OvmfPkg/Library/VirtioLib/VirtioLib.c

   1 /** @file
   2
   3   Utility functions used by virtio device drivers.
   4
   5   Copyright (C) 2012-2016, Red Hat, Inc.
   6   Portion of Copyright (C) 2013, ARM Ltd.
   7   Copyright (C) 2017, AMD Inc, All rights reserved.<BR>
   8
   9   SPDX-License-Identifier: BSD-2-Clause-Patent
  10
  11 **/
  12
  13 #include <Library/BaseLib.h>
  14 #include <Library/BaseMemoryLib.h>
  15 #include <Library/DebugLib.h>
  16 #include <Library/UefiBootServicesTableLib.h>
  17
  18 #include <Library/VirtioLib.h>
  19
  20 /**
  21
  22   Configure a virtio ring.
  23
  24   This function sets up internal storage (the guest-host communication area)
  25   and lays out several "navigation" (ie. no-ownership) pointers to parts of
  26   that storage.
  27
  28   Relevant sections from the virtio-0.9.5 spec:
  29   - 1.1 Virtqueues,
  30   - 2.3 Virtqueue Configuration.
  31
  32   @param[in]  VirtIo            The virtio device which will use the ring.
  33
  34   @param[in]                    The number of descriptors to allocate for the
  35                                 virtio ring, as requested by the host.
  36
  37   @param[out] Ring              The virtio ring to set up.
  38
  39   @return                       Status codes propagated from
  40                                 VirtIo->AllocateSharedPages().
  41
  42   @retval EFI_SUCCESS           Allocation and setup successful. Ring->Base
  43                                 (and nothing else) is responsible for
  44                                 deallocation.
  45
  46 **/
  47 EFI_STATUS
  48 EFIAPI
  49 VirtioRingInit (
  50   IN  VIRTIO_DEVICE_PROTOCOL  *VirtIo,
  51   IN  UINT16                  QueueSize,
  52   OUT VRING                   *Ring
  53   )
  54 {
  55   EFI_STATUS      Status;
  56   UINTN           RingSize;
  57   volatile UINT8  *RingPagesPtr;
  58
  59   RingSize = ALIGN_VALUE (
  60                sizeof *Ring->Desc            * QueueSize +
  61                sizeof *Ring->Avail.Flags                 +
  62                sizeof *Ring->Avail.Idx                   +
  63                sizeof *Ring->Avail.Ring      * QueueSize +
  64                sizeof *Ring->Avail.UsedEvent,
  65                EFI_PAGE_SIZE
  66                );
  67
  68   RingSize += ALIGN_VALUE (
  69                 sizeof *Ring->Used.Flags                  +
  70                 sizeof *Ring->Used.Idx                    +
  71                 sizeof *Ring->Used.UsedElem   * QueueSize +
  72                 sizeof *Ring->Used.AvailEvent,
  73                 EFI_PAGE_SIZE
  74                 );
  75
  76   //
  77   // Allocate a shared ring buffer
  78   //
  79   Ring->NumPages = EFI_SIZE_TO_PAGES (RingSize);
  80   Status         = VirtIo->AllocateSharedPages (
  81                              VirtIo,
  82                              Ring->NumPages,
  83                              &Ring->Base
  84                              );
  85   if (EFI_ERROR (Status)) {
  86     return Status;
  87   }
  88
  89   SetMem (Ring->Base, RingSize, 0x00);
  90   RingPagesPtr = Ring->Base;
  91
  92   Ring->Desc    = (volatile VOID *)RingPagesPtr;
  93   RingPagesPtr += sizeof *Ring->Desc * QueueSize;
  94
  95   Ring->Avail.Flags = (volatile VOID *)RingPagesPtr;
  96   RingPagesPtr     += sizeof *Ring->Avail.Flags;
  97
  98   Ring->Avail.Idx = (volatile VOID *)RingPagesPtr;
  99   RingPagesPtr   += sizeof *Ring->Avail.Idx;
 100
 101   Ring->Avail.Ring = (volatile VOID *)RingPagesPtr;
 102   RingPagesPtr    += sizeof *Ring->Avail.Ring * QueueSize;
 103
 104   Ring->Avail.UsedEvent = (volatile VOID *)RingPagesPtr;
 105   RingPagesPtr         += sizeof *Ring->Avail.UsedEvent;
 106
 107   RingPagesPtr = (volatile UINT8 *)Ring->Base +
 108                  ALIGN_VALUE (
 109                    RingPagesPtr - (volatile UINT8 *)Ring->Base,
 110                    EFI_PAGE_SIZE
 111                    );
 112
 113   Ring->Used.Flags = (volatile VOID *)RingPagesPtr;
 114   RingPagesPtr    += sizeof *Ring->Used.Flags;
 115
 116   Ring->Used.Idx = (volatile VOID *)RingPagesPtr;
 117   RingPagesPtr  += sizeof *Ring->Used.Idx;
 118
 119   Ring->Used.UsedElem = (volatile VOID *)RingPagesPtr;
 120   RingPagesPtr       += sizeof *Ring->Used.UsedElem * QueueSize;
 121
 122   Ring->Used.AvailEvent = (volatile VOID *)RingPagesPtr;
 123   RingPagesPtr         += sizeof *Ring->Used.AvailEvent;
 124
 125   Ring->QueueSize = QueueSize;
 126   return EFI_SUCCESS;
 127 }
 128
 129 /**
 130
 131   Tear down the internal resources of a configured virtio ring.
 132
 133   The caller is responsible to stop the host from using this ring before
 134   invoking this function: the VSTAT_DRIVER_OK bit must be clear in
 135   VhdrDeviceStatus.
 136
 137   @param[in]  VirtIo  The virtio device which was using the ring.
 138
 139   @param[out] Ring    The virtio ring to clean up.
 140
 141 **/
 142 VOID
 143 EFIAPI
 144 VirtioRingUninit (
 145   IN     VIRTIO_DEVICE_PROTOCOL  *VirtIo,
 146   IN OUT VRING                   *Ring
 147   )
 148 {
 149   VirtIo->FreeSharedPages (VirtIo, Ring->NumPages, Ring->Base);
 150   SetMem (Ring, sizeof *Ring, 0x00);
 151 }
 152
 153 /**
 154
 155   Turn off interrupt notifications from the host, and prepare for appending
 156   multiple descriptors to the virtio ring.
 157
 158   The calling driver must be in VSTAT_DRIVER_OK state.
 159
 160   @param[in,out] Ring  The virtio ring we intend to append descriptors to.
 161
 162   @param[out] Indices  The DESC_INDICES structure to initialize.
 163
 164 **/
 165 VOID
 166 EFIAPI
 167 VirtioPrepare (
 168   IN OUT VRING         *Ring,
 169   OUT    DESC_INDICES  *Indices
 170   )
 171 {
 172   //
 173   // Prepare for virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device.
 174   // We're going to poll the answer, the host should not send an interrupt.
 175   //
 176   *Ring->Avail.Flags = (UINT16)VRING_AVAIL_F_NO_INTERRUPT;
 177
 178   //
 179   // Prepare for virtio-0.9.5, 2.4.1 Supplying Buffers to the Device.
 180   //
 181   // Since we support only one in-flight descriptor chain, we can always build
 182   // that chain starting at entry #0 of the descriptor table.
 183   //
 184   Indices->HeadDescIdx = 0;
 185   Indices->NextDescIdx = Indices->HeadDescIdx;
 186 }
 187
 188 /**
 189
 190   Append a contiguous buffer for transmission / reception via the virtio ring.
 191
 192   This function implements the following section from virtio-0.9.5:
 193   - 2.4.1.1 Placing Buffers into the Descriptor Table
 194
 195   Free space is taken as granted, since the individual drivers support only
 196   synchronous requests and host side status is processed in lock-step with
 197   request submission. It is the calling driver's responsibility to verify the
 198   ring size in advance.
 199
 200   The caller is responsible for initializing *Indices with VirtioPrepare()
 201   first.
 202
 203   @param[in,out] Ring               The virtio ring to append the buffer to,
 204                                     as a descriptor.
 205
 206   @param[in] BufferDeviceAddress    (Bus master device) start address of the
 207                                     transmit / receive buffer.
 208
 209   @param[in] BufferSize             Number of bytes to transmit or receive.
 210
 211   @param[in] Flags                  A bitmask of VRING_DESC_F_* flags. The
 212                                     caller computes this mask dependent on
 213                                     further buffers to append and transfer
 214                                     direction. VRING_DESC_F_INDIRECT is
 215                                     unsupported. The VRING_DESC.Next field is
 216                                     always set, but the host only interprets
 217                                     it dependent on VRING_DESC_F_NEXT.
 218
 219   @param[in,out] Indices            Indices->HeadDescIdx is not accessed.
 220                                     On input, Indices->NextDescIdx identifies
 221                                     the next descriptor to carry the buffer.
 222                                     On output, Indices->NextDescIdx is
 223                                     incremented by one, modulo 2^16.
 224
 225 **/
 226 VOID
 227 EFIAPI
 228 VirtioAppendDesc (
 229   IN OUT VRING         *Ring,
 230   IN     UINT64        BufferDeviceAddress,
 231   IN     UINT32        BufferSize,
 232   IN     UINT16        Flags,
 233   IN OUT DESC_INDICES  *Indices
 234   )
 235 {
 236   volatile VRING_DESC  *Desc;
 237
 238   Desc        = &Ring->Desc[Indices->NextDescIdx++ % Ring->QueueSize];
 239   Desc->Addr  = BufferDeviceAddress;
 240   Desc->Len   = BufferSize;
 241   Desc->Flags = Flags;
 242   Desc->Next  = Indices->NextDescIdx % Ring->QueueSize;
 243 }
 244
 245 /**
 246
 247   Notify the host about the descriptor chain just built, and wait until the
 248   host processes it.
 249
 250   @param[in] VirtIo       The target virtio device to notify.
 251
 252   @param[in] VirtQueueId  Identifies the queue for the target device.
 253
 254   @param[in,out] Ring     The virtio ring with descriptors to submit.
 255
 256   @param[in] Indices      Indices->NextDescIdx is not accessed.
 257                           Indices->HeadDescIdx identifies the head descriptor
 258                           of the descriptor chain.
 259
 260   @param[out] UsedLen     On success, the total number of bytes, consecutively
 261                           across the buffers linked by the descriptor chain,
 262                           that the host wrote. May be NULL if the caller
 263                           doesn't care, or can compute the same information
 264                           from device-specific request structures linked by the
 265                           descriptor chain.
 266
 267   @return              Error code from VirtIo->SetQueueNotify() if it fails.
 268
 269   @retval EFI_SUCCESS  Otherwise, the host processed all descriptors.
 270
 271 **/
 272 EFI_STATUS
 273 EFIAPI
 274 VirtioFlush (
 275   IN     VIRTIO_DEVICE_PROTOCOL  *VirtIo,
 276   IN     UINT16                  VirtQueueId,
 277   IN OUT VRING                   *Ring,
 278   IN     DESC_INDICES            *Indices,
 279   OUT    UINT32                  *UsedLen    OPTIONAL
 280   )
 281 {
 282   UINT16      NextAvailIdx;
 283   UINT16      LastUsedIdx;
 284   EFI_STATUS  Status;
 285   UINTN       PollPeriodUsecs;
 286
 287   //
 288   // virtio-0.9.5, 2.4.1.2 Updating the Available Ring
 289   //
 290   // It is not exactly clear from the wording of the virtio-0.9.5
 291   // specification, but each entry in the Available Ring references only the
 292   // head descriptor of any given descriptor chain.
 293   //
 294   NextAvailIdx = *Ring->Avail.Idx;
 295   //
 296   // (Due to our lock-step progress, this is where the host will produce the
 297   // used element with the head descriptor's index in it.)
 298   //
 299   LastUsedIdx                                        = NextAvailIdx;
 300   Ring->Avail.Ring[NextAvailIdx++ % Ring->QueueSize] =
 301     Indices->HeadDescIdx % Ring->QueueSize;
 302
 303   //
 304   // virtio-0.9.5, 2.4.1.3 Updating the Index Field
 305   //
 306   MemoryFence ();
 307   *Ring->Avail.Idx = NextAvailIdx;
 308
 309   //
 310   // virtio-0.9.5, 2.4.1.4 Notifying the Device -- gratuitous notifications are
 311   // OK.
 312   //
 313   MemoryFence ();
 314   Status = VirtIo->SetQueueNotify (VirtIo, VirtQueueId);
 315   if (EFI_ERROR (Status)) {
 316     return Status;
 317   }
 318
 319   //
 320   // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
 321   // Wait until the host processes and acknowledges our descriptor chain. The
 322   // condition we use for polling is greatly simplified and relies on the
 323   // synchronous, lock-step progress.
 324   //
 325   // Keep slowing down until we reach a poll period of slightly above 1 ms.
 326   //
 327   PollPeriodUsecs = 1;
 328   MemoryFence ();
 329   while (*Ring->Used.Idx != NextAvailIdx) {
 330     gBS->Stall (PollPeriodUsecs); // calls AcpiTimerLib::MicroSecondDelay
 331
 332     if (PollPeriodUsecs < 1024) {
 333       PollPeriodUsecs *= 2;
 334     }
 335
 336     MemoryFence ();
 337   }
 338
 339   MemoryFence ();
 340
 341   if (UsedLen != NULL) {
 342     volatile CONST VRING_USED_ELEM  *UsedElem;
 343
 344     UsedElem = &Ring->Used.UsedElem[LastUsedIdx % Ring->QueueSize];
 345     ASSERT (UsedElem->Id == Indices->HeadDescIdx);
 346     *UsedLen = UsedElem->Len;
 347   }
 348
 349   return EFI_SUCCESS;
 350 }
 351
 352 /**
 353
 354   Report the feature bits to the VirtIo 1.0 device that the VirtIo 1.0 driver
 355   understands.
 356
 357   In VirtIo 1.0, a device can reject a self-inconsistent feature bitmap through
 358   the new VSTAT_FEATURES_OK status bit. (For example if the driver requests a
 359   higher level feature but clears a prerequisite feature.) This function is a
 360   small wrapper around VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures() that also
 361   verifies if the VirtIo 1.0 device accepts the feature bitmap.
 362
 363   @param[in]     VirtIo        Report feature bits to this device.
 364
 365   @param[in]     Features      The set of feature bits that the driver wishes
 366                                to report. The caller is responsible to perform
 367                                any masking before calling this function; the
 368                                value is directly written with
 369                                VIRTIO_DEVICE_PROTOCOL.SetGuestFeatures().
 370
 371   @param[in,out] DeviceStatus  On input, the status byte most recently written
 372                                to the device's status register. On output (even
 373                                on error), DeviceStatus will be updated so that
 374                                it is suitable for further status bit
 375                                manipulation and writing to the device's status
 376                                register.
 377
 378   @retval  EFI_SUCCESS      The device accepted the configuration in Features.
 379
 380   @return  EFI_UNSUPPORTED  The device rejected the configuration in Features.
 381
 382   @retval  EFI_UNSUPPORTED  VirtIo->Revision is smaller than 1.0.0.
 383
 384   @return                   Error codes from the SetGuestFeatures(),
 385                             SetDeviceStatus(), GetDeviceStatus() member
 386                             functions.
 387
 388 **/
 389 EFI_STATUS
 390 EFIAPI
 391 Virtio10WriteFeatures (
 392   IN     VIRTIO_DEVICE_PROTOCOL  *VirtIo,
 393   IN     UINT64                  Features,
 394   IN OUT UINT8                   *DeviceStatus
 395   )
 396 {
 397   EFI_STATUS  Status;
 398
 399   if (VirtIo->Revision < VIRTIO_SPEC_REVISION (1, 0, 0)) {
 400     return EFI_UNSUPPORTED;
 401   }
 402
 403   Status = VirtIo->SetGuestFeatures (VirtIo, Features);
 404   if (EFI_ERROR (Status)) {
 405     return Status;
 406   }
 407
 408   *DeviceStatus |= VSTAT_FEATURES_OK;
 409   Status         = VirtIo->SetDeviceStatus (VirtIo, *DeviceStatus);
 410   if (EFI_ERROR (Status)) {
 411     return Status;
 412   }
 413
 414   Status = VirtIo->GetDeviceStatus (VirtIo, DeviceStatus);
 415   if (EFI_ERROR (Status)) {
 416     return Status;
 417   }
 418
 419   if ((*DeviceStatus & VSTAT_FEATURES_OK) == 0) {
 420     Status = EFI_UNSUPPORTED;
 421   }
 422
 423   return Status;
 424 }
 425
 426 /**
 427   Provides the virtio device address required to access system memory from a
 428   DMA bus master.
 429
 430   The interface follows the same usage pattern as defined in UEFI spec 2.6
 431   (Section 13.2 PCI Root Bridge I/O Protocol)
 432
 433   The VirtioMapAllBytesInSharedBuffer() is similar to VIRTIO_MAP_SHARED
 434   with exception that NumberOfBytes is IN-only parameter. The function
 435   maps all the bytes specified in NumberOfBytes param in one consecutive
 436   range.
 437
 438   @param[in]     VirtIo           The virtio device for which the mapping is
 439                                   requested.
 440
 441   @param[in]     Operation        Indicates if the bus master is going to
 442                                   read or write to system memory.
 443
 444   @param[in]     HostAddress      The system memory address to map to shared
 445                                   buffer address.
 446
 447   @param[in]     NumberOfBytes    Number of bytes to map.
 448
 449   @param[out]    DeviceAddress    The resulting shared map address for the
 450                                   bus master to access the hosts HostAddress.
 451
 452   @param[out]    Mapping          A resulting token to pass to
 453                                   VIRTIO_UNMAP_SHARED.
 454
 455
 456   @retval EFI_SUCCESS             The NumberOfBytes is successfully mapped.
 457   @retval EFI_UNSUPPORTED         The HostAddress cannot be mapped as a
 458                                   common buffer.
 459   @retval EFI_INVALID_PARAMETER   One or more parameters are invalid.
 460   @retval EFI_OUT_OF_RESOURCES    The request could not be completed due to
 461                                   a lack of resources. This includes the case
 462                                   when NumberOfBytes bytes cannot be mapped
 463                                   in one consecutive range.
 464   @retval EFI_DEVICE_ERROR        The system hardware could not map the
 465                                   requested address.
 466 **/
 467 EFI_STATUS
 468 EFIAPI
 469 VirtioMapAllBytesInSharedBuffer (
 470   IN  VIRTIO_DEVICE_PROTOCOL  *VirtIo,
 471   IN  VIRTIO_MAP_OPERATION    Operation,
 472   IN  VOID                    *HostAddress,
 473   IN  UINTN                   NumberOfBytes,
 474   OUT EFI_PHYSICAL_ADDRESS    *DeviceAddress,
 475   OUT VOID                    **Mapping
 476   )
 477 {
 478   EFI_STATUS            Status;
 479   VOID                  *MapInfo;
 480   UINTN                 Size;
 481   EFI_PHYSICAL_ADDRESS  PhysicalAddress;
 482
 483   Size   = NumberOfBytes;
 484   Status = VirtIo->MapSharedBuffer (
 485                      VirtIo,
 486                      Operation,
 487                      HostAddress,
 488                      &Size,
 489                      &PhysicalAddress,
 490                      &MapInfo
 491                      );
 492   if (EFI_ERROR (Status)) {
 493     return Status;
 494   }
 495
 496   if (Size < NumberOfBytes) {
 497     goto Failed;
 498   }
 499
 500   *Mapping       = MapInfo;
 501   *DeviceAddress = PhysicalAddress;
 502
 503   return EFI_SUCCESS;
 504
 505 Failed:
 506   VirtIo->UnmapSharedBuffer (VirtIo, MapInfo);
 507   return EFI_OUT_OF_RESOURCES;
 508 }
 509
 510 /**
 511
 512   Map the ring buffer so that it can be accessed equally by both guest
 513   and hypervisor.
 514
 515   @param[in]      VirtIo          The virtio device instance.
 516
 517   @param[in]      Ring            The virtio ring to map.
 518
 519   @param[out]     RingBaseShift   A resulting translation offset, to be
 520                                   passed to VirtIo->SetQueueAddress().
 521
 522   @param[out]     Mapping         A resulting token to pass to
 523                                   VirtIo->UnmapSharedBuffer().
 524
 525   @return         Status code from VirtIo->MapSharedBuffer()
 526 **/
 527 EFI_STATUS
 528 EFIAPI
 529 VirtioRingMap (
 530   IN  VIRTIO_DEVICE_PROTOCOL  *VirtIo,
 531   IN  VRING                   *Ring,
 532   OUT UINT64                  *RingBaseShift,
 533   OUT VOID                    **Mapping
 534   )
 535 {
 536   EFI_STATUS            Status;
 537   EFI_PHYSICAL_ADDRESS  DeviceAddress;
 538
 539   Status = VirtioMapAllBytesInSharedBuffer (
 540              VirtIo,
 541              VirtioOperationBusMasterCommonBuffer,
 542              Ring->Base,
 543              EFI_PAGES_TO_SIZE (Ring->NumPages),
 544              &DeviceAddress,
 545              Mapping
 546              );
 547   if (EFI_ERROR (Status)) {
 548     return Status;
 549   }
 550
 551   *RingBaseShift = DeviceAddress - (UINT64)(UINTN)Ring->Base;
 552   return EFI_SUCCESS;
 553 }