contrib/vhost-user-blk/vhost-user-blk.c

   1 /*
   2  * vhost-user-blk sample application
   3  *
   4  * Copyright (c) 2017 Intel Corporation. All rights reserved.
   5  *
   6  * Author:
   7  *  Changpeng Liu <changpeng.liu@intel.com>
   8  *
   9  * This work is based on the "vhost-user-scsi" sample and "virtio-blk" driver
  10  * implementation by:
  11  *  Felipe Franciosi <felipe@nutanix.com>
  12  *  Anthony Liguori <aliguori@us.ibm.com>
  13  *
  14  * This work is licensed under the terms of the GNU GPL, version 2 only.
  15  * See the COPYING file in the top-level directory.
  16  */
  17
  18 #include "qemu/osdep.h"
  19 #include "standard-headers/linux/virtio_blk.h"
  20 #include "contrib/libvhost-user/libvhost-user-glib.h"
  21 #include "contrib/libvhost-user/libvhost-user.h"
  22
  23 #if defined(__linux__)
  24 #include <linux/fs.h>
  25 #include <sys/ioctl.h>
  26 #endif
  27
  28 struct virtio_blk_inhdr {
  29     unsigned char status;
  30 };
  31
  32 /* vhost user block device */
  33 typedef struct VubDev {
  34     VugDev parent;
  35     int blk_fd;
  36     struct virtio_blk_config blkcfg;
  37     bool enable_ro;
  38     char *blk_name;
  39     GMainLoop *loop;
  40 } VubDev;
  41
  42 typedef struct VubReq {
  43     VuVirtqElement *elem;
  44     int64_t sector_num;
  45     size_t size;
  46     struct virtio_blk_inhdr *in;
  47     struct virtio_blk_outhdr *out;
  48     VubDev *vdev_blk;
  49     struct VuVirtq *vq;
  50 } VubReq;
  51
  52 /* refer util/iov.c */
  53 static size_t vub_iov_size(const struct iovec *iov,
  54                               const unsigned int iov_cnt)
  55 {
  56     size_t len;
  57     unsigned int i;
  58
  59     len = 0;
  60     for (i = 0; i < iov_cnt; i++) {
  61         len += iov[i].iov_len;
  62     }
  63     return len;
  64 }
  65
  66 static size_t vub_iov_to_buf(const struct iovec *iov,
  67                              const unsigned int iov_cnt, void *buf)
  68 {
  69     size_t len;
  70     unsigned int i;
  71
  72     len = 0;
  73     for (i = 0; i < iov_cnt; i++) {
  74         memcpy(buf + len,  iov[i].iov_base, iov[i].iov_len);
  75         len += iov[i].iov_len;
  76     }
  77     return len;
  78 }
  79
  80 static void vub_panic_cb(VuDev *vu_dev, const char *buf)
  81 {
  82     VugDev *gdev;
  83     VubDev *vdev_blk;
  84
  85     assert(vu_dev);
  86
  87     gdev = container_of(vu_dev, VugDev, parent);
  88     vdev_blk = container_of(gdev, VubDev, parent);
  89     if (buf) {
  90         g_warning("vu_panic: %s", buf);
  91     }
  92
  93     g_main_loop_quit(vdev_blk->loop);
  94 }
  95
  96 static void vub_req_complete(VubReq *req)
  97 {
  98     VugDev *gdev = &req->vdev_blk->parent;
  99     VuDev *vu_dev = &gdev->parent;
 100
 101     /* IO size with 1 extra status byte */
 102     vu_queue_push(vu_dev, req->vq, req->elem,
 103                   req->size + 1);
 104     vu_queue_notify(vu_dev, req->vq);
 105
 106     if (req->elem) {
 107         free(req->elem);
 108     }
 109
 110     g_free(req);
 111 }
 112
 113 static int vub_open(const char *file_name, bool wce)
 114 {
 115     int fd;
 116     int flags = O_RDWR;
 117
 118     if (!wce) {
 119         flags |= O_DIRECT;
 120     }
 121
 122     fd = open(file_name, flags);
 123     if (fd < 0) {
 124         fprintf(stderr, "Cannot open file %s, %s\n", file_name,
 125                 strerror(errno));
 126         return -1;
 127     }
 128
 129     return fd;
 130 }
 131
 132 static ssize_t
 133 vub_readv(VubReq *req, struct iovec *iov, uint32_t iovcnt)
 134 {
 135     VubDev *vdev_blk = req->vdev_blk;
 136     ssize_t rc;
 137
 138     if (!iovcnt) {
 139         fprintf(stderr, "Invalid Read IOV count\n");
 140         return -1;
 141     }
 142
 143     req->size = vub_iov_size(iov, iovcnt);
 144     rc = preadv(vdev_blk->blk_fd, iov, iovcnt, req->sector_num * 512);
 145     if (rc < 0) {
 146         fprintf(stderr, "%s, Sector %"PRIu64", Size %lu failed with %s\n",
 147                 vdev_blk->blk_name, req->sector_num, req->size,
 148                 strerror(errno));
 149         return -1;
 150     }
 151
 152     return rc;
 153 }
 154
 155 static ssize_t
 156 vub_writev(VubReq *req, struct iovec *iov, uint32_t iovcnt)
 157 {
 158     VubDev *vdev_blk = req->vdev_blk;
 159     ssize_t rc;
 160
 161     if (!iovcnt) {
 162         fprintf(stderr, "Invalid Write IOV count\n");
 163         return -1;
 164     }
 165
 166     req->size = vub_iov_size(iov, iovcnt);
 167     rc = pwritev(vdev_blk->blk_fd, iov, iovcnt, req->sector_num * 512);
 168     if (rc < 0) {
 169         fprintf(stderr, "%s, Sector %"PRIu64", Size %lu failed with %s\n",
 170                 vdev_blk->blk_name, req->sector_num, req->size,
 171                 strerror(errno));
 172         return -1;
 173     }
 174
 175     return rc;
 176 }
 177
 178 static int
 179 vub_discard_write_zeroes(VubReq *req, struct iovec *iov, uint32_t iovcnt,
 180                          uint32_t type)
 181 {
 182     struct virtio_blk_discard_write_zeroes *desc;
 183     ssize_t size;
 184     void *buf;
 185
 186     size = vub_iov_size(iov, iovcnt);
 187     if (size != sizeof(*desc)) {
 188         fprintf(stderr, "Invalid size %ld, expect %ld\n", size, sizeof(*desc));
 189         return -1;
 190     }
 191     buf = g_new0(char, size);
 192     vub_iov_to_buf(iov, iovcnt, buf);
 193
 194     #if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
 195     VubDev *vdev_blk = req->vdev_blk;
 196     desc = (struct virtio_blk_discard_write_zeroes *)buf;
 197     uint64_t range[2] = { le64toh(desc->sector) << 9,
 198                           le32toh(desc->num_sectors) << 9 };
 199     if (type == VIRTIO_BLK_T_DISCARD) {
 200         if (ioctl(vdev_blk->blk_fd, BLKDISCARD, range) == 0) {
 201             g_free(buf);
 202             return 0;
 203         }
 204     } else if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
 205         if (ioctl(vdev_blk->blk_fd, BLKZEROOUT, range) == 0) {
 206             g_free(buf);
 207             return 0;
 208         }
 209     }
 210     #endif
 211
 212     g_free(buf);
 213     return -1;
 214 }
 215
 216 static void
 217 vub_flush(VubReq *req)
 218 {
 219     VubDev *vdev_blk = req->vdev_blk;
 220
 221     fdatasync(vdev_blk->blk_fd);
 222 }
 223
 224 static int vub_virtio_process_req(VubDev *vdev_blk,
 225                                      VuVirtq *vq)
 226 {
 227     VugDev *gdev = &vdev_blk->parent;
 228     VuDev *vu_dev = &gdev->parent;
 229     VuVirtqElement *elem;
 230     uint32_t type;
 231     unsigned in_num;
 232     unsigned out_num;
 233     VubReq *req;
 234
 235     elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement) + sizeof(VubReq));
 236     if (!elem) {
 237         return -1;
 238     }
 239
 240     /* refer to hw/block/virtio_blk.c */
 241     if (elem->out_num < 1 || elem->in_num < 1) {
 242         fprintf(stderr, "virtio-blk request missing headers\n");
 243         free(elem);
 244         return -1;
 245     }
 246
 247     req = g_new0(VubReq, 1);
 248     req->vdev_blk = vdev_blk;
 249     req->vq = vq;
 250     req->elem = elem;
 251
 252     in_num = elem->in_num;
 253     out_num = elem->out_num;
 254
 255     /* don't support VIRTIO_F_ANY_LAYOUT and virtio 1.0 only */
 256     if (elem->out_sg[0].iov_len < sizeof(struct virtio_blk_outhdr)) {
 257         fprintf(stderr, "Invalid outhdr size\n");
 258         goto err;
 259     }
 260     req->out = (struct virtio_blk_outhdr *)elem->out_sg[0].iov_base;
 261     out_num--;
 262
 263     if (elem->in_sg[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
 264         fprintf(stderr, "Invalid inhdr size\n");
 265         goto err;
 266     }
 267     req->in = (struct virtio_blk_inhdr *)elem->in_sg[in_num - 1].iov_base;
 268     in_num--;
 269
 270     type = le32toh(req->out->type);
 271     switch (type & ~VIRTIO_BLK_T_BARRIER) {
 272     case VIRTIO_BLK_T_IN:
 273     case VIRTIO_BLK_T_OUT: {
 274         ssize_t ret = 0;
 275         bool is_write = type & VIRTIO_BLK_T_OUT;
 276         req->sector_num = le64toh(req->out->sector);
 277         if (is_write) {
 278             ret  = vub_writev(req, &elem->out_sg[1], out_num);
 279         } else {
 280             ret = vub_readv(req, &elem->in_sg[0], in_num);
 281         }
 282         if (ret >= 0) {
 283             req->in->status = VIRTIO_BLK_S_OK;
 284         } else {
 285             req->in->status = VIRTIO_BLK_S_IOERR;
 286         }
 287         vub_req_complete(req);
 288         break;
 289     }
 290     case VIRTIO_BLK_T_FLUSH:
 291         vub_flush(req);
 292         req->in->status = VIRTIO_BLK_S_OK;
 293         vub_req_complete(req);
 294         break;
 295     case VIRTIO_BLK_T_GET_ID: {
 296         size_t size = MIN(vub_iov_size(&elem->in_sg[0], in_num),
 297                           VIRTIO_BLK_ID_BYTES);
 298         snprintf(elem->in_sg[0].iov_base, size, "%s", "vhost_user_blk");
 299         req->in->status = VIRTIO_BLK_S_OK;
 300         req->size = elem->in_sg[0].iov_len;
 301         vub_req_complete(req);
 302         break;
 303     }
 304     case VIRTIO_BLK_T_DISCARD:
 305     case VIRTIO_BLK_T_WRITE_ZEROES: {
 306         int rc;
 307         rc = vub_discard_write_zeroes(req, &elem->out_sg[1], out_num, type);
 308         if (rc == 0) {
 309             req->in->status = VIRTIO_BLK_S_OK;
 310         } else {
 311             req->in->status = VIRTIO_BLK_S_IOERR;
 312         }
 313         vub_req_complete(req);
 314         break;
 315     }
 316     default:
 317         req->in->status = VIRTIO_BLK_S_UNSUPP;
 318         vub_req_complete(req);
 319         break;
 320     }
 321
 322     return 0;
 323
 324 err:
 325     free(elem);
 326     g_free(req);
 327     return -1;
 328 }
 329
 330 static void vub_process_vq(VuDev *vu_dev, int idx)
 331 {
 332     VugDev *gdev;
 333     VubDev *vdev_blk;
 334     VuVirtq *vq;
 335     int ret;
 336
 337     if ((idx < 0) || (idx >= VHOST_MAX_NR_VIRTQUEUE)) {
 338         fprintf(stderr, "VQ Index out of range: %d\n", idx);
 339         vub_panic_cb(vu_dev, NULL);
 340         return;
 341     }
 342
 343     gdev = container_of(vu_dev, VugDev, parent);
 344     vdev_blk = container_of(gdev, VubDev, parent);
 345     assert(vdev_blk);
 346
 347     vq = vu_get_queue(vu_dev, idx);
 348     assert(vq);
 349
 350     while (1) {
 351         ret = vub_virtio_process_req(vdev_blk, vq);
 352         if (ret) {
 353             break;
 354         }
 355     }
 356 }
 357
 358 static void vub_queue_set_started(VuDev *vu_dev, int idx, bool started)
 359 {
 360     VuVirtq *vq;
 361
 362     assert(vu_dev);
 363
 364     vq = vu_get_queue(vu_dev, idx);
 365     vu_set_queue_handler(vu_dev, vq, started ? vub_process_vq : NULL);
 366 }
 367
 368 static uint64_t
 369 vub_get_features(VuDev *dev)
 370 {
 371     uint64_t features;
 372     VugDev *gdev;
 373     VubDev *vdev_blk;
 374
 375     gdev = container_of(dev, VugDev, parent);
 376     vdev_blk = container_of(gdev, VubDev, parent);
 377
 378     features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
 379                1ull << VIRTIO_BLK_F_SEG_MAX |
 380                1ull << VIRTIO_BLK_F_TOPOLOGY |
 381                1ull << VIRTIO_BLK_F_BLK_SIZE |
 382                1ull << VIRTIO_BLK_F_FLUSH |
 383                #if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
 384                1ull << VIRTIO_BLK_F_DISCARD |
 385                1ull << VIRTIO_BLK_F_WRITE_ZEROES |
 386                #endif
 387                1ull << VIRTIO_BLK_F_CONFIG_WCE |
 388                1ull << VIRTIO_F_VERSION_1 |
 389                1ull << VHOST_USER_F_PROTOCOL_FEATURES;
 390
 391     if (vdev_blk->enable_ro) {
 392         features |= 1ull << VIRTIO_BLK_F_RO;
 393     }
 394
 395     return features;
 396 }
 397
 398 static uint64_t
 399 vub_get_protocol_features(VuDev *dev)
 400 {
 401     return 1ull << VHOST_USER_PROTOCOL_F_CONFIG;
 402 }
 403
 404 static int
 405 vub_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
 406 {
 407     VugDev *gdev;
 408     VubDev *vdev_blk;
 409
 410     gdev = container_of(vu_dev, VugDev, parent);
 411     vdev_blk = container_of(gdev, VubDev, parent);
 412     memcpy(config, &vdev_blk->blkcfg, len);
 413
 414     return 0;
 415 }
 416
 417 static int
 418 vub_set_config(VuDev *vu_dev, const uint8_t *data,
 419                uint32_t offset, uint32_t size, uint32_t flags)
 420 {
 421     VugDev *gdev;
 422     VubDev *vdev_blk;
 423     uint8_t wce;
 424     int fd;
 425
 426     /* don't support live migration */
 427     if (flags != VHOST_SET_CONFIG_TYPE_MASTER) {
 428         return -1;
 429     }
 430
 431     gdev = container_of(vu_dev, VugDev, parent);
 432     vdev_blk = container_of(gdev, VubDev, parent);
 433
 434     if (offset != offsetof(struct virtio_blk_config, wce) ||
 435         size != 1) {
 436         return -1;
 437     }
 438
 439     wce = *data;
 440     if (wce == vdev_blk->blkcfg.wce) {
 441         /* Do nothing as same with old configuration */
 442         return 0;
 443     }
 444
 445     vdev_blk->blkcfg.wce = wce;
 446     fprintf(stdout, "Write Cache Policy Changed\n");
 447     if (vdev_blk->blk_fd >= 0) {
 448         close(vdev_blk->blk_fd);
 449         vdev_blk->blk_fd = -1;
 450     }
 451
 452     fd = vub_open(vdev_blk->blk_name, wce);
 453     if (fd < 0) {
 454         fprintf(stderr, "Error to open block device %s\n", vdev_blk->blk_name);
 455         vdev_blk->blk_fd = -1;
 456         return -1;
 457     }
 458     vdev_blk->blk_fd = fd;
 459
 460     return 0;
 461 }
 462
 463 static const VuDevIface vub_iface = {
 464     .get_features = vub_get_features,
 465     .queue_set_started = vub_queue_set_started,
 466     .get_protocol_features = vub_get_protocol_features,
 467     .get_config = vub_get_config,
 468     .set_config = vub_set_config,
 469 };
 470
 471 static int unix_sock_new(char *unix_fn)
 472 {
 473     int sock;
 474     struct sockaddr_un un;
 475     size_t len;
 476
 477     assert(unix_fn);
 478
 479     sock = socket(AF_UNIX, SOCK_STREAM, 0);
 480     if (sock <= 0) {
 481         perror("socket");
 482         return -1;
 483     }
 484
 485     un.sun_family = AF_UNIX;
 486     (void)snprintf(un.sun_path, sizeof(un.sun_path), "%s", unix_fn);
 487     len = sizeof(un.sun_family) + strlen(un.sun_path);
 488
 489     (void)unlink(unix_fn);
 490     if (bind(sock, (struct sockaddr *)&un, len) < 0) {
 491         perror("bind");
 492         goto fail;
 493     }
 494
 495     if (listen(sock, 1) < 0) {
 496         perror("listen");
 497         goto fail;
 498     }
 499
 500     return sock;
 501
 502 fail:
 503     (void)close(sock);
 504
 505     return -1;
 506 }
 507
 508 static void vub_free(struct VubDev *vdev_blk)
 509 {
 510     if (!vdev_blk) {
 511         return;
 512     }
 513
 514     g_main_loop_unref(vdev_blk->loop);
 515     if (vdev_blk->blk_fd >= 0) {
 516         close(vdev_blk->blk_fd);
 517     }
 518     g_free(vdev_blk);
 519 }
 520
 521 static uint32_t
 522 vub_get_blocksize(int fd)
 523 {
 524     uint32_t blocksize = 512;
 525
 526 #if defined(__linux__) && defined(BLKSSZGET)
 527     if (ioctl(fd, BLKSSZGET, &blocksize) == 0) {
 528         return blocksize;
 529     }
 530 #endif
 531
 532     return blocksize;
 533 }
 534
 535 static void
 536 vub_initialize_config(int fd, struct virtio_blk_config *config)
 537 {
 538     off64_t capacity;
 539
 540     capacity = lseek64(fd, 0, SEEK_END);
 541     config->capacity = capacity >> 9;
 542     config->blk_size = vub_get_blocksize(fd);
 543     config->size_max = 65536;
 544     config->seg_max = 128 - 2;
 545     config->min_io_size = 1;
 546     config->opt_io_size = 1;
 547     config->num_queues = 1;
 548     #if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
 549     config->max_discard_sectors = 32768;
 550     config->max_discard_seg = 1;
 551     config->discard_sector_alignment = config->blk_size >> 9;
 552     config->max_write_zeroes_sectors = 32768;
 553     config->max_write_zeroes_seg = 1;
 554     #endif
 555 }
 556
 557 static VubDev *
 558 vub_new(char *blk_file)
 559 {
 560     VubDev *vdev_blk;
 561
 562     vdev_blk = g_new0(VubDev, 1);
 563     vdev_blk->loop = g_main_loop_new(NULL, FALSE);
 564     vdev_blk->blk_fd = vub_open(blk_file, 0);
 565     if (vdev_blk->blk_fd  < 0) {
 566         fprintf(stderr, "Error to open block device %s\n", blk_file);
 567         vub_free(vdev_blk);
 568         return NULL;
 569     }
 570     vdev_blk->enable_ro = false;
 571     vdev_blk->blkcfg.wce = 0;
 572     vdev_blk->blk_name = blk_file;
 573
 574     /* fill virtio_blk_config with block parameters */
 575     vub_initialize_config(vdev_blk->blk_fd, &vdev_blk->blkcfg);
 576
 577     return vdev_blk;
 578 }
 579
 580 int main(int argc, char **argv)
 581 {
 582     int opt;
 583     char *unix_socket = NULL;
 584     char *blk_file = NULL;
 585     bool enable_ro = false;
 586     int lsock = -1, csock = -1;
 587     VubDev *vdev_blk = NULL;
 588
 589     while ((opt = getopt(argc, argv, "b:rs:h")) != -1) {
 590         switch (opt) {
 591         case 'b':
 592             blk_file = g_strdup(optarg);
 593             break;
 594         case 's':
 595             unix_socket = g_strdup(optarg);
 596             break;
 597         case 'r':
 598             enable_ro = true;
 599             break;
 600         case 'h':
 601         default:
 602             printf("Usage: %s [ -b block device or file, -s UNIX domain socket"
 603                    " | -r Enable read-only ] | [ -h ]\n", argv[0]);
 604             return 0;
 605         }
 606     }
 607
 608     if (!unix_socket || !blk_file) {
 609         printf("Usage: %s [ -b block device or file, -s UNIX domain socket"
 610                " | -r Enable read-only ] | [ -h ]\n", argv[0]);
 611         return -1;
 612     }
 613
 614     lsock = unix_sock_new(unix_socket);
 615     if (lsock < 0) {
 616         goto err;
 617     }
 618
 619     csock = accept(lsock, (void *)0, (void *)0);
 620     if (csock < 0) {
 621         fprintf(stderr, "Accept error %s\n", strerror(errno));
 622         goto err;
 623     }
 624
 625     vdev_blk = vub_new(blk_file);
 626     if (!vdev_blk) {
 627         goto err;
 628     }
 629     if (enable_ro) {
 630         vdev_blk->enable_ro = true;
 631     }
 632
 633     vug_init(&vdev_blk->parent, csock, vub_panic_cb, &vub_iface);
 634
 635     g_main_loop_run(vdev_blk->loop);
 636
 637     vug_deinit(&vdev_blk->parent);
 638
 639 err:
 640     vub_free(vdev_blk);
 641     if (csock >= 0) {
 642         close(csock);
 643     }
 644     if (lsock >= 0) {
 645         close(lsock);
 646     }
 647     g_free(unix_socket);
 648     g_free(blk_file);
 649
 650     return 0;
 651 }