summaryrefslogtreecommitdiffstats
path: root/OvmfPkg/Library/CcProbeLib
diff options
context:
space:
mode:
authorMin M Xu <min.m.xu@intel.com>2022-07-07 10:51:20 +0800
committermergify[bot] <37929162+mergify[bot]@users.noreply.github.com>2022-09-06 06:03:45 +0000
commit1b1c58ab32c30d32ba7d037c0ea1da198c1b372b (patch)
treecd61b7b8df12f2f9837f8334457e9236b36339bf /OvmfPkg/Library/CcProbeLib
parentc4bc1a9498f4e176cefaeba3211287b444a53882 (diff)
downloadedk2-1b1c58ab32c30d32ba7d037c0ea1da198c1b372b.tar.gz
edk2-1b1c58ab32c30d32ba7d037c0ea1da198c1b372b.tar.bz2
edk2-1b1c58ab32c30d32ba7d037c0ea1da198c1b372b.zip
OvmfPkg: Update CcProbeLib to DxeCcProbeLib
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3974 CcProbeLib once was designed to probe the Confidential Computing guest type by checking the PcdOvmfWorkArea. But this memory is allocated with either EfiACPIMemoryNVS or EfiBootServicesData. It cannot be accessed after ExitBootService. Please see the detailed analysis in BZ#3974. To fix this issue, CcProbeLib is redesigned as 2 implementation: - SecPeiCcProbeLib - DxeCcProbeLib In SecPeiCcProbeLib we check the CC guest type by reading the PcdOvmfWorkArea. Because it is used in SEC / PEI and we don't worry about the issues in BZ#3974. In DxeCcProbeLib we cache the GuestType in Ovmf work area in a variable. After that the Guest type is returned with the cached value. So that we don't need to worry about the access to Ovmf work area after ExitBootService. The reason why we probe CC guest type in 2 different ways is the global varialbe. Global variable cannot be used in SEC/PEI and CcProbe is called very frequently. Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Erdem Aktas <erdemaktas@google.com> Cc: James Bottomley <jejb@linux.ibm.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Min Xu <min.m.xu@intel.com> Acked-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Diffstat (limited to 'OvmfPkg/Library/CcProbeLib')
-rw-r--r--OvmfPkg/Library/CcProbeLib/CcProbeLib.c31
-rw-r--r--OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.c68
-rw-r--r--OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.inf (renamed from OvmfPkg/Library/CcProbeLib/CcProbeLib.inf)7
3 files changed, 72 insertions, 34 deletions
diff --git a/OvmfPkg/Library/CcProbeLib/CcProbeLib.c b/OvmfPkg/Library/CcProbeLib/CcProbeLib.c
deleted file mode 100644
index d698e5c8d7..0000000000
--- a/OvmfPkg/Library/CcProbeLib/CcProbeLib.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/** @file
-
- CcProbeLib is used to probe the Confidential computing guest type.
-
- Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
-
-**/
-
-#include <Library/CcProbeLib.h>
-#include <WorkArea.h>
-
-/**
- Probe the ConfidentialComputing Guest type. See defition of
- CC_GUEST_TYPE in <ConfidentialComputingGuestAttr.h>.
-
- @return The guest type
-
-**/
-UINT8
-EFIAPI
-CcProbe (
- VOID
- )
-{
- OVMF_WORK_AREA *WorkArea;
-
- WorkArea = (OVMF_WORK_AREA *)FixedPcdGet32 (PcdOvmfWorkAreaBase);
-
- return WorkArea != NULL ? WorkArea->Header.GuestType : CcGuestTypeNonEncrypted;
-}
diff --git a/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.c b/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.c
new file mode 100644
index 0000000000..868e32bf7f
--- /dev/null
+++ b/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.c
@@ -0,0 +1,68 @@
+/** @file
+
+ CcProbeLib is used to probe the Confidential computing guest type.
+
+ Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi/UefiBaseType.h>
+#include <Library/CcProbeLib.h>
+#include <WorkArea.h>
+
+STATIC UINT8 mCcProbeGuestType = 0;
+STATIC BOOLEAN mCcProbed = FALSE;
+
+/**
+ * Read the the ConfidentialComputing Guest type from Ovmf work-area.
+ *
+ * @return The ConfidentialComputing Guest type
+ */
+STATIC
+UINT8
+ReadCcGuestType (
+ VOID
+ )
+{
+ OVMF_WORK_AREA *WorkArea;
+
+ if (!mCcProbed) {
+ WorkArea = (OVMF_WORK_AREA *)FixedPcdGet32 (PcdOvmfWorkAreaBase);
+ mCcProbeGuestType = WorkArea != NULL ? WorkArea->Header.GuestType : CcGuestTypeNonEncrypted;
+ mCcProbed = TRUE;
+ }
+
+ return mCcProbeGuestType;
+}
+
+/**
+ Probe the ConfidentialComputing Guest type. See defition of
+ CC_GUEST_TYPE in <ConfidentialComputingGuestAttr.h>.
+
+ @return The guest type
+
+**/
+UINT8
+EFIAPI
+CcProbe (
+ VOID
+ )
+{
+ return ReadCcGuestType ();
+}
+
+/**
+ * Constructor of DxeCcProbeLib
+ *
+ * @return EFI_SUCCESS Successfully called of constructor
+ */
+EFI_STATUS
+EFIAPI
+DxeCcProbeLibConstructor (
+ VOID
+ )
+{
+ ReadCcGuestType ();
+ return EFI_SUCCESS;
+}
diff --git a/OvmfPkg/Library/CcProbeLib/CcProbeLib.inf b/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.inf
index 5300c9ba26..2fd0b4d46d 100644
--- a/OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
+++ b/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.inf
@@ -8,14 +8,15 @@
[Defines]
INF_VERSION = 0x00010005
- BASE_NAME = CcProbeLib
+ BASE_NAME = DxeCcProbeLib
FILE_GUID = 05184ec9-abb0-4491-8584-e388639a7c48
MODULE_TYPE = BASE
VERSION_STRING = 1.0
- LIBRARY_CLASS = CcProbeLib
+ LIBRARY_CLASS = CcProbeLib|DXE_CORE DXE_DRIVER DXE_RUNTIME_DRIVER DXE_SMM_DRIVER UEFI_DRIVER UEFI_APPLICATION
+ CONSTRUCTOR = DxeCcProbeLibConstructor
[Sources]
- CcProbeLib.c
+ DxeCcProbeLib.c
[Packages]
MdePkg/MdePkg.dec