OvmfPkg/PlatformPei/FeatureControl.c

   1 /**@file
   2   Install a callback when necessary for setting the Feature Control MSR on all
   3   processors.
   4
   5   Copyright (C) 2016, Red Hat, Inc.
   6
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8 **/
   9
  10 #include <Library/DebugLib.h>
  11 #include <Library/PeiServicesLib.h>
  12 #include <Library/QemuFwCfgLib.h>
  13 #include <Ppi/MpServices.h>
  14 #include <Register/Msr/Core2Msr.h>
  15
  16 #include "Platform.h"
  17
  18 //
  19 // The value to be written to the Feature Control MSR, retrieved from fw_cfg.
  20 //
  21 STATIC UINT64 mFeatureControlValue;
  22
  23 /**
  24   Write the Feature Control MSR on an Application Processor or the Boot
  25   Processor.
  26
  27   All APs execute this function in parallel. The BSP executes the function
  28   separately.
  29
  30   @param[in,out] WorkSpace  Pointer to the input/output argument workspace
  31                             shared by all processors.
  32 **/
  33 STATIC
  34 VOID
  35 EFIAPI
  36 WriteFeatureControl (
  37   IN OUT VOID *WorkSpace
  38   )
  39 {
  40   AsmWriteMsr64 (MSR_CORE2_FEATURE_CONTROL, mFeatureControlValue);
  41 }
  42
  43 /**
  44   Notification function called when EFI_PEI_MP_SERVICES_PPI becomes available.
  45
  46   @param[in] PeiServices      Indirect reference to the PEI Services Table.
  47   @param[in] NotifyDescriptor Address of the notification descriptor data
  48                               structure.
  49   @param[in] Ppi              Address of the PPI that was installed.
  50
  51   @return  Status of the notification. The status code returned from this
  52            function is ignored.
  53 **/
  54 STATIC
  55 EFI_STATUS
  56 EFIAPI
  57 OnMpServicesAvailable (
  58   IN EFI_PEI_SERVICES           **PeiServices,
  59   IN EFI_PEI_NOTIFY_DESCRIPTOR  *NotifyDescriptor,
  60   IN VOID                       *Ppi
  61   )
  62 {
  63   EFI_PEI_MP_SERVICES_PPI *MpServices;
  64   EFI_STATUS              Status;
  65
  66   DEBUG ((EFI_D_VERBOSE, "%a: %a\n", gEfiCallerBaseName, __FUNCTION__));
  67
  68   //
  69   // Write the MSR on all the APs in parallel.
  70   //
  71   MpServices = Ppi;
  72   Status = MpServices->StartupAllAPs (
  73                          (CONST EFI_PEI_SERVICES **)PeiServices,
  74                          MpServices,
  75                          WriteFeatureControl, // Procedure
  76                          FALSE,               // SingleThread
  77                          0,                   // TimeoutInMicroSeconds: inf.
  78                          NULL                 // ProcedureArgument
  79                          );
  80   if (EFI_ERROR (Status) && Status != EFI_NOT_STARTED) {
  81     DEBUG ((EFI_D_ERROR, "%a: StartupAllAps(): %r\n", __FUNCTION__, Status));
  82     return Status;
  83   }
  84
  85   //
  86   // Now write the MSR on the BSP too.
  87   //
  88   WriteFeatureControl (NULL);
  89   return EFI_SUCCESS;
  90 }
  91
  92 //
  93 // Notification object for registering the callback, for when
  94 // EFI_PEI_MP_SERVICES_PPI becomes available.
  95 //
  96 STATIC CONST EFI_PEI_NOTIFY_DESCRIPTOR mMpServicesNotify = {
  97   EFI_PEI_PPI_DESCRIPTOR_NOTIFY_CALLBACK | // Flags
  98   EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST,
  99   &gEfiPeiMpServicesPpiGuid,               // Guid
 100   OnMpServicesAvailable                    // Notify
 101 };
 102
 103 VOID
 104 InstallFeatureControlCallback (
 105   VOID
 106   )
 107 {
 108   EFI_STATUS           Status;
 109   FIRMWARE_CONFIG_ITEM FwCfgItem;
 110   UINTN                FwCfgSize;
 111
 112   Status = QemuFwCfgFindFile ("etc/msr_feature_control", &FwCfgItem,
 113              &FwCfgSize);
 114   if (EFI_ERROR (Status) || FwCfgSize != sizeof mFeatureControlValue) {
 115     //
 116     // Nothing to do.
 117     //
 118     return;
 119   }
 120   QemuFwCfgSelectItem (FwCfgItem);
 121   QemuFwCfgReadBytes (sizeof mFeatureControlValue, &mFeatureControlValue);
 122
 123   Status = PeiServicesNotifyPpi (&mMpServicesNotify);
 124   if (EFI_ERROR (Status)) {
 125     DEBUG ((EFI_D_ERROR, "%a: failed to set up MP Services callback: %r\n",
 126       __FUNCTION__, Status));
 127   }
 128 }