#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, 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 (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',
        },
        {
        }
};

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

        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;
                default:
                        assert(0);
                        break;
                }
        }

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