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 "libvhost-user-glib.h"
  21
  22 #if defined(__linux__)
  23 #include <linux/fs.h>
  24 #include <sys/ioctl.h>
  25 #endif
  26
  27 enum {
  28     VHOST_USER_BLK_MAX_QUEUES = 8,
  29 };
  30
  31 struct virtio_blk_inhdr {
  32     unsigned char status;
  33 };
  34
  35 /* vhost user block device */
  36 typedef struct VubDev {
  37     VugDev parent;
  38     int blk_fd;
  39     struct virtio_blk_config blkcfg;
  40     bool enable_ro;
  41     char *blk_name;
  42     GMainLoop *loop;
  43 } VubDev;
  44
  45 typedef struct VubReq {
  46     VuVirtqElement *elem;
  47     int64_t sector_num;
  48     size_t size;
  49     struct virtio_blk_inhdr *in;
  50     struct virtio_blk_outhdr *out;
  51     VubDev *vdev_blk;
  52     struct VuVirtq *vq;
  53 } VubReq;
  54
  55 /* refer util/iov.c */
  56 static size_t vub_iov_size(const struct iovec *iov,
  57                               const unsigned int iov_cnt)
  58 {
  59     size_t len;
  60     unsigned int i;
  61
  62     len = 0;
  63     for (i = 0; i < iov_cnt; i++) {
  64         len += iov[i].iov_len;
  65     }
  66     return len;
  67 }
  68
  69 static size_t vub_iov_to_buf(const struct iovec *iov,
  70                              const unsigned int iov_cnt, void *buf)
  71 {
  72     size_t len;
  73     unsigned int i;
  74
  75     len = 0;
  76     for (i = 0; i < iov_cnt; i++) {
  77         memcpy(buf + len,  iov[i].iov_base, iov[i].iov_len);
  78         len += iov[i].iov_len;
  79     }
  80     return len;
  81 }
  82
  83 static void vub_panic_cb(VuDev *vu_dev, const char *buf)
  84 {
  85     VugDev *gdev;
  86     VubDev *vdev_blk;
  87
  88     assert(vu_dev);
  89
  90     gdev = container_of(vu_dev, VugDev, parent);
  91     vdev_blk = container_of(gdev, VubDev, parent);
  92     if (buf) {
  93         g_warning("vu_panic: %s", buf);
  94     }
  95
  96     g_main_loop_quit(vdev_blk->loop);
  97 }
  98
  99 static void vub_req_complete(VubReq *req)
 100 {
 101     VugDev *gdev = &req->vdev_blk->parent;
 102     VuDev *vu_dev = &gdev->parent;
 103
 104     /* IO size with 1 extra status byte */
 105     vu_queue_push(vu_dev, req->vq, req->elem,
 106                   req->size + 1);
 107     vu_queue_notify(vu_dev, req->vq);
 108
 109     g_free(req->elem);
 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 %zu 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 %zu 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 %zd, expect %zd\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 = 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         g_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     g_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     gdev = container_of(vu_dev, VugDev, parent);
 338     vdev_blk = container_of(gdev, VubDev, parent);
 339     assert(vdev_blk);
 340
 341     vq = vu_get_queue(vu_dev, idx);
 342     assert(vq);
 343
 344     while (1) {
 345         ret = vub_virtio_process_req(vdev_blk, vq);
 346         if (ret) {
 347             break;
 348         }
 349     }
 350 }
 351
 352 static void vub_queue_set_started(VuDev *vu_dev, int idx, bool started)
 353 {
 354     VuVirtq *vq;
 355
 356     assert(vu_dev);
 357
 358     vq = vu_get_queue(vu_dev, idx);
 359     vu_set_queue_handler(vu_dev, vq, started ? vub_process_vq : NULL);
 360 }
 361
 362 static uint64_t
 363 vub_get_features(VuDev *dev)
 364 {
 365     uint64_t features;
 366     VugDev *gdev;
 367     VubDev *vdev_blk;
 368
 369     gdev = container_of(dev, VugDev, parent);
 370     vdev_blk = container_of(gdev, VubDev, parent);
 371
 372     features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
 373                1ull << VIRTIO_BLK_F_SEG_MAX |
 374                1ull << VIRTIO_BLK_F_TOPOLOGY |
 375                1ull << VIRTIO_BLK_F_BLK_SIZE |
 376                1ull << VIRTIO_BLK_F_FLUSH |
 377                #if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
 378                1ull << VIRTIO_BLK_F_DISCARD |
 379                1ull << VIRTIO_BLK_F_WRITE_ZEROES |
 380                #endif
 381                1ull << VIRTIO_BLK_F_CONFIG_WCE;
 382
 383     if (vdev_blk->enable_ro) {
 384         features |= 1ull << VIRTIO_BLK_F_RO;
 385     }
 386
 387     return features;
 388 }
 389
 390 static uint64_t
 391 vub_get_protocol_features(VuDev *dev)
 392 {
 393     return 1ull << VHOST_USER_PROTOCOL_F_CONFIG |
 394            1ull << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD;
 395 }
 396
 397 static int
 398 vub_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
 399 {
 400     VugDev *gdev;
 401     VubDev *vdev_blk;
 402
 403     if (len > sizeof(struct virtio_blk_config)) {
 404         return -1;
 405     }
 406
 407     gdev = container_of(vu_dev, VugDev, parent);
 408     vdev_blk = container_of(gdev, VubDev, parent);
 409     memcpy(config, &vdev_blk->blkcfg, len);
 410
 411     return 0;
 412 }
 413
 414 static int
 415 vub_set_config(VuDev *vu_dev, const uint8_t *data,
 416                uint32_t offset, uint32_t size, uint32_t flags)
 417 {
 418     VugDev *gdev;
 419     VubDev *vdev_blk;
 420     uint8_t wce;
 421     int fd;
 422
 423     /* don't support live migration */
 424     if (flags != VHOST_SET_CONFIG_TYPE_FRONTEND) {
 425         return -1;
 426     }
 427
 428     gdev = container_of(vu_dev, VugDev, parent);
 429     vdev_blk = container_of(gdev, VubDev, parent);
 430
 431     if (offset != offsetof(struct virtio_blk_config, wce) ||
 432         size != 1) {
 433         return -1;
 434     }
 435
 436     wce = *data;
 437     if (wce == vdev_blk->blkcfg.wce) {
 438         /* Do nothing as same with old configuration */
 439         return 0;
 440     }
 441
 442     vdev_blk->blkcfg.wce = wce;
 443     fprintf(stdout, "Write Cache Policy Changed\n");
 444     if (vdev_blk->blk_fd >= 0) {
 445         close(vdev_blk->blk_fd);
 446         vdev_blk->blk_fd = -1;
 447     }
 448
 449     fd = vub_open(vdev_blk->blk_name, wce);
 450     if (fd < 0) {
 451         fprintf(stderr, "Error to open block device %s\n", vdev_blk->blk_name);
 452         vdev_blk->blk_fd = -1;
 453         return -1;
 454     }
 455     vdev_blk->blk_fd = fd;
 456
 457     return 0;
 458 }
 459
 460 static const VuDevIface vub_iface = {
 461     .get_features = vub_get_features,
 462     .queue_set_started = vub_queue_set_started,
 463     .get_protocol_features = vub_get_protocol_features,
 464     .get_config = vub_get_config,
 465     .set_config = vub_set_config,
 466 };
 467
 468 static int unix_sock_new(char *unix_fn)
 469 {
 470     int sock;
 471     struct sockaddr_un un;
 472     size_t len;
 473
 474     assert(unix_fn);
 475
 476     sock = socket(AF_UNIX, SOCK_STREAM, 0);
 477     if (sock < 0) {
 478         perror("socket");
 479         return -1;
 480     }
 481
 482     un.sun_family = AF_UNIX;
 483     (void)snprintf(un.sun_path, sizeof(un.sun_path), "%s", unix_fn);
 484     len = sizeof(un.sun_family) + strlen(un.sun_path);
 485
 486     (void)unlink(unix_fn);
 487     if (bind(sock, (struct sockaddr *)&un, len) < 0) {
 488         perror("bind");
 489         goto fail;
 490     }
 491
 492     if (listen(sock, 1) < 0) {
 493         perror("listen");
 494         goto fail;
 495     }
 496
 497     return sock;
 498
 499 fail:
 500     (void)close(sock);
 501
 502     return -1;
 503 }
 504
 505 static void vub_free(struct VubDev *vdev_blk)
 506 {
 507     if (!vdev_blk) {
 508         return;
 509     }
 510
 511     g_main_loop_unref(vdev_blk->loop);
 512     if (vdev_blk->blk_fd >= 0) {
 513         close(vdev_blk->blk_fd);
 514     }
 515     g_free(vdev_blk);
 516 }
 517
 518 static uint32_t
 519 vub_get_blocksize(int fd)
 520 {
 521     uint32_t blocksize = 512;
 522
 523 #if defined(__linux__) && defined(BLKSSZGET)
 524     if (ioctl(fd, BLKSSZGET, &blocksize) == 0) {
 525         return blocksize;
 526     }
 527 #endif
 528
 529     return blocksize;
 530 }
 531
 532 static void
 533 vub_initialize_config(int fd, struct virtio_blk_config *config)
 534 {
 535     off_t capacity;
 536
 537     capacity = lseek(fd, 0, SEEK_END);
 538     config->capacity = capacity >> 9;
 539     config->blk_size = vub_get_blocksize(fd);
 540     config->size_max = 65536;
 541     config->seg_max = 128 - 2;
 542     config->min_io_size = 1;
 543     config->opt_io_size = 1;
 544     config->num_queues = 1;
 545     #if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
 546     config->max_discard_sectors = 32768;
 547     config->max_discard_seg = 1;
 548     config->discard_sector_alignment = config->blk_size >> 9;
 549     config->max_write_zeroes_sectors = 32768;
 550     config->max_write_zeroes_seg = 1;
 551     #endif
 552 }
 553
 554 static VubDev *
 555 vub_new(char *blk_file)
 556 {
 557     VubDev *vdev_blk;
 558
 559     vdev_blk = g_new0(VubDev, 1);
 560     vdev_blk->loop = g_main_loop_new(NULL, FALSE);
 561     vdev_blk->blk_fd = vub_open(blk_file, 0);
 562     if (vdev_blk->blk_fd  < 0) {
 563         fprintf(stderr, "Error to open block device %s\n", blk_file);
 564         vub_free(vdev_blk);
 565         return NULL;
 566     }
 567     vdev_blk->enable_ro = false;
 568     vdev_blk->blkcfg.wce = 0;
 569     vdev_blk->blk_name = blk_file;
 570
 571     /* fill virtio_blk_config with block parameters */
 572     vub_initialize_config(vdev_blk->blk_fd, &vdev_blk->blkcfg);
 573
 574     return vdev_blk;
 575 }
 576
 577 static int opt_fdnum = -1;
 578 static char *opt_socket_path;
 579 static char *opt_blk_file;
 580 static gboolean opt_print_caps;
 581 static gboolean opt_read_only;
 582
 583 static GOptionEntry entries[] = {
 584     { "print-capabilities", 'c', 0, G_OPTION_ARG_NONE, &opt_print_caps,
 585       "Print capabilities", NULL },
 586     { "fd", 'f', 0, G_OPTION_ARG_INT, &opt_fdnum,
 587       "Use inherited fd socket", "FDNUM" },
 588     { "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &opt_socket_path,
 589       "Use UNIX socket path", "PATH" },
 590     {"blk-file", 'b', 0, G_OPTION_ARG_FILENAME, &opt_blk_file,
 591      "block device or file path", "PATH"},
 592     { "read-only", 'r', 0, G_OPTION_ARG_NONE, &opt_read_only,
 593       "Enable read-only", NULL },
 594     { NULL, },
 595 };
 596
 597 int main(int argc, char **argv)
 598 {
 599     int lsock = -1, csock = -1;
 600     VubDev *vdev_blk = NULL;
 601     GError *error = NULL;
 602     GOptionContext *context;
 603
 604     context = g_option_context_new(NULL);
 605     g_option_context_add_main_entries(context, entries, NULL);
 606     if (!g_option_context_parse(context, &argc, &argv, &error)) {
 607         g_printerr("Option parsing failed: %s\n", error->message);
 608         exit(EXIT_FAILURE);
 609     }
 610     if (opt_print_caps) {
 611         g_print("{\n");
 612         g_print("  \"type\": \"block\",\n");
 613         g_print("  \"features\": [\n");
 614         g_print("    \"read-only\",\n");
 615         g_print("    \"blk-file\"\n");
 616         g_print("  ]\n");
 617         g_print("}\n");
 618         exit(EXIT_SUCCESS);
 619     }
 620
 621     if (!opt_blk_file) {
 622         g_print("%s\n", g_option_context_get_help(context, true, NULL));
 623         exit(EXIT_FAILURE);
 624     }
 625
 626     if (opt_socket_path) {
 627         lsock = unix_sock_new(opt_socket_path);
 628         if (lsock < 0) {
 629             exit(EXIT_FAILURE);
 630         }
 631     } else if (opt_fdnum < 0) {
 632         g_print("%s\n", g_option_context_get_help(context, true, NULL));
 633         exit(EXIT_FAILURE);
 634     } else {
 635         lsock = opt_fdnum;
 636     }
 637
 638     csock = accept(lsock, NULL, NULL);
 639     if (csock < 0) {
 640         g_printerr("Accept error %s\n", strerror(errno));
 641         exit(EXIT_FAILURE);
 642     }
 643
 644     vdev_blk = vub_new(opt_blk_file);
 645     if (!vdev_blk) {
 646         exit(EXIT_FAILURE);
 647     }
 648     if (opt_read_only) {
 649         vdev_blk->enable_ro = true;
 650     }
 651
 652     if (!vug_init(&vdev_blk->parent, VHOST_USER_BLK_MAX_QUEUES, csock,
 653                   vub_panic_cb, &vub_iface)) {
 654         g_printerr("Failed to initialize libvhost-user-glib\n");
 655         exit(EXIT_FAILURE);
 656     }
 657
 658     g_main_loop_run(vdev_blk->loop);
 659     g_main_loop_unref(vdev_blk->loop);
 660     g_option_context_free(context);
 661     vug_deinit(&vdev_blk->parent);
 662     vub_free(vdev_blk);
 663     if (csock >= 0) {
 664         close(csock);
 665     }
 666     if (lsock >= 0) {
 667         close(lsock);
 668     }
 669     g_free(opt_socket_path);
 670     g_free(opt_blk_file);
 671
 672     return 0;
 673 }