public inbox for devel@edk2.groups.io
 help / color / mirror / Atom feed
From: marcandre.lureau@redhat.com
To: edk2-devel@lists.01.org
Cc: "Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Jordan Justen" <jordan.l.justen@intel.com>,
	"Laszlo Ersek" <lersek@redhat.com>,
	"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
	"Anthony Perard" <anthony.perard@citrix.com>,
	"Julien Grall" <julien.grall@linaro.org>
Subject: [PATCH v1 1/1] OvmfPkg/PlatformPei: clear CPU caches
Date: Mon,  1 Oct 2018 15:45:29 +0400	[thread overview]
Message-ID: <20181001114529.26741-1-marcandre.lureau@redhat.com> (raw)

From: Marc-André Lureau <marcandre.lureau@redhat.com>

The TCG "Platform Reset Attack Mitigation Specification" requires to
clear the processor caches when the MOR bit is set at boot time.

According to Paolo Bonzini, clearing the CPU cache takes only a few
hundred clock cycles, so it can be done unconditionally.

Flush the cache on all logical processors, thanks to
EFI_PEI_MP_SERVICES_PPI, calling WBINVD "Write Back and Invalidate
Cache" x86 instruction.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Julien Grall <julien.grall@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 OvmfPkg/PlatformPei/PlatformPei.inf |   1 +
 OvmfPkg/PlatformPei/Platform.h      |   5 +
 OvmfPkg/PlatformPei/ClearCache.c    | 110 ++++++++++++++++++++
 OvmfPkg/PlatformPei/Platform.c      |   1 +
 4 files changed, 117 insertions(+)

diff --git a/OvmfPkg/PlatformPei/PlatformPei.inf b/OvmfPkg/PlatformPei/PlatformPei.inf
index 9c5ad9961c4a..9c9a95fb3fe5 100644
--- a/OvmfPkg/PlatformPei/PlatformPei.inf
+++ b/OvmfPkg/PlatformPei/PlatformPei.inf
@@ -30,6 +30,7 @@
 
 [Sources]
   AmdSev.c
+  ClearCache.c
   Cmos.c
   Cmos.h
   FeatureControl.c
diff --git a/OvmfPkg/PlatformPei/Platform.h b/OvmfPkg/PlatformPei/Platform.h
index f942e61bb4f9..b12a5c1f5f78 100644
--- a/OvmfPkg/PlatformPei/Platform.h
+++ b/OvmfPkg/PlatformPei/Platform.h
@@ -83,6 +83,11 @@ InstallFeatureControlCallback (
   VOID
   );
 
+VOID
+InstallClearCacheCallback (
+  VOID
+  );
+
 EFI_STATUS
 InitializeXen (
   VOID
diff --git a/OvmfPkg/PlatformPei/ClearCache.c b/OvmfPkg/PlatformPei/ClearCache.c
new file mode 100644
index 000000000000..a1fff8446d13
--- /dev/null
+++ b/OvmfPkg/PlatformPei/ClearCache.c
@@ -0,0 +1,110 @@
+/**@file
+  Install a callback to clear cache on all processors.
+
+  Copyright (C) 2018, 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 <Ppi/MpServices.h>
+
+#include "Platform.h"
+
+/**
+  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
+ClearCache (
+  IN OUT VOID *WorkSpace
+  )
+{
+  AsmWbinvd ();
+}
+
+/**
+  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 ((DEBUG_INFO, "%a: %a\n", gEfiCallerBaseName, __FUNCTION__));
+
+  //
+  // Clear cache on all the APs in parallel.
+  //
+  MpServices = Ppi;
+  Status = MpServices->StartupAllAPs (
+                         (CONST EFI_PEI_SERVICES **)PeiServices,
+                         MpServices,
+                         ClearCache,          // Procedure
+                         FALSE,               // SingleThread
+                         0,                   // TimeoutInMicroSeconds: inf.
+                         NULL                 // ProcedureArgument
+                         );
+  if (EFI_ERROR (Status) && Status != EFI_NOT_STARTED) {
+    DEBUG ((DEBUG_ERROR, "%a: StartupAllAps(): %r\n", __FUNCTION__, Status));
+    return Status;
+  }
+
+  //
+  // Now clear cache on the BSP too.
+  //
+  ClearCache (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
+InstallClearCacheCallback (
+  VOID
+  )
+{
+  EFI_STATUS           Status;
+
+  Status = PeiServicesNotifyPpi (&mMpServicesNotify);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "%a: failed to set up MP Services callback: %r\n",
+      __FUNCTION__, Status));
+  }
+}
diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c
index 5a78668126b4..22139a64cbf4 100644
--- a/OvmfPkg/PlatformPei/Platform.c
+++ b/OvmfPkg/PlatformPei/Platform.c
@@ -672,6 +672,7 @@ InitializePlatform (
     NoexecDxeInitialization ();
   }
 
+  InstallClearCacheCallback ();
   AmdSevInitialize ();
   MiscInitialization ();
   InstallFeatureControlCallback ();
-- 
2.19.0.271.gfe8321ec05



             reply	other threads:[~2018-10-01 11:45 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-01 11:45 marcandre.lureau [this message]
2018-10-01 15:17 ` [PATCH v1 1/1] OvmfPkg/PlatformPei: clear CPU caches Kinney, Michael D
2018-10-01 16:57 ` Laszlo Ersek

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-list from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181001114529.26741-1-marcandre.lureau@redhat.com \
    --to=devel@edk2.groups.io \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox