The mechanism behind is the same as NULL pointer detection enabled in EDK-II
core. SMM has its own page table and we have to disable page 0 again in SMM
mode.
Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Ayellet Wolman <ayellet.wolman@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
https://bugzilla.tianocore.org/show_bug.cgi?id=674
Add CPUID check to see if the CPU supports the Machine
Check Architecture before accessing the Machine Check
Architecture related MSRs.
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
If PcdCpuHotPlugSupport is TRUE, gSmst->NumberOfCpus will be the
PcdCpuMaxLogicalProcessorNumber. If gSmst->SmmStartupThisAp() is invoked for
those un-existed processors, ASSERT() happened in ConfigSmmCodeAccessCheck().
This fix is to check if ProcessorId is valid before invoke
gSmst->SmmStartupThisAp() in ConfigSmmCodeAccessCheck() and to check if
ProcessorId is valid in InternalSmmStartupThisAp() to avoid unexpected DEBUG
error message displayed.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
SMM BSP's *busy* state should be acquired. We could use AcquireSpinLock()
instead of AcquireSpinLockOrFail().
Cc: Hao Wu <hao.a.wu@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Hao Wu <hao.a.wu@intel.com>
The commit is a follow-up of commit 8491e30.
In file MpService.c line 786:
Pte[Index] = (UINT64)((UINTN)PageTable + EFI_PAGE_SIZE * (Index + 1)) |
mAddressEncMask ...
(Where PageTable is of type VOID*, Index is of type UINTN, mAddressEncMask
is of type UINT64 and Pte[Index] is of type UINT64.)
Since in this case, the code logic ensures that the expression will not
exceed the range of UINTN, the commit will remove the explicit type cast
'(UINT64)'.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
This PCD holds the address mask for page table entries when memory
encryption is enabled on AMD processors supporting the Secure Encrypted
Virtualization (SEV) feature.
The mask is applied when page tables entriees are created or modified.
CC: Jeff Fan <jeff.fan@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Leo Duran <leo.duran@amd.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
https://bugzilla.tianocore.org/show_bug.cgi?id=277
Remove dependency on layout of PROCESSOR_SMM_DESCRIPTOR
everywhere possible. The only exception is the standard
SMI entry handler template that is included with the
PiSmmCpuDxeSmm module. This allows an instance of the
SmmCpuFeaturesLib to provide alternate
PROCESSOR_SMM_DESCRIPTOR structure layouts.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
https://bugzilla.tianocore.org/show_bug.cgi?id=277
All CPUs use the same MTRR settings. Move MTRR settings
from a field in the PROCESSOR_SMM_DESCRIPTOR structure into
a module global variable.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Some semaphores are not cleared on S3 boot path. For example,
mSmmMpSyncData->CpuData[CpuIndex].Present. It may still keeps the value set at
SMM runtime during S3 resume. It may causes BSP have the wrong judgement on SMM
AP's present state.
We have one related fix at e78a2a49ee. But that is
not completed.
This fix is to clear Busy/Run/Present semaphores in InitializeMpSyncData().
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Move the declaration of these PCDs from the
[PcdsFixedAtBuild, PcdsPatchableInModule]
section of "UefiCpuPkg/UefiCpuPkg.dec" to the
[PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
section. Their types, default values, and token values remain unchanged.
Only UefiCpuPkg/PiSmmCpuDxeSmm consumes these PCDs, specifically on the
call stack of its entry point function, and it turns them into static or
dynamically allocated data in SMRAM:
PiCpuSmmEntry() [PiSmmCpuDxeSmm.c]
InitializeSmmTimer() [SyncTimer.c]
PcdCpuSmmApSyncTimeout
-> mTimeoutTicker
InitializeMpServiceData() [MpService.c]
InitializeMpSyncData() [MpService.c]
PcdCpuSmmSyncMode
-> mSmmMpSyncData->EffectiveSyncMode
However, there's another call path to fetching "PcdCpuSmmSyncMode", namely
SmmInitHandler() [PiSmmCpuDxeSmm.c]
InitializeMpSyncData() [MpService.c]
PcdCpuSmmSyncMode
-> mSmmMpSyncData->EffectiveSyncMode
and this path is exercised during S3 resume (as stated by the comment in
SmmInitHandler() too, "Initialize private data during S3 resume").
While we can call the PCD protocol (via PcdLib) for fetching dynamic PCDs
in the entry point function, we cannot do that at S3 resume. Therefore
pre-fetch PcdCpuSmmSyncMode into a new global variable (which lives in
SMRAM) in InitializeMpServiceData(), just before calling
InitializeMpSyncData(). This way InitializeMpSyncData() can retrieve the
stashed PCD value from SMRAM, regardless of the boot mode.
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=230
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
PiSmmCpuDxeSmm consumes SmmAttributesTable and setup page table:
1) Code region is marked as read-only and Data region is non-executable,
if the PE image is 4K aligned.
2) Important data structure is set to RO, such as GDT/IDT.
3) SmmSaveState is set to non-executable,
and SmmEntrypoint is set to read-only.
4) If static page is supported, page table is read-only.
We use page table to protect other components, and itself.
If we use dynamic paging, we can still provide *partial* protection.
And hope page table is not modified by other components.
The XD enabling code is moved to SmiEntry to let NX take effect.
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiewen Yao <jiewen.yao@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
The commit 8b9311 changed the zeroing of mSmmMpSyncData of type
SMM_DISPATCHER_MP_SYNC_DATA by the following patch.
- ZeroMem (mSmmMpSyncData, mSmmMpSyncDataSize);
+ mSmmMpSyncData->SwitchBsp = FALSE;
mSmmMpSyncDataSize not only includes SMM_DISPATCHER_MP_SYNC_DATA, but
also includes the SMM_CPU_DATA_BLOCK array and one BOOLEAN variable
array as shown here:
mSmmMpSyncDataSize = sizeof (SMM_DISPATCHER_MP_SYNC_DATA) +
(sizeof (SMM_CPU_DATA_BLOCK) + sizeof (BOOLEAN)) *
gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus;
This patch restores the original ZeroMem() to clear all CPU Sync data.
The commit 8b9311 may cause unexpected behavior.
v2:
Mentioned CandidateBsp array in comments to make it more accurate.
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
REGISTER_TYPE in UefiCpuPkg/Include/AcpiCpuData.h defines a MemoryMapped
enum value. However support for the MemoryMapped enum is missing from
the implementation of SetProcessorRegister(). This patch adds support
for MemoryMapped type SetProcessorRegister().
One spin lock is added to avoid potential conflict when multiple processor
update the same memory space.
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
InitializeMpSyncData() invokes InitializeSmmCpuSemaphores() to allocate an
aligned buffer for all locks and semaphores. However, this function is
invoked on S3 resume path again to reset mSmmMpSyncData. It causes
an additional aligned buffer to be allocated.
This update moves InitializeSmmCpuSemaphores() into
InitializeMpServiceData() that is only invoked on normal boot.
InitializeMpSyncData() is updated to reset the locks/semaphore in
mSmmMpSyncData.
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Update each CPU semaphores to the ones in allocated aligned
semaphores buffer.
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Allocate each CPU semaphores in allocated aligned semaphores buffer.
And add it into semaphores structure.
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Update all global semaphores to the ones in allocated aligned
semaphores buffer.
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Move MP sync data initialization in front of the place that initialize
page table, because the page fault spin lock is allocated in
InitializeMpSyncData() while it is initialized in SmmInitPageTable().
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Get semaphores alignment/size requirement and allocate aligned
buffer for all global spin lock and semaphores.
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Use the MSR MSR_IA32_MISC_ENABLE definition defined in UefiCpuPkg/Include and
remove the local definition.
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
If XD is supported, then SMM enables it. The non-SMM execution
environment can choose to enable or disable XD, so the state of
XD must be detected in each SMI and be enabled/restored.
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
If PcdCpuSmmDebug is set to TRUE, then the first time the function
CpuSmmDebugEntry () is called during the first normal SMI, the
registers DR6 or DR7 may be set to invalid values due to gSmst
not being fully initialized yet. Instead, use gSmmCpuPrivate that
is fully initialized for the first SMI to look up CpuSaveState
for the currently executing CPU.
Cc: Jeff Fan <jeff.fan@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19502 6f19259b-4bc3-4df7-8a09-765794883524
So that we can use write-protection for code later.
This is REPOST.
It includes the bug fix from "Paolo Bonzini" <pbonzini@redhat.com>:
Title: fix generation of 32-bit PAE page tables
"Bits 1 and 2 are reserved in 32-bit PAE Page Directory Pointer Table
Entries (PDPTEs); see Table 4-8 in the SDM. With VMX extended page
tables, the processor notices and fails the VM entry as soon as CR0.PG
is set to 1."
And thanks "Laszlo Ersek" <lersek@redhat.com> to validate the fix.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Signed-off-by: "Paolo Bonzini" <pbonzini@redhat.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Cc: "Fan, Jeff" <jeff.fan@intel.com>
Cc: "Kinney, Michael D" <michael.d.kinney@intel.com>
Cc: "Laszlo Ersek" <lersek@redhat.com>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19067 6f19259b-4bc3-4df7-8a09-765794883524
Always set RW+P bit for page table by default.
So that we can use write-protection for code later.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Reviewed-by: "Kinney, Michael D" <michael.d.kinney@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18960 6f19259b-4bc3-4df7-8a09-765794883524
Add NULL func for 2 new APIs in SmmCpuFeaturesLib.
SmmCpuFeaturesCompleteSmmReadyToLock() is a hook point to allow
CPU specific code to do more registers setting after
the gEfiSmmReadyToLockProtocolGuid notification is completely processed.
Add SmmCpuFeaturesCompleteSmmReadyToLock() to PerformRemainingTasks() and PerformPreTasks().
SmmCpuFeaturesAllocatePageTableMemory() is an API to allow
CPU to allocate a specific region for storing page tables.
All page table allocation will use AllocatePageTableMemory().
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Reviewed-by: "Kinney, Michael D" <michael.d.kinney@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18958 6f19259b-4bc3-4df7-8a09-765794883524
SmmDebug feature is implemented in ASM, which is not easy to maintain.
So we move it to C function.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Reviewed-by: "Kinney, Michael D" <michael.d.kinney@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18946 6f19259b-4bc3-4df7-8a09-765794883524
In this way, we can centralize the silicon configuration in
PerformRemainingTasks()/PerformPreTasks() function.
If there are more features need to be configured, they can put in
PerformRemainingTasks()/PerformPreTasks() only.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Reviewed-by: "Kinney, Michael D" <michael.d.kinney@intel.com>
Reviewed-by: "Laszlo Ersek" <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18938 6f19259b-4bc3-4df7-8a09-765794883524
Move Gdt initialization from InitializeMpServiceData() to CPU Arch specific function.
We create SmmFuncsArch.c for hold CPU specific function, so that
EFI_IMAGE_MACHINE_TYPE_SUPPORTED(EFI_IMAGE_MACHINE_X64) can be removed.
For IA32 version, we always allocate new page for GDT entry, for easy maintenance.
For X64 version, we fixed TssBase in GDT entry to make sure TSS data is correct.
Remove TSS fixup for GDT in ASM file.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Reviewed-by: "Fan, Jeff" <jeff.fan@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18937 6f19259b-4bc3-4df7-8a09-765794883524
Add module that initializes a CPU for the SMM environment and
installs the first level SMI handler. This module along with the
SMM IPL and SMM Core provide the services required for
DXE_SMM_DRIVERS to register hardware and software SMI handlers.
CPU specific features are abstracted through the SmmCpuFeaturesLib
Platform specific features are abstracted through the
SmmCpuPlatformHookLib
Several PCDs are added to enable/disable features and configure
settings for the PiSmmCpuDxeSmm module
Changes between [PATCH v1] and [PATCH v2]:
1) Swap PTE init order for QEMU compatibility.
Current PTE initialization algorithm works on HW but breaks QEMU
emulator. Update the PTE initialization order to be compatible
with both.
2) Update comment block that describes 32KB SMBASE alignment requirement
to match contents of Intel(R) 64 and IA-32 Architectures Software
Developer's Manual
3) Remove BUGBUG comment and call to ClearSmi() that is not required.
SMI should be cleared by root SMI handler.
[jeff.fan@intel.com: Fix code style issues reported by ECC]
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
[pbonzini@redhat.com: InitPaging: prepare PT before filling in PDE]
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18645 6f19259b-4bc3-4df7-8a09-765794883524