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 - 2014, 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,
 328         NULL) == EFI_SUCCESS &&
 329       HostStatus == VIRTIO_BLK_S_OK) {
 330     return EFI_SUCCESS;
 331   }
 332
 333   return EFI_DEVICE_ERROR;
 334 }
 335
 336
 337 /**
 338
 339   ReadBlocks() operation for virtio-blk.
 340
 341   See
 342   - UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
 343     Protocol, EFI_BLOCK_IO_PROTOCOL.ReadBlocks().
 344   - Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.2. ReadBlocks() and
 345     ReadBlocksEx() Implementation.
 346
 347   Parameter checks and conformant return values are implemented in
 348   VerifyReadWriteRequest() and SynchronousRequest().
 349
 350   A zero BufferSize doesn't seem to be prohibited, so do nothing in that case,
 351   successfully.
 352
 353 **/
 354
 355 EFI_STATUS
 356 EFIAPI
 357 VirtioBlkReadBlocks (
 358   IN  EFI_BLOCK_IO_PROTOCOL *This,
 359   IN  UINT32                MediaId,
 360   IN  EFI_LBA               Lba,
 361   IN  UINTN                 BufferSize,
 362   OUT VOID                  *Buffer
 363   )
 364 {
 365   VBLK_DEV   *Dev;
 366   EFI_STATUS Status;
 367
 368   if (BufferSize == 0) {
 369     return EFI_SUCCESS;
 370   }
 371
 372   Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
 373   Status = VerifyReadWriteRequest (
 374              &Dev->BlockIoMedia,
 375              Lba,
 376              BufferSize,
 377              FALSE               // RequestIsWrite
 378              );
 379   if (EFI_ERROR (Status)) {
 380     return Status;
 381   }
 382
 383   return SynchronousRequest (
 384            Dev,
 385            Lba,
 386            BufferSize,
 387            Buffer,
 388            FALSE       // RequestIsWrite
 389            );
 390 }
 391
 392 /**
 393
 394   WriteBlocks() operation for virtio-blk.
 395
 396   See
 397   - UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
 398     Protocol, EFI_BLOCK_IO_PROTOCOL.WriteBlocks().
 399   - Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.3 WriteBlocks() and
 400     WriteBlockEx() Implementation.
 401
 402   Parameter checks and conformant return values are implemented in
 403   VerifyReadWriteRequest() and SynchronousRequest().
 404
 405   A zero BufferSize doesn't seem to be prohibited, so do nothing in that case,
 406   successfully.
 407
 408 **/
 409
 410 EFI_STATUS
 411 EFIAPI
 412 VirtioBlkWriteBlocks (
 413   IN EFI_BLOCK_IO_PROTOCOL *This,
 414   IN UINT32                MediaId,
 415   IN EFI_LBA               Lba,
 416   IN UINTN                 BufferSize,
 417   IN VOID                  *Buffer
 418   )
 419 {
 420   VBLK_DEV   *Dev;
 421   EFI_STATUS Status;
 422
 423   if (BufferSize == 0) {
 424     return EFI_SUCCESS;
 425   }
 426
 427   Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
 428   Status = VerifyReadWriteRequest (
 429              &Dev->BlockIoMedia,
 430              Lba,
 431              BufferSize,
 432              TRUE                // RequestIsWrite
 433              );
 434   if (EFI_ERROR (Status)) {
 435     return Status;
 436   }
 437
 438   return SynchronousRequest (
 439            Dev,
 440            Lba,
 441            BufferSize,
 442            Buffer,
 443            TRUE        // RequestIsWrite
 444            );
 445 }
 446
 447
 448 /**
 449
 450   FlushBlocks() operation for virtio-blk.
 451
 452   See
 453   - UEFI Spec 2.3.1 + Errata C, 12.8 EFI Block I/O Protocol, 12.8 EFI Block I/O
 454     Protocol, EFI_BLOCK_IO_PROTOCOL.FlushBlocks().
 455   - Driver Writer's Guide for UEFI 2.3.1 v1.01, 24.2.4 FlushBlocks() and
 456     FlushBlocksEx() Implementation.
 457
 458   If the underlying virtio-blk device doesn't support flushing (ie.
 459   write-caching), then this function should not be called by higher layers,
 460   according to EFI_BLOCK_IO_MEDIA characteristics set in VirtioBlkInit().
 461   Should they do nonetheless, we do nothing, successfully.
 462
 463 **/
 464
 465 EFI_STATUS
 466 EFIAPI
 467 VirtioBlkFlushBlocks (
 468   IN EFI_BLOCK_IO_PROTOCOL *This
 469   )
 470 {
 471   VBLK_DEV *Dev;
 472
 473   Dev = VIRTIO_BLK_FROM_BLOCK_IO (This);
 474   return Dev->BlockIoMedia.WriteCaching ?
 475            SynchronousRequest (
 476              Dev,
 477              0,    // Lba
 478              0,    // BufferSize
 479              NULL, // Buffer
 480              TRUE  // RequestIsWrite
 481              ) :
 482            EFI_SUCCESS;
 483 }
 484
 485
 486 /**
 487
 488   Device probe function for this driver.
 489
 490   The DXE core calls this function for any given device in order to see if the
 491   driver can drive the device.
 492
 493   Specs relevant in the general sense:
 494
 495   - UEFI Spec 2.3.1 + Errata C:
 496     - 6.3 Protocol Handler Services -- for accessing the underlying device
 497     - 10.1 EFI Driver Binding Protocol -- for exporting ourselves
 498
 499   - Driver Writer's Guide for UEFI 2.3.1 v1.01:
 500     - 5.1.3.4 OpenProtocol() and CloseProtocol() -- for accessing the
 501       underlying device
 502     - 9 Driver Binding Protocol -- for exporting ourselves
 503
 504   @param[in]  This                The EFI_DRIVER_BINDING_PROTOCOL object
 505                                   incorporating this driver (independently of
 506                                   any device).
 507
 508   @param[in] DeviceHandle         The device to probe.
 509
 510   @param[in] RemainingDevicePath  Relevant only for bus drivers, ignored.
 511
 512
 513   @retval EFI_SUCCESS      The driver supports the device being probed.
 514
 515   @retval EFI_UNSUPPORTED  Based on virtio-blk discovery, we do not support
 516                            the device.
 517
 518   @return                  Error codes from the OpenProtocol() boot service or
 519                            the VirtIo protocol.
 520
 521 **/
 522
 523 EFI_STATUS
 524 EFIAPI
 525 VirtioBlkDriverBindingSupported (
 526   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 527   IN EFI_HANDLE                  DeviceHandle,
 528   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
 529   )
 530 {
 531   EFI_STATUS          Status;
 532   VIRTIO_DEVICE_PROTOCOL *VirtIo;
 533
 534   //
 535   // Attempt to open the device with the VirtIo set of interfaces. On success,
 536   // the protocol is "instantiated" for the VirtIo device. Covers duplicate
 537   // open attempts (EFI_ALREADY_STARTED).
 538   //
 539   Status = gBS->OpenProtocol (
 540                   DeviceHandle,               // candidate device
 541                   &gVirtioDeviceProtocolGuid, // for generic VirtIo access
 542                   (VOID **)&VirtIo,           // handle to instantiate
 543                   This->DriverBindingHandle,  // requestor driver identity
 544                   DeviceHandle,               // ControllerHandle, according to
 545                                               // the UEFI Driver Model
 546                   EFI_OPEN_PROTOCOL_BY_DRIVER // get exclusive VirtIo access to
 547                                               // the device; to be released
 548                   );
 549   if (EFI_ERROR (Status)) {
 550     return Status;
 551   }
 552
 553   if (VirtIo->SubSystemDeviceId != VIRTIO_SUBSYSTEM_BLOCK_DEVICE) {
 554     Status = EFI_UNSUPPORTED;
 555   }
 556
 557   //
 558   // We needed VirtIo access only transitorily, to see whether we support the
 559   // device or not.
 560   //
 561   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
 562          This->DriverBindingHandle, DeviceHandle);
 563   return Status;
 564 }
 565
 566
 567 /**
 568
 569   Set up all BlockIo and virtio-blk aspects of this driver for the specified
 570   device.
 571
 572   @param[in out] Dev  The driver instance to configure. The caller is
 573                       responsible for Dev->VirtIo's validity (ie. working IO
 574                       access to the underlying virtio-blk device).
 575
 576   @retval EFI_SUCCESS      Setup complete.
 577
 578   @retval EFI_UNSUPPORTED  The driver is unable to work with the virtio ring or
 579                            virtio-blk attributes the host provides.
 580
 581   @return                  Error codes from VirtioRingInit() or
 582                            VIRTIO_CFG_READ() / VIRTIO_CFG_WRITE().
 583
 584 **/
 585
 586 STATIC
 587 EFI_STATUS
 588 EFIAPI
 589 VirtioBlkInit (
 590   IN OUT VBLK_DEV *Dev
 591   )
 592 {
 593   UINT8      NextDevStat;
 594   EFI_STATUS Status;
 595
 596   UINT64     Features;
 597   UINT64     NumSectors;
 598   UINT32     BlockSize;
 599   UINT8      PhysicalBlockExp;
 600   UINT8      AlignmentOffset;
 601   UINT32     OptIoSize;
 602   UINT16     QueueSize;
 603
 604   PhysicalBlockExp = 0;
 605   AlignmentOffset = 0;
 606   OptIoSize = 0;
 607
 608   //
 609   // Execute virtio-0.9.5, 2.2.1 Device Initialization Sequence.
 610   //
 611   NextDevStat = 0;             // step 1 -- reset device
 612   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 613   if (EFI_ERROR (Status)) {
 614     goto Failed;
 615   }
 616
 617   NextDevStat |= VSTAT_ACK;    // step 2 -- acknowledge device presence
 618   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 619   if (EFI_ERROR (Status)) {
 620     goto Failed;
 621   }
 622
 623   NextDevStat |= VSTAT_DRIVER; // step 3 -- we know how to drive it
 624   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 625   if (EFI_ERROR (Status)) {
 626     goto Failed;
 627   }
 628
 629   //
 630   // Set Page Size - MMIO VirtIo Specific
 631   //
 632   Status = Dev->VirtIo->SetPageSize (Dev->VirtIo, EFI_PAGE_SIZE);
 633   if (EFI_ERROR (Status)) {
 634     goto Failed;
 635   }
 636
 637   //
 638   // step 4a -- retrieve and validate features
 639   //
 640   Status = Dev->VirtIo->GetDeviceFeatures (Dev->VirtIo, &Features);
 641   if (EFI_ERROR (Status)) {
 642     goto Failed;
 643   }
 644
 645   Status = VIRTIO_CFG_READ (Dev, Capacity, &NumSectors);
 646   if (EFI_ERROR (Status)) {
 647     goto Failed;
 648   }
 649   if (NumSectors == 0) {
 650     Status = EFI_UNSUPPORTED;
 651     goto Failed;
 652   }
 653
 654   if (Features & VIRTIO_BLK_F_BLK_SIZE) {
 655     Status = VIRTIO_CFG_READ (Dev, BlkSize, &BlockSize);
 656     if (EFI_ERROR (Status)) {
 657       goto Failed;
 658     }
 659     if (BlockSize == 0 || BlockSize % 512 != 0 ||
 660         ModU64x32 (NumSectors, BlockSize / 512) != 0) {
 661       //
 662       // We can only handle a logical block consisting of whole sectors,
 663       // and only a disk composed of whole logical blocks.
 664       //
 665       Status = EFI_UNSUPPORTED;
 666       goto Failed;
 667     }
 668   }
 669   else {
 670     BlockSize = 512;
 671   }
 672
 673   if (Features & VIRTIO_BLK_F_TOPOLOGY) {
 674     Status = VIRTIO_CFG_READ (Dev, Topology.PhysicalBlockExp,
 675                &PhysicalBlockExp);
 676     if (EFI_ERROR (Status)) {
 677       goto Failed;
 678     }
 679     if (PhysicalBlockExp >= 32) {
 680       Status = EFI_UNSUPPORTED;
 681       goto Failed;
 682     }
 683
 684     Status = VIRTIO_CFG_READ (Dev, Topology.AlignmentOffset, &AlignmentOffset);
 685     if (EFI_ERROR (Status)) {
 686       goto Failed;
 687     }
 688
 689     Status = VIRTIO_CFG_READ (Dev, Topology.OptIoSize, &OptIoSize);
 690     if (EFI_ERROR (Status)) {
 691       goto Failed;
 692     }
 693   }
 694
 695   //
 696   // step 4b -- allocate virtqueue
 697   //
 698   Status = Dev->VirtIo->SetQueueSel (Dev->VirtIo, 0);
 699   if (EFI_ERROR (Status)) {
 700     goto Failed;
 701   }
 702   Status = Dev->VirtIo->GetQueueNumMax (Dev->VirtIo, &QueueSize);
 703   if (EFI_ERROR (Status)) {
 704     goto Failed;
 705   }
 706   if (QueueSize < 3) { // SynchronousRequest() uses at most three descriptors
 707     Status = EFI_UNSUPPORTED;
 708     goto Failed;
 709   }
 710
 711   Status = VirtioRingInit (QueueSize, &Dev->Ring);
 712   if (EFI_ERROR (Status)) {
 713     goto Failed;
 714   }
 715
 716   //
 717   // Additional steps for MMIO: align the queue appropriately, and set the
 718   // size. If anything fails from here on, we must release the ring resources.
 719   //
 720   Status = Dev->VirtIo->SetQueueNum (Dev->VirtIo, QueueSize);
 721   if (EFI_ERROR (Status)) {
 722     goto ReleaseQueue;
 723   }
 724
 725   Status = Dev->VirtIo->SetQueueAlign (Dev->VirtIo, EFI_PAGE_SIZE);
 726   if (EFI_ERROR (Status)) {
 727     goto ReleaseQueue;
 728   }
 729
 730   //
 731   // step 4c -- Report GPFN (guest-physical frame number) of queue.
 732   //
 733   Status = Dev->VirtIo->SetQueueAddress (Dev->VirtIo,
 734       (UINT32) ((UINTN) Dev->Ring.Base >> EFI_PAGE_SHIFT));
 735   if (EFI_ERROR (Status)) {
 736     goto ReleaseQueue;
 737   }
 738
 739
 740   //
 741   // step 5 -- Report understood features. There are no virtio-blk specific
 742   // features to negotiate in virtio-0.9.5, plus we do not want any of the
 743   // device-independent (known or unknown) VIRTIO_F_* capabilities (see
 744   // Appendix B).
 745   //
 746   Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo, 0);
 747   if (EFI_ERROR (Status)) {
 748     goto ReleaseQueue;
 749   }
 750
 751   //
 752   // step 6 -- initialization complete
 753   //
 754   NextDevStat |= VSTAT_DRIVER_OK;
 755   Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 756   if (EFI_ERROR (Status)) {
 757     goto ReleaseQueue;
 758   }
 759
 760   //
 761   // Populate the exported interface's attributes; see UEFI spec v2.4, 12.9 EFI
 762   // Block I/O Protocol.
 763   //
 764   Dev->BlockIo.Revision              = 0;
 765   Dev->BlockIo.Media                 = &Dev->BlockIoMedia;
 766   Dev->BlockIo.Reset                 = &VirtioBlkReset;
 767   Dev->BlockIo.ReadBlocks            = &VirtioBlkReadBlocks;
 768   Dev->BlockIo.WriteBlocks           = &VirtioBlkWriteBlocks;
 769   Dev->BlockIo.FlushBlocks           = &VirtioBlkFlushBlocks;
 770   Dev->BlockIoMedia.MediaId          = 0;
 771   Dev->BlockIoMedia.RemovableMedia   = FALSE;
 772   Dev->BlockIoMedia.MediaPresent     = TRUE;
 773   Dev->BlockIoMedia.LogicalPartition = FALSE;
 774   Dev->BlockIoMedia.ReadOnly         = (BOOLEAN) ((Features & VIRTIO_BLK_F_RO) != 0);
 775   Dev->BlockIoMedia.WriteCaching     = (BOOLEAN) ((Features & VIRTIO_BLK_F_FLUSH) != 0);
 776   Dev->BlockIoMedia.BlockSize        = BlockSize;
 777   Dev->BlockIoMedia.IoAlign          = 0;
 778   Dev->BlockIoMedia.LastBlock        = DivU64x32 (NumSectors,
 779                                          BlockSize / 512) - 1;
 780
 781   DEBUG ((DEBUG_INFO, "%a: LbaSize=0x%x[B] NumBlocks=0x%Lx[Lba]\n",
 782     __FUNCTION__, Dev->BlockIoMedia.BlockSize,
 783     Dev->BlockIoMedia.LastBlock + 1));
 784
 785   if (Features & VIRTIO_BLK_F_TOPOLOGY) {
 786     Dev->BlockIo.Revision = EFI_BLOCK_IO_PROTOCOL_REVISION3;
 787
 788     Dev->BlockIoMedia.LowestAlignedLba = AlignmentOffset;
 789     Dev->BlockIoMedia.LogicalBlocksPerPhysicalBlock = 1u << PhysicalBlockExp;
 790     Dev->BlockIoMedia.OptimalTransferLengthGranularity = OptIoSize;
 791
 792     DEBUG ((DEBUG_INFO, "%a: FirstAligned=0x%Lx[Lba] PhysBlkSize=0x%x[Lba]\n",
 793       __FUNCTION__, Dev->BlockIoMedia.LowestAlignedLba,
 794       Dev->BlockIoMedia.LogicalBlocksPerPhysicalBlock));
 795     DEBUG ((DEBUG_INFO, "%a: OptimalTransferLengthGranularity=0x%x[Lba]\n",
 796       __FUNCTION__, Dev->BlockIoMedia.OptimalTransferLengthGranularity));
 797   }
 798   return EFI_SUCCESS;
 799
 800 ReleaseQueue:
 801   VirtioRingUninit (&Dev->Ring);
 802
 803 Failed:
 804   //
 805   // Notify the host about our failure to setup: virtio-0.9.5, 2.2.2.1 Device
 806   // Status. VirtIo access failure here should not mask the original error.
 807   //
 808   NextDevStat |= VSTAT_FAILED;
 809   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);
 810
 811   return Status; // reached only via Failed above
 812 }
 813
 814
 815 /**
 816
 817   Uninitialize the internals of a virtio-blk device that has been successfully
 818   set up with VirtioBlkInit().
 819
 820   @param[in out]  Dev  The device to clean up.
 821
 822 **/
 823
 824 STATIC
 825 VOID
 826 EFIAPI
 827 VirtioBlkUninit (
 828   IN OUT VBLK_DEV *Dev
 829   )
 830 {
 831   //
 832   // Reset the virtual device -- see virtio-0.9.5, 2.2.2.1 Device Status. When
 833   // VIRTIO_CFG_WRITE() returns, the host will have learned to stay away from
 834   // the old comms area.
 835   //
 836   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
 837
 838   VirtioRingUninit (&Dev->Ring);
 839
 840   SetMem (&Dev->BlockIo,      sizeof Dev->BlockIo,      0x00);
 841   SetMem (&Dev->BlockIoMedia, sizeof Dev->BlockIoMedia, 0x00);
 842 }
 843
 844
 845 /**
 846
 847   Event notification function enqueued by ExitBootServices().
 848
 849   @param[in] Event    Event whose notification function is being invoked.
 850
 851   @param[in] Context  Pointer to the VBLK_DEV structure.
 852
 853 **/
 854
 855 STATIC
 856 VOID
 857 EFIAPI
 858 VirtioBlkExitBoot (
 859   IN  EFI_EVENT Event,
 860   IN  VOID      *Context
 861   )
 862 {
 863   VBLK_DEV *Dev;
 864
 865   //
 866   // Reset the device. This causes the hypervisor to forget about the virtio
 867   // ring.
 868   //
 869   // We allocated said ring in EfiBootServicesData type memory, and code
 870   // executing after ExitBootServices() is permitted to overwrite it.
 871   //
 872   Dev = Context;
 873   Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
 874 }
 875
 876 /**
 877
 878   After we've pronounced support for a specific device in
 879   DriverBindingSupported(), we start managing said device (passed in by the
 880   Driver Exeuction Environment) with the following service.
 881
 882   See DriverBindingSupported() for specification references.
 883
 884   @param[in]  This                The EFI_DRIVER_BINDING_PROTOCOL object
 885                                   incorporating this driver (independently of
 886                                   any device).
 887
 888   @param[in] DeviceHandle         The supported device to drive.
 889
 890   @param[in] RemainingDevicePath  Relevant only for bus drivers, ignored.
 891
 892
 893   @retval EFI_SUCCESS           Driver instance has been created and
 894                                 initialized  for the virtio-blk device, it
 895                                 is now accessibla via EFI_BLOCK_IO_PROTOCOL.
 896
 897   @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
 898
 899   @return                       Error codes from the OpenProtocol() boot
 900                                 service, the VirtIo protocol, VirtioBlkInit(),
 901                                 or the InstallProtocolInterface() boot service.
 902
 903 **/
 904
 905 EFI_STATUS
 906 EFIAPI
 907 VirtioBlkDriverBindingStart (
 908   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 909   IN EFI_HANDLE                  DeviceHandle,
 910   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
 911   )
 912 {
 913   VBLK_DEV   *Dev;
 914   EFI_STATUS Status;
 915
 916   Dev = (VBLK_DEV *) AllocateZeroPool (sizeof *Dev);
 917   if (Dev == NULL) {
 918     return EFI_OUT_OF_RESOURCES;
 919   }
 920
 921   Status = gBS->OpenProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
 922                   (VOID **)&Dev->VirtIo, This->DriverBindingHandle,
 923                   DeviceHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);
 924   if (EFI_ERROR (Status)) {
 925     goto FreeVirtioBlk;
 926   }
 927
 928   //
 929   // VirtIo access granted, configure virtio-blk device.
 930   //
 931   Status = VirtioBlkInit (Dev);
 932   if (EFI_ERROR (Status)) {
 933     goto CloseVirtIo;
 934   }
 935
 936   Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
 937                   &VirtioBlkExitBoot, Dev, &Dev->ExitBoot);
 938   if (EFI_ERROR (Status)) {
 939     goto UninitDev;
 940   }
 941
 942   //
 943   // Setup complete, attempt to export the driver instance's BlockIo interface.
 944   //
 945   Dev->Signature = VBLK_SIG;
 946   Status = gBS->InstallProtocolInterface (&DeviceHandle,
 947                   &gEfiBlockIoProtocolGuid, EFI_NATIVE_INTERFACE,
 948                   &Dev->BlockIo);
 949   if (EFI_ERROR (Status)) {
 950     goto CloseExitBoot;
 951   }
 952
 953   return EFI_SUCCESS;
 954
 955 CloseExitBoot:
 956   gBS->CloseEvent (Dev->ExitBoot);
 957
 958 UninitDev:
 959   VirtioBlkUninit (Dev);
 960
 961 CloseVirtIo:
 962   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
 963          This->DriverBindingHandle, DeviceHandle);
 964
 965 FreeVirtioBlk:
 966   FreePool (Dev);
 967
 968   return Status;
 969 }
 970
 971
 972 /**
 973
 974   Stop driving a virtio-blk device and remove its BlockIo interface.
 975
 976   This function replays the success path of DriverBindingStart() in reverse.
 977   The host side virtio-blk device is reset, so that the OS boot loader or the
 978   OS may reinitialize it.
 979
 980   @param[in] This               The EFI_DRIVER_BINDING_PROTOCOL object
 981                                 incorporating this driver (independently of any
 982                                 device).
 983
 984   @param[in] DeviceHandle       Stop driving this device.
 985
 986   @param[in] NumberOfChildren   Since this function belongs to a device driver
 987                                 only (as opposed to a bus driver), the caller
 988                                 environment sets NumberOfChildren to zero, and
 989                                 we ignore it.
 990
 991   @param[in] ChildHandleBuffer  Ignored (corresponding to NumberOfChildren).
 992
 993 **/
 994
 995 EFI_STATUS
 996 EFIAPI
 997 VirtioBlkDriverBindingStop (
 998   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 999   IN EFI_HANDLE                  DeviceHandle,
1000   IN UINTN                       NumberOfChildren,
1001   IN EFI_HANDLE                  *ChildHandleBuffer
1002   )
1003 {
1004   EFI_STATUS            Status;
1005   EFI_BLOCK_IO_PROTOCOL *BlockIo;
1006   VBLK_DEV              *Dev;
1007
1008   Status = gBS->OpenProtocol (
1009                   DeviceHandle,                  // candidate device
1010                   &gEfiBlockIoProtocolGuid,      // retrieve the BlockIo iface
1011                   (VOID **)&BlockIo,             // target pointer
1012                   This->DriverBindingHandle,     // requestor driver identity
1013                   DeviceHandle,                  // requesting lookup for dev.
1014                   EFI_OPEN_PROTOCOL_GET_PROTOCOL // lookup only, no ref. added
1015                   );
1016   if (EFI_ERROR (Status)) {
1017     return Status;
1018   }
1019
1020   Dev = VIRTIO_BLK_FROM_BLOCK_IO (BlockIo);
1021
1022   //
1023   // Handle Stop() requests for in-use driver instances gracefully.
1024   //
1025   Status = gBS->UninstallProtocolInterface (DeviceHandle,
1026                   &gEfiBlockIoProtocolGuid, &Dev->BlockIo);
1027   if (EFI_ERROR (Status)) {
1028     return Status;
1029   }
1030
1031   gBS->CloseEvent (Dev->ExitBoot);
1032
1033   VirtioBlkUninit (Dev);
1034
1035   gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,
1036          This->DriverBindingHandle, DeviceHandle);
1037
1038   FreePool (Dev);
1039
1040   return EFI_SUCCESS;
1041 }
1042
1043
1044 //
1045 // The static object that groups the Supported() (ie. probe), Start() and
1046 // Stop() functions of the driver together. Refer to UEFI Spec 2.3.1 + Errata
1047 // C, 10.1 EFI Driver Binding Protocol.
1048 //
1049 STATIC EFI_DRIVER_BINDING_PROTOCOL gDriverBinding = {
1050   &VirtioBlkDriverBindingSupported,
1051   &VirtioBlkDriverBindingStart,
1052   &VirtioBlkDriverBindingStop,
1053   0x10, // Version, must be in [0x10 .. 0xFFFFFFEF] for IHV-developed drivers
1054   NULL, // ImageHandle, to be overwritten by
1055         // EfiLibInstallDriverBindingComponentName2() in VirtioBlkEntryPoint()
1056   NULL  // DriverBindingHandle, ditto
1057 };
1058
1059
1060 //
1061 // The purpose of the following scaffolding (EFI_COMPONENT_NAME_PROTOCOL and
1062 // EFI_COMPONENT_NAME2_PROTOCOL implementation) is to format the driver's name
1063 // in English, for display on standard console devices. This is recommended for
1064 // UEFI drivers that follow the UEFI Driver Model. Refer to the Driver Writer's
1065 // Guide for UEFI 2.3.1 v1.01, 11 UEFI Driver and Controller Names.
1066 //
1067 // Device type names ("Virtio Block Device") are not formatted because the
1068 // driver supports only that device type. Therefore the driver name suffices
1069 // for unambiguous identification.
1070 //
1071
1072 STATIC
1073 EFI_UNICODE_STRING_TABLE mDriverNameTable[] = {
1074   { "eng;en", L"Virtio Block Driver" },
1075   { NULL,     NULL                   }
1076 };
1077
1078 STATIC
1079 EFI_COMPONENT_NAME_PROTOCOL gComponentName;
1080
1081 EFI_STATUS
1082 EFIAPI
1083 VirtioBlkGetDriverName (
1084   IN  EFI_COMPONENT_NAME_PROTOCOL *This,
1085   IN  CHAR8                       *Language,
1086   OUT CHAR16                      **DriverName
1087   )
1088 {
1089   return LookupUnicodeString2 (
1090            Language,
1091            This->SupportedLanguages,
1092            mDriverNameTable,
1093            DriverName,
1094            (BOOLEAN)(This == &gComponentName) // Iso639Language
1095            );
1096 }
1097
1098 EFI_STATUS
1099 EFIAPI
1100 VirtioBlkGetDeviceName (
1101   IN  EFI_COMPONENT_NAME_PROTOCOL *This,
1102   IN  EFI_HANDLE                  DeviceHandle,
1103   IN  EFI_HANDLE                  ChildHandle,
1104   IN  CHAR8                       *Language,
1105   OUT CHAR16                      **ControllerName
1106   )
1107 {
1108   return EFI_UNSUPPORTED;
1109 }
1110
1111 STATIC
1112 EFI_COMPONENT_NAME_PROTOCOL gComponentName = {
1113   &VirtioBlkGetDriverName,
1114   &VirtioBlkGetDeviceName,
1115   "eng" // SupportedLanguages, ISO 639-2 language codes
1116 };
1117
1118 STATIC
1119 EFI_COMPONENT_NAME2_PROTOCOL gComponentName2 = {
1120   (EFI_COMPONENT_NAME2_GET_DRIVER_NAME)     &VirtioBlkGetDriverName,
1121   (EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME) &VirtioBlkGetDeviceName,
1122   "en" // SupportedLanguages, RFC 4646 language codes
1123 };
1124
1125
1126 //
1127 // Entry point of this driver.
1128 //
1129 EFI_STATUS
1130 EFIAPI
1131 VirtioBlkEntryPoint (
1132   IN EFI_HANDLE       ImageHandle,
1133   IN EFI_SYSTEM_TABLE *SystemTable
1134   )
1135 {
1136   return EfiLibInstallDriverBindingComponentName2 (
1137            ImageHandle,
1138            SystemTable,
1139            &gDriverBinding,
1140            ImageHandle,
1141            &gComponentName,
1142            &gComponentName2
1143            );
1144 }
1145