examples/vhost_blk/vhost_blk.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2019 Intel Corporation
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <pthread.h>
#include <sched.h>

#include <stdint.h>
#include <unistd.h>
#include <stdbool.h>
#include <signal.h>
#include <assert.h>
#include <semaphore.h>
#include <linux/virtio_blk.h>
#include <linux/virtio_ring.h>

#include <rte_atomic.h>
#include <rte_cycles.h>
#include <rte_log.h>
#include <rte_malloc.h>
#include <rte_vhost.h>

#include "vhost_blk.h"
#include "blk_spec.h"

#define VIRTQ_DESC_F_NEXT   1
#define VIRTQ_DESC_F_AVAIL  (1 << 7)
#define VIRTQ_DESC_F_USED   (1 << 15)

#define MAX_TASK        12

#define VHOST_BLK_FEATURES ((1ULL << VIRTIO_F_RING_PACKED) | \
                (1ULL << VIRTIO_F_VERSION_1) |\
                (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | \
                (1ULL << VHOST_USER_F_PROTOCOL_FEATURES))

struct vhost_blk_ctrlr *g_vhost_ctrlr;

/* Path to folder where character device will be created. Can be set by user. */
static char dev_pathname[PATH_MAX] = "";
static sem_t exit_sem;
static int g_should_stop = -1;

struct vhost_blk_ctrlr *
vhost_blk_ctrlr_find(const char *ctrlr_name)
{
    if (ctrlr_name == NULL)
        return NULL;

    /* currently we only support 1 socket file fd */
    return g_vhost_ctrlr;
}

static uint64_t gpa_to_vva(int vid, uint64_t gpa, uint64_t *len)
{
    char path[PATH_MAX];
    struct vhost_blk_ctrlr *ctrlr;
    int ret = 0;

    ret = rte_vhost_get_ifname(vid, path, PATH_MAX);
    if (ret) {
        fprintf(stderr, "Cannot get socket name\n");
        assert(ret != 0);
    }

    ctrlr = vhost_blk_ctrlr_find(path);
    if (!ctrlr) {
        fprintf(stderr, "Controller is not ready\n");
        assert(ctrlr != NULL);
    }

    assert(ctrlr->mem != NULL);

    return rte_vhost_va_from_guest_pa(ctrlr->mem, gpa, len);
}

static struct vring_packed_desc *
descriptor_get_next_packed(struct rte_vhost_vring *vq,
                 uint16_t *idx)
{
    if (vq->desc_packed[*idx % vq->size].flags & VIRTQ_DESC_F_NEXT) {
        *idx += 1;
        return &vq->desc_packed[*idx % vq->size];
    }

    return NULL;
}

static bool
descriptor_has_next_packed(struct vring_packed_desc *cur_desc)
{
    return !!(cur_desc->flags & VRING_DESC_F_NEXT);
}

static bool
descriptor_is_wr_packed(struct vring_packed_desc *cur_desc)
{
    return !!(cur_desc->flags & VRING_DESC_F_WRITE);
}

static struct rte_vhost_inflight_desc_packed *
inflight_desc_get_next(struct rte_vhost_inflight_info_packed *inflight_packed,
                   struct rte_vhost_inflight_desc_packed *cur_desc)
{
    if (!!(cur_desc->flags & VIRTQ_DESC_F_NEXT))
        return &inflight_packed->desc[cur_desc->next];

    return NULL;
}

static bool
inflight_desc_has_next(struct rte_vhost_inflight_desc_packed *cur_desc)
{
    return !!(cur_desc->flags & VRING_DESC_F_NEXT);
}

static bool
inflight_desc_is_wr(struct rte_vhost_inflight_desc_packed *cur_desc)
{
    return !!(cur_desc->flags & VRING_DESC_F_WRITE);
}

static void
inflight_process_payload_chain_packed(struct inflight_blk_task *task)
{
    void *data;
    uint64_t chunck_len;
    struct vhost_blk_task *blk_task;
    struct rte_vhost_inflight_desc_packed *desc;

    blk_task = &task->blk_task;
    blk_task->iovs_cnt = 0;

    do {
        desc = task->inflight_desc;
        chunck_len = desc->len;
        data = (void *)(uintptr_t)gpa_to_vva(blk_task->bdev->vid,
                             desc->addr,
                             &chunck_len);
        if (!data || chunck_len != desc->len) {
            fprintf(stderr, "failed to translate desc address.\n");
            return;
        }

        blk_task->iovs[blk_task->iovs_cnt].iov_base = data;
        blk_task->iovs[blk_task->iovs_cnt].iov_len = desc->len;
        blk_task->data_len += desc->len;
        blk_task->iovs_cnt++;
        task->inflight_desc = inflight_desc_get_next(
                    task->inflight_packed, desc);
    } while (inflight_desc_has_next(task->inflight_desc));

    chunck_len = task->inflight_desc->len;
    blk_task->status = (void *)(uintptr_t)gpa_to_vva(
        blk_task->bdev->vid, task->inflight_desc->addr, &chunck_len);
    if (!blk_task->status || chunck_len != task->inflight_desc->len)
        fprintf(stderr, "failed to translate desc address.\n");
}

static void
inflight_submit_completion_packed(struct inflight_blk_task *task,
                          uint32_t q_idx, uint16_t *used_id,
                          bool *used_wrap_counter)
{
    struct vhost_blk_ctrlr *ctrlr;
    struct rte_vhost_vring *vq;
    struct vring_packed_desc *desc;
    int ret;

    ctrlr = vhost_blk_ctrlr_find(dev_pathname);
    vq = task->blk_task.vq;

    ret = rte_vhost_set_last_inflight_io_packed(ctrlr->bdev->vid, q_idx,
                            task->blk_task.head_idx);
    if (ret != 0)
        fprintf(stderr, "failed to set last inflight io\n");

    desc = &vq->desc_packed[*used_id];
    desc->id = task->blk_task.buffer_id;
    rte_smp_mb();
    if (*used_wrap_counter)
        desc->flags |= VIRTQ_DESC_F_AVAIL | VIRTQ_DESC_F_USED;
    else
        desc->flags &= ~(VIRTQ_DESC_F_AVAIL | VIRTQ_DESC_F_USED);
    rte_smp_mb();

    *used_id += task->blk_task.iovs_cnt + 2;
    if (*used_id >= vq->size) {
        *used_id -= vq->size;
        *used_wrap_counter = !(*used_wrap_counter);
    }

    ret = rte_vhost_clr_inflight_desc_packed(ctrlr->bdev->vid, q_idx,
                         task->blk_task.head_idx);
    if (ret != 0)
        fprintf(stderr, "failed to clear inflight io\n");

    /* Send an interrupt back to the guest VM so that it knows
     * a completion is ready to be processed.
     */
    rte_vhost_vring_call(task->blk_task.bdev->vid, q_idx);
}

static void
submit_completion_packed(struct vhost_blk_task *task, uint32_t q_idx,
                  uint16_t *used_id, bool *used_wrap_counter)
{
    struct vhost_blk_ctrlr *ctrlr;
    struct rte_vhost_vring *vq;
    struct vring_packed_desc *desc;
    int ret;

    ctrlr = vhost_blk_ctrlr_find(dev_pathname);
    vq = task->vq;

    ret = rte_vhost_set_last_inflight_io_packed(ctrlr->bdev->vid, q_idx,
                            task->inflight_idx);
    if (ret != 0)
        fprintf(stderr, "failed to set last inflight io\n");

    desc = &vq->desc_packed[*used_id];
    desc->id = task->buffer_id;
    rte_smp_mb();
    if (*used_wrap_counter)
        desc->flags |= VIRTQ_DESC_F_AVAIL | VIRTQ_DESC_F_USED;
    else
        desc->flags &= ~(VIRTQ_DESC_F_AVAIL | VIRTQ_DESC_F_USED);
    rte_smp_mb();

    *used_id += task->iovs_cnt + 2;
    if (*used_id >= vq->size) {
        *used_id -= vq->size;
        *used_wrap_counter = !(*used_wrap_counter);
    }

    ret = rte_vhost_clr_inflight_desc_packed(ctrlr->bdev->vid, q_idx,
                         task->inflight_idx);
    if (ret != 0)
        fprintf(stderr, "failed to clear inflight io\n");

    /* Send an interrupt back to the guest VM so that it knows
     * a completion is ready to be processed.
     */
    rte_vhost_vring_call(task->bdev->vid, q_idx);
}

static void
vhost_process_payload_chain_packed(struct vhost_blk_task *task,
    uint16_t *idx)
{
    void *data;
    uint64_t chunck_len;

    task->iovs_cnt = 0;

    do {
        chunck_len = task->desc_packed->len;
        data = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
                             task->desc_packed->addr,
                             &chunck_len);
        if (!data || chunck_len != task->desc_packed->len) {
            fprintf(stderr, "failed to translate desc address.\n");
            return;
        }

        task->iovs[task->iovs_cnt].iov_base = data;
        task->iovs[task->iovs_cnt].iov_len = task->desc_packed->len;
        task->data_len += task->desc_packed->len;
        task->iovs_cnt++;
        task->desc_packed = descriptor_get_next_packed(task->vq, idx);
    } while (descriptor_has_next_packed(task->desc_packed));

    task->last_idx = *idx % task->vq->size;
    chunck_len = task->desc_packed->len;
    task->status = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
                           task->desc_packed->addr,
                           &chunck_len);
    if (!task->status || chunck_len != task->desc_packed->len)
        fprintf(stderr, "failed to translate desc address.\n");
}


static int
descriptor_is_available(struct rte_vhost_vring *vring, uint16_t idx,
                    bool avail_wrap_counter)
{
    uint16_t flags = vring->desc_packed[idx].flags;

    return ((!!(flags & VIRTQ_DESC_F_AVAIL) == avail_wrap_counter) &&
        (!!(flags & VIRTQ_DESC_F_USED) != avail_wrap_counter));
}

static void
process_requestq_packed(struct vhost_blk_ctrlr *ctrlr, uint32_t q_idx)
{
    bool avail_wrap_counter, used_wrap_counter;
    uint16_t avail_idx, used_idx;
    int ret;
    uint64_t chunck_len;
    struct vhost_blk_queue *blk_vq;
    struct rte_vhost_vring *vq;
    struct vhost_blk_task *task;

    blk_vq = &ctrlr->bdev->queues[q_idx];
    vq = &blk_vq->vq;

    avail_idx = blk_vq->last_avail_idx;
    avail_wrap_counter = blk_vq->avail_wrap_counter;
    used_idx = blk_vq->last_used_idx;
    used_wrap_counter = blk_vq->used_wrap_counter;

    task = rte_zmalloc(NULL, sizeof(*task), 0);
    assert(task != NULL);
    task->vq = vq;
    task->bdev = ctrlr->bdev;

    while (descriptor_is_available(vq, avail_idx, avail_wrap_counter)) {
        task->head_idx = avail_idx;
        task->desc_packed = &task->vq->desc_packed[task->head_idx];
        task->iovs_cnt = 0;
        task->data_len = 0;
        task->req = NULL;
        task->status = NULL;

        /* does not support indirect descriptors */
        assert((task->desc_packed->flags & VRING_DESC_F_INDIRECT) == 0);

        chunck_len = task->desc_packed->len;
        task->req = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
            task->desc_packed->addr, &chunck_len);
        if (!task->req || chunck_len != task->desc_packed->len) {
            fprintf(stderr, "failed to translate desc address.\n");
            rte_free(task);
            return;
        }

        task->desc_packed = descriptor_get_next_packed(task->vq,
                                &avail_idx);
        assert(task->desc_packed != NULL);
        if (!descriptor_has_next_packed(task->desc_packed)) {
            task->dxfer_dir = BLK_DIR_NONE;
            task->last_idx = avail_idx % vq->size;
            chunck_len = task->desc_packed->len;
            task->status = (void *)(uintptr_t)
                          gpa_to_vva(task->bdev->vid,
                            task->desc_packed->addr,
                            &chunck_len);
            if (!task->status ||
                chunck_len != task->desc_packed->len) {
                fprintf(stderr,
                    "failed to translate desc address.\n");
                rte_free(task);
                return;
            }
        } else {
            task->readtype = descriptor_is_wr_packed(
                            task->desc_packed);
            vhost_process_payload_chain_packed(task, &avail_idx);
        }
        task->buffer_id = vq->desc_packed[task->last_idx].id;
        rte_vhost_set_inflight_desc_packed(ctrlr->bdev->vid, q_idx,
                           task->head_idx,
                           task->last_idx,
                           &task->inflight_idx);

        if (++avail_idx >= vq->size) {
            avail_idx -= vq->size;
            avail_wrap_counter = !avail_wrap_counter;
        }
        blk_vq->last_avail_idx = avail_idx;
        blk_vq->avail_wrap_counter = avail_wrap_counter;

        ret = vhost_bdev_process_blk_commands(ctrlr->bdev, task);
        if (ret) {
            /* invalid response */
            *task->status = VIRTIO_BLK_S_IOERR;
        } else {
            /* successfully */
            *task->status = VIRTIO_BLK_S_OK;
        }

        submit_completion_packed(task, q_idx, &used_idx,
                        &used_wrap_counter);
        blk_vq->last_used_idx = used_idx;
        blk_vq->used_wrap_counter = used_wrap_counter;
    }

    rte_free(task);
}

static void
submit_inflight_vq_packed(struct vhost_blk_ctrlr *ctrlr,
    uint16_t q_idx)
{
    bool used_wrap_counter;
    int req_idx, ret;
    uint16_t used_idx;
    uint64_t chunck_len;
    struct vhost_blk_queue *blk_vq;
    struct rte_vhost_ring_inflight *inflight_vq;
    struct rte_vhost_resubmit_info *resubmit_info;
    struct rte_vhost_vring *vq;
    struct inflight_blk_task *task;
    struct vhost_blk_task *blk_task;
    struct rte_vhost_inflight_info_packed *inflight_info;

    blk_vq = &ctrlr->bdev->queues[q_idx];
    vq = &blk_vq->vq;
    inflight_vq = &blk_vq->inflight_vq;
    resubmit_info = inflight_vq->resubmit_inflight;
    inflight_info = inflight_vq->inflight_packed;
    used_idx = blk_vq->last_used_idx;
    used_wrap_counter = blk_vq->used_wrap_counter;

    task = rte_malloc(NULL, sizeof(*task), 0);
    if (!task) {
        fprintf(stderr, "failed to allocate memory\n");
        return;
    }
    blk_task = &task->blk_task;
    blk_task->vq = vq;
    blk_task->bdev = ctrlr->bdev;
    task->inflight_packed = inflight_vq->inflight_packed;

    while (resubmit_info->resubmit_num-- > 0) {
        req_idx = resubmit_info->resubmit_num;
        blk_task->head_idx =
            resubmit_info->resubmit_list[req_idx].index;
        task->inflight_desc =
            &inflight_info->desc[blk_task->head_idx];
        task->blk_task.iovs_cnt = 0;
        task->blk_task.data_len = 0;
        task->blk_task.req = NULL;
        task->blk_task.status = NULL;

        /* update the avail idx too
         * as it's initial value equals to used idx
         */
        blk_vq->last_avail_idx += task->inflight_desc->num;
        if (blk_vq->last_avail_idx >= vq->size) {
            blk_vq->last_avail_idx -= vq->size;
            blk_vq->avail_wrap_counter =
                !blk_vq->avail_wrap_counter;
        }

        /* does not support indirect descriptors */
        assert(task->inflight_desc != NULL);
        assert((task->inflight_desc->flags &
            VRING_DESC_F_INDIRECT) == 0);

        chunck_len = task->inflight_desc->len;
        blk_task->req = (void *)(uintptr_t)
                     gpa_to_vva(blk_task->bdev->vid,
                        task->inflight_desc->addr,
                        &chunck_len);
        if (!blk_task->req ||
            chunck_len != task->inflight_desc->len) {
            fprintf(stderr, "failed to translate desc address.\n");
            rte_free(task);
            return;
        }

        task->inflight_desc = inflight_desc_get_next(
            task->inflight_packed, task->inflight_desc);
        assert(task->inflight_desc != NULL);
        if (!inflight_desc_has_next(task->inflight_desc)) {
            blk_task->dxfer_dir = BLK_DIR_NONE;
            chunck_len = task->inflight_desc->len;
            blk_task->status = (void *)(uintptr_t)
                gpa_to_vva(blk_task->bdev->vid,
                        task->inflight_desc->addr,
                        &chunck_len);
            if (!blk_task->status ||
                chunck_len != task->inflight_desc->len) {
                fprintf(stderr,
                    "failed to translate desc address.\n");
                rte_free(task);
                return;
            }
        } else {
            blk_task->readtype =
            inflight_desc_is_wr(task->inflight_desc);
            inflight_process_payload_chain_packed(task);
        }

        blk_task->buffer_id = task->inflight_desc->id;

        ret = vhost_bdev_process_blk_commands(ctrlr->bdev, blk_task);
        if (ret)
            /* invalid response */
            *blk_task->status = VIRTIO_BLK_S_IOERR;
        else
            /* successfully */
            *blk_task->status = VIRTIO_BLK_S_OK;

        inflight_submit_completion_packed(task, q_idx, &used_idx,
                          &used_wrap_counter);

        blk_vq->last_used_idx = used_idx;
        blk_vq->used_wrap_counter = used_wrap_counter;
    }

    rte_free(task);
}

static struct vring_desc *
descriptor_get_next_split(struct vring_desc *vq_desc,
                   struct vring_desc *cur_desc)
{
    return &vq_desc[cur_desc->next];
}

static bool
descriptor_has_next_split(struct vring_desc *cur_desc)
{
    return !!(cur_desc->flags & VRING_DESC_F_NEXT);
}

static bool
descriptor_is_wr_split(struct vring_desc *cur_desc)
{
    return !!(cur_desc->flags & VRING_DESC_F_WRITE);
}

static void
vhost_process_payload_chain_split(struct vhost_blk_task *task)
{
    void *data;
    uint64_t chunck_len;

    task->iovs_cnt = 0;

    do {
        chunck_len = task->desc_split->len;
        data = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
                             task->desc_split->addr,
                             &chunck_len);
        if (!data || chunck_len != task->desc_split->len) {
            fprintf(stderr, "failed to translate desc address.\n");
            return;
        }

        task->iovs[task->iovs_cnt].iov_base = data;
        task->iovs[task->iovs_cnt].iov_len = task->desc_split->len;
        task->data_len += task->desc_split->len;
        task->iovs_cnt++;
        task->desc_split =
        descriptor_get_next_split(task->vq->desc, task->desc_split);
    } while (descriptor_has_next_split(task->desc_split));

    chunck_len = task->desc_split->len;
    task->status = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
                             task->desc_split->addr,
                             &chunck_len);
    if (!task->status || chunck_len != task->desc_split->len)
        fprintf(stderr, "failed to translate desc address.\n");
}

static void
submit_completion_split(struct vhost_blk_task *task, uint32_t vid,
    uint32_t q_idx)
{
    struct rte_vhost_vring *vq;
    struct vring_used *used;

    vq = task->vq;
    used = vq->used;

    rte_vhost_set_last_inflight_io_split(vid, q_idx, task->req_idx);

    /* Fill out the next entry in the "used" ring.  id = the
     * index of the descriptor that contained the blk request.
     * len = the total amount of data transferred for the blk
     * request. We must report the correct len, for variable
     * length blk CDBs, where we may return less data than
     * allocated by the guest VM.
     */
    used->ring[used->idx & (vq->size - 1)].id = task->req_idx;
    used->ring[used->idx & (vq->size - 1)].len = task->data_len;
    rte_smp_mb();
    used->idx++;
    rte_smp_mb();

    rte_vhost_clr_inflight_desc_split(vid, q_idx, used->idx, task->req_idx);

    /* Send an interrupt back to the guest VM so that it knows
     * a completion is ready to be processed.
     */
    rte_vhost_vring_call(task->bdev->vid, q_idx);
}

static void
submit_inflight_vq_split(struct vhost_blk_ctrlr *ctrlr,
    uint32_t q_idx)
{
    struct vhost_blk_queue *blk_vq;
    struct rte_vhost_ring_inflight *inflight_vq;
    struct rte_vhost_resubmit_info *resubmit_inflight;
    struct rte_vhost_resubmit_desc *resubmit_list;
    struct vhost_blk_task *task;
    int req_idx;
    uint64_t chunck_len;
    int ret;

    blk_vq = &ctrlr->bdev->queues[q_idx];
    inflight_vq = &blk_vq->inflight_vq;
    resubmit_inflight = inflight_vq->resubmit_inflight;
    resubmit_list = resubmit_inflight->resubmit_list;

    task = rte_zmalloc(NULL, sizeof(*task), 0);
    assert(task != NULL);

    task->ctrlr = ctrlr;
    task->bdev = ctrlr->bdev;
    task->vq = &blk_vq->vq;

    while (resubmit_inflight->resubmit_num-- > 0) {
        req_idx = resubmit_list[resubmit_inflight->resubmit_num].index;
        task->req_idx = req_idx;
        task->desc_split = &task->vq->desc[task->req_idx];
        task->iovs_cnt = 0;
        task->data_len = 0;
        task->req = NULL;
        task->status = NULL;

        /* does not support indirect descriptors */
        assert(task->desc_split != NULL);
        assert((task->desc_split->flags & VRING_DESC_F_INDIRECT) == 0);

        chunck_len = task->desc_split->len;
        task->req = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
                task->desc_split->addr, &chunck_len);
        if (!task->req || chunck_len != task->desc_split->len) {
            fprintf(stderr, "failed to translate desc address.\n");
            rte_free(task);
            return;
        }

        task->desc_split = descriptor_get_next_split(task->vq->desc,
                                 task->desc_split);
        if (!descriptor_has_next_split(task->desc_split)) {
            task->dxfer_dir = BLK_DIR_NONE;
            chunck_len = task->desc_split->len;
            task->status = (void *)(uintptr_t)
                       gpa_to_vva(task->bdev->vid,
                          task->desc_split->addr,
                          &chunck_len);
            if (!task->status ||
                chunck_len != task->desc_split->len) {
                fprintf(stderr,
                    "failed to translate desc address.\n");
                rte_free(task);
                return;
            }
        } else {
            task->readtype =
                descriptor_is_wr_split(task->desc_split);
            vhost_process_payload_chain_split(task);
        }

        ret = vhost_bdev_process_blk_commands(ctrlr->bdev, task);
        if (ret) {
            /* invalid response */
            *task->status = VIRTIO_BLK_S_IOERR;
        } else {
            /* successfully */
            *task->status = VIRTIO_BLK_S_OK;
        }
        submit_completion_split(task, ctrlr->bdev->vid, q_idx);
    }

    rte_free(task);
}

static void
process_requestq_split(struct vhost_blk_ctrlr *ctrlr, uint32_t q_idx)
{
    int ret;
    int req_idx;
    uint16_t last_idx;
    uint64_t chunck_len;
    struct vhost_blk_queue *blk_vq;
    struct rte_vhost_vring *vq;
    struct vhost_blk_task *task;

    blk_vq = &ctrlr->bdev->queues[q_idx];
    vq = &blk_vq->vq;

    task = rte_zmalloc(NULL, sizeof(*task), 0);
    assert(task != NULL);
    task->ctrlr = ctrlr;
    task->bdev = ctrlr->bdev;
    task->vq = vq;

    while (vq->avail->idx != blk_vq->last_avail_idx) {
        last_idx = blk_vq->last_avail_idx & (vq->size - 1);
        req_idx = vq->avail->ring[last_idx];
        task->req_idx = req_idx;
        task->desc_split = &task->vq->desc[task->req_idx];
        task->iovs_cnt = 0;
        task->data_len = 0;
        task->req = NULL;
        task->status = NULL;

        rte_vhost_set_inflight_desc_split(ctrlr->bdev->vid, q_idx,
                            task->req_idx);

        /* does not support indirect descriptors */
        assert((task->desc_split->flags & VRING_DESC_F_INDIRECT) == 0);

        chunck_len = task->desc_split->len;
        task->req = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
                task->desc_split->addr, &chunck_len);
        if (!task->req || chunck_len != task->desc_split->len) {
            fprintf(stderr, "failed to translate desc address.\n");
            rte_free(task);
            return;
        }

        task->desc_split = descriptor_get_next_split(task->vq->desc,
                                 task->desc_split);
        if (!descriptor_has_next_split(task->desc_split)) {
            task->dxfer_dir = BLK_DIR_NONE;
            chunck_len = task->desc_split->len;
            task->status = (void *)(uintptr_t)
                          gpa_to_vva(task->bdev->vid,
                             task->desc_split->addr,
                             &chunck_len);
            if (!task->status ||
                chunck_len != task->desc_split->len) {
                fprintf(stderr,
                    "failed to translate desc address.\n");
                rte_free(task);
                return;
            }
        } else {
            task->readtype =
                descriptor_is_wr_split(task->desc_split);
            vhost_process_payload_chain_split(task);
        }
        blk_vq->last_avail_idx++;

        ret = vhost_bdev_process_blk_commands(ctrlr->bdev, task);
        if (ret) {
            /* invalid response */
            *task->status = VIRTIO_BLK_S_IOERR;
        } else {
            /* successfully */
            *task->status = VIRTIO_BLK_S_OK;
        }

        submit_completion_split(task, ctrlr->bdev->vid, q_idx);
    }

    rte_free(task);
}

static void *
ctrlr_worker(void *arg)
{
    struct vhost_blk_ctrlr *ctrlr = (struct vhost_blk_ctrlr *)arg;
    struct vhost_blk_queue *blk_vq;
    struct rte_vhost_ring_inflight *inflight_vq;
    cpu_set_t cpuset;
    pthread_t thread;
    int i;

    fprintf(stdout, "Ctrlr Worker Thread start\n");

    if (ctrlr == NULL || ctrlr->bdev == NULL) {
        fprintf(stderr,
            "%s: Error, invalid argument passed to worker thread\n",
            __func__);
        exit(0);
    }

    thread = pthread_self();
    CPU_ZERO(&cpuset);
    CPU_SET(0, &cpuset);
    pthread_setaffinity_np(thread, sizeof(cpu_set_t), &cpuset);

    for (i = 0; i < NUM_OF_BLK_QUEUES; i++) {
        blk_vq = &ctrlr->bdev->queues[i];
        inflight_vq = &blk_vq->inflight_vq;
        if (inflight_vq->resubmit_inflight != NULL &&
            inflight_vq->resubmit_inflight->resubmit_num != 0) {
            if (ctrlr->packed_ring)
                submit_inflight_vq_packed(ctrlr, i);
            else
                submit_inflight_vq_split(ctrlr, i);
        }
    }

    while (!g_should_stop && ctrlr->bdev != NULL) {
        for (i = 0; i < NUM_OF_BLK_QUEUES; i++) {
            if (ctrlr->packed_ring)
                process_requestq_packed(ctrlr, i);
            else
                process_requestq_split(ctrlr, i);
        }
    }

    g_should_stop = 2;
    fprintf(stdout, "Ctrlr Worker Thread Exiting\n");
    sem_post(&exit_sem);
    return NULL;
}

static int
new_device(int vid)
{
    struct vhost_blk_ctrlr *ctrlr;
    struct vhost_blk_queue *blk_vq;
    struct rte_vhost_vring *vq;
    uint64_t features;
    pthread_t tid;
    int i, ret;

    ctrlr = vhost_blk_ctrlr_find(dev_pathname);
    if (!ctrlr) {
        fprintf(stderr, "Controller is not ready\n");
        return -1;
    }

    if (ctrlr->started)
        return 0;

    ctrlr->bdev->vid = vid;
    ret = rte_vhost_get_negotiated_features(vid, &features);
    if (ret) {
        fprintf(stderr, "failed to get the negotiated features\n");
        return -1;
    }
    ctrlr->packed_ring = !!(features & (1ULL << VIRTIO_F_RING_PACKED));

    ret = rte_vhost_get_mem_table(vid, &ctrlr->mem);
    if (ret)
        fprintf(stderr, "Get Controller memory region failed\n");
    assert(ctrlr->mem != NULL);

    /* Disable Notifications and init last idx */
    for (i = 0; i < NUM_OF_BLK_QUEUES; i++) {
        blk_vq = &ctrlr->bdev->queues[i];
        vq = &blk_vq->vq;

        ret = rte_vhost_get_vhost_vring(ctrlr->bdev->vid, i, vq);
        assert(ret == 0);

        ret = rte_vhost_get_vring_base(ctrlr->bdev->vid, i,
                           &blk_vq->last_avail_idx,
                           &blk_vq->last_used_idx);
        assert(ret == 0);

        ret = rte_vhost_get_vhost_ring_inflight(ctrlr->bdev->vid, i,
                            &blk_vq->inflight_vq);
        assert(ret == 0);

        if (ctrlr->packed_ring) {
            /* for the reconnection */
            ret = rte_vhost_get_vring_base_from_inflight(
                ctrlr->bdev->vid, i,
                &blk_vq->last_avail_idx,
                &blk_vq->last_used_idx);
            assert(ret == 0);

            blk_vq->avail_wrap_counter = blk_vq->last_avail_idx &
                (1 << 15);
            blk_vq->last_avail_idx = blk_vq->last_avail_idx &
                0x7fff;
            blk_vq->used_wrap_counter = blk_vq->last_used_idx &
                (1 << 15);
            blk_vq->last_used_idx = blk_vq->last_used_idx &
                0x7fff;
        }

        rte_vhost_enable_guest_notification(vid, i, 0);
    }

    /* start polling vring */
    g_should_stop = 0;
    fprintf(stdout, "New Device %s, Device ID %d\n", dev_pathname, vid);
    if (pthread_create(&tid, NULL, &ctrlr_worker, ctrlr) < 0) {
        fprintf(stderr, "Worker Thread Started Failed\n");
        return -1;
    }

    /* device has been started */
    ctrlr->started = 1;
    pthread_detach(tid);
    return 0;
}

static void
destroy_device(int vid)
{
    char path[PATH_MAX];
    struct vhost_blk_ctrlr *ctrlr;
    struct vhost_blk_queue *blk_vq;
    int i, ret;

    ret = rte_vhost_get_ifname(vid, path, PATH_MAX);
    if (ret) {
        fprintf(stderr, "Destroy Ctrlr Failed\n");
        return;
    }

    fprintf(stdout, "Destroy %s Device ID %d\n", path, vid);
    ctrlr = vhost_blk_ctrlr_find(path);
    if (!ctrlr) {
        fprintf(stderr, "Destroy Ctrlr Failed\n");
        return;
    }

    if (!ctrlr->started)
        return;

    g_should_stop = 1;
    while (g_should_stop != 2)
        ;

    for (i = 0; i < NUM_OF_BLK_QUEUES; i++) {
        blk_vq = &ctrlr->bdev->queues[i];
        if (ctrlr->packed_ring) {
            blk_vq->last_avail_idx |= (blk_vq->avail_wrap_counter <<
                15);
            blk_vq->last_used_idx |= (blk_vq->used_wrap_counter <<
                15);
        }
        rte_vhost_set_vring_base(ctrlr->bdev->vid, i,
                     blk_vq->last_avail_idx,
                     blk_vq->last_used_idx);
    }

    free(ctrlr->mem);

    ctrlr->started = 0;
    sem_wait(&exit_sem);
}

static int
new_connection(int vid)
{
    /* extend the proper features for block device */
    vhost_session_install_rte_compat_hooks(vid);

    return 0;
}

struct vhost_device_ops vhost_blk_device_ops = {
    .new_device =  new_device,
    .destroy_device = destroy_device,
    .new_connection = new_connection,
};

static struct vhost_block_dev *
vhost_blk_bdev_construct(const char *bdev_name,
    const char *bdev_serial, uint32_t blk_size, uint64_t blk_cnt,
    bool wce_enable)
{
    struct vhost_block_dev *bdev;

    bdev = rte_zmalloc(NULL, sizeof(*bdev), RTE_CACHE_LINE_SIZE);
    if (!bdev)
        return NULL;

    strncpy(bdev->name, bdev_name, sizeof(bdev->name));
    strncpy(bdev->product_name, bdev_serial, sizeof(bdev->product_name));
    bdev->blocklen = blk_size;
    bdev->blockcnt = blk_cnt;
    bdev->write_cache = wce_enable;

    fprintf(stdout, "blocklen=%d, blockcnt=%"PRIx64"\n", bdev->blocklen,
        bdev->blockcnt);

    /* use memory as disk storage space */
    bdev->data = rte_zmalloc(NULL, blk_cnt * blk_size, 0);
    if (!bdev->data) {
        fprintf(stderr, "no enough reserved huge memory for disk\n");
        free(bdev);
        return NULL;
    }

    return bdev;
}

static struct vhost_blk_ctrlr *
vhost_blk_ctrlr_construct(const char *ctrlr_name)
{
    int ret;
    struct vhost_blk_ctrlr *ctrlr;
    char *path;
    char cwd[PATH_MAX];

    /* always use current directory */
    path = getcwd(cwd, PATH_MAX);
    if (!path) {
        fprintf(stderr, "Cannot get current working directory\n");
        return NULL;
    }
    snprintf(dev_pathname, sizeof(dev_pathname), "%s/%s", path, ctrlr_name);

    unlink(dev_pathname);

    if (rte_vhost_driver_register(dev_pathname, 0) != 0) {
        fprintf(stderr, "socket %s already exists\n", dev_pathname);
        return NULL;
    }

    ret = rte_vhost_driver_set_features(dev_pathname, VHOST_BLK_FEATURES);
    if (ret != 0) {
        fprintf(stderr, "Set vhost driver features failed\n");
        rte_vhost_driver_unregister(dev_pathname);
        return NULL;
    }

    /* set proper features */
    vhost_dev_install_rte_compat_hooks(dev_pathname);

    ctrlr = rte_zmalloc(NULL, sizeof(*ctrlr), RTE_CACHE_LINE_SIZE);
    if (!ctrlr) {
        rte_vhost_driver_unregister(dev_pathname);
        return NULL;
    }

    /* hardcoded block device information with 128MiB */
    ctrlr->bdev = vhost_blk_bdev_construct("malloc0", "vhost_blk_malloc0",
                        4096, 32768, 0);
    if (!ctrlr->bdev) {
        rte_free(ctrlr);
        rte_vhost_driver_unregister(dev_pathname);
        return NULL;
    }

    rte_vhost_driver_callback_register(dev_pathname,
                       &vhost_blk_device_ops);

    return ctrlr;
}

static void
signal_handler(__rte_unused int signum)
{
    struct vhost_blk_ctrlr *ctrlr;

    unlink(dev_pathname);

    if (g_should_stop != -1) {
        g_should_stop = 1;
        while (g_should_stop != 2)
            ;
    }

    ctrlr = vhost_blk_ctrlr_find(dev_pathname);
    if (ctrlr != NULL) {
        if (ctrlr->bdev != NULL) {
            rte_free(ctrlr->bdev->data);
            rte_free(ctrlr->bdev);
        }
        rte_free(ctrlr);
    }

    rte_vhost_driver_unregister(dev_pathname);
    exit(0);
}

int main(int argc, char *argv[])
{
    int ret;

    signal(SIGINT, signal_handler);

    /* init EAL */
    ret = rte_eal_init(argc, argv);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");

    g_vhost_ctrlr = vhost_blk_ctrlr_construct("vhost.socket");
    if (g_vhost_ctrlr == NULL) {
        fprintf(stderr, "Construct vhost blk controller failed\n");
        return 0;
    }

    if (sem_init(&exit_sem, 0, 0) < 0) {
        fprintf(stderr, "Error init exit_sem\n");
        return -1;
    }

    ret = rte_vhost_driver_start(dev_pathname);
    if (ret < 0) {
        fprintf(stderr, "Failed to start vhost driver.\n");
        return -1;
    }

    /* loop for exit the application */
    while (1)
        sleep(1);

    /* clean up the EAL */
    rte_eal_cleanup();

    return 0;
}