OvmfPkg/PlatformPei/FeatureControl.c

/**@file
  Install a callback when necessary for setting the Feature Control MSR on all
  processors.

  Copyright (C) 2016, Red Hat, Inc.

  This program and the accompanying materials are licensed and made available
  under the terms and conditions of the BSD License which accompanies this
  distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/

#include <Library/DebugLib.h>
#include <Library/PeiServicesLib.h>
#include <Library/QemuFwCfgLib.h>
#include <Ppi/MpServices.h>
#include <Register/Msr/Core2Msr.h>

#include "Platform.h"

//
// The value to be written to the Feature Control MSR, retrieved from fw_cfg.
//
STATIC UINT64 mFeatureControlValue;

/**
  Write the Feature Control MSR on an Application Processor or the Boot
  Processor.

  All APs execute this function in parallel. The BSP executes the function
  separately.

  @param[in,out] WorkSpace  Pointer to the input/output argument workspace
                            shared by all processors.
**/
STATIC
VOID
EFIAPI
WriteFeatureControl (
  IN OUT VOID *WorkSpace
  )
{
  AsmWriteMsr64 (MSR_CORE2_FEATURE_CONTROL, mFeatureControlValue);
}

/**
  Notification function called when EFI_PEI_MP_SERVICES_PPI becomes available.

  @param[in] PeiServices      Indirect reference to the PEI Services Table.
  @param[in] NotifyDescriptor Address of the notification descriptor data
                              structure.
  @param[in] Ppi              Address of the PPI that was installed.

  @return  Status of the notification. The status code returned from this
           function is ignored.
**/
STATIC
EFI_STATUS
EFIAPI
OnMpServicesAvailable (
  IN EFI_PEI_SERVICES           **PeiServices,
  IN EFI_PEI_NOTIFY_DESCRIPTOR  *NotifyDescriptor,
  IN VOID                       *Ppi
  )
{
  EFI_PEI_MP_SERVICES_PPI *MpServices;
  EFI_STATUS              Status;

  DEBUG ((EFI_D_VERBOSE, "%a: %a\n", gEfiCallerBaseName, __FUNCTION__));

  //
  // Write the MSR on all the APs in parallel.
  //
  MpServices = Ppi;
  Status = MpServices->StartupAllAPs (
                         (CONST EFI_PEI_SERVICES **)PeiServices,
                         MpServices,
                         WriteFeatureControl, // Procedure
                         FALSE,               // SingleThread
                         0,                   // TimeoutInMicroSeconds: inf.
                         NULL                 // ProcedureArgument
                         );
  if (EFI_ERROR (Status) && Status != EFI_NOT_STARTED) {
    DEBUG ((EFI_D_ERROR, "%a: StartupAllAps(): %r\n", __FUNCTION__, Status));
    return Status;
  }

  //
  // Now write the MSR on the BSP too.
  //
  WriteFeatureControl (NULL);
  return EFI_SUCCESS;
}

//
// Notification object for registering the callback, for when
// EFI_PEI_MP_SERVICES_PPI becomes available.
//
STATIC CONST EFI_PEI_NOTIFY_DESCRIPTOR mMpServicesNotify = {
  EFI_PEI_PPI_DESCRIPTOR_NOTIFY_CALLBACK | // Flags
  EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST,
  &gEfiPeiMpServicesPpiGuid,               // Guid
  OnMpServicesAvailable                    // Notify
};

VOID
InstallFeatureControlCallback (
  VOID
  )
{
  EFI_STATUS           Status;
  FIRMWARE_CONFIG_ITEM FwCfgItem;
  UINTN                FwCfgSize;

  Status = QemuFwCfgFindFile ("etc/msr_feature_control", &FwCfgItem,
             &FwCfgSize);
  if (EFI_ERROR (Status) || FwCfgSize != sizeof mFeatureControlValue) {
    //
    // Nothing to do.
    //
    return;
  }
  QemuFwCfgSelectItem (FwCfgItem);
  QemuFwCfgReadBytes (sizeof mFeatureControlValue, &mFeatureControlValue);

  Status = PeiServicesNotifyPpi (&mMpServicesNotify);
  if (EFI_ERROR (Status)) {
    DEBUG ((EFI_D_ERROR, "%a: failed to set up MP Services callback: %r\n",
      __FUNCTION__, Status));
  }
}