OvmfPkg/PlatformPei: program MSR_IA32_FEATURE_CONTROL from fw_cfg

Under certain circumstances, QEMU exposes the "etc/msr_feature_control"
fw_cfg file, with a 64-bit little endian value. The firmware is supposed
to write this value to MSR_IA32_FEATURE_CONTROL (0x3a), on all processors,
on the normal and the S3 resume boot paths.

Utilize EFI_PEI_MPSERVICES_PPI to implement this feature.

Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Fixes: https://github.com/tianocore/edk2/issues/97
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

OvmfPkg/PlatformPei/FeatureControl.c

@@ -0,0 +1,134 @@
+/**@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));
+  }
+}

OvmfPkg/PlatformPei/Platform.c

@@ -612,6 +612,7 @@ InitializePlatform (
   }
 
   MiscInitialization ();
+  InstallFeatureControlCallback ();
 
   return EFI_SUCCESS;
 }

OvmfPkg/PlatformPei/Platform.h

@@ -73,6 +73,11 @@ PeiFvInitialization (
   VOID
   );
 
+VOID
+InstallFeatureControlCallback (
+  VOID
+  );
+
 EFI_STATUS
 InitializeXen (
   VOID

OvmfPkg/PlatformPei/PlatformPei.inf

@@ -30,6 +30,7 @@
 
 [Sources]
   Cmos.c
+  FeatureControl.c
   Fv.c
   MemDetect.c
   Platform.c
@@ -104,6 +105,7 @@
 
 [Ppis]
   gEfiPeiMasterBootModePpiGuid
+  gEfiPeiMpServicesPpiGuid
 
 [Depex]
   TRUE