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/Pci.h>
  27 #include <IndustryStandard/VirtioBlk.h>
  28 #include <Library/BaseMemoryLib.h>
  29 #include <Library/DebugLib.h>
  30 #include <Library/MemoryAllocationLib.h>
  31 #include <Library/UefiBootServicesTableLib.h>
  32 #include <Library/UefiLib.h>
  33 #include <Library/VirtioLib.h>
  34
  35 #include "VirtioBlk.h"
  36
  37 /**
  38
  39   Convenience macros to read and write region 0 IO space elements of the
  40   virtio-blk PCI device, for configuration purposes.
  41
  42   The following macros make it possible to specify only the "core parameters"
  43   for such accesses and to derive the rest. By the time VIRTIO_CFG_WRITE()
  44   returns, the transaction will have been completed.
  45
  46   @param[in] Dev       Pointer to the VBLK_DEV structure whose PCI IO space
  47                        we're accessing. Dev->PciIo must be valid.
  48
  49   @param[in] Field     A field name from VBLK_HDR, identifying the virtio-blk
  50                        configuration item to access.
  51
  52   @param[in] Value     (VIRTIO_CFG_WRITE() only.) The value to write to the
  53                        selected configuration item.
  54
  55   @param[out] Pointer  (VIRTIO_CFG_READ() only.) The object to receive the
  56                        value read from the configuration item. Its type must be
  57                        one of UINT8, UINT16, UINT32, UINT64.
  58
  59
  60   @return  Status code returned by VirtioWrite() / VirtioRead().
  61
  62 **/
  63
  64 #define VIRTIO_CFG_WRITE(Dev, Field, Value)  (VirtioWrite (             \
  65                                                 (Dev)->PciIo,           \
  66                                                 OFFSET_OF_VBLK (Field), \
  67                                                 SIZE_OF_VBLK (Field),   \
  68                                                 (Value)                 \
  69                                                 ))
  70
  71 #define VIRTIO_CFG_READ(Dev, Field, Pointer) (VirtioRead (              \
  72                                                 (Dev)->PciIo,           \
  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 PCI 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->PciIo, 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   Specs relevant in the specific sense:
 504   - UEFI Spec 2.3.1 + Errata C, 13.4 EFI PCI I/O Protocol
 505   - Driver Writer's Guide for UEFI 2.3.1 v1.01, 18 PCI Driver Design
 506     Guidelines, 18.3 PCI drivers.
 507
 508   @param[in]  This                The EFI_DRIVER_BINDING_PROTOCOL object
 509                                   incorporating this driver (independently of
 510                                   any device).
 511
 512   @param[in] DeviceHandle         The device to probe.
 513
 514   @param[in] RemainingDevicePath  Relevant only for bus drivers, ignored.
 515
 516
 517   @retval EFI_SUCCESS      The driver supports the device being probed.
 518
 519   @retval EFI_UNSUPPORTED  Based on virtio-blk PCI discovery, we do not support
 520                            the device.
 521
 522   @return                  Error codes from the OpenProtocol() boot service or
 523                            the PciIo protocol.
 524
 525 **/
 526
 527 EFI_STATUS
 528 EFIAPI
 529 VirtioBlkDriverBindingSupported (
 530   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 531   IN EFI_HANDLE                  DeviceHandle,
 532   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
 533   )
 534 {
 535   EFI_STATUS          Status;
 536   EFI_PCI_IO_PROTOCOL *PciIo;
 537   PCI_TYPE00          Pci;
 538
 539   //
 540   // Attempt to open the device with the PciIo set of interfaces. On success,
 541   // the protocol is "instantiated" for the PCI device. Covers duplicate open
 542   // attempts (EFI_ALREADY_STARTED).
 543   //
 544   Status = gBS->OpenProtocol (
 545                   DeviceHandle,               // candidate device
 546                   &gEfiPciIoProtocolGuid,     // for generic PCI access
 547                   (VOID **)&PciIo,            // handle to instantiate
 548                   This->DriverBindingHandle,  // requestor driver identity
 549                   DeviceHandle,               // ControllerHandle, according to
 550                                               // the UEFI Driver Model
 551                   EFI_OPEN_PROTOCOL_BY_DRIVER // get exclusive PciIo access to
 552                                               // the device; to be released
 553                   );
 554   if (EFI_ERROR (Status)) {
 555     return Status;
 556   }
 557
 558   //
 559   // Read entire PCI configuration header for more extensive check ahead.
 560   //
 561   Status = PciIo->Pci.Read (
 562                         PciIo,                        // (protocol, device)
 563                                                       // handle
 564                         EfiPciIoWidthUint32,          // access width & copy
 565                                                       // mode
 566                         0,                            // Offset
 567                         sizeof Pci / sizeof (UINT32), // Count
 568                         &Pci                          // target buffer
 569                         );
 570
 571   if (Status == EFI_SUCCESS) {
 572     //
 573     // virtio-0.9.5, 2.1 PCI Discovery
 574     //
 575     Status = (Pci.Hdr.VendorId == 0x1AF4 &&
 576               Pci.Hdr.DeviceId >= 0x1000 && Pci.Hdr.DeviceId <= 0x103F &&
 577               Pci.Hdr.RevisionID == 0x00 &&
 578               Pci.Device.SubsystemID == VIRTIO_SUBSYSTEM_BLOCK_DEVICE) ? EFI_SUCCESS : EFI_UNSUPPORTED;
 579   }
 580
 581   //
 582   // We needed PCI IO access only transitorily, to see whether we support the
 583   // device or not.
 584   //
 585   gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
 586          This->DriverBindingHandle, DeviceHandle);
 587   return Status;
 588 }
 589
 590
 591 /**
 592
 593   Set up all BlockIo and virtio-blk aspects of this driver for the specified
 594   device.
 595
 596   @param[in out] Dev  The driver instance to configure. The caller is
 597                       responsible for Dev->PciIo's validity (ie. working IO
 598                       access to the underlying virtio-blk PCI device).
 599
 600   @retval EFI_SUCCESS      Setup complete.
 601
 602   @retval EFI_UNSUPPORTED  The driver is unable to work with the virtio ring or
 603                            virtio-blk attributes the host provides.
 604
 605   @return                  Error codes from VirtioRingInit() or
 606                            VIRTIO_CFG_READ() / VIRTIO_CFG_WRITE().
 607
 608 **/
 609
 610 STATIC
 611 EFI_STATUS
 612 EFIAPI
 613 VirtioBlkInit (
 614   IN OUT VBLK_DEV *Dev
 615   )
 616 {
 617   UINT8      NextDevStat;
 618   EFI_STATUS Status;
 619
 620   UINT32     Features;
 621   UINT64     NumSectors;
 622   UINT32     BlockSize;
 623   UINT16     QueueSize;
 624
 625   //
 626   // Execute virtio-0.9.5, 2.2.1 Device Initialization Sequence.
 627   //
 628   NextDevStat = 0;             // step 1 -- reset device
 629   Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
 630   if (EFI_ERROR (Status)) {
 631     goto Failed;
 632   }
 633
 634   NextDevStat |= VSTAT_ACK;    // step 2 -- acknowledge device presence
 635   Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
 636   if (EFI_ERROR (Status)) {
 637     goto Failed;
 638   }
 639
 640   NextDevStat |= VSTAT_DRIVER; // step 3 -- we know how to drive it
 641   Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
 642   if (EFI_ERROR (Status)) {
 643     goto Failed;
 644   }
 645
 646   //
 647   // step 4a -- retrieve and validate features
 648   //
 649   Status = VIRTIO_CFG_READ (Dev, Generic.VhdrDeviceFeatureBits, &Features);
 650   if (EFI_ERROR (Status)) {
 651     goto Failed;
 652   }
 653   Status = VIRTIO_CFG_READ (Dev, VhdrCapacity, &NumSectors);
 654   if (EFI_ERROR (Status)) {
 655     goto Failed;
 656   }
 657   if (NumSectors == 0) {
 658     Status = EFI_UNSUPPORTED;
 659     goto Failed;
 660   }
 661
 662   if (Features & VIRTIO_BLK_F_BLK_SIZE) {
 663     Status = VIRTIO_CFG_READ (Dev, VhdrBlkSize, &BlockSize);
 664     if (EFI_ERROR (Status)) {
 665       goto Failed;
 666     }
 667     if (BlockSize == 0 || BlockSize % 512 != 0 ||
 668         ModU64x32 (NumSectors, BlockSize / 512) != 0) {
 669       //
 670       // We can only handle a logical block consisting of whole sectors,
 671       // and only a disk composed of whole logical blocks.
 672       //
 673       Status = EFI_UNSUPPORTED;
 674       goto Failed;
 675     }
 676   }
 677   else {
 678     BlockSize = 512;
 679   }
 680
 681   //
 682   // step 4b -- allocate virtqueue
 683   //
 684   Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrQueueSelect, 0);
 685   if (EFI_ERROR (Status)) {
 686     goto Failed;
 687   }
 688   Status = VIRTIO_CFG_READ (Dev, Generic.VhdrQueueSize, &QueueSize);
 689   if (EFI_ERROR (Status)) {
 690     goto Failed;
 691   }
 692   if (QueueSize < 3) { // SynchronousRequest() uses at most three descriptors
 693     Status = EFI_UNSUPPORTED;
 694     goto Failed;
 695   }
 696
 697   Status = VirtioRingInit (QueueSize, &Dev->Ring);
 698   if (EFI_ERROR (Status)) {
 699     goto Failed;
 700   }
 701
 702   //
 703   // step 4c -- Report GPFN (guest-physical frame number) of queue. If anything
 704   // fails from here on, we must release the ring resources.
 705   //
 706   Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrQueueAddress,
 707              (UINTN) Dev->Ring.Base >> EFI_PAGE_SHIFT);
 708   if (EFI_ERROR (Status)) {
 709     goto ReleaseQueue;
 710   }
 711
 712   //
 713   // step 5 -- Report understood features. There are no virtio-blk specific
 714   // features to negotiate in virtio-0.9.5, plus we do not want any of the
 715   // device-independent (known or unknown) VIRTIO_F_* capabilities (see
 716   // Appendix B).
 717   //
 718   Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrGuestFeatureBits, 0);
 719   if (EFI_ERROR (Status)) {
 720     goto ReleaseQueue;
 721   }
 722
 723   //
 724   // step 6 -- initialization complete
 725   //
 726   NextDevStat |= VSTAT_DRIVER_OK;
 727   Status = VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
 728   if (EFI_ERROR (Status)) {
 729     goto ReleaseQueue;
 730   }
 731
 732   //
 733   // Populate the exported interface's attributes; see UEFI spec v2.3.1 +
 734   // Errata C, 12.8 EFI Block I/O Protocol. We stick to the lowest possible
 735   // EFI_BLOCK_IO_PROTOCOL revision for now.
 736   //
 737   Dev->BlockIo.Revision              = 0;
 738   Dev->BlockIo.Media                 = &Dev->BlockIoMedia;
 739   Dev->BlockIo.Reset                 = &VirtioBlkReset;
 740   Dev->BlockIo.ReadBlocks            = &VirtioBlkReadBlocks;
 741   Dev->BlockIo.WriteBlocks           = &VirtioBlkWriteBlocks;
 742   Dev->BlockIo.FlushBlocks           = &VirtioBlkFlushBlocks;
 743   Dev->BlockIoMedia.MediaId          = 0;
 744   Dev->BlockIoMedia.RemovableMedia   = FALSE;
 745   Dev->BlockIoMedia.MediaPresent     = TRUE;
 746   Dev->BlockIoMedia.LogicalPartition = FALSE;
 747   Dev->BlockIoMedia.ReadOnly         = !!(Features & VIRTIO_BLK_F_RO);
 748   Dev->BlockIoMedia.WriteCaching     = !!(Features & VIRTIO_BLK_F_FLUSH);
 749   Dev->BlockIoMedia.BlockSize        = BlockSize;
 750   Dev->BlockIoMedia.IoAlign          = 0;
 751   Dev->BlockIoMedia.LastBlock        = DivU64x32 (NumSectors,
 752                                          BlockSize / 512) - 1;
 753   return EFI_SUCCESS;
 754
 755 ReleaseQueue:
 756   VirtioRingUninit (&Dev->Ring);
 757
 758 Failed:
 759   //
 760   // Notify the host about our failure to setup: virtio-0.9.5, 2.2.2.1 Device
 761   // Status. PCI IO access failure here should not mask the original error.
 762   //
 763   NextDevStat |= VSTAT_FAILED;
 764   VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, NextDevStat);
 765
 766   return Status; // reached only via Failed above
 767 }
 768
 769
 770 /**
 771
 772   Uninitialize the internals of a virtio-blk device that has been successfully
 773   set up with VirtioBlkInit().
 774
 775   @param[in out]  Dev  The device to clean up.
 776
 777 **/
 778
 779 STATIC
 780 VOID
 781 EFIAPI
 782 VirtioBlkUninit (
 783   IN OUT VBLK_DEV *Dev
 784   )
 785 {
 786   //
 787   // Reset the virtual device -- see virtio-0.9.5, 2.2.2.1 Device Status. When
 788   // VIRTIO_CFG_WRITE() returns, the host will have learned to stay away from
 789   // the old comms area.
 790   //
 791   VIRTIO_CFG_WRITE (Dev, Generic.VhdrDeviceStatus, 0);
 792
 793   VirtioRingUninit (&Dev->Ring);
 794
 795   SetMem (&Dev->BlockIo,      sizeof Dev->BlockIo,      0x00);
 796   SetMem (&Dev->BlockIoMedia, sizeof Dev->BlockIoMedia, 0x00);
 797 }
 798
 799
 800 /**
 801
 802   After we've pronounced support for a specific device in
 803   DriverBindingSupported(), we start managing said device (passed in by the
 804   Driver Exeuction Environment) with the following service.
 805
 806   See DriverBindingSupported() for specification references.
 807
 808   @param[in]  This                The EFI_DRIVER_BINDING_PROTOCOL object
 809                                   incorporating this driver (independently of
 810                                   any device).
 811
 812   @param[in] DeviceHandle         The supported device to drive.
 813
 814   @param[in] RemainingDevicePath  Relevant only for bus drivers, ignored.
 815
 816
 817   @retval EFI_SUCCESS           Driver instance has been created and
 818                                 initialized  for the virtio-blk PCI device, it
 819                                 is now accessibla via EFI_BLOCK_IO_PROTOCOL.
 820
 821   @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
 822
 823   @return                       Error codes from the OpenProtocol() boot
 824                                 service, the PciIo protocol, VirtioBlkInit(),
 825                                 or the InstallProtocolInterface() boot service.
 826
 827 **/
 828
 829 EFI_STATUS
 830 EFIAPI
 831 VirtioBlkDriverBindingStart (
 832   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 833   IN EFI_HANDLE                  DeviceHandle,
 834   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath
 835   )
 836 {
 837   VBLK_DEV   *Dev;
 838   EFI_STATUS Status;
 839
 840   Dev = (VBLK_DEV *) AllocateZeroPool (sizeof *Dev);
 841   if (Dev == NULL) {
 842     return EFI_OUT_OF_RESOURCES;
 843   }
 844
 845   Status = gBS->OpenProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
 846                   (VOID **)&Dev->PciIo, This->DriverBindingHandle,
 847                   DeviceHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);
 848   if (EFI_ERROR (Status)) {
 849     goto FreeVirtioBlk;
 850   }
 851
 852   //
 853   // We must retain and ultimately restore the original PCI attributes of the
 854   // device. See Driver Writer's Guide for UEFI 2.3.1 v1.01, 18.3 PCI drivers /
 855   // 18.3.2 Start() and Stop().
 856   //
 857   // The third parameter ("Attributes", input) is ignored by the Get operation.
 858   // The fourth parameter ("Result", output) is ignored by the Enable and Set
 859   // operations.
 860   //
 861   // For virtio-blk we only need IO space access.
 862   //
 863   Status = Dev->PciIo->Attributes (Dev->PciIo, EfiPciIoAttributeOperationGet,
 864                          0, &Dev->OriginalPciAttributes);
 865   if (EFI_ERROR (Status)) {
 866     goto ClosePciIo;
 867   }
 868
 869   Status = Dev->PciIo->Attributes (Dev->PciIo,
 870                          EfiPciIoAttributeOperationEnable,
 871                          EFI_PCI_IO_ATTRIBUTE_IO, NULL);
 872   if (EFI_ERROR (Status)) {
 873     goto ClosePciIo;
 874   }
 875
 876   //
 877   // PCI IO access granted, configure virtio-blk device.
 878   //
 879   Status = VirtioBlkInit (Dev);
 880   if (EFI_ERROR (Status)) {
 881     goto RestorePciAttributes;
 882   }
 883
 884   //
 885   // Setup complete, attempt to export the driver instance's BlockIo interface.
 886   //
 887   Dev->Signature = VBLK_SIG;
 888   Status = gBS->InstallProtocolInterface (&DeviceHandle,
 889                   &gEfiBlockIoProtocolGuid, EFI_NATIVE_INTERFACE,
 890                   &Dev->BlockIo);
 891   if (EFI_ERROR (Status)) {
 892     goto UninitDev;
 893   }
 894
 895   return EFI_SUCCESS;
 896
 897 UninitDev:
 898   VirtioBlkUninit (Dev);
 899
 900 RestorePciAttributes:
 901   Dev->PciIo->Attributes (Dev->PciIo, EfiPciIoAttributeOperationSet,
 902                 Dev->OriginalPciAttributes, NULL);
 903
 904 ClosePciIo:
 905   gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
 906          This->DriverBindingHandle, DeviceHandle);
 907
 908 FreeVirtioBlk:
 909   FreePool (Dev);
 910
 911   return Status;
 912 }
 913
 914
 915 /**
 916
 917   Stop driving a virtio-blk device and remove its BlockIo interface.
 918
 919   This function replays the success path of DriverBindingStart() in reverse.
 920   The host side virtio-blk device is reset, so that the OS boot loader or the
 921   OS may reinitialize it.
 922
 923   @param[in] This               The EFI_DRIVER_BINDING_PROTOCOL object
 924                                 incorporating this driver (independently of any
 925                                 device).
 926
 927   @param[in] DeviceHandle       Stop driving this device.
 928
 929   @param[in] NumberOfChildren   Since this function belongs to a device driver
 930                                 only (as opposed to a bus driver), the caller
 931                                 environment sets NumberOfChildren to zero, and
 932                                 we ignore it.
 933
 934   @param[in] ChildHandleBuffer  Ignored (corresponding to NumberOfChildren).
 935
 936 **/
 937
 938 EFI_STATUS
 939 EFIAPI
 940 VirtioBlkDriverBindingStop (
 941   IN EFI_DRIVER_BINDING_PROTOCOL *This,
 942   IN EFI_HANDLE                  DeviceHandle,
 943   IN UINTN                       NumberOfChildren,
 944   IN EFI_HANDLE                  *ChildHandleBuffer
 945   )
 946 {
 947   EFI_STATUS            Status;
 948   EFI_BLOCK_IO_PROTOCOL *BlockIo;
 949   VBLK_DEV              *Dev;
 950
 951   Status = gBS->OpenProtocol (
 952                   DeviceHandle,                  // candidate device
 953                   &gEfiBlockIoProtocolGuid,      // retrieve the BlockIo iface
 954                   (VOID **)&BlockIo,             // target pointer
 955                   This->DriverBindingHandle,     // requestor driver identity
 956                   DeviceHandle,                  // requesting lookup for dev.
 957                   EFI_OPEN_PROTOCOL_GET_PROTOCOL // lookup only, no ref. added
 958                   );
 959   if (EFI_ERROR (Status)) {
 960     return Status;
 961   }
 962
 963   Dev = VIRTIO_BLK_FROM_BLOCK_IO (BlockIo);
 964
 965   //
 966   // Handle Stop() requests for in-use driver instances gracefully.
 967   //
 968   Status = gBS->UninstallProtocolInterface (DeviceHandle,
 969                   &gEfiBlockIoProtocolGuid, &Dev->BlockIo);
 970   if (EFI_ERROR (Status)) {
 971     return Status;
 972   }
 973
 974   VirtioBlkUninit (Dev);
 975
 976   Dev->PciIo->Attributes (Dev->PciIo, EfiPciIoAttributeOperationSet,
 977                 Dev->OriginalPciAttributes, NULL);
 978
 979   gBS->CloseProtocol (DeviceHandle, &gEfiPciIoProtocolGuid,
 980          This->DriverBindingHandle, DeviceHandle);
 981
 982   FreePool (Dev);
 983
 984   return EFI_SUCCESS;
 985 }
 986
 987
 988 //
 989 // The static object that groups the Supported() (ie. probe), Start() and
 990 // Stop() functions of the driver together. Refer to UEFI Spec 2.3.1 + Errata
 991 // C, 10.1 EFI Driver Binding Protocol.
 992 //
 993 STATIC EFI_DRIVER_BINDING_PROTOCOL gDriverBinding = {
 994   &VirtioBlkDriverBindingSupported,
 995   &VirtioBlkDriverBindingStart,
 996   &VirtioBlkDriverBindingStop,
 997   0x10, // Version, must be in [0x10 .. 0xFFFFFFEF] for IHV-developed drivers
 998   NULL, // ImageHandle, to be overwritten by
 999         // EfiLibInstallDriverBindingComponentName2() in VirtioBlkEntryPoint()
1000   NULL  // DriverBindingHandle, ditto
1001 };
1002
1003
1004 //
1005 // The purpose of the following scaffolding (EFI_COMPONENT_NAME_PROTOCOL and
1006 // EFI_COMPONENT_NAME2_PROTOCOL implementation) is to format the driver's name
1007 // in English, for display on standard console devices. This is recommended for
1008 // UEFI drivers that follow the UEFI Driver Model. Refer to the Driver Writer's
1009 // Guide for UEFI 2.3.1 v1.01, 11 UEFI Driver and Controller Names.
1010 //
1011 // Device type names ("Virtio Block Device") are not formatted because the
1012 // driver supports only that device type. Therefore the driver name suffices
1013 // for unambiguous identification.
1014 //
1015
1016 STATIC
1017 EFI_UNICODE_STRING_TABLE mDriverNameTable[] = {
1018   { "eng;en", L"Virtio Block Driver" },
1019   { NULL,     NULL                   }
1020 };
1021
1022 STATIC
1023 EFI_COMPONENT_NAME_PROTOCOL gComponentName;
1024
1025 EFI_STATUS
1026 EFIAPI
1027 VirtioBlkGetDriverName (
1028   IN  EFI_COMPONENT_NAME_PROTOCOL *This,
1029   IN  CHAR8                       *Language,
1030   OUT CHAR16                      **DriverName
1031   )
1032 {
1033   return LookupUnicodeString2 (
1034            Language,
1035            This->SupportedLanguages,
1036            mDriverNameTable,
1037            DriverName,
1038            (BOOLEAN)(This == &gComponentName) // Iso639Language
1039            );
1040 }
1041
1042 EFI_STATUS
1043 EFIAPI
1044 VirtioBlkGetDeviceName (
1045   IN  EFI_COMPONENT_NAME_PROTOCOL *This,
1046   IN  EFI_HANDLE                  DeviceHandle,
1047   IN  EFI_HANDLE                  ChildHandle,
1048   IN  CHAR8                       *Language,
1049   OUT CHAR16                      **ControllerName
1050   )
1051 {
1052   return EFI_UNSUPPORTED;
1053 }
1054
1055 STATIC
1056 EFI_COMPONENT_NAME_PROTOCOL gComponentName = {
1057   &VirtioBlkGetDriverName,
1058   &VirtioBlkGetDeviceName,
1059   "eng" // SupportedLanguages, ISO 639-2 language codes
1060 };
1061
1062 STATIC
1063 EFI_COMPONENT_NAME2_PROTOCOL gComponentName2 = {
1064   (EFI_COMPONENT_NAME2_GET_DRIVER_NAME)     &VirtioBlkGetDriverName,
1065   (EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME) &VirtioBlkGetDeviceName,
1066   "en" // SupportedLanguages, RFC 4646 language codes
1067 };
1068
1069
1070 //
1071 // Entry point of this driver.
1072 //
1073 EFI_STATUS
1074 EFIAPI
1075 VirtioBlkEntryPoint (
1076   IN EFI_HANDLE       ImageHandle,
1077   IN EFI_SYSTEM_TABLE *SystemTable
1078   )
1079 {
1080   return EfiLibInstallDriverBindingComponentName2 (
1081            ImageHandle,
1082            SystemTable,
1083            &gDriverBinding,
1084            ImageHandle,
1085            &gComponentName,
1086            &gComponentName2
1087            );
1088 }
1089