[PATCH v1 1/3] MdeModulePkg: Add Variable Flash Info HOB

Michael Kubacki

From: Michael Kubacki <michael.kubacki@...>


Adds a new GUID that is used to identify a HOB that passes variable
flash information to UEFI variable drivers in HOB consumption phases
such as DXE, Traditional MM, and Standalone MM.

This information was previously passed directly with PCDs such
as EfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase
and gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize.

However, the Standalone MM variable driver instance does not have
direct access to the PCD database. Therefore, this HOB will first
be considered as the source for variable flash information and
if platforms do not produce the HOB, reading the information from
the PCDs directly will be a backup to provide backward

Cc: Jian J Wang <jian.j.wang@...>
Cc: Hao A Wu <hao.a.wu@...>
Cc: Liming Gao <gaoliming@...>
Signed-off-by: Michael Kubacki <michael.kubacki@...>
MdeModulePkg/Include/Guid/VariableFlashInfo.h | 36 ++++++++++++++++++++
MdeModulePkg/MdeModulePkg.dec | 4 +++
2 files changed, 40 insertions(+)

diff --git a/MdeModulePkg/Include/Guid/VariableFlashInfo.h b/MdeModulePkg=
new file mode 100644
index 000000000000..07aaa69fb748
--- /dev/null
+++ b/MdeModulePkg/Include/Guid/VariableFlashInfo.h
@@ -0,0 +1,36 @@
+/** @file
+ This file defines the GUID and data structure used to pass information=
+ a variable store mapped on flash (i.e. a MMIO firmware volume) to the =
DXE and MM environment.
+ Copyright (c) Microsoft Corporation.<BR>
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+ { 0x5d11c653, 0x8154, 0x4ac3, { 0xa8, 0xc2, 0xfb, 0xa2, 0x89, 0x20, 0x=
fc, 0x90 }}
+extern EFI_GUID gVariableFlashInfoHobGuid;
+#pragma pack (push, 1)
+/// This structure can be used to describe UEFI variable
+/// flash information.
+typedef struct {
+ EFI_PHYSICAL_ADDRESS NvStorageBaseAddress;
+ UINT64 NvStorageLength;
+ UINT64 FtwSpareLength;
+ EFI_PHYSICAL_ADDRESS FtwWorkingBaseAddress;
+ UINT64 FtwWorkingLength;
+#pragma pack (pop)
diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.de=
index cf79292ec877..4e82f5836096 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -226,6 +226,10 @@ [Guids]
# Include/Guid/SmmVariableCommon.h
gSmmVariableWriteGuid =3D { 0x93ba1826, 0xdffb, 0x45dd, { 0x82, 0xa7,=
0xe7, 0xdc, 0xaa, 0x3b, 0xbd, 0xf3 }}
+ ## Guid of the variable flash information HOB.
+ # Include/Guid/VariableFlashInfo.h
+ gVariableFlashInfoHobGuid =3D { 0x5d11c653, 0x8154, 0x4ac3, { 0xa8, 0x=
c2, 0xfb, 0xa2, 0x89, 0x20, 0xfc, 0x90 }}
## Performance protocol guid that also acts as the performance HOB gui=
d and performance variable GUID
# Include/Guid/Performance.h
gPerformanceProtocolGuid =3D { 0x76B6BDFA, 0x2ACD, 0x4462, { 0x9=
E, 0x3F, 0xCB, 0x58, 0xC9, 0x69, 0xD9, 0x37 } }

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