examples/vhost_blk/blk.c

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

#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <assert.h>
#include <ctype.h>
#include <string.h>
#include <stddef.h>

#include <rte_cycles.h>
#include <rte_log.h>
#include <rte_malloc.h>
#include <rte_byteorder.h>
#include <rte_string_fns.h>

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

static void
vhost_strcpy_pad(void *dst, const char *src, size_t size, int pad)
{
    size_t len;

    len = strlen(src);
    if (len < size) {
        memcpy(dst, src, len);
        memset((char *)dst + len, pad, size - len);
    } else {
        memcpy(dst, src, size);
    }
}

static int
vhost_bdev_blk_readwrite(struct vhost_block_dev *bdev,
              struct vhost_blk_task *task,
              uint64_t lba_512, __rte_unused uint32_t xfer_len)
{
    uint32_t i;
    uint64_t offset;
    uint32_t nbytes = 0;

    offset = lba_512 * 512;

    /* iovs[0] is the head and iovs[iovs_cnt - 1] is the tail
     * Middle is the data range
     */
    for (i = 1; i < task->iovs_cnt - 1; i++) {
        if (task->dxfer_dir == BLK_DIR_TO_DEV)
            memcpy(bdev->data + offset, task->iovs[i].iov_base,
                   task->iovs[i].iov_len);
        else
            memcpy(task->iovs[i].iov_base, bdev->data + offset,
                   task->iovs[i].iov_len);
        offset += task->iovs[i].iov_len;
        nbytes += task->iovs[i].iov_len;
    }

    return nbytes;
}

int
vhost_bdev_process_blk_commands(struct vhost_block_dev *bdev,
                 struct vhost_blk_task *task)
{
    size_t used_len;

    if (unlikely(task->data_len > (bdev->blockcnt * bdev->blocklen))) {
        fprintf(stderr, "read or write beyond capacity\n");
        return VIRTIO_BLK_S_UNSUPP;
    }

    switch (task->req->type) {
    case VIRTIO_BLK_T_IN:
        if (unlikely(task->data_len == 0 ||
            (task->data_len & (512 - 1)) != 0)) {
            fprintf(stderr,
                "%s - passed IO buffer is not multiple of 512b"
                "(req_idx = %"PRIu16").\n",
                task->req->type ? "WRITE" : "READ",
                task->req_idx);
            return VIRTIO_BLK_S_UNSUPP;
        }

        task->dxfer_dir = BLK_DIR_FROM_DEV;
        vhost_bdev_blk_readwrite(bdev, task,
                     task->req->sector, task->data_len);
        break;
    case VIRTIO_BLK_T_OUT:
        if (unlikely(task->data_len == 0 ||
            (task->data_len & (512 - 1)) != 0)) {
            fprintf(stderr,
                "%s - passed IO buffer is not multiple of 512b"
                "(req_idx = %"PRIu16").\n",
                task->req->type ? "WRITE" : "READ",
                task->req_idx);
            return VIRTIO_BLK_S_UNSUPP;
        }

        task->dxfer_dir = BLK_DIR_TO_DEV;
        vhost_bdev_blk_readwrite(bdev, task,
                     task->req->sector, task->data_len);
        break;
    case VIRTIO_BLK_T_GET_ID:
        if (!task->iovs_cnt || task->data_len)
            return VIRTIO_BLK_S_UNSUPP;
        used_len = RTE_MIN((size_t)VIRTIO_BLK_ID_BYTES, task->data_len);
        vhost_strcpy_pad(task->iovs[0].iov_base,
                 bdev->product_name, used_len, ' ');
        break;
    default:
        fprintf(stderr, "unsupported cmd\n");
        return VIRTIO_BLK_S_UNSUPP;
    }

    return VIRTIO_BLK_S_OK;
}