[mirror_edk2.git] / OvmfPkg / VirtioRngDxe / VirtioRng.c

/** @file\r
\r
  This driver produces EFI_RNG_PROTOCOL instances for virtio-rng devices.\r
\r
  The implementation is based on OvmfPkg/VirtioScsiDxe/VirtioScsi.c\r
\r
  Copyright (C) 2012, Red Hat, Inc.\r
  Copyright (c) 2012 - 2014, Intel Corporation. All rights reserved.<BR>\r
  Copyright (c) 2017, AMD Inc, All rights reserved.<BR>\r
\r
  This driver:\r
\r
  Copyright (C) 2016, Linaro Ltd.\r
\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include <Library/BaseMemoryLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/MemoryAllocationLib.h>\r
#include <Library/UefiBootServicesTableLib.h>\r
#include <Library/UefiLib.h>\r
#include <Library/VirtioLib.h>\r
\r
#include "VirtioRng.h"\r
\r
/**\r
  Returns information about the random number generation implementation.\r
\r
  @param[in]     This                 A pointer to the EFI_RNG_PROTOCOL\r
                                      instance.\r
  @param[in,out] RNGAlgorithmListSize On input, the size in bytes of\r
                                      RNGAlgorithmList.\r
                                      On output with a return code of\r
                                      EFI_SUCCESS, the size in bytes of the\r
                                      data returned in RNGAlgorithmList. On\r
                                      output with a return code of\r
                                      EFI_BUFFER_TOO_SMALL, the size of\r
                                      RNGAlgorithmList required to obtain the\r
                                      list.\r
  @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled\r
                                      by the driver with one EFI_RNG_ALGORITHM\r
                                      element for each supported RNG algorithm.\r
                                      The list must not change across multiple\r
                                      calls to the same driver. The first\r
                                      algorithm in the list is the default\r
                                      algorithm for the driver.\r
\r
  @retval EFI_SUCCESS                 The RNG algorithm list was returned\r
                                      successfully.\r
  @retval EFI_UNSUPPORTED             The services is not supported by this\r
                                      driver.\r
  @retval EFI_DEVICE_ERROR            The list of algorithms could not be\r
                                      retrieved due to a hardware or firmware\r
                                      error.\r
  @retval EFI_INVALID_PARAMETER       One or more of the parameters are\r
                                      incorrect.\r
  @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small\r
                                      to hold the result.\r
\r
**/\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
VirtioRngGetInfo (\r
  IN      EFI_RNG_PROTOCOL        *This,\r
  IN OUT  UINTN                   *RNGAlgorithmListSize,\r
  OUT     EFI_RNG_ALGORITHM       *RNGAlgorithmList\r
  )\r
{\r
  if (This == NULL || RNGAlgorithmListSize == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  if (*RNGAlgorithmListSize < sizeof (EFI_RNG_ALGORITHM)) {\r
    *RNGAlgorithmListSize = sizeof (EFI_RNG_ALGORITHM);\r
    return EFI_BUFFER_TOO_SMALL;\r
  }\r
\r
  if (RNGAlgorithmList == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  *RNGAlgorithmListSize = sizeof (EFI_RNG_ALGORITHM);\r
  CopyGuid (RNGAlgorithmList, &gEfiRngAlgorithmRaw);\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Produces and returns an RNG value using either the default or specified RNG\r
  algorithm.\r
\r
  @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL\r
                                      instance.\r
  @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that\r
                                      identifies the RNG algorithm to use. May\r
                                      be NULL in which case the function will\r
                                      use its default RNG algorithm.\r
  @param[in]  RNGValueLength          The length in bytes of the memory buffer\r
                                      pointed to by RNGValue. The driver shall\r
                                      return exactly this numbers of bytes.\r
  @param[out] RNGValue                A caller-allocated memory buffer filled\r
                                      by the driver with the resulting RNG\r
                                      value.\r
\r
  @retval EFI_SUCCESS                 The RNG value was returned successfully.\r
  @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm\r
                                      is not supported by this driver.\r
  @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due\r
                                      to a hardware or firmware error.\r
  @retval EFI_NOT_READY               There is not enough random data available\r
                                      to satisfy the length requested by\r
                                      RNGValueLength.\r
  @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is\r
                                      zero.\r
\r
**/\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
VirtioRngGetRNG (\r
  IN EFI_RNG_PROTOCOL            *This,\r
  IN EFI_RNG_ALGORITHM           *RNGAlgorithm, OPTIONAL\r
  IN UINTN                       RNGValueLength,\r
  OUT UINT8                      *RNGValue\r
  )\r
{\r
  VIRTIO_RNG_DEV            *Dev;\r
  DESC_INDICES              Indices;\r
  volatile UINT8            *Buffer;\r
  UINTN                     Index;\r
  UINT32                    Len;\r
  UINT32                    BufferSize;\r
  EFI_STATUS                Status;\r
  EFI_PHYSICAL_ADDRESS      DeviceAddress;\r
  VOID                      *Mapping;\r
\r
  if (This == NULL || RNGValueLength == 0 || RNGValue == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  //\r
  // We only support the raw algorithm, so reject requests for anything else\r
  //\r
  if (RNGAlgorithm != NULL &&\r
      !CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) {\r
    return EFI_UNSUPPORTED;\r
  }\r
\r
  Buffer = (volatile UINT8 *)AllocatePool (RNGValueLength);\r
  if (Buffer == NULL) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  Dev = VIRTIO_ENTROPY_SOURCE_FROM_RNG (This);\r
  //\r
  // Map Buffer's system phyiscal address to device address\r
  //\r
  Status = VirtioMapAllBytesInSharedBuffer (\r
             Dev->VirtIo,\r
             VirtioOperationBusMasterWrite,\r
             (VOID *)Buffer,\r
             RNGValueLength,\r
             &DeviceAddress,\r
             &Mapping\r
             );\r
  if (EFI_ERROR (Status)) {\r
    Status = EFI_DEVICE_ERROR;\r
    goto FreeBuffer;\r
  }\r
\r
  //\r
  // The Virtio RNG device may return less data than we asked it to, and can\r
  // only return MAX_UINT32 bytes per invocation. So loop as long as needed to\r
  // get all the entropy we were asked for.\r
  //\r
  for (Index = 0; Index < RNGValueLength; Index += Len) {\r
    BufferSize = (UINT32)MIN (RNGValueLength - Index, (UINTN)MAX_UINT32);\r
\r
    VirtioPrepare (&Dev->Ring, &Indices);\r
    VirtioAppendDesc (&Dev->Ring,\r
      DeviceAddress + Index,\r
      BufferSize,\r
      VRING_DESC_F_WRITE,\r
      &Indices);\r
\r
    if (VirtioFlush (Dev->VirtIo, 0, &Dev->Ring, &Indices, &Len) !=\r
        EFI_SUCCESS) {\r
      Status = EFI_DEVICE_ERROR;\r
      goto UnmapBuffer;\r
    }\r
    ASSERT (Len > 0);\r
    ASSERT (Len <= BufferSize);\r
  }\r
\r
  //\r
  // Unmap the device buffer before accessing it.\r
  //\r
  Status = Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Mapping);\r
  if (EFI_ERROR (Status)) {\r
    Status = EFI_DEVICE_ERROR;\r
    goto FreeBuffer;\r
  }\r
\r
  for (Index = 0; Index < RNGValueLength; Index++) {\r
    RNGValue[Index] = Buffer[Index];\r
  }\r
  Status = EFI_SUCCESS;\r
\r
UnmapBuffer:\r
  //\r
  // If we are reached here due to the error then unmap the buffer otherwise\r
  // the buffer is already unmapped after VirtioFlush().\r
  //\r
  if (EFI_ERROR (Status)) {\r
    Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Mapping);\r
  }\r
\r
FreeBuffer:\r
  FreePool ((VOID *)Buffer);\r
  return Status;\r
}\r
\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
VirtioRngInit (\r
  IN OUT VIRTIO_RNG_DEV *Dev\r
  )\r
{\r
  UINT8      NextDevStat;\r
  EFI_STATUS Status;\r
  UINT16     QueueSize;\r
  UINT64     Features;\r
  UINT64     RingBaseShift;\r
\r
  //\r
  // Execute virtio-0.9.5, 2.2.1 Device Initialization Sequence.\r
  //\r
  NextDevStat = 0;             // step 1 -- reset device\r
  Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);\r
  if (EFI_ERROR (Status)) {\r
    goto Failed;\r
  }\r
\r
  NextDevStat |= VSTAT_ACK;    // step 2 -- acknowledge device presence\r
  Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);\r
  if (EFI_ERROR (Status)) {\r
    goto Failed;\r
  }\r
\r
  NextDevStat |= VSTAT_DRIVER; // step 3 -- we know how to drive it\r
  Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);\r
  if (EFI_ERROR (Status)) {\r
    goto Failed;\r
  }\r
\r
  //\r
  // Set Page Size - MMIO VirtIo Specific\r
  //\r
  Status = Dev->VirtIo->SetPageSize (Dev->VirtIo, EFI_PAGE_SIZE);\r
  if (EFI_ERROR (Status)) {\r
    goto Failed;\r
  }\r
\r
  //\r
  // step 4a -- retrieve and validate features\r
  //\r
  Status = Dev->VirtIo->GetDeviceFeatures (Dev->VirtIo, &Features);\r
  if (EFI_ERROR (Status)) {\r
    goto Failed;\r
  }\r
\r
  Features &= VIRTIO_F_VERSION_1 | VIRTIO_F_IOMMU_PLATFORM;\r
\r
  //\r
  // In virtio-1.0, feature negotiation is expected to complete before queue\r
  // discovery, and the device can also reject the selected set of features.\r
  //\r
  if (Dev->VirtIo->Revision >= VIRTIO_SPEC_REVISION (1, 0, 0)) {\r
    Status = Virtio10WriteFeatures (Dev->VirtIo, Features, &NextDevStat);\r
    if (EFI_ERROR (Status)) {\r
      goto Failed;\r
    }\r
  }\r
\r
  //\r
  // step 4b -- allocate request virtqueue, just use #0\r
  //\r
  Status = Dev->VirtIo->SetQueueSel (Dev->VirtIo, 0);\r
  if (EFI_ERROR (Status)) {\r
    goto Failed;\r
  }\r
  Status = Dev->VirtIo->GetQueueNumMax (Dev->VirtIo, &QueueSize);\r
  if (EFI_ERROR (Status)) {\r
    goto Failed;\r
  }\r
\r
  //\r
  // VirtioRngGetRNG() uses one descriptor\r
  //\r
  if (QueueSize < 1) {\r
    Status = EFI_UNSUPPORTED;\r
    goto Failed;\r
  }\r
\r
  Status = VirtioRingInit (Dev->VirtIo, QueueSize, &Dev->Ring);\r
  if (EFI_ERROR (Status)) {\r
    goto Failed;\r
  }\r
\r
  //\r
  // If anything fails from here on, we must release the ring resources.\r
  //\r
  Status = VirtioRingMap (\r
             Dev->VirtIo,\r
             &Dev->Ring,\r
             &RingBaseShift,\r
             &Dev->RingMap\r
             );\r
  if (EFI_ERROR (Status)) {\r
    goto ReleaseQueue;\r
  }\r
\r
  //\r
  // Additional steps for MMIO: align the queue appropriately, and set the\r
  // size. If anything fails from here on, we must unmap the ring resources.\r
  //\r
  Status = Dev->VirtIo->SetQueueNum (Dev->VirtIo, QueueSize);\r
  if (EFI_ERROR (Status)) {\r
    goto UnmapQueue;\r
  }\r
\r
  Status = Dev->VirtIo->SetQueueAlign (Dev->VirtIo, EFI_PAGE_SIZE);\r
  if (EFI_ERROR (Status)) {\r
    goto UnmapQueue;\r
  }\r
\r
  //\r
  // step 4c -- Report GPFN (guest-physical frame number) of queue.\r
  //\r
  Status = Dev->VirtIo->SetQueueAddress (\r
                          Dev->VirtIo,\r
                          &Dev->Ring,\r
                          RingBaseShift\r
                          );\r
  if (EFI_ERROR (Status)) {\r
    goto UnmapQueue;\r
  }\r
\r
  //\r
  // step 5 -- Report understood features and guest-tuneables.\r
  //\r
  if (Dev->VirtIo->Revision < VIRTIO_SPEC_REVISION (1, 0, 0)) {\r
    Features &= ~(UINT64)(VIRTIO_F_VERSION_1 | VIRTIO_F_IOMMU_PLATFORM);\r
    Status = Dev->VirtIo->SetGuestFeatures (Dev->VirtIo, Features);\r
    if (EFI_ERROR (Status)) {\r
      goto UnmapQueue;\r
    }\r
  }\r
\r
  //\r
  // step 6 -- initialization complete\r
  //\r
  NextDevStat |= VSTAT_DRIVER_OK;\r
  Status = Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);\r
  if (EFI_ERROR (Status)) {\r
    goto UnmapQueue;\r
  }\r
\r
  //\r
  // populate the exported interface's attributes\r
  //\r
  Dev->Rng.GetInfo    = VirtioRngGetInfo;\r
  Dev->Rng.GetRNG     = VirtioRngGetRNG;\r
\r
  return EFI_SUCCESS;\r
\r
UnmapQueue:\r
  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RingMap);\r
\r
ReleaseQueue:\r
  VirtioRingUninit (Dev->VirtIo, &Dev->Ring);\r
\r
Failed:\r
  //\r
  // Notify the host about our failure to setup: virtio-0.9.5, 2.2.2.1 Device\r
  // Status. VirtIo access failure here should not mask the original error.\r
  //\r
  NextDevStat |= VSTAT_FAILED;\r
  Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, NextDevStat);\r
\r
  return Status; // reached only via Failed above\r
}\r
\r
\r
STATIC\r
VOID\r
EFIAPI\r
VirtioRngUninit (\r
  IN OUT VIRTIO_RNG_DEV *Dev\r
  )\r
{\r
  //\r
  // Reset the virtual device -- see virtio-0.9.5, 2.2.2.1 Device Status. When\r
  // VIRTIO_CFG_WRITE() returns, the host will have learned to stay away from\r
  // the old comms area.\r
  //\r
  Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);\r
\r
  Dev->VirtIo->UnmapSharedBuffer (Dev->VirtIo, Dev->RingMap);\r
\r
  VirtioRingUninit (Dev->VirtIo, &Dev->Ring);\r
}\r
\r
//\r
// Event notification function enqueued by ExitBootServices().\r
//\r
\r
STATIC\r
VOID\r
EFIAPI\r
VirtioRngExitBoot (\r
  IN  EFI_EVENT Event,\r
  IN  VOID      *Context\r
  )\r
{\r
  VIRTIO_RNG_DEV *Dev;\r
\r
  DEBUG ((DEBUG_VERBOSE, "%a: Context=0x%p\n", __FUNCTION__, Context));\r
  //\r
  // Reset the device. This causes the hypervisor to forget about the virtio\r
  // ring.\r
  //\r
  // We allocated said ring in EfiBootServicesData type memory, and code\r
  // executing after ExitBootServices() is permitted to overwrite it.\r
  //\r
  Dev = Context;\r
  Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);\r
}\r
\r
\r
//\r
// Probe, start and stop functions of this driver, called by the DXE core for\r
// specific devices.\r
//\r
// The following specifications document these interfaces:\r
// - Driver Writer's Guide for UEFI 2.3.1 v1.01, 9 Driver Binding Protocol\r
// - UEFI Spec 2.3.1 + Errata C, 10.1 EFI Driver Binding Protocol\r
//\r
// The implementation follows:\r
// - Driver Writer's Guide for UEFI 2.3.1 v1.01\r
//   - 5.1.3.4 OpenProtocol() and CloseProtocol()\r
// - UEFI Spec 2.3.1 + Errata C\r
//   -  6.3 Protocol Handler Services\r
//\r
\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
VirtioRngDriverBindingSupported (\r
  IN EFI_DRIVER_BINDING_PROTOCOL *This,\r
  IN EFI_HANDLE                  DeviceHandle,\r
  IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath\r
  )\r
{\r
  EFI_STATUS             Status;\r
  VIRTIO_DEVICE_PROTOCOL *VirtIo;\r
\r
  //\r
  // Attempt to open the device with the VirtIo set of interfaces. On success,\r
  // the protocol is "instantiated" for the VirtIo device. Covers duplicate\r
  // open attempts (EFI_ALREADY_STARTED).\r
  //\r
  Status = gBS->OpenProtocol (\r
                  DeviceHandle,               // candidate device\r
                  &gVirtioDeviceProtocolGuid, // for generic VirtIo access\r
                  (VOID **)&VirtIo,           // handle to instantiate\r
                  This->DriverBindingHandle,  // requestor driver identity\r
                  DeviceHandle,               // ControllerHandle, according to\r
                                              // the UEFI Driver Model\r
                  EFI_OPEN_PROTOCOL_BY_DRIVER // get exclusive VirtIo access to\r
                                              // the device; to be released\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  if (VirtIo->SubSystemDeviceId != VIRTIO_SUBSYSTEM_ENTROPY_SOURCE) {\r
    Status = EFI_UNSUPPORTED;\r
  }\r
\r
  //\r
  // We needed VirtIo access only transitorily, to see whether we support the\r
  // device or not.\r
  //\r
  gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,\r
         This->DriverBindingHandle, DeviceHandle);\r
  return Status;\r
}\r
\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
VirtioRngDriverBindingStart (\r
  IN EFI_DRIVER_BINDING_PROTOCOL *This,\r
  IN EFI_HANDLE                  DeviceHandle,\r
  IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath\r
  )\r
{\r
  VIRTIO_RNG_DEV  *Dev;\r
  EFI_STATUS Status;\r
\r
  Dev = (VIRTIO_RNG_DEV *) AllocateZeroPool (sizeof *Dev);\r
  if (Dev == NULL) {\r
    return EFI_OUT_OF_RESOURCES;\r
  }\r
\r
  Status = gBS->OpenProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,\r
                  (VOID **)&Dev->VirtIo, This->DriverBindingHandle,\r
                  DeviceHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);\r
  if (EFI_ERROR (Status)) {\r
    goto FreeVirtioRng;\r
  }\r
\r
  //\r
  // VirtIo access granted, configure virtio-rng device.\r
  //\r
  Status = VirtioRngInit (Dev);\r
  if (EFI_ERROR (Status)) {\r
    goto CloseVirtIo;\r
  }\r
\r
  Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,\r
                  &VirtioRngExitBoot, Dev, &Dev->ExitBoot);\r
  if (EFI_ERROR (Status)) {\r
    goto UninitDev;\r
  }\r
\r
  //\r
  // Setup complete, attempt to export the driver instance's EFI_RNG_PROTOCOL\r
  // interface.\r
  //\r
  Dev->Signature = VIRTIO_RNG_SIG;\r
  Status = gBS->InstallProtocolInterface (&DeviceHandle,\r
                  &gEfiRngProtocolGuid, EFI_NATIVE_INTERFACE,\r
                  &Dev->Rng);\r
  if (EFI_ERROR (Status)) {\r
    goto CloseExitBoot;\r
  }\r
\r
  return EFI_SUCCESS;\r
\r
CloseExitBoot:\r
  gBS->CloseEvent (Dev->ExitBoot);\r
\r
UninitDev:\r
  VirtioRngUninit (Dev);\r
\r
CloseVirtIo:\r
  gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,\r
         This->DriverBindingHandle, DeviceHandle);\r
\r
FreeVirtioRng:\r
  FreePool (Dev);\r
\r
  return Status;\r
}\r
\r
\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
VirtioRngDriverBindingStop (\r
  IN EFI_DRIVER_BINDING_PROTOCOL *This,\r
  IN EFI_HANDLE                  DeviceHandle,\r
  IN UINTN                       NumberOfChildren,\r
  IN EFI_HANDLE                  *ChildHandleBuffer\r
  )\r
{\r
  EFI_STATUS                      Status;\r
  EFI_RNG_PROTOCOL                *Rng;\r
  VIRTIO_RNG_DEV                  *Dev;\r
\r
  Status = gBS->OpenProtocol (\r
                  DeviceHandle,                     // candidate device\r
                  &gEfiRngProtocolGuid,             // retrieve the RNG iface\r
                  (VOID **)&Rng,                    // target pointer\r
                  This->DriverBindingHandle,        // requestor driver ident.\r
                  DeviceHandle,                     // lookup req. for dev.\r
                  EFI_OPEN_PROTOCOL_GET_PROTOCOL    // lookup only, no new ref.\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  Dev = VIRTIO_ENTROPY_SOURCE_FROM_RNG (Rng);\r
\r
  //\r
  // Handle Stop() requests for in-use driver instances gracefully.\r
  //\r
  Status = gBS->UninstallProtocolInterface (DeviceHandle,\r
                  &gEfiRngProtocolGuid, &Dev->Rng);\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  gBS->CloseEvent (Dev->ExitBoot);\r
\r
  VirtioRngUninit (Dev);\r
\r
  gBS->CloseProtocol (DeviceHandle, &gVirtioDeviceProtocolGuid,\r
         This->DriverBindingHandle, DeviceHandle);\r
\r
  FreePool (Dev);\r
\r
  return EFI_SUCCESS;\r
}\r
\r
\r
//\r
// The static object that groups the Supported() (ie. probe), Start() and\r
// Stop() functions of the driver together. Refer to UEFI Spec 2.3.1 + Errata\r
// C, 10.1 EFI Driver Binding Protocol.\r
//\r
STATIC EFI_DRIVER_BINDING_PROTOCOL gDriverBinding = {\r
  &VirtioRngDriverBindingSupported,\r
  &VirtioRngDriverBindingStart,\r
  &VirtioRngDriverBindingStop,\r
  0x10, // Version, must be in [0x10 .. 0xFFFFFFEF] for IHV-developed drivers\r
  NULL, // ImageHandle, to be overwritten by\r
        // EfiLibInstallDriverBindingComponentName2() in VirtioRngEntryPoint()\r
  NULL  // DriverBindingHandle, ditto\r
};\r
\r
\r
//\r
// The purpose of the following scaffolding (EFI_COMPONENT_NAME_PROTOCOL and\r
// EFI_COMPONENT_NAME2_PROTOCOL implementation) is to format the driver's name\r
// in English, for display on standard console devices. This is recommended for\r
// UEFI drivers that follow the UEFI Driver Model. Refer to the Driver Writer's\r
// Guide for UEFI 2.3.1 v1.01, 11 UEFI Driver and Controller Names.\r
//\r
\r
STATIC\r
EFI_UNICODE_STRING_TABLE mDriverNameTable[] = {\r
  { "eng;en", L"Virtio Random Number Generator Driver" },\r
  { NULL,     NULL                   }\r
};\r
\r
STATIC\r
EFI_COMPONENT_NAME_PROTOCOL gComponentName;\r
\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
VirtioRngGetDriverName (\r
  IN  EFI_COMPONENT_NAME_PROTOCOL *This,\r
  IN  CHAR8                       *Language,\r
  OUT CHAR16                      **DriverName\r
  )\r
{\r
  return LookupUnicodeString2 (\r
           Language,\r
           This->SupportedLanguages,\r
           mDriverNameTable,\r
           DriverName,\r
           (BOOLEAN)(This == &gComponentName) // Iso639Language\r
           );\r
}\r
\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
VirtioRngGetDeviceName (\r
  IN  EFI_COMPONENT_NAME_PROTOCOL *This,\r
  IN  EFI_HANDLE                  DeviceHandle,\r
  IN  EFI_HANDLE                  ChildHandle,\r
  IN  CHAR8                       *Language,\r
  OUT CHAR16                      **ControllerName\r
  )\r
{\r
  return EFI_UNSUPPORTED;\r
}\r
\r
STATIC\r
EFI_COMPONENT_NAME_PROTOCOL gComponentName = {\r
  &VirtioRngGetDriverName,\r
  &VirtioRngGetDeviceName,\r
  "eng" // SupportedLanguages, ISO 639-2 language codes\r
};\r
\r
STATIC\r
EFI_COMPONENT_NAME2_PROTOCOL gComponentName2 = {\r
  (EFI_COMPONENT_NAME2_GET_DRIVER_NAME)     &VirtioRngGetDriverName,\r
  (EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME) &VirtioRngGetDeviceName,\r
  "en" // SupportedLanguages, RFC 4646 language codes\r
};\r
\r
\r
//\r
// Entry point of this driver.\r
//\r
EFI_STATUS\r
EFIAPI\r
VirtioRngEntryPoint (\r
  IN EFI_HANDLE       ImageHandle,\r
  IN EFI_SYSTEM_TABLE *SystemTable\r
  )\r
{\r
  return EfiLibInstallDriverBindingComponentName2 (\r
           ImageHandle,\r
           SystemTable,\r
           &gDriverBinding,\r
           ImageHandle,\r
           &gComponentName,\r
           &gComponentName2\r
           );\r
}\r