audk/OvmfPkg/TdxDxe/TdxDxe.c

/** @file

  TDX Dxe driver. This driver is dispatched early in DXE, due to being list
  in APRIORI.

  This module is responsible for:
    - Sets max logical cpus based on TDINFO
    - Sets PCI PCDs based on resource hobs
    - Alter MATD table to record address of Mailbox

  Copyright (c) 2020 - 2021, Intel Corporation. All rights reserved.<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/DxeServicesTableLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiLib.h>
#include <Library/HobLib.h>
#include <Protocol/Cpu.h>
#include <Library/UefiBootServicesTableLib.h>
#include <IndustryStandard/Tdx.h>
#include <Library/PlatformInitLib.h>
#include <Library/TdxLib.h>
#include <TdxAcpiTable.h>
#include <Library/MemEncryptTdxLib.h>

/**
  Location of resource hob matching type and starting address

  @param[in]  Type             The type of resource hob to locate.

  @param[in]  Start            The resource hob must at least begin at address.

  @retval pointer to resource  Return pointer to a resource hob that matches or NULL.
**/
STATIC
EFI_HOB_RESOURCE_DESCRIPTOR *
GetResourceDescriptor (
  EFI_RESOURCE_TYPE     Type,
  EFI_PHYSICAL_ADDRESS  Start,
  EFI_PHYSICAL_ADDRESS  End
  )
{
  EFI_PEI_HOB_POINTERS         Hob;
  EFI_HOB_RESOURCE_DESCRIPTOR  *ResourceDescriptor = NULL;

  Hob.Raw = GetFirstHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR);
  while (Hob.Raw != NULL) {
    DEBUG ((
      DEBUG_INFO,
      "%a:%d: resource type 0x%x %llx %llx\n",
      __func__,
      __LINE__,
      Hob.ResourceDescriptor->ResourceType,
      Hob.ResourceDescriptor->PhysicalStart,
      Hob.ResourceDescriptor->ResourceLength
      ));

    if ((Hob.ResourceDescriptor->ResourceType == Type) &&
        (Hob.ResourceDescriptor->PhysicalStart >= Start) &&
        ((Hob.ResourceDescriptor->PhysicalStart + Hob.ResourceDescriptor->ResourceLength) < End))
    {
      ResourceDescriptor = Hob.ResourceDescriptor;
      break;
    }

    Hob.Raw = GET_NEXT_HOB (Hob);
    Hob.Raw = GetNextHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR, Hob.Raw);
  }

  return ResourceDescriptor;
}

/**
  Location of resource hob matching type and highest address below end

  @param[in]  Type             The type of resource hob to locate.

  @param[in]  End              The resource hob return is the closest to the End address

  @retval pointer to resource  Return pointer to a resource hob that matches or NULL.
**/
STATIC
EFI_HOB_RESOURCE_DESCRIPTOR *
GetHighestResourceDescriptor (
  EFI_RESOURCE_TYPE     Type,
  EFI_PHYSICAL_ADDRESS  End
  )
{
  EFI_PEI_HOB_POINTERS         Hob;
  EFI_HOB_RESOURCE_DESCRIPTOR  *ResourceDescriptor = NULL;

  Hob.Raw = GetFirstHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR);
  while (Hob.Raw != NULL) {
    if ((Hob.ResourceDescriptor->ResourceType == Type) &&
        (Hob.ResourceDescriptor->PhysicalStart < End))
    {
      if (!ResourceDescriptor ||
          (ResourceDescriptor->PhysicalStart < Hob.ResourceDescriptor->PhysicalStart))
      {
        ResourceDescriptor = Hob.ResourceDescriptor;
      }
    }

    Hob.Raw = GET_NEXT_HOB (Hob);
    Hob.Raw = GetNextHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR, Hob.Raw);
  }

  return ResourceDescriptor;
}

/**
  Set the shared bit for mmio region in Tdx guest.

  In Tdx guest there are 2 ways to access mmio, TdVmcall or direct access.
  For direct access, the shared bit of the PageTableEntry should be set.
  The mmio region information is retrieved from hob list.

  @retval EFI_SUCCESS                 The shared bit is set successfully.
  @retval EFI_UNSUPPORTED             Setting the shared bit of memory region
                                      is not supported
**/
EFI_STATUS
SetMmioSharedBit (
  VOID
  )
{
  EFI_PEI_HOB_POINTERS  Hob;

  Hob.Raw = (UINT8 *)GetHobList ();

  //
  // Parse the HOB list until end of list or matching type is found.
  //
  while (!END_OF_HOB_LIST (Hob)) {
    if (  (Hob.Header->HobType == EFI_HOB_TYPE_RESOURCE_DESCRIPTOR)
       && (Hob.ResourceDescriptor->ResourceType == EFI_RESOURCE_MEMORY_MAPPED_IO))
    {
      MemEncryptTdxSetPageSharedBit (
        0,
        Hob.ResourceDescriptor->PhysicalStart,
        EFI_SIZE_TO_PAGES (Hob.ResourceDescriptor->ResourceLength)
        );
    }

    Hob.Raw = GET_NEXT_HOB (Hob);
  }

  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
TdxDxeEntryPoint (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS                   Status;
  RETURN_STATUS                PcdStatus;
  EFI_HOB_RESOURCE_DESCRIPTOR  *Res          = NULL;
  EFI_HOB_RESOURCE_DESCRIPTOR  *MemRes       = NULL;
  EFI_HOB_PLATFORM_INFO        *PlatformInfo = NULL;
  EFI_HOB_GUID_TYPE            *GuidHob;
  UINT32                       CpuMaxLogicalProcessorNumber;
  TD_RETURN_DATA               TdReturnData;
  EFI_EVENT                    QemuAcpiTableEvent;
  void                         *Registration;

  GuidHob = GetFirstGuidHob (&gUefiOvmfPkgPlatformInfoGuid);

  if (GuidHob == NULL) {
    return EFI_UNSUPPORTED;
  }

  //
  // Both Td and Non-Td guest have PlatformInfoHob which contains the HostBridgePciDevId
  //
  PlatformInfo = (EFI_HOB_PLATFORM_INFO *)GET_GUID_HOB_DATA (GuidHob);
  ASSERT (PlatformInfo->HostBridgeDevId != 0);
  PcdStatus = PcdSet16S (PcdOvmfHostBridgePciDevId, PlatformInfo->HostBridgeDevId);
  ASSERT_RETURN_ERROR (PcdStatus);

  if (!TdIsEnabled ()) {
    return EFI_UNSUPPORTED;
  }

  SetMmioSharedBit ();

  //
  // Call TDINFO to get actual number of cpus in domain
  //
  Status = TdCall (TDCALL_TDINFO, 0, 0, 0, &TdReturnData);
  ASSERT (Status == EFI_SUCCESS);

  CpuMaxLogicalProcessorNumber = PcdGet32 (PcdCpuMaxLogicalProcessorNumber);

  //
  // Adjust PcdCpuMaxLogicalProcessorNumber, if needed. If firmware is configured for
  // more than number of reported cpus, update.
  //
  if (CpuMaxLogicalProcessorNumber > TdReturnData.TdInfo.NumVcpus) {
    PcdStatus = PcdSet32S (PcdCpuMaxLogicalProcessorNumber, TdReturnData.TdInfo.NumVcpus);
    ASSERT_RETURN_ERROR (PcdStatus);
  }

  //
  // Register for protocol notifications to call the AlterAcpiTable(),
  // the protocol will be installed in AcpiPlatformDxe when the ACPI
  // table provided by Qemu is ready.
  //
  Status = gBS->CreateEvent (
                  EVT_NOTIFY_SIGNAL,
                  TPL_CALLBACK,
                  AlterAcpiTable,
                  NULL,
                  &QemuAcpiTableEvent
                  );

  Status = gBS->RegisterProtocolNotify (
                  &gQemuAcpiTableNotifyProtocolGuid,
                  QemuAcpiTableEvent,
                  &Registration
                  );

  #define INIT_PCDSET(NAME, RES)  do {\
  PcdStatus = PcdSet64S (NAME##Base, (RES)->PhysicalStart); \
  ASSERT_RETURN_ERROR (PcdStatus); \
  PcdStatus = PcdSet64S (NAME##Size, (RES)->ResourceLength); \
  ASSERT_RETURN_ERROR (PcdStatus); \
} while(0)

  if (PlatformInfo) {
    PcdSet16S (PcdOvmfHostBridgePciDevId, PlatformInfo->HostBridgeDevId);

    if ((Res = GetResourceDescriptor (EFI_RESOURCE_MEMORY_MAPPED_IO, (EFI_PHYSICAL_ADDRESS)0x100000000, (EFI_PHYSICAL_ADDRESS)-1)) != NULL) {
      INIT_PCDSET (PcdPciMmio64, Res);
    }

    if ((Res = GetResourceDescriptor (EFI_RESOURCE_IO, 0, 0x10001)) != NULL) {
      INIT_PCDSET (PcdPciIo, Res);
    }

    //
    // To find low mmio, first find top of low memory, and then search for io space.
    //
    if ((MemRes = GetHighestResourceDescriptor (EFI_RESOURCE_SYSTEM_MEMORY, 0xffc00000)) != NULL) {
      if ((Res = GetResourceDescriptor (EFI_RESOURCE_MEMORY_MAPPED_IO, MemRes->PhysicalStart, 0x100000000)) != NULL) {
        INIT_PCDSET (PcdPciMmio32, Res);
      }
    }
  }

  return EFI_SUCCESS;
}