From: Min M Xu <min.m...@intel.com>
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 first-call.
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 <kra...@redhat.com>
Cc: Erdem Aktas <erdemak...@google.com>
Cc: James Bottomley <j...@linux.ibm.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Signed-off-by: Min Xu <min.m...@intel.com>
---
OvmfPkg/IntelTdx/IntelTdxX64.dsc | 3 ++-
.../CcProbeLib/{CcProbeLib.c => DxeCcProbeLib.c} | 11 +++++++++--
.../CcProbeLib/{CcProbeLib.inf => DxeCcProbeLib.inf} | 6 +++---
OvmfPkg/OvmfPkgX64.dsc | 5 ++++-
4 files changed, 18 insertions(+), 7 deletions(-)
rename OvmfPkg/Library/CcProbeLib/{CcProbeLib.c => DxeCcProbeLib.c} (55%)
rename OvmfPkg/Library/CcProbeLib/{CcProbeLib.inf => DxeCcProbeLib.inf} (70%)
diff --git a/OvmfPkg/IntelTdx/IntelTdxX64.dsc b/OvmfPkg/IntelTdx/IntelTdxX64.dsc
index 71b1cf8e7090..1a7ecd503e50 100644
--- a/OvmfPkg/IntelTdx/IntelTdxX64.dsc
+++ b/OvmfPkg/IntelTdx/IntelTdxX64.dsc
@@ -140,7 +140,7 @@
PciCapLib|OvmfPkg/Library/BasePciCapLib/BasePciCapLib.inf
PciCapPciSegmentLib|OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.inf
PciCapPciIoLib|OvmfPkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.inf
- CcProbeLib|OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
+ CcProbeLib|OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.inf
IoLib|MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsicSev.inf
OemHookStatusCodeLib|MdeModulePkg/Library/OemHookStatusCodeLibNull/OemHookStatusCodeLibNull.inf
SerialPortLib|PcAtChipsetPkg/Library/SerialIoLib/SerialIoLib.inf
@@ -234,6 +234,7 @@
HobLib|EmbeddedPkg/Library/PrePiHobLib/PrePiHobLib.inf
PrePiLib|EmbeddedPkg/Library/PrePiLib/PrePiLib.inf
PeilessStartupLib|OvmfPkg/Library/PeilessStartupLib/PeilessStartupLib.inf
+ CcProbeLib|OvmfPkg/Library/CcProbeLib/SecPeiCcProbeLib.inf
[LibraryClasses.common.DXE_CORE]
HobLib|MdePkg/Library/DxeCoreHobLib/DxeCoreHobLib.inf
diff --git a/OvmfPkg/Library/CcProbeLib/CcProbeLib.c
b/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.c
similarity index 55%
rename from OvmfPkg/Library/CcProbeLib/CcProbeLib.c
rename to OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.c
index d698e5c8d7f8..11b2eef390cf 100644
--- a/OvmfPkg/Library/CcProbeLib/CcProbeLib.c
+++ b/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.c
@@ -10,6 +10,9 @@
#include <Library/CcProbeLib.h>
#include <WorkArea.h>
+STATIC UINT8 mCcProbeGuestType = 0;
+STATIC BOOLEAN mCcProbed = FALSE;
+
/**
Probe the ConfidentialComputing Guest type. See defition of
CC_GUEST_TYPE in <ConfidentialComputingGuestAttr.h>.
@@ -25,7 +28,11 @@ CcProbe (
{
OVMF_WORK_AREA *WorkArea;
- WorkArea = (OVMF_WORK_AREA *)FixedPcdGet32 (PcdOvmfWorkAreaBase);
+ if (!mCcProbed) {
+ WorkArea = (OVMF_WORK_AREA *)FixedPcdGet32 (PcdOvmfWorkAreaBase);
+ mCcProbeGuestType = WorkArea != NULL ? WorkArea->Header.GuestType :
CcGuestTypeNonEncrypted;
+ mCcProbed = TRUE;
+ }
- return WorkArea != NULL ? WorkArea->Header.GuestType :
CcGuestTypeNonEncrypted;
+ return mCcProbeGuestType;
}
diff --git a/OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
b/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.inf
similarity index 70%
rename from OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
rename to OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.inf
index 5300c9ba2644..9bdba4312755 100644
--- a/OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
+++ b/OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.inf
@@ -8,14 +8,14 @@
[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
[Sources]
- CcProbeLib.c
+ DxeCcProbeLib.c
[Packages]
MdePkg/MdePkg.dec
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 6e68f60dc90f..2741f4d988b7 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -199,7 +199,7 @@
!if $(SMM_REQUIRE) == FALSE
LockBoxLib|OvmfPkg/Library/LockBoxLib/LockBoxBaseLib.inf
- CcProbeLib|OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
+ CcProbeLib|OvmfPkg/Library/CcProbeLib/DxeCcProbeLib.inf
!else
CcProbeLib|MdePkg/Library/CcProbeLibNull/CcProbeLibNull.inf
!endif
@@ -287,6 +287,7 @@
!endif
VmgExitLib|OvmfPkg/Library/VmgExitLib/SecVmgExitLib.inf
MemEncryptSevLib|OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
+ CcProbeLib|OvmfPkg/Library/CcProbeLib/SecPeiCcProbeLib.inf
[LibraryClasses.common.PEI_CORE]
HobLib|MdePkg/Library/PeiHobLib/PeiHobLib.inf
@@ -303,6 +304,7 @@
DebugLib|OvmfPkg/Library/PlatformDebugLibIoPort/PlatformDebugLibIoPort.inf
!endif
PeCoffLib|MdePkg/Library/BasePeCoffLib/BasePeCoffLib.inf
+ CcProbeLib|OvmfPkg/Library/CcProbeLib/SecPeiCcProbeLib.inf
[LibraryClasses.common.PEIM]
HobLib|MdePkg/Library/PeiHobLib/PeiHobLib.inf
@@ -332,6 +334,7 @@
PlatformInitLib|OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf
MemEncryptSevLib|OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
+ CcProbeLib|OvmfPkg/Library/CcProbeLib/SecPeiCcProbeLib.inf
[LibraryClasses.common.DXE_CORE]
HobLib|MdePkg/Library/DxeCoreHobLib/DxeCoreHobLib.inf
--
2.29.2.windows.2
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