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