OvmfPkg/VirtioBlkDxe/VirtioBlk.c

   1 /** @file
   2
   3   This driver produces Block I/O Protocol instances for virtio-blk devices.
   4
   5   The implementation is basic:
   6
   7   - No attach/detach (ie. removable media).
   8
   9   - Although the non-blocking interfaces of EFI_BLOCK_IO2_PROTOCOL could be a
  10     good match for multiple in-flight virtio-blk requests, we stick to
  11     synchronous requests and EFI_BLOCK_IO_PROTOCOL for now.
  12
  13   Copyright (C) 2012, Red Hat, Inc.
  14   Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
  15
  16   This program and the accompanying materials are licensed and made available
  17   under the terms and conditions of the BSD License which accompanies this
  18   distribution. The full text of the license may be found at
  19   http://opensource.org/licenses/bsd-license.php
  20
  21   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  22   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  23
  24 **/
  25
  26 #include <IndustryStandard/VirtioBlk.h>
  27 #include <Library/BaseMemoryLib.h>
  28 #include <Library/DebugLib.h>
  29 #include <Library/MemoryAllocationLib.h>
  30 #include <Library/UefiBootServicesTableLib.h>
  31 #include <Library/UefiLib.h>
  32 #include <Library/VirtioLib.h>
  33
  34 #include "VirtioBlk.h"
  35
  36 /**
  37
  38   Convenience macros to read and write region 0 IO space elements of the
  39   virtio-blk device, for configuration purposes.
  40
  41   The following macros make it possible to specify only the "core parameters"
  42   for such accesses and to derive the rest. By the time VIRTIO_CFG_WRITE()
  43   returns, the transaction will have been completed.
  44
  45   @param[in] Dev       Pointer to the VBLK_DEV structure whose VirtIo space
  46                        we're accessing. Dev->VirtIo must be valid.
  47
  48   @param[in] Field     A field name from VBLK_HDR, identifying the virtio-blk
  49                        configuration item to access.
  50
  51   @param[in] Value     (VIRTIO_CFG_WRITE() only.) The value to write to the
  52                        selected configuration item.
  53
  54   @param[out] Pointer  (VIRTIO_CFG_READ() only.) The object to receive the
  55                        value read from the configuration item. Its type must be
  56                        one of UINT8, UINT16, UINT32, UINT64.
  57
  58
  59   @return  Status code returned by Virtio->WriteDevice() /
  60            Virtio->ReadDevice().
  61
  62 **/
  63
  64 #define VIRTIO_CFG_WRITE(Dev, Field, Value)  ((Dev)->VirtIo->WriteDevice ( \
  65                                                 (Dev)->VirtIo,             \
  66                                                 OFFSET_OF_VBLK (Field),    \
  67                                                 SIZE_OF_VBLK (Field),      \
  68                                                 (Value)                    \
  69                                                 ))
  70
  71 #define VIRTIO_CFG_READ(Dev, Field, Pointer) ((Dev)->VirtIo->ReadDevice (  \
  72                                                 (Dev)->VirtIo,             \
  73                                                 OFFSET_OF_VBLK (Field),    \
  74                                                 SIZE_OF_VBLK (Field),      \
  75                                                 sizeof *(Pointer),         \
  76                                                 (Pointer)                  \
  77                                                 ))
  78
  79
  80 //
  81 // UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol
  82 // Driver Writer's Guide for UEFI 2.3.1 v1.01,
  83 //   24.2 Block I/O Protocol Implementations
  84 //
  85 EFI_STATUS
  86 EFIAPI
  87 VirtioBlkReset (
  88   IN EFI_BLOCK_IO_PROTOCOL *This,
  89   IN BOOLEAN               ExtendedVerification
  90   )
  91 {
  92   //
  93   // If we managed to initialize and install the driver, then the device is
  94   // working correctly.
  95   //
  96   return EFI_SUCCESS;
  97 }
  98
  99 /**
 100
 101   Verify correctness of the read/write (not flush) request submitted to the
 102   EFI_BLOCK_IO_PROTOCOL instance.
 103
 104   This function provides most verification steps described in:
 105
 106     UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
 107     Protocol,
 108     - EFI_BLOCK_IO_PROTOCOL.ReadBlocks()
 109     - EFI_BLOCK_IO_PROTOCOL.WriteBlocks()
 110
 111     Driver Writer's Guide for UEFI 2.3.1 v1.01,
 112     - 24.2.2. ReadBlocks() and ReadBlocksEx() Implementation
 113     - 24.2.3 WriteBlocks() and WriteBlockEx() Implementation
 114
 115   Request sizes are limited to 1 GB (checked). This is not a practical
 116   limitation, just conformance to virtio-0.9.5, 2.3.2 Descriptor Table: "no
 117   descriptor chain may be more than 2^32 bytes long in total".
 118
 119   Some Media characteristics are hardcoded in VirtioBlkInit() below (like
 120   non-removable media, no restriction on buffer alignment etc); we rely on
 121   those here without explicit mention.
 122
 123   @param[in] Media               The EFI_BLOCK_IO_MEDIA characteristics for
 124                                  this driver instance, extracted from the
 125                                  underlying virtio-blk device at initialization
 126                                  time. We validate the request against this set
 127                                  of attributes.
 128
 129
 130   @param[in] Lba                 Logical Block Address: number of logical
 131                                  blocks to skip from the beginning of the
 132                                  device.
 133
 134   @param[in] PositiveBufferSize  Size of buffer to transfer, in bytes. The
 135                                  caller is responsible to ensure this parameter
 136                                  is positive.
 137
 138   @param[in] RequestIsWrite      TRUE iff data transfer goes from guest to
 139                                  device.
 140
 141
 142   @@return                       Validation result to be forwarded outwards by
 143                                  ReadBlocks() and WriteBlocks, as required by
 144                                  the specs above.
 145
 146 **/
 147 STATIC
 148 EFI_STATUS
 149 EFIAPI
 150 VerifyReadWriteRequest (
 151   IN  EFI_BLOCK_IO_MEDIA *Media,
 152   IN  EFI_LBA            Lba,
 153   IN  UINTN              PositiveBufferSize,
 154   IN  BOOLEAN            RequestIsWrite
 155   )
 156 {
 157   UINTN BlockCount;
 158
 159   ASSERT (PositiveBufferSize > 0);
 160
 161   if (PositiveBufferSize > SIZE_1GB ||
 162       PositiveBufferSize % Media->BlockSize > 0) {
 163     return EFI_BAD_BUFFER_SIZE;
 164   }
 165   BlockCount = PositiveBufferSize / Media->BlockSize;
 166
 167   //
 168   // Avoid unsigned wraparound on either side in the second comparison.
 169   //
 170   if (Lba > Media->LastBlock || BlockCount - 1 > Media->LastBlock - Lba) {
 171     return EFI_INVALID_PARAMETER;
 172   }
 173
 174   if (RequestIsWrite && Media->ReadOnly) {
 175     return EFI_WRITE_PROTECTED;
 176   }
 177
 178   return EFI_SUCCESS;
 179 }
 180
 181
 182
 183
 184 /**
 185
 186   Format a read / write / flush request as three consecutive virtio
 187   descriptors, push them to the host, and poll for the response.
 188
 189   This is the main workhorse function. Two use cases are supported, read/write
 190   and flush. The function may only be called after the request parameters have
 191   been verified by
 192   - specific checks in ReadBlocks() / WriteBlocks() / FlushBlocks(), and
 193   - VerifyReadWriteRequest() (for read/write only).
 194
 195   Parameters handled commonly:
 196
 197     @param[in] Dev             The virtio-blk device the request is targeted
 198                                at.
 199
 200   Flush request:
 201
 202     @param[in] Lba             Must be zero.
 203
 204     @param[in] BufferSize      Must be zero.
 205
 206     @param[in out] Buffer      Ignored by the function.
 207
 208     @param[in] RequestIsWrite  Must be TRUE.
 209
 210   Read/Write request:
 211
 212     @param[in] Lba             Logical Block Address: number of logical blocks
 213                                to skip from the beginning of the device.
 214
 215     @param[in] BufferSize      Size of buffer to transfer, in bytes. The caller
 216                                is responsible to ensure this parameter is
 217                                positive.
 218
 219     @param[in out] Buffer      The guest side area to read data from the device
 220                                into, or write data to the device from.
 221
 222     @param[in] RequestIsWrite  TRUE iff data transfer goes from guest to
 223                                device.
 224
 225   Return values are common to both use cases, and are appropriate to be
 226   forwarded by the EFI_BLOCK_IO_PROTOCOL functions (ReadBlocks(),
 227   WriteBlocks(), FlushBlocks()).
 228
 229
 230   @retval EFI_SUCCESS          Transfer complete.
 231
 232   @retval EFI_DEVICE_ERROR     Failed to notify host side via VirtIo write, or
 233                                unable to parse host response, or host response
 234                                is not VIRTIO_BLK_S_OK.
 235
 236 **/
 237
 238 STATIC
 239 EFI_STATUS
 240 EFIAPI
 241 SynchronousRequest (
 242   IN              VBLK_DEV *Dev,
 243   IN              EFI_LBA  Lba,
 244   IN              UINTN    BufferSize,
 245   IN OUT volatile VOID     *Buffer,
 246   IN              BOOLEAN  RequestIsWrite
 247   )
 248 {
 249   UINT32                  BlockSize;
 250   volatile VIRTIO_BLK_REQ Request;
 251   volatile UINT8          HostStatus;
 252   DESC_INDICES            Indices;
 253
 254   BlockSize = Dev->BlockIoMedia.BlockSize;
 255
 256   //
 257   // ensured by VirtioBlkInit()
 258   //
 259   ASSERT (BlockSize > 0);
 260   ASSERT (BlockSize % 512 == 0);
 261
 262   //
 263   // ensured by contract above, plus VerifyReadWriteRequest()
 264   //
 265   ASSERT (BufferSize % BlockSize == 0);
 266
 267   //
 268   // Prepare virtio-blk request header, setting zero size for flush.
 269   // IO Priority is homogeneously 0.
 270   //
 271   Request.Type   = RequestIsWrite ?
 272                    (BufferSize == 0 ? VIRTIO_BLK_T_FLUSH : VIRTIO_BLK_T_OUT) :
 273                    VIRTIO_BLK_T_IN;
 274   Request.IoPrio = 0;
 275   Request.Sector = MultU64x32(Lba, BlockSize / 512);
 276
 277   VirtioPrepare (&Dev->Ring, &Indices);
 278
 279   //
 280   // preset a host status for ourselves that we do not accept as success
 281   //
 282   HostStatus = VIRTIO_BLK_S_IOERR;
 283
 284   //
 285   // ensured by VirtioBlkInit() -- this predicate, in combination with the
 286   // lock-step progress, ensures we don't have to track free descriptors.
 287   //
 288   ASSERT (Dev->Ring.QueueSize >= 3);
 289
 290   //
 291   // virtio-blk header in first desc
 292   //
 293   VirtioAppendDesc (&Dev->Ring, (UINTN) &Request, sizeof Request,
 294     VRING_DESC_F_NEXT, &Indices);
 295
 296   //
 297   // data buffer for read/write in second desc
 298   //
 299   if (BufferSize > 0) {
 300     //
 301     // From virtio-0.9.5, 2.3.2 Descriptor Table:
 302     // "no descriptor chain may be more than 2^32 bytes long in total".
 303     //
 304     // The predicate is ensured by the call contract above (for flush), or
 305     // VerifyReadWriteRequest() (for read/write). It also implies that
 306     // converting BufferSize to UINT32 will not truncate it.
 307     //
 308     ASSERT (BufferSize <= SIZE_1GB);
 309
 310     //
 311     // VRING_DESC_F_WRITE is interpreted from the host's point of view.
 312     //
 313     VirtioAppendDesc (&Dev->Ring, (UINTN) Buffer, (UINT32) BufferSize,
 314       VRING_DESC_F_NEXT | (RequestIsWrite ? 0 : VRING_DESC_F_WRITE),
 315       &Indices);
 316   }
 317
 318   //
 319   // host status in last (second or third) desc
 320   //
 321   VirtioAppendDesc (&Dev->Ring, (UINTN) &HostStatus, sizeof HostStatus,
 322     VRING_DESC_F_WRITE, &Indices);
 323
 324   //
 325   // virtio-blk's only virtqueue is #0, called "requestq" (see Appendix D).
 326   //
 327   if (VirtioFlush (Dev->VirtIo, 0, &Dev->Ring, &Indices) == EFI_SUCCESS &&
 328       HostStatus == VIRTIO_BLK_S_OK) {
 329     return EFI_SUCCESS;
 330   }
 331
 332   return EFI_DEVICE_ERROR;
 333 }
 334
 335
 336 /**
 337
 338   ReadBlocks() operation for virtio-blk.
 339
 340   See
 341   - UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
 342     Protocol, EFI_BLOCK_IO_PROTOCOL.ReadBlocks().
 343   - Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.2. ReadBlocks() and
 344     ReadBlocksEx() Implementation.
 345
 346   Parameter checks and conformant return values are implemented in
 347   VerifyReadWriteRequest() and SynchronousRequest().
 348
 349   A zero BufferSize doesn't seem to be prohibited, so do nothing in that case,
 350   successfully.
 351
 352 **/
 353
 354 EFI_STATUS
 355 EFIAPI
 356 VirtioBlkReadBlocks (
 357   IN  EFI_BLOCK_IO_PROTOCOL *This,
 358   IN  UINT32                MediaId,
 359   IN  EFI_LBA               Lba,
 360   IN  UINTN                 BufferSize,
 361   OUT VOID                  *Buffer
 362   )
 363 {
 364   VBLK_DEV   *Dev;
 365   EFI_STATUS Status;
 366
 367   if (BufferSize == 0) {
 368     return EFI_SUCCESS;
 369   }
 370
 371   Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
 372   Status = VerifyReadWriteRequest (
 373              &Dev->BlockIoMedia,
 374              Lba,
 375              BufferSize,
 376              FALSE               // RequestIsWrite
 377              );
 378   if (EFI_ERROR (Status)) {
 379     return Status;
 380   }
 381
 382   return SynchronousRequest (
 383            Dev,
 384            Lba,
 385            BufferSize,
 386            Buffer,
 387            FALSE       // RequestIsWrite
 388            );
 389 }
 390
 391 /**
 392
 393   WriteBlocks() operation for virtio-blk.
 394
 395   See
 396   - UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
 397     Protocol, EFI_BLOCK_IO_PROTOCOL.WriteBlocks().
 398   - Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.3 WriteBlocks() and
 399     WriteBlockEx() Implementation.
 400
 401   Parameter checks and conformant return values are implemented in
 402   VerifyReadWriteRequest() and SynchronousRequest().
 403
 404   A zero BufferSize doesn't seem to be prohibited, so do nothing in that case,
 405   successfully.
 406
 407 **/
 408
 409 EFI_STATUS
 410 EFIAPI
 411 VirtioBlkWriteBlocks (
 412   IN EFI_BLOCK_IO_PROTOCOL *This,
 413   IN UINT32                MediaId,
 414   IN EFI_LBA               Lba,
 415   IN UINTN                 BufferSize,
 416   IN VOID                  *Buffer
 417   )
 418 {
 419   VBLK_DEV   *Dev;
 420   EFI_STATUS Status;
 421
 422   if (BufferSize == 0) {
 423     return EFI_SUCCESS;
 424   }
 425
 426   Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
 427   Status = VerifyReadWriteRequest (
 428              &Dev->BlockIoMedia,
 429              Lba,
 430              BufferSize,
 431              TRUE                // RequestIsWrite
 432              );
 433   if (EFI_ERROR (Status)) {
 434     return Status;
 435   }
 436
 437   return SynchronousRequest (
 438            Dev,
 439            Lba,
 440            BufferSize,
 441            Buffer,
 442            TRUE        // RequestIsWrite
 443            );
 444 }
 445
 446
 447 /**
 448
 449   FlushBlocks() operation for virtio-blk.
 450
 451   See
 452   - UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
 453     Protocol, EFI_BLOCK_IO_PROTOCOL.FlushBlocks().
 454   - Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.4 FlushBlocks() and
 455     FlushBlocksEx() Implementation.
 456
 457   If the underlying virtio-blk device doesn't support flushing (ie.
 458   write-caching), then this function should not be called by higher layers,
 459   according to EFI_BLOCK_IO_MEDIA characteristics set in VirtioBlkInit().
 460   Should they do nonetheless, we do nothing, successfully.
 461
 462 **/
 463
 464 EFI_STATUS
 465 EFIAPI
 466 VirtioBlkFlushBlocks (
 467   IN EFI_BLOCK_IO_PROTOCOL *This
 468   )
 469 {
 470   VBLK_DEV *Dev;
 471
 472   Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
 473   return Dev->BlockIoMedia.WriteCaching ?
 474            SynchronousRequest (
 475              Dev,
 476              0,    // Lba
 477              0,    // BufferSize
 478              NULL, // Buffer
 479              TRUE  // RequestIsWrite
 480              ) :
 481            EFI_SUCCESS;
 482 }
 483
 484
 485 /**
 486
 487   Device probe function for this driver.
 488
 489   The DXE core calls this function for any given device in order to see if the
 490   driver can drive the device.
 491
 492   Specs relevant in the general sense:
 493
 494   - UEFI Spec 2.3.1 + Errata C:
 495     - 6.3 Protocol Handler Services -- for accessing the underlying device
 496     - 10.1 EFI Driver Binding Protocol -- for exporting ourselves
 497
 498   - Driver Writer's Guide for UEFI 2.3.1 v1.01:
 499     - 5.1.3.4 OpenProtocol() and CloseProtocol() -- for accessing the
 500       underlying device
 501     - 9 Driver Binding Protocol -- for exporting ourselves
 502
 503   @param[in]  This                The EFI_DRIVER_BINDING_PROTOCOL object
 504                                   incorporating this driver (independently of
 505                                   any device).
 506
 507   @param[in] DeviceHandle         The device to probe.
 508
 509   @param[in] RemainingDevicePath  Relevant only for bus drivers, ignored.
 510
 511
 512   @retval EFI_SUCCESS      The driver supports the device being probed.
 513
 514   @retval EFI_UNSUPPORTED  Based on virtio-blk discovery, we do not support
 515                            the device.
 516
 517   @return                  Error codes from the OpenProtocol() boot service or
 518                            the VirtIo protocol.
 519
 520 **/
 521
 522 EFI_STATUS
 523 EFIAPI
 524 VirtioBlkDriverBindingSupported (
 525   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 526   IN EFI_HANDLE                  DeviceHandle,
 527   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
 528   )
 529 {
 530   EFI_STATUS          Status;
 531   VIRTIO_DEVICE_PROTOCOL *VirtIo;
 532
 533   //
 534   // Attempt to open the device with the VirtIo set of interfaces. On success,
 535   // the protocol is "instantiated" for the VirtIo device. Covers duplicate
 536   // open attempts (EFI_ALREADY_STARTED).
 537   //
 538   Status = gBS->OpenProtocol (
 539                   DeviceHandle,               // candidate device
 540                   &gVirtioDeviceProtocolGuid, // for generic VirtIo access
 541                   (VOID **)&VirtIo,           // handle to instantiate
 542                   This->DriverBindingHandle,  // requestor driver identity
 543                   DeviceHandle,               // ControllerHandle, according to
 544                                               // the UEFI Driver Model
 545                   EFI_OPEN_PROTOCOL_BY_DRIVER // get exclusive VirtIo access to
 546                                               // the device; to be released
 547                   );
 548   if (EFI_ERROR (Status)) {
 549     return Status;
 550   }
 551
 552   if (VirtIo->SubSystemDeviceId != VIRTIO_SUBSYSTEM_BLOCK_DEVICE) {
 553     Status = EFI_UNSUPPORTED;
 554   }
 555
 556   //
 557   // We needed VirtIo access only transitorily, to see whether we support the
 558   // device or not.
 559   //
 560   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
 561          This->DriverBindingHandle, DeviceHandle);
 562   return Status;
 563 }
 564
 565
 566 /**
 567
 568   Set up all BlockIo and virtio-blk aspects of this driver for the specified
 569   device.
 570
 571   @param[in out] Dev  The driver instance to configure. The caller is
 572                       responsible for Dev->VirtIo's validity (ie. working IO
 573                       access to the underlying virtio-blk device).
 574
 575   @retval EFI_SUCCESS      Setup complete.
 576
 577   @retval EFI_UNSUPPORTED  The driver is unable to work with the virtio ring or
 578                            virtio-blk attributes the host provides.
 579
 580   @return                  Error codes from VirtioRingInit() or
 581                            VIRTIO_CFG_READ() / VIRTIO_CFG_WRITE().
 582
 583 **/
 584
 585 STATIC
 586 EFI_STATUS
 587 EFIAPI
 588 VirtioBlkInit (
 589   IN OUT VBLK_DEV *Dev
 590   )
 591 {
 592   UINT8      NextDevStat;
 593   EFI_STATUS Status;
 594
 595   UINT32     Features;
 596   UINT64     NumSectors;
 597   UINT32     BlockSize;
 598   UINT8      PhysicalBlockExp;
 599   UINT8      AlignmentOffset;
 600   UINT32     OptIoSize;
 601   UINT16     QueueSize;
 602
 603   PhysicalBlockExp = 0;
 604   AlignmentOffset = 0;
 605   OptIoSize = 0;
 606
 607   //
 608   // Execute virtio-0.9.5, 2.2.1 Device Initialization Sequence.
 609   //
 610   NextDevStat = 0;             // step 1 -- reset device
 611   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 612   if (EFI_ERROR (Status)) {
 613     goto Failed;
 614   }
 615
 616   NextDevStat |= VSTAT_ACK;    // step 2 -- acknowledge device presence
 617   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 618   if (EFI_ERROR (Status)) {
 619     goto Failed;
 620   }
 621
 622   NextDevStat |= VSTAT_DRIVER; // step 3 -- we know how to drive it
 623   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 624   if (EFI_ERROR (Status)) {
 625     goto Failed;
 626   }
 627
 628   //
 629   // Set Page Size - MMIO VirtIo Specific
 630   //
 631   Status = Dev->VirtIo->SetPageSize (Dev->VirtIo, EFI_PAGE_SIZE);
 632   if (EFI_ERROR (Status)) {
 633     goto Failed;
 634   }
 635
 636   //
 637   // step 4a -- retrieve and validate features
 638   //
 639   Status = Dev->VirtIo->GetDeviceFeatures (Dev->VirtIo, &Features);
 640   if (EFI_ERROR (Status)) {
 641     goto Failed;
 642   }
 643
 644   Status = VIRTIO_CFG_READ (Dev, Capacity, &NumSectors);
 645   if (EFI_ERROR (Status)) {
 646     goto Failed;
 647   }
 648   if (NumSectors == 0) {
 649     Status = EFI_UNSUPPORTED;
 650     goto Failed;
 651   }
 652
 653   if (Features & VIRTIO_BLK_F_BLK_SIZE) {
 654     Status = VIRTIO_CFG_READ (Dev, BlkSize, &BlockSize);
 655     if (EFI_ERROR (Status)) {
 656       goto Failed;
 657     }
 658     if (BlockSize == 0 || BlockSize % 512 != 0 ||
 659         ModU64x32 (NumSectors, BlockSize / 512) != 0) {
 660       //
 661       // We can only handle a logical block consisting of whole sectors,
 662       // and only a disk composed of whole logical blocks.
 663       //
 664       Status = EFI_UNSUPPORTED;
 665       goto Failed;
 666     }
 667   }
 668   else {
 669     BlockSize = 512;
 670   }
 671
 672   if (Features & VIRTIO_BLK_F_TOPOLOGY) {
 673     Status = VIRTIO_CFG_READ (Dev, Topology.PhysicalBlockExp,
 674                &PhysicalBlockExp);
 675     if (EFI_ERROR (Status)) {
 676       goto Failed;
 677     }
 678     if (PhysicalBlockExp >= 32) {
 679       Status = EFI_UNSUPPORTED;
 680       goto Failed;
 681     }
 682
 683     Status = VIRTIO_CFG_READ (Dev, Topology.AlignmentOffset, &AlignmentOffset);
 684     if (EFI_ERROR (Status)) {
 685       goto Failed;
 686     }
 687
 688     Status = VIRTIO_CFG_READ (Dev, Topology.OptIoSize, &OptIoSize);
 689     if (EFI_ERROR (Status)) {
 690       goto Failed;
 691     }
 692   }
 693
 694   //
 695   // step 4b -- allocate virtqueue
 696   //
 697   Status = Dev->VirtIo->SetQueueSel (Dev->VirtIo, 0);
 698   if (EFI_ERROR (Status)) {
 699     goto Failed;
 700   }
 701   Status = Dev->VirtIo->GetQueueNumMax (Dev->VirtIo, &QueueSize);
 702   if (EFI_ERROR (Status)) {
 703     goto Failed;
 704   }
 705   if (QueueSize < 3) { // SynchronousRequest() uses at most three descriptors
 706     Status = EFI_UNSUPPORTED;
 707     goto Failed;
 708   }
 709
 710   Status = VirtioRingInit (QueueSize, &Dev->Ring);
 711   if (EFI_ERROR (Status)) {
 712     goto Failed;
 713   }
 714
 715   //
 716   // Additional steps for MMIO: align the queue appropriately, and set the
 717   // size. If anything fails from here on, we must release the ring resources.
 718   //
 719   Status = Dev->VirtIo->SetQueueNum (Dev->VirtIo, QueueSize);
 720   if (EFI_ERROR (Status)) {
 721     goto ReleaseQueue;
 722   }
 723
 724   Status = Dev->VirtIo->SetQueueAlign (Dev->VirtIo, EFI_PAGE_SIZE);
 725   if (EFI_ERROR (Status)) {
 726     goto ReleaseQueue;
 727   }
 728
 729   //
 730   // step 4c -- Report GPFN (guest-physical frame number) of queue.
 731   //
 732   Status = Dev->VirtIo->SetQueueAddress (Dev->VirtIo,
 733       (UINT32) ((UINTN) Dev->Ring.Base >> EFI_PAGE_SHIFT));
 734   if (EFI_ERROR (Status)) {
 735     goto ReleaseQueue;
 736   }
 737
 738
 739   //
 740   // step 5 -- Report understood features. There are no virtio-blk specific
 741   // features to negotiate in virtio-0.9.5, plus we do not want any of the
 742   // device-independent (known or unknown) VIRTIO_F_* capabilities (see
 743   // Appendix B).
 744   //
 745   Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo, 0);
 746   if (EFI_ERROR (Status)) {
 747     goto ReleaseQueue;
 748   }
 749
 750   //
 751   // step 6 -- initialization complete
 752   //
 753   NextDevStat |= VSTAT_DRIVER_OK;
 754   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 755   if (EFI_ERROR (Status)) {
 756     goto ReleaseQueue;
 757   }
 758
 759   //
 760   // Populate the exported interface's attributes; see UEFI spec v2.4, 12.9 EFI
 761   // Block I/O Protocol.
 762   //
 763   Dev->BlockIo.Revision              = 0;
 764   Dev->BlockIo.Media                 = &Dev->BlockIoMedia;
 765   Dev->BlockIo.Reset                 = &VirtioBlkReset;
 766   Dev->BlockIo.ReadBlocks            = &VirtioBlkReadBlocks;
 767   Dev->BlockIo.WriteBlocks           = &VirtioBlkWriteBlocks;
 768   Dev->BlockIo.FlushBlocks           = &VirtioBlkFlushBlocks;
 769   Dev->BlockIoMedia.MediaId          = 0;
 770   Dev->BlockIoMedia.RemovableMedia   = FALSE;
 771   Dev->BlockIoMedia.MediaPresent     = TRUE;
 772   Dev->BlockIoMedia.LogicalPartition = FALSE;
 773   Dev->BlockIoMedia.ReadOnly         = !!(Features & VIRTIO_BLK_F_RO);
 774   Dev->BlockIoMedia.WriteCaching     = !!(Features & VIRTIO_BLK_F_FLUSH);
 775   Dev->BlockIoMedia.BlockSize        = BlockSize;
 776   Dev->BlockIoMedia.IoAlign          = 0;
 777   Dev->BlockIoMedia.LastBlock        = DivU64x32 (NumSectors,
 778                                          BlockSize / 512) - 1;
 779
 780   if (Features & VIRTIO_BLK_F_TOPOLOGY) {
 781     Dev->BlockIo.Revision = EFI_BLOCK_IO_PROTOCOL_REVISION3;
 782
 783     Dev->BlockIoMedia.LowestAlignedLba = AlignmentOffset;
 784     Dev->BlockIoMedia.LogicalBlocksPerPhysicalBlock = 1u << PhysicalBlockExp;
 785     Dev->BlockIoMedia.OptimalTransferLengthGranularity = OptIoSize;
 786   }
 787   return EFI_SUCCESS;
 788
 789 ReleaseQueue:
 790   VirtioRingUninit (&Dev->Ring);
 791
 792 Failed:
 793   //
 794   // Notify the host about our failure to setup: virtio-0.9.5, 2.2.2.1 Device
 795   // Status. VirtIo access failure here should not mask the original error.
 796   //
 797   NextDevStat |= VSTAT_FAILED;
 798   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 799
 800   return Status; // reached only via Failed above
 801 }
 802
 803
 804 /**
 805
 806   Uninitialize the internals of a virtio-blk device that has been successfully
 807   set up with VirtioBlkInit().
 808
 809   @param[in out]  Dev  The device to clean up.
 810
 811 **/
 812
 813 STATIC
 814 VOID
 815 EFIAPI
 816 VirtioBlkUninit (
 817   IN OUT VBLK_DEV *Dev
 818   )
 819 {
 820   //
 821   // Reset the virtual device -- see virtio-0.9.5, 2.2.2.1 Device Status. When
 822   // VIRTIO_CFG_WRITE() returns, the host will have learned to stay away from
 823   // the old comms area.
 824   //
 825   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
 826
 827   VirtioRingUninit (&Dev->Ring);
 828
 829   SetMem (&Dev->BlockIo,      sizeof Dev->BlockIo,      0x00);
 830   SetMem (&Dev->BlockIoMedia, sizeof Dev->BlockIoMedia, 0x00);
 831 }
 832
 833
 834 /**
 835
 836   After we've pronounced support for a specific device in
 837   DriverBindingSupported(), we start managing said device (passed in by the
 838   Driver Exeuction Environment) with the following service.
 839
 840   See DriverBindingSupported() for specification references.
 841
 842   @param[in]  This                The EFI_DRIVER_BINDING_PROTOCOL object
 843                                   incorporating this driver (independently of
 844                                   any device).
 845
 846   @param[in] DeviceHandle         The supported device to drive.
 847
 848   @param[in] RemainingDevicePath  Relevant only for bus drivers, ignored.
 849
 850
 851   @retval EFI_SUCCESS           Driver instance has been created and
 852                                 initialized  for the virtio-blk device, it
 853                                 is now accessibla via EFI_BLOCK_IO_PROTOCOL.
 854
 855   @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
 856
 857   @return                       Error codes from the OpenProtocol() boot
 858                                 service, the VirtIo protocol, VirtioBlkInit(),
 859                                 or the InstallProtocolInterface() boot service.
 860
 861 **/
 862
 863 EFI_STATUS
 864 EFIAPI
 865 VirtioBlkDriverBindingStart (
 866   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 867   IN EFI_HANDLE                  DeviceHandle,
 868   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
 869   )
 870 {
 871   VBLK_DEV   *Dev;
 872   EFI_STATUS Status;
 873
 874   Dev = (VBLK_DEV *) AllocateZeroPool (sizeof *Dev);
 875   if (Dev == NULL) {
 876     return EFI_OUT_OF_RESOURCES;
 877   }
 878
 879   Status = gBS->OpenProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
 880                   (VOID **)&Dev->VirtIo, This->DriverBindingHandle,
 881                   DeviceHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);
 882   if (EFI_ERROR (Status)) {
 883     goto FreeVirtioBlk;
 884   }
 885
 886   //
 887   // VirtIo access granted, configure virtio-blk device.
 888   //
 889   Status = VirtioBlkInit (Dev);
 890   if (EFI_ERROR (Status)) {
 891     goto CloseVirtIo;
 892   }
 893
 894   //
 895   // Setup complete, attempt to export the driver instance's BlockIo interface.
 896   //
 897   Dev->Signature = VBLK_SIG;
 898   Status = gBS->InstallProtocolInterface (&DeviceHandle,
 899                   &gEfiBlockIoProtocolGuid, EFI_NATIVE_INTERFACE,
 900                   &Dev->BlockIo);
 901   if (EFI_ERROR (Status)) {
 902     goto UninitDev;
 903   }
 904
 905   return EFI_SUCCESS;
 906
 907 UninitDev:
 908   VirtioBlkUninit (Dev);
 909
 910 CloseVirtIo:
 911   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
 912          This->DriverBindingHandle, DeviceHandle);
 913
 914 FreeVirtioBlk:
 915   FreePool (Dev);
 916
 917   return Status;
 918 }
 919
 920
 921 /**
 922
 923   Stop driving a virtio-blk device and remove its BlockIo interface.
 924
 925   This function replays the success path of DriverBindingStart() in reverse.
 926   The host side virtio-blk device is reset, so that the OS boot loader or the
 927   OS may reinitialize it.
 928
 929   @param[in] This               The EFI_DRIVER_BINDING_PROTOCOL object
 930                                 incorporating this driver (independently of any
 931                                 device).
 932
 933   @param[in] DeviceHandle       Stop driving this device.
 934
 935   @param[in] NumberOfChildren   Since this function belongs to a device driver
 936                                 only (as opposed to a bus driver), the caller
 937                                 environment sets NumberOfChildren to zero, and
 938                                 we ignore it.
 939
 940   @param[in] ChildHandleBuffer  Ignored (corresponding to NumberOfChildren).
 941
 942 **/
 943
 944 EFI_STATUS
 945 EFIAPI
 946 VirtioBlkDriverBindingStop (
 947   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 948   IN EFI_HANDLE                  DeviceHandle,
 949   IN UINTN                       NumberOfChildren,
 950   IN EFI_HANDLE                  *ChildHandleBuffer
 951   )
 952 {
 953   EFI_STATUS            Status;
 954   EFI_BLOCK_IO_PROTOCOL *BlockIo;
 955   VBLK_DEV              *Dev;
 956
 957   Status = gBS->OpenProtocol (
 958                   DeviceHandle,                  // candidate device
 959                   &gEfiBlockIoProtocolGuid,      // retrieve the BlockIo iface
 960                   (VOID **)&BlockIo,             // target pointer
 961                   This->DriverBindingHandle,     // requestor driver identity
 962                   DeviceHandle,                  // requesting lookup for dev.
 963                   EFI_OPEN_PROTOCOL_GET_PROTOCOL // lookup only, no ref. added
 964                   );
 965   if (EFI_ERROR (Status)) {
 966     return Status;
 967   }
 968
 969   Dev = VIRTIO_BLK_FROM_BLOCK_IO (BlockIo);
 970
 971   //
 972   // Handle Stop() requests for in-use driver instances gracefully.
 973   //
 974   Status = gBS->UninstallProtocolInterface (DeviceHandle,
 975                   &gEfiBlockIoProtocolGuid, &Dev->BlockIo);
 976   if (EFI_ERROR (Status)) {
 977     return Status;
 978   }
 979
 980   VirtioBlkUninit (Dev);
 981
 982   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
 983          This->DriverBindingHandle, DeviceHandle);
 984
 985   FreePool (Dev);
 986
 987   return EFI_SUCCESS;
 988 }
 989
 990
 991 //
 992 // The static object that groups the Supported() (ie. probe), Start() and
 993 // Stop() functions of the driver together. Refer to UEFI Spec 2.3.1 + Errata
 994 // C, 10.1 EFI Driver Binding Protocol.
 995 //
 996 STATIC EFI_DRIVER_BINDING_PROTOCOL gDriverBinding = {
 997   &VirtioBlkDriverBindingSupported,
 998   &VirtioBlkDriverBindingStart,
 999   &VirtioBlkDriverBindingStop,
1000   0x10, // Version, must be in [0x10 .. 0xFFFFFFEF] for IHV-developed drivers
1001   NULL, // ImageHandle, to be overwritten by
1002         // EfiLibInstallDriverBindingComponentName2() in VirtioBlkEntryPoint()
1003   NULL  // DriverBindingHandle, ditto
1004 };
1005
1006
1007 //
1008 // The purpose of the following scaffolding (EFI_COMPONENT_NAME_PROTOCOL and
1009 // EFI_COMPONENT_NAME2_PROTOCOL implementation) is to format the driver's name
1010 // in English, for display on standard console devices. This is recommended for
1011 // UEFI drivers that follow the UEFI Driver Model. Refer to the Driver Writer's
1012 // Guide for UEFI 2.3.1 v1.01, 11 UEFI Driver and Controller Names.
1013 //
1014 // Device type names ("Virtio Block Device") are not formatted because the
1015 // driver supports only that device type. Therefore the driver name suffices
1016 // for unambiguous identification.
1017 //
1018
1019 STATIC
1020 EFI_UNICODE_STRING_TABLE mDriverNameTable[] = {
1021   { "eng;en", L"Virtio Block Driver" },
1022   { NULL,     NULL                   }
1023 };
1024
1025 STATIC
1026 EFI_COMPONENT_NAME_PROTOCOL gComponentName;
1027
1028 EFI_STATUS
1029 EFIAPI
1030 VirtioBlkGetDriverName (
1031   IN  EFI_COMPONENT_NAME_PROTOCOL *This,
1032   IN  CHAR8                       *Language,
1033   OUT CHAR16                      **DriverName
1034   )
1035 {
1036   return LookupUnicodeString2 (
1037            Language,
1038            This->SupportedLanguages,
1039            mDriverNameTable,
1040            DriverName,
1041            (BOOLEAN)(This == &gComponentName) // Iso639Language
1042            );
1043 }
1044
1045 EFI_STATUS
1046 EFIAPI
1047 VirtioBlkGetDeviceName (
1048   IN  EFI_COMPONENT_NAME_PROTOCOL *This,
1049   IN  EFI_HANDLE                  DeviceHandle,
1050   IN  EFI_HANDLE                  ChildHandle,
1051   IN  CHAR8                       *Language,
1052   OUT CHAR16                      **ControllerName
1053   )
1054 {
1055   return EFI_UNSUPPORTED;
1056 }
1057
1058 STATIC
1059 EFI_COMPONENT_NAME_PROTOCOL gComponentName = {
1060   &VirtioBlkGetDriverName,
1061   &VirtioBlkGetDeviceName,
1062   "eng" // SupportedLanguages, ISO 639-2 language codes
1063 };
1064
1065 STATIC
1066 EFI_COMPONENT_NAME2_PROTOCOL gComponentName2 = {
1067   (EFI_COMPONENT_NAME2_GET_DRIVER_NAME)     &VirtioBlkGetDriverName,
1068   (EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME) &VirtioBlkGetDeviceName,
1069   "en" // SupportedLanguages, RFC 4646 language codes
1070 };
1071
1072
1073 //
1074 // Entry point of this driver.
1075 //
1076 EFI_STATUS
1077 EFIAPI
1078 VirtioBlkEntryPoint (
1079   IN EFI_HANDLE       ImageHandle,
1080   IN EFI_SYSTEM_TABLE *SystemTable
1081   )
1082 {
1083   return EfiLibInstallDriverBindingComponentName2 (
1084            ImageHandle,
1085            SystemTable,
1086            &gDriverBinding,
1087            ImageHandle,
1088            &gComponentName,
1089            &gComponentName2
1090            );
1091 }
1092