palacios/src/devices/lnx_virtio_blk.c

   1 /*
   2  * This file is part of the Palacios Virtual Machine Monitor developed
   3  * by the V3VEE Project with funding from the United States National
   4  * Science Foundation and the Department of Energy.
   5  *
   6  * The V3VEE Project is a joint project between Northwestern University
   7  * and the University of New Mexico.  You can find out more at
   8  * http://www.v3vee.org
   9  *
  10  * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu>
  11  * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
  12  * All rights reserved.
  13  *
  14  * Author: Jack Lange <jarusl@cs.northwestern.edu>
  15  *
  16  * This is free software.  You are permitted to use,
  17  * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
  18  */
  19
  20 #include <palacios/vmm.h>
  21 #include <palacios/vmm_dev_mgr.h>
  22 #include <devices/lnx_virtio_pci.h>
  23 #include <palacios/vm_guest_mem.h>
  24
  25 #include <devices/pci.h>
  26
  27
  28
  29 #ifndef CONFIG_DEBUG_VIRTIO_BLK
  30 #undef PrintDebug
  31 #define PrintDebug(fmt, args...)
  32 #endif
  33
  34
  35 #define SECTOR_SIZE 512
  36
  37 #define BLK_CAPACITY_PORT     20
  38 #define BLK_MAX_SIZE_PORT     28
  39 #define BLK_MAX_SEG_PORT      32
  40 #define BLK_CYLINDERS_PORT    36
  41 #define BLK_HEADS_PORT        38
  42 #define BLK_SECTS_PORT        39
  43
  44 #define BLK_IN_REQ            0
  45 #define BLK_OUT_REQ           1
  46 #define BLK_SCSI_CMD          2
  47
  48 #define BLK_BARRIER_FLAG     0x80000000
  49
  50 #define BLK_STATUS_OK             0
  51 #define BLK_STATUS_ERR            1
  52 #define BLK_STATUS_NOT_SUPPORTED  2
  53
  54
  55 struct blk_config {
  56     uint64_t capacity;
  57     uint32_t max_size;
  58     uint32_t max_seg;
  59     uint16_t cylinders;
  60     uint8_t heads;
  61     uint8_t sectors;
  62 } __attribute__((packed));
  63
  64
  65
  66 struct blk_op_hdr {
  67     uint32_t type;
  68     uint32_t prior;
  69     uint64_t sector;
  70 } __attribute__((packed));
  71
  72 #define QUEUE_SIZE 128
  73
  74 /* Host Feature flags */
  75 #define VIRTIO_BARRIER       0x01       /* Does host support barriers? */
  76 #define VIRTIO_SIZE_MAX      0x02       /* Indicates maximum segment size */
  77 #define VIRTIO_SEG_MAX       0x04       /* Indicates maximum # of segments */
  78 #define VIRTIO_LEGACY_GEOM   0x10       /* Indicates support of legacy geometry */
  79
  80
  81 struct virtio_dev_state {
  82     struct vm_device * pci_bus;
  83     struct list_head dev_list;
  84 };
  85
  86 struct virtio_blk_state {
  87
  88     struct pci_device * pci_dev;
  89     struct blk_config block_cfg;
  90     struct virtio_config virtio_cfg;
  91
  92
  93     struct virtio_queue queue;
  94
  95     struct v3_dev_blk_ops * ops;
  96
  97     void * backend_data;
  98
  99     int io_range_size;
 100
 101     struct virtio_dev_state * virtio_dev;
 102
 103     struct list_head dev_link;
 104 };
 105
 106
 107 static int virtio_free(struct vm_device * dev) {
 108     return -1;
 109 }
 110
 111 static int blk_reset(struct virtio_blk_state * virtio) {
 112
 113     virtio->queue.ring_desc_addr = 0;
 114     virtio->queue.ring_avail_addr = 0;
 115     virtio->queue.ring_used_addr = 0;
 116     virtio->queue.pfn = 0;
 117     virtio->queue.cur_avail_idx = 0;
 118
 119     virtio->virtio_cfg.status = 0;
 120     virtio->virtio_cfg.pci_isr = 0;
 121     return 0;
 122 }
 123
 124
 125 static int virtio_reset(struct vm_device * dev) {
 126     struct virtio_dev_state * dev_state = (struct virtio_dev_state *)(dev->private_data);
 127     struct virtio_blk_state * blk_state = NULL;
 128
 129     list_for_each_entry(blk_state, &(dev_state->dev_list), dev_link) {
 130         blk_reset(blk_state);
 131     }
 132
 133     return 0;
 134 }
 135
 136 static int handle_read_op(struct virtio_blk_state * blk_state, uint8_t * buf, uint64_t * sector, uint64_t len) {
 137     int ret = -1;
 138
 139     PrintDebug("Reading Disk\n");
 140     ret = blk_state->ops->read(buf, (*sector) * SECTOR_SIZE, len, (void *)(blk_state->backend_data));
 141     *sector += (len / SECTOR_SIZE);
 142
 143     return ret;
 144 }
 145
 146
 147 static int handle_write_op(struct virtio_blk_state * blk_state, uint8_t * buf, uint64_t * sector, uint64_t len) {
 148     int ret = -1;
 149
 150     PrintDebug("Writing Disk\n");
 151     ret = blk_state->ops->write(buf, (*sector) * SECTOR_SIZE, len, (void *)(blk_state->backend_data));
 152     *sector += (len / SECTOR_SIZE);
 153
 154     return ret;
 155 }
 156
 157
 158
 159 // multiple block operations need to increment the sector
 160
 161 static int handle_block_op(struct guest_info * core, struct virtio_blk_state * blk_state, struct blk_op_hdr * hdr,
 162                            struct vring_desc * buf_desc, uint8_t * status) {
 163     uint8_t * buf = NULL;
 164
 165     PrintDebug("Handling Block op\n");
 166     if (v3_gpa_to_hva(core, buf_desc->addr_gpa, (addr_t *)&(buf)) == -1) {
 167         PrintError("Could not translate buffer address\n");
 168         return -1;
 169     }
 170
 171     PrintDebug("Sector=%p Length=%d\n", (void *)(addr_t)(hdr->sector), buf_desc->length);
 172
 173     if (hdr->type == BLK_IN_REQ) {
 174         if (handle_read_op(blk_state, buf, &(hdr->sector), buf_desc->length) == -1) {
 175             *status = BLK_STATUS_ERR;
 176             return -1;
 177         } else {
 178             *status = BLK_STATUS_OK;
 179         }
 180     } else if (hdr->type == BLK_OUT_REQ) {
 181         if (handle_write_op(blk_state, buf, &(hdr->sector), buf_desc->length) == -1) {
 182             *status = BLK_STATUS_ERR;
 183             return -1;
 184         } else {
 185             *status = BLK_STATUS_OK;
 186         }
 187     } else if (hdr->type == BLK_SCSI_CMD) {
 188         PrintError("VIRTIO: SCSI Command Not supported!!!\n");
 189         *status = BLK_STATUS_NOT_SUPPORTED;
 190         return -1;
 191     }
 192
 193     PrintDebug("Returning Status: %d\n", *status);
 194
 195     return 0;
 196 }
 197
 198 static int get_desc_count(struct virtio_queue * q, int index) {
 199     struct vring_desc * tmp_desc = &(q->desc[index]);
 200     int cnt = 1;
 201
 202     while (tmp_desc->flags & VIRTIO_NEXT_FLAG) {
 203         tmp_desc = &(q->desc[tmp_desc->next]);
 204         cnt++;
 205     }
 206
 207     return cnt;
 208 }
 209
 210
 211
 212 static int handle_kick(struct guest_info * core, struct virtio_blk_state * blk_state) {
 213     struct virtio_queue * q = &(blk_state->queue);
 214
 215     PrintDebug("VIRTIO KICK: cur_index=%d (mod=%d), avail_index=%d\n",
 216                q->cur_avail_idx, q->cur_avail_idx % QUEUE_SIZE, q->avail->index);
 217
 218     while (q->cur_avail_idx != q->avail->index) {
 219         struct vring_desc * hdr_desc = NULL;
 220         struct vring_desc * buf_desc = NULL;
 221         struct vring_desc * status_desc = NULL;
 222         struct blk_op_hdr hdr;
 223         addr_t hdr_addr = 0;
 224         uint16_t desc_idx = q->avail->ring[q->cur_avail_idx % QUEUE_SIZE];
 225         int desc_cnt = get_desc_count(q, desc_idx);
 226         int i = 0;
 227         uint8_t * status_ptr = NULL;
 228         uint8_t status = BLK_STATUS_OK;
 229         uint32_t req_len = 0;
 230
 231         PrintDebug("Descriptor Count=%d, index=%d\n", desc_cnt, q->cur_avail_idx % QUEUE_SIZE);
 232
 233         if (desc_cnt < 3) {
 234             PrintError("Block operations must include at least 3 descriptors\n");
 235             return -1;
 236         }
 237
 238         hdr_desc = &(q->desc[desc_idx]);
 239
 240
 241         PrintDebug("Header Descriptor (ptr=%p) gpa=%p, len=%d, flags=%x, next=%d\n", hdr_desc,
 242                    (void *)(hdr_desc->addr_gpa), hdr_desc->length, hdr_desc->flags, hdr_desc->next);
 243
 244         if (v3_gpa_to_hva(core, hdr_desc->addr_gpa, &(hdr_addr)) == -1) {
 245             PrintError("Could not translate block header address\n");
 246             return -1;
 247         }
 248
 249         // We copy the block op header out because we are going to modify its contents
 250         memcpy(&hdr, (void *)hdr_addr, sizeof(struct blk_op_hdr));
 251
 252         PrintDebug("Blk Op Hdr (ptr=%p) type=%d, sector=%p\n", (void *)hdr_addr, hdr.type, (void *)hdr.sector);
 253
 254         desc_idx = hdr_desc->next;
 255
 256         for (i = 0; i < desc_cnt - 2; i++) {
 257             uint8_t tmp_status = BLK_STATUS_OK;
 258
 259             buf_desc = &(q->desc[desc_idx]);
 260
 261             PrintDebug("Buffer Descriptor (ptr=%p) gpa=%p, len=%d, flags=%x, next=%d\n", buf_desc,
 262                        (void *)(buf_desc->addr_gpa), buf_desc->length, buf_desc->flags, buf_desc->next);
 263
 264             if (handle_block_op(core, blk_state, &hdr, buf_desc, &tmp_status) == -1) {
 265                 PrintError("Error handling block operation\n");
 266                 return -1;
 267             }
 268
 269             if (tmp_status != BLK_STATUS_OK) {
 270                 status = tmp_status;
 271             }
 272
 273             req_len += buf_desc->length;
 274             desc_idx = buf_desc->next;
 275         }
 276
 277         status_desc = &(q->desc[desc_idx]);
 278
 279         PrintDebug("Status Descriptor (ptr=%p) gpa=%p, len=%d, flags=%x, next=%d\n", status_desc,
 280                    (void *)(status_desc->addr_gpa), status_desc->length, status_desc->flags, status_desc->next);
 281
 282         if (v3_gpa_to_hva(core, status_desc->addr_gpa, (addr_t *)&(status_ptr)) == -1) {
 283             PrintError("Could not translate status address\n");
 284             return -1;
 285         }
 286
 287         req_len += status_desc->length;
 288         *status_ptr = status;
 289
 290         q->used->ring[q->used->index % QUEUE_SIZE].id = q->avail->ring[q->cur_avail_idx % QUEUE_SIZE];
 291         q->used->ring[q->used->index % QUEUE_SIZE].length = req_len; // What do we set this to????
 292
 293         q->used->index++;
 294         q->cur_avail_idx++;
 295     }
 296
 297     if (!(q->avail->flags & VIRTIO_NO_IRQ_FLAG)) {
 298         PrintDebug("Raising IRQ %d\n",  blk_state->pci_dev->config_header.intr_line);
 299         v3_pci_raise_irq(blk_state->virtio_dev->pci_bus, 0, blk_state->pci_dev);
 300         blk_state->virtio_cfg.pci_isr = 1;
 301     }
 302
 303     return 0;
 304 }
 305
 306 static int virtio_io_write(struct guest_info * core, uint16_t port, void * src, uint_t length, void * private_data) {
 307     struct virtio_blk_state * blk_state = (struct virtio_blk_state *)private_data;
 308     int port_idx = port % blk_state->io_range_size;
 309
 310
 311     PrintDebug("VIRTIO BLOCK Write for port %d (index=%d) len=%d, value=%x\n",
 312                port, port_idx,  length, *(uint32_t *)src);
 313
 314
 315
 316     switch (port_idx) {
 317         case GUEST_FEATURES_PORT:
 318             if (length != 4) {
 319                 PrintError("Illegal write length for guest features\n");
 320                 return -1;
 321             }
 322
 323             blk_state->virtio_cfg.guest_features = *(uint32_t *)src;
 324             PrintDebug("Setting Guest Features to %x\n", blk_state->virtio_cfg.guest_features);
 325
 326             break;
 327         case VRING_PG_NUM_PORT:
 328             if (length == 4) {
 329                 addr_t pfn = *(uint32_t *)src;
 330                 addr_t page_addr = (pfn << VIRTIO_PAGE_SHIFT);
 331
 332
 333                 blk_state->queue.pfn = pfn;
 334
 335                 blk_state->queue.ring_desc_addr = page_addr ;
 336                 blk_state->queue.ring_avail_addr = page_addr + (QUEUE_SIZE * sizeof(struct vring_desc));
 337                 blk_state->queue.ring_used_addr = ( blk_state->queue.ring_avail_addr + \
 338                                                  sizeof(struct vring_avail)    + \
 339                                                  (QUEUE_SIZE * sizeof(uint16_t)));
 340
 341                 // round up to next page boundary.
 342                 blk_state->queue.ring_used_addr = (blk_state->queue.ring_used_addr + 0xfff) & ~0xfff;
 343
 344                 if (v3_gpa_to_hva(core, blk_state->queue.ring_desc_addr, (addr_t *)&(blk_state->queue.desc)) == -1) {
 345                     PrintError("Could not translate ring descriptor address\n");
 346                     return -1;
 347                 }
 348
 349
 350                 if (v3_gpa_to_hva(core, blk_state->queue.ring_avail_addr, (addr_t *)&(blk_state->queue.avail)) == -1) {
 351                     PrintError("Could not translate ring available address\n");
 352                     return -1;
 353                 }
 354
 355
 356                 if (v3_gpa_to_hva(core, blk_state->queue.ring_used_addr, (addr_t *)&(blk_state->queue.used)) == -1) {
 357                     PrintError("Could not translate ring used address\n");
 358                     return -1;
 359                 }
 360
 361                 PrintDebug("RingDesc_addr=%p, Avail_addr=%p, Used_addr=%p\n",
 362                            (void *)(blk_state->queue.ring_desc_addr),
 363                            (void *)(blk_state->queue.ring_avail_addr),
 364                            (void *)(blk_state->queue.ring_used_addr));
 365
 366                 PrintDebug("RingDesc=%p, Avail=%p, Used=%p\n",
 367                            blk_state->queue.desc, blk_state->queue.avail, blk_state->queue.used);
 368
 369             } else {
 370                 PrintError("Illegal write length for page frame number\n");
 371                 return -1;
 372             }
 373             break;
 374         case VRING_Q_SEL_PORT:
 375             blk_state->virtio_cfg.vring_queue_selector = *(uint16_t *)src;
 376
 377             if (blk_state->virtio_cfg.vring_queue_selector != 0) {
 378                 PrintError("Virtio Block device only uses 1 queue, selected %d\n",
 379                            blk_state->virtio_cfg.vring_queue_selector);
 380                 return -1;
 381             }
 382
 383             break;
 384         case VRING_Q_NOTIFY_PORT:
 385             PrintDebug("Handling Kick\n");
 386             if (handle_kick(core, blk_state) == -1) {
 387                 PrintError("Could not handle Block Notification\n");
 388                 return -1;
 389             }
 390             break;
 391         case VIRTIO_STATUS_PORT:
 392             blk_state->virtio_cfg.status = *(uint8_t *)src;
 393
 394             if (blk_state->virtio_cfg.status == 0) {
 395                 PrintDebug("Resetting device\n");
 396                 blk_reset(blk_state);
 397             }
 398
 399             break;
 400
 401         case VIRTIO_ISR_PORT:
 402             blk_state->virtio_cfg.pci_isr = *(uint8_t *)src;
 403             break;
 404         default:
 405             return -1;
 406             break;
 407     }
 408
 409     return length;
 410 }
 411
 412
 413 static int virtio_io_read(struct guest_info * core, uint16_t port, void * dst, uint_t length, void * private_data) {
 414     struct virtio_blk_state * blk_state = (struct virtio_blk_state *)private_data;
 415     int port_idx = port % blk_state->io_range_size;
 416
 417
 418     PrintDebug("VIRTIO BLOCK Read  for port %d (index =%d), length=%d\n",
 419                port, port_idx, length);
 420
 421     switch (port_idx) {
 422         case HOST_FEATURES_PORT:
 423             if (length != 4) {
 424                 PrintError("Illegal read length for host features\n");
 425                 return -1;
 426             }
 427
 428             *(uint32_t *)dst = blk_state->virtio_cfg.host_features;
 429
 430             break;
 431         case VRING_PG_NUM_PORT:
 432             if (length != 4) {
 433                 PrintError("Illegal read length for page frame number\n");
 434                 return -1;
 435             }
 436
 437             *(uint32_t *)dst = blk_state->queue.pfn;
 438
 439             break;
 440         case VRING_SIZE_PORT:
 441             if (length != 2) {
 442                 PrintError("Illegal read length for vring size\n");
 443                 return -1;
 444             }
 445
 446             *(uint16_t *)dst = blk_state->queue.queue_size;
 447
 448             break;
 449
 450         case VIRTIO_STATUS_PORT:
 451             if (length != 1) {
 452                 PrintError("Illegal read length for status\n");
 453                 return -1;
 454             }
 455
 456             *(uint8_t *)dst = blk_state->virtio_cfg.status;
 457             break;
 458
 459         case VIRTIO_ISR_PORT:
 460             *(uint8_t *)dst = blk_state->virtio_cfg.pci_isr;
 461             blk_state->virtio_cfg.pci_isr = 0;
 462             v3_pci_lower_irq(blk_state->virtio_dev->pci_bus, 0, blk_state->pci_dev);
 463             break;
 464
 465         default:
 466             if ( (port_idx >= sizeof(struct virtio_config)) &&
 467                  (port_idx < (sizeof(struct virtio_config) + sizeof(struct blk_config))) ) {
 468                 int cfg_offset = port_idx - sizeof(struct virtio_config);
 469                 uint8_t * cfg_ptr = (uint8_t *)&(blk_state->block_cfg);
 470
 471                 memcpy(dst, cfg_ptr + cfg_offset, length);
 472
 473             } else {
 474                 PrintError("Read of Unhandled Virtio Read\n");
 475                 return -1;
 476             }
 477
 478             break;
 479     }
 480
 481     return length;
 482 }
 483
 484
 485
 486
 487 static struct v3_device_ops dev_ops = {
 488     .free = virtio_free,
 489     .reset = virtio_reset,
 490     .start = NULL,
 491     .stop = NULL,
 492 };
 493
 494
 495
 496
 497
 498 static int register_dev(struct virtio_dev_state * virtio, struct virtio_blk_state * blk_state) {
 499     // initialize PCI
 500     struct pci_device * pci_dev = NULL;
 501     struct v3_pci_bar bars[6];
 502     int num_ports = sizeof(struct virtio_config) + sizeof(struct blk_config);
 503     int tmp_ports = num_ports;
 504     int i;
 505
 506
 507
 508     // This gets the number of ports, rounded up to a power of 2
 509     blk_state->io_range_size = 1; // must be a power of 2
 510
 511     while (tmp_ports > 0) {
 512         tmp_ports >>= 1;
 513         blk_state->io_range_size <<= 1;
 514     }
 515
 516     // this is to account for any low order bits being set in num_ports
 517     // if there are none, then num_ports was already a power of 2 so we shift right to reset it
 518     if ((num_ports & ((blk_state->io_range_size >> 1) - 1)) == 0) {
 519         blk_state->io_range_size >>= 1;
 520     }
 521
 522
 523     for (i = 0; i < 6; i++) {
 524         bars[i].type = PCI_BAR_NONE;
 525     }
 526
 527     PrintDebug("Virtio-BLK io_range_size = %d\n", blk_state->io_range_size);
 528
 529     bars[0].type = PCI_BAR_IO;
 530     bars[0].default_base_port = -1;
 531     bars[0].num_ports = blk_state->io_range_size;
 532
 533     bars[0].io_read = virtio_io_read;
 534     bars[0].io_write = virtio_io_write;
 535     bars[0].private_data = blk_state;
 536
 537     pci_dev = v3_pci_register_device(virtio->pci_bus, PCI_STD_DEVICE,
 538                                      0, PCI_AUTO_DEV_NUM, 0,
 539                                      "LNX_VIRTIO_BLK", bars,
 540                                      NULL, NULL, NULL, blk_state);
 541
 542     if (!pci_dev) {
 543         PrintError("Could not register PCI Device\n");
 544         return -1;
 545     }
 546
 547     pci_dev->config_header.vendor_id = VIRTIO_VENDOR_ID;
 548     pci_dev->config_header.subsystem_vendor_id = VIRTIO_SUBVENDOR_ID;
 549
 550
 551     pci_dev->config_header.device_id = VIRTIO_BLOCK_DEV_ID;
 552     pci_dev->config_header.class = PCI_CLASS_STORAGE;
 553     pci_dev->config_header.subclass = PCI_STORAGE_SUBCLASS_OTHER;
 554
 555     pci_dev->config_header.subsystem_id = VIRTIO_BLOCK_SUBDEVICE_ID;
 556
 557
 558     pci_dev->config_header.intr_pin = 1;
 559
 560     pci_dev->config_header.max_latency = 1; // ?? (qemu does it...)
 561
 562
 563     blk_state->pci_dev = pci_dev;
 564
 565     /* Block configuration */
 566     blk_state->virtio_cfg.host_features = VIRTIO_SEG_MAX;
 567     blk_state->block_cfg.max_seg = QUEUE_SIZE - 2;
 568
 569     // Virtio Block only uses one queue
 570     blk_state->queue.queue_size = QUEUE_SIZE;
 571
 572     blk_state->virtio_dev = virtio;
 573
 574     blk_reset(blk_state);
 575
 576
 577     return 0;
 578 }
 579
 580
 581 static int connect_fn(struct v3_vm_info * vm,
 582                       void * frontend_data,
 583                       struct v3_dev_blk_ops * ops,
 584                       v3_cfg_tree_t * cfg,
 585                       void * private_data) {
 586
 587     struct virtio_dev_state * virtio = (struct virtio_dev_state *)frontend_data;
 588
 589     struct virtio_blk_state * blk_state  = (struct virtio_blk_state *)V3_Malloc(sizeof(struct virtio_blk_state));
 590     memset(blk_state, 0, sizeof(struct virtio_blk_state));
 591
 592     register_dev(virtio, blk_state);
 593
 594     blk_state->ops = ops;
 595     blk_state->backend_data = private_data;
 596
 597     blk_state->block_cfg.capacity = ops->get_capacity(private_data) / SECTOR_SIZE;
 598
 599     PrintDebug("Virtio Capacity = %d -- 0x%p\n", (int)(blk_state->block_cfg.capacity),
 600                (void *)(addr_t)(blk_state->block_cfg.capacity));
 601
 602     return 0;
 603 }
 604
 605
 606 static int virtio_init(struct v3_vm_info * vm, v3_cfg_tree_t * cfg) {
 607     struct vm_device * pci_bus = v3_find_dev(vm, v3_cfg_val(cfg, "bus"));
 608     struct virtio_dev_state * virtio_state = NULL;
 609     char * dev_id = v3_cfg_val(cfg, "ID");
 610
 611     PrintDebug("Initializing VIRTIO Block device\n");
 612
 613     if (pci_bus == NULL) {
 614         PrintError("VirtIO devices require a PCI Bus");
 615         return -1;
 616     }
 617
 618
 619     virtio_state  = (struct virtio_dev_state *)V3_Malloc(sizeof(struct virtio_dev_state));
 620     memset(virtio_state, 0, sizeof(struct virtio_dev_state));
 621
 622     INIT_LIST_HEAD(&(virtio_state->dev_list));
 623     virtio_state->pci_bus = pci_bus;
 624
 625
 626     struct vm_device * dev = v3_allocate_device(dev_id, &dev_ops, virtio_state);
 627     if (v3_attach_device(vm, dev) == -1) {
 628         PrintError("Could not attach device %s\n", dev_id);
 629         return -1;
 630     }
 631
 632     if (v3_dev_add_blk_frontend(vm, dev_id, connect_fn, (void *)virtio_state) == -1) {
 633         PrintError("Could not register %s as block frontend\n", dev_id);
 634         return -1;
 635     }
 636
 637     return 0;
 638 }
 639
 640
 641 device_register("LNX_VIRTIO_BLK", virtio_init)