virtio_test.c

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#define _GNU_SOURCE
#include <getopt.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 <linux/vhost.h>
#include <linux/virtio.h>
#include <linux/virtio_ring.h>
#include "../../drivers/vhost/test.h"

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;
};

void 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);
}

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[0];
    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_info_add(struct vdev_info *dev, int num)
{
    struct vq_info *info = &dev->vqs[dev->nvqs];
    int r;
    info->idx = dev->nvqs;
    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);
    memset(info->ring, 0, vring_size(num, 4096));
    vring_init(&info->vring, num, info->ring, 4096);
    info->vq = vring_new_virtqueue(info->vring.num, 4096, &dev->vdev,
                       true, info->ring,
                       vq_notify, vq_callback, "test");
    assert(info->vq);
    info->vq->priv = info;
    vhost_vq_setup(dev, info);
    dev->fds[info->idx].fd = info->call;
    dev->fds[info->idx].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[0] = features;
    dev->vdev.features[1] = features >> 32;
    dev->buf_size = 1024;
    dev->buf = malloc(dev->buf_size);
    assert(dev->buf);
        dev->control = open("/dev/vhost-test", 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 bufs)
{
    struct scatterlist sl;
    long started = 0, completed = 0;
    long completed_before;
    int r, test = 1;
    unsigned len;
    long long spurious = 0;
    r = ioctl(dev->control, VHOST_TEST_RUN, &test);
    assert(r >= 0);
    for (;;) {
        virtqueue_disable_cb(vq->vq);
        completed_before = completed;
        do {
            if (started < bufs) {
                sg_init_one(&sl, dev->buf, dev->buf_size);
                r = virtqueue_add_buf(vq->vq, &sl, 1, 0,
                              dev->buf + started,
                              GFP_ATOMIC);
                if (likely(r >= 0)) {
                    ++started;
                    virtqueue_kick(vq->vq);
                }
            } else
                r = -1;

            /* Flush out completed bufs if any */
            if (virtqueue_get_buf(vq->vq, &len)) {
                ++completed;
                r = 0;
            }

        } while (r >= 0);
        if (completed == completed_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);
        }
    }
    test = 0;
    r = ioctl(dev->control, VHOST_TEST_RUN, &test);
    assert(r >= 0);
    fprintf(stderr, "spurious wakeus: 0x%llx\n", spurious);
}

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 = "delayed-interrupt",
        .val = 'D',
    },
    {
        .name = "no-delayed-interrupt",
        .val = 'd',
    },
    {
    }
};

static void help()
{
    fprintf(stderr, "Usage: virtio_test [--help]"
        " [--no-indirect]"
        " [--no-event-idx]"
        " [--delayed-interrupt]"
        "\n");
}

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);
    int o;
    bool delayed = false;

    for (;;) {
        o = getopt_long(argc, argv, optstring, longopts, NULL);
        switch (o) {
        case -1:
            goto done;
        case '?':
            help();
            exit(2);
        case 'e':
            features &= ~(1ULL << VIRTIO_RING_F_EVENT_IDX);
            break;
        case 'h':
            help();
            goto done;
        case 'i':
            features &= ~(1ULL << VIRTIO_RING_F_INDIRECT_DESC);
            break;
        case 'D':
            delayed = true;
            break;
        default:
            assert(0);
            break;
        }
    }

done:
    vdev_info_init(&dev, features);
    vq_info_add(&dev, 256);
    run_test(&dev, &dev.vqs[0], delayed, 0x100000);
    return 0;
}