed here?
> >
> > I meant a const char *ifname for this function and let the caller to
> > pass the name.
>
> Sure.
>
> >
> >>
>
> >>>> +
> >>>> +static void run_rx_test(struct vdev_info *dev, struct vq_info *vq,
> >>>> +                       bool delayed, int batch, int bufs)
> >>>> +{
> >>>> +       const bool random_batch = batch == RANDOM_BATCH;
> >>>> +       long long spurious = 0;
> >>>> +       struct scatterlist sl;
> >>>> +       unsigned int len;
> >>>> +       int r;
> >>>> +
> >>>> +       for (;;) {
> >>>> +               long started_before = vq->started;
> >>>> +               long completed_before = vq->completed;
> >>>> +
> >>>> +               do {
> >>>> +                       if (random_batch)
> >>>> +                               batch = (random() % vq->vring.num) + 1;
> >>>> +
> >>>> +                       while (vq->started < bufs &&
> >>>> +                              (vq->started - vq->completed) < batch) {
> >>>> +                               sg_init_one(&sl, dev->res_buf, HDR_LEN + TEST_BUF_LEN);
> >>>> +
> >>>> +                               r = virtqueue_add_inbuf(vq->vq, &sl, 1,
> >>>> +                                                       dev->res_buf + vq->started,
> >>>> +                                                       GFP_ATOMIC);
> >>>> +                               if (unlikely(r != 0)) {
> >>>> +                                       if (r == -ENOSPC &&
> >>>
> >>> Drivers usually maintain a #free_slots, this can help to avoid the
> >>> trick for checking ENOSPC?
> >>
> >> The above "(vq->started - vq->completed) < batch" seems to ensure that
> >> the 'r' can't be '-ENOSPC'?
> >
> > Well, if this is true any reason we still check ENOSPEC here?
>
> As mentioned above, It was a copy & paste code of virtio_test.c.
> Will remove 'r == -ENOSPC' checking.

I see.

>
> >
> >> We just need to ensure the batch <= desc_num,
> >> and the 'r == -ENOSPC' checking seems to be unnecessary.
> >>
> >>>
> >>>> +                                           vq->started > started_before)
> >>>> +                                               r = 0;
> >>>> +                                       else
> >>>> +                                               r = -1;
> >>>> +                                       break;
> >>>> +                               }
> >>>> +
> >>>> +                               ++vq->started;
> >>>> +
> >>>> +                               vdev_send_packet(dev);
> >>>> +
> >>>> +                               if (unlikely(!virtqueue_kick(vq->vq))) {
> >>>> +                                       r = -1;
> >>>> +                                       break;
> >>>> +                               }
> >>>> +                       }
> >>>> +
> >>>> +                       if (vq->started >= bufs)
> >>>> +                               r = -1;
> >>>> +
> >>>> +                       /* Flush out completed bufs if any */
> >>>> +                       while (virtqueue_get_buf(vq->vq, &len)) {
> >>>> +                               struct ether_header *eh;
> >>>> +
> >>>> +                               eh = (struct ether_header *)(dev->res_buf + HDR_LEN);
> >>>> +
> >>>> +                               /* tun netdev is up and running, ignore the
> >>>> +                                * non-TEST_PTYPE packet.
> >>>> +                                */
> >>>
> >>> I wonder if it's better to set up some kind of qdisc to avoid the
> >>> unexpected packet here, or is it too complicated?
> >>
> >> Yes, at least I don't know to do that yet.
> >
> > For example, the blackhole qdisc?
>
> It seems the blackhole_enqueue() just drop everything, which includes
> the packet sent using the raw socket in vdev_send_packet()?

I vaguely remember there's a mode that af_packet will bypass the qdisc
but I might be wrong.

But rethink of this, though it facilitates the code but it introduces
unnecessary dependencies like black hole which seems to be suboptimal.

>
> We may bypass qdisc for the raw socket in vdev_send_packet(),but it
> means other caller may bypass qdisc, and even cook up a packet with
> ethertype being ETH_P_LOOPBACK, there is part of the reason I added a
> simple payload verification in verify_res_buf().

Fine.

Thanks

>
> >
> > Thanks
> >
> > .
> >
>
  

Patch

diff --git a/tools/virtio/.gitignore b/tools/virtio/.gitignore
index 9934d48d9a55..7e47b281c442 100644
--- a/tools/virtio/.gitignore
+++ b/tools/virtio/.gitignore
@@ -1,5 +1,6 @@ 
 # SPDX-License-Identifier: GPL-2.0-only
 *.d
 virtio_test
+vhost_net_test
 vringh_test
 virtio-trace/trace-agent
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..e336792a0d77
--- /dev/null
+++ b/tools/virtio/vhost_net_test.c
@@ -0,0 +1,576 @@ 
+// 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>
+#include <linux/in.h>
+#include <linux/if_packet.h>
+#include <netinet/ether.h>
+
+#define RANDOM_BATCH	-1
+#define HDR_LEN		12
+#define TEST_BUF_LEN	256
+#define TEST_PTYPE	ETH_P_LOOPBACK
+
+/* Used by implementation of kmalloc() in tools/virtio/linux/kernel.h */
+void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end;
+
+struct vq_info {
+	int kick;
+	int call;
+	int idx;
+	long started;
+	long completed;
+	struct pollfd fds;
+	void *ring;
+	/* copy used for control */
+	struct vring vring;
+	struct virtqueue *vq;
+};
+
+struct vdev_info {
+	struct virtio_device vdev;
+	int control;
+	struct vq_info vqs[2];
+	int nvqs;
+	void *buf;
+	size_t buf_size;
+	char *test_buf;
+	char *res_buf;
+	struct vhost_memory *mem;
+	int sock;
+	int ifindex;
+	unsigned char mac[ETHER_ADDR_LEN];
+};
+
+static int tun_alloc(struct vdev_info *dev)
+{
+	struct ifreq ifr;
+	int len = HDR_LEN;
+	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_TAP | IFF_NO_PI | IFF_VNET_HDR;
+	snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
+
+	e = ioctl(fd, TUNSETIFF, &ifr);
+	if (e < 0) {
+		perror("ioctl[TUNSETIFF]");
+		close(fd);
+		return e;
+	}
+
+	e = ioctl(fd, TUNSETVNETHDRSZ, &len);
+	if (e < 0) {
+		perror("ioctl[TUNSETVNETHDRSZ]");
+		close(fd);
+		return e;
+	}
+
+	e = ioctl(fd, SIOCGIFHWADDR, &ifr);
+	if (e < 0) {
+		perror("ioctl[SIOCGIFHWADDR]");
+		close(fd);
+		return e;
+	}
+
+	memcpy(dev->mac, &ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
+	return fd;
+}
+
+static void vdev_create_socket(struct vdev_info *dev)
+{
+	struct ifreq ifr;
+
+	dev->sock = socket(AF_PACKET, SOCK_RAW, htons(TEST_PTYPE));
+	assert(dev->sock != -1);
+
+	snprintf(ifr.ifr_name, IFNAMSIZ, "tun_%d", getpid());
+	assert(ioctl(dev->sock, SIOCGIFINDEX, &ifr) >= 0);
+
+	dev->ifindex = ifr.ifr_ifindex;
+
+	/* Set the flags that bring the device up */
+	assert(ioctl(dev->sock, SIOCGIFFLAGS, &ifr) >= 0);
+	ifr.ifr_flags |= (IFF_UP | IFF_RUNNING);
+	assert(ioctl(dev->sock, SIOCSIFFLAGS, &ifr) >= 0);
+}
+
+static void vdev_send_packet(struct vdev_info *dev)
+{
+	char *sendbuf = dev->test_buf + HDR_LEN;
+	struct sockaddr_ll saddrll = {0};
+	int sockfd = dev->sock;
+	int ret;
+
+	saddrll.sll_family = PF_PACKET;
+	saddrll.sll_ifindex = dev->ifindex;
+	saddrll.sll_halen = ETH_ALEN;
+	saddrll.sll_protocol = htons(TEST_PTYPE);
+
+	ret = sendto(sockfd, sendbuf, TEST_BUF_LEN, 0,
+		     (struct sockaddr *)&saddrll,
+		     sizeof(struct sockaddr_ll));
+	assert(ret >= 0);
+}
+
+static 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;
+}
+
+static void vq_callback(struct virtqueue *vq)
+{
+}
+
+static void vhost_vq_setup(struct vdev_info *dev, struct vq_info *info)
+{
+	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,
+	};
+	struct vhost_vring_state state = { .index = info->idx };
+	struct vhost_vring_file file = { .index = info->idx };
+	int r;
+
+	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 idx, int num, int fd)
+{
+	struct vhost_vring_file backend = { .index = idx, .fd = fd };
+	struct vq_info *info = &dev->vqs[idx];
+	int r;
+
+	info->idx = idx;
+	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);
+	info->fds.fd = info->call;
+	info->fds.events = POLLIN;
+
+	r = ioctl(dev->control, VHOST_NET_SET_BACKEND, &backend);
+	assert(!r);
+}
+
+static void vdev_info_init(struct vdev_info *dev, unsigned long long features)
+{
+	struct ether_header *eh;
+	int i, r;
+
+	dev->vdev.features = features;
+	INIT_LIST_HEAD(&dev->vdev.vqs);
+	spin_lock_init(&dev->vdev.vqs_list_lock);
+
+	dev->buf_size = (HDR_LEN + TEST_BUF_LEN) * 2;
+	dev->buf = malloc(dev->buf_size);
+	assert(dev->buf);
+	dev->test_buf = dev->buf;
+	dev->res_buf = dev->test_buf + HDR_LEN + TEST_BUF_LEN;
+
+	memset(dev->test_buf, 0, HDR_LEN + TEST_BUF_LEN);
+	eh = (struct ether_header *)(dev->test_buf + HDR_LEN);
+	eh->ether_type = htons(TEST_PTYPE);
+	memcpy(eh->ether_dhost, dev->mac, ETHER_ADDR_LEN);
+	memcpy(eh->ether_shost, dev->mac, ETHER_ADDR_LEN);
+
+	for (i = sizeof(*eh); i < TEST_BUF_LEN; i++)
+		dev->test_buf[i + HDR_LEN] = (char)i;
+
+	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);
+
+	r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
+	assert(r >= 0);
+
+	dev->nvqs = 2;
+}
+
+static void wait_for_interrupt(struct vq_info *vq)
+{
+	unsigned long long val;
+
+	poll(&vq->fds, 1, -1);
+
+	if (vq->fds.revents & POLLIN)
+		read(vq->fds.fd, &val, sizeof(val));
+}
+
+static void verify_res_buf(char *res_buf)
+{
+	int i;
+
+	for (i = ETHER_HDR_LEN; i < TEST_BUF_LEN; i++)
+		assert(res_buf[i] == (char)i);
+}
+
+static void run_tx_test(struct vdev_info *dev, struct vq_info *vq,
+			bool delayed, int batch, int bufs)
+{
+	const bool random_batch = batch == RANDOM_BATCH;
+	long long spurious = 0;
+	struct scatterlist sl;
+	unsigned int len;
+	int r;
+
+	for (;;) {
+		long started_before = vq->started;
+		long completed_before = vq->completed;
+
+		virtqueue_disable_cb(vq->vq);
+		do {
+			if (random_batch)
+				batch = (random() % vq->vring.num) + 1;
+
+			while (vq->started < bufs &&
+			       (vq->started - vq->completed) < batch) {
+				sg_init_one(&sl, dev->test_buf, HDR_LEN + TEST_BUF_LEN);
+				r = virtqueue_add_outbuf(vq->vq, &sl, 1,
+							 dev->test_buf + vq->started,
+							 GFP_ATOMIC);
+				if (unlikely(r != 0)) {
+					if (r == -ENOSPC &&
+					    vq->started > started_before)
+						r = 0;
+					else
+						r = -1;
+					break;
+				}
+
+				++vq->started;
+
+				if (unlikely(!virtqueue_kick(vq->vq))) {
+					r = -1;
+					break;
+				}
+			}
+
+			if (vq->started >= bufs)
+				r = -1;
+
+			/* Flush out completed bufs if any */
+			while (virtqueue_get_buf(vq->vq, &len)) {
+				int n;
+
+				n = recvfrom(dev->sock, dev->res_buf, TEST_BUF_LEN, 0, NULL, NULL);
+				assert(n == TEST_BUF_LEN);
+				verify_res_buf(dev->res_buf);
+
+				++vq->completed;
+				r = 0;
+			}
+		} while (r == 0);
+
+		if (vq->completed == completed_before && vq->started == started_before)
+			++spurious;
+
+		assert(vq->completed <= bufs);
+		assert(vq->started <= bufs);
+		if (vq->completed == bufs)
+			break;
+
+		if (delayed) {
+			if (virtqueue_enable_cb_delayed(vq->vq))
+				wait_for_interrupt(vq);
+		} else {
+			if (virtqueue_enable_cb(vq->vq))
+				wait_for_interrupt(vq);
+		}
+	}
+	printf("TX spurious wakeups: 0x%llx started=0x%lx completed=0x%lx\n",
+	       spurious, vq->started, vq->completed);
+}
+
+static void run_rx_test(struct vdev_info *dev, struct vq_info *vq,
+			bool delayed, int batch, int bufs)
+{
+	const bool random_batch = batch == RANDOM_BATCH;
+	long long spurious = 0;
+	struct scatterlist sl;
+	unsigned int len;
+	int r;
+
+	for (;;) {
+		long started_before = vq->started;
+		long completed_before = vq->completed;
+
+		do {
+			if (random_batch)
+				batch = (random() % vq->vring.num) + 1;
+
+			while (vq->started < bufs &&
+			       (vq->started - vq->completed) < batch) {
+				sg_init_one(&sl, dev->res_buf, HDR_LEN + TEST_BUF_LEN);
+
+				r = virtqueue_add_inbuf(vq->vq, &sl, 1,
+							dev->res_buf + vq->started,
+							GFP_ATOMIC);
+				if (unlikely(r != 0)) {
+					if (r == -ENOSPC &&
+					    vq->started > started_before)
+						r = 0;
+					else
+						r = -1;
+					break;
+				}
+
+				++vq->started;
+
+				vdev_send_packet(dev);
+
+				if (unlikely(!virtqueue_kick(vq->vq))) {
+					r = -1;
+					break;
+				}
+			}
+
+			if (vq->started >= bufs)
+				r = -1;
+
+			/* Flush out completed bufs if any */
+			while (virtqueue_get_buf(vq->vq, &len)) {
+				struct ether_header *eh;
+
+				eh = (struct ether_header *)(dev->res_buf + HDR_LEN);
+
+				/* tun netdev is up and running, ignore the
+				 * non-TEST_PTYPE packet.
+				 */
+				if (eh->ether_type != htons(TEST_PTYPE)) {
+					++vq->completed;
+					r = 0;
+					continue;
+				}
+
+				assert(len == TEST_BUF_LEN + HDR_LEN);
+				verify_res_buf(dev->res_buf + HDR_LEN);
+
+				++vq->completed;
+				r = 0;
+			}
+		} while (r == 0);
+		if (vq->completed == completed_before && vq->started == started_before)
+			++spurious;
+
+		assert(vq->completed <= bufs);
+		assert(vq->started <= bufs);
+		if (vq->completed == bufs)
+			break;
+	}
+
+	printf("RX spurious wakeups: 0x%llx started=0x%lx completed=0x%lx\n",
+	       spurious, vq->started, vq->completed);
+}
+
+static const char optstring[] = "h";
+static 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,
+	},
+	{
+	}
+};
+
+static void help(int status)
+{
+	fprintf(stderr, "Usage: vhost_net_test [--help]"
+		" [--no-indirect]"
+		" [--no-event-idx]"
+		" [--no-virtio-1]"
+		" [--delayed-interrupt]"
+		" [--buf-num]"
+		" [--batch=random/N]"
+		"\n");
+
+	exit(status);
+}
+
+int main(int argc, char **argv)
+{
+	unsigned long long features = (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
+		(1ULL << VIRTIO_RING_F_EVENT_IDX) | (1ULL << VIRTIO_F_VERSION_1);
+	long batch = 1, nbufs = 0x100000;
+	struct vdev_info dev;
+	bool delayed = false;
+	int o, fd;
+
+	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 (!strcmp(optarg, "random")) {
+				batch = RANDOM_BATCH;
+			} else {
+				batch = strtol(optarg, NULL, 10);
+				assert(batch > 0);
+				assert(batch < (long)INT_MAX + 1);
+			}
+			break;
+		case 'n':
+			nbufs = strtol(optarg, NULL, 10);
+			assert(nbufs > 0);
+			break;
+		default:
+			assert(0);
+			break;
+		}
+	}
+
+done:
+	memset(&dev, 0, sizeof(dev));
+
+	fd = tun_alloc(&dev);
+	assert(fd >= 0);
+
+	vdev_info_init(&dev, features);
+	vq_info_add(&dev, 0, 256, fd);
+	vq_info_add(&dev, 1, 256, fd);
+	vdev_create_socket(&dev);
+
+	run_rx_test(&dev, &dev.vqs[0], delayed, batch, nbufs);
+	run_tx_test(&dev, &dev.vqs[1], delayed, batch, nbufs);
+
+	return 0;
+}