[edk2-devel] [RFC PATCH v1 01/30] ArmVirtPkg: kvmtool: Add Emulated Runtime variable support

[Sami Mujawar]

Although Kvmtool supports a CFI flash interface, it is currently
implemented using file backed support on the Host. This scenario
requires the VMM to be within the trust boundary.

In Confidential Compute Architecture the VMM is outside the trust
boundary. For such architectures Emulated Runtime variable storage
is desirable.

Therefore, make Emulated Runtime variable storage as the default
option and add a build flag ENABLE_CFI_FLASH to configure the
firmware build to use the CFI Flash as the Variable storage.

Signed-off-by: Sami Mujawar <sami.mujawar at arm.com>
---
 ArmVirtPkg/ArmVirtKvmTool.dsc | 22 +++++++++++++++++++-
 ArmVirtPkg/ArmVirtKvmTool.fdf |  4 +++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/ArmVirtPkg/ArmVirtKvmTool.dsc b/ArmVirtPkg/ArmVirtKvmTool.dsc
index d0afe1b49e250c554313c2077b89650d6f6d67cb..d2228a95726b24fe5c2edfbc84b1f5c23a85feba 100644
--- a/ArmVirtPkg/ArmVirtKvmTool.dsc
+++ b/ArmVirtPkg/ArmVirtKvmTool.dsc
@@ -1,7 +1,7 @@
 #  @file
 #  Workspace file for KVMTool virtual platform.
 #
-#  Copyright (c) 2018 - 2022, ARM Limited. All rights reserved.
+#  Copyright (c) 2018 - 2023, ARM Limited. All rights reserved.
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
@@ -50,7 +50,9 @@ [LibraryClasses.common]
   ArmVirtMemInfoLib|ArmVirtPkg/Library/KvmtoolVirtMemInfoLib/KvmtoolVirtMemInfoLib.inf
 
   TimerLib|ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.inf
+!ifdef ENABLE_CFI_FLASH
   VirtNorFlashPlatformLib|ArmVirtPkg/Library/NorFlashKvmtoolLib/NorFlashKvmtoolLib.inf
+!endif
 
   CapsuleLib|MdeModulePkg/Library/DxeCapsuleLibNull/DxeCapsuleLibNull.inf
 
@@ -156,6 +158,13 @@ [PcdsFixedAtBuild.common]
   #
   gEmbeddedTokenSpaceGuid.PcdPrePiCpuIoSize|16
 
+!ifndef ENABLE_CFI_FLASH
+  # Emulate Runtime Variable storage
+  gEfiMdeModulePkgTokenSpaceGuid.PcdEmuVariableNvModeEnable|TRUE
+  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize|0x2000
+  gEfiMdeModulePkgTokenSpaceGuid.PcdMaxAuthVariableSize|0x2800
+!endif
+
 [PcdsPatchableInModule.common]
   #
   # This will be overridden in the code
@@ -211,6 +220,7 @@ [PcdsDynamicDefault.common]
   gEfiMdeModulePkgTokenSpaceGuid.PcdSetupVideoHorizontalResolution|640
   gEfiMdeModulePkgTokenSpaceGuid.PcdSetupVideoVerticalResolution|480
 
+!ifdef ENABLE_CFI_FLASH
   # Setup Flash storage variables
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase|0
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize|0x40000
@@ -218,6 +228,10 @@ [PcdsDynamicDefault.common]
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingSize|0x40000
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareBase|0
   gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareSize|0x40000
+!else
+  # Emulate Runtime Variable storage
+  gEfiMdeModulePkgTokenSpaceGuid.PcdEmuVariableNvStoreReserved|0
+!endif
 
   ## RTC Register address in MMIO space.
   gPcAtChipsetPkgTokenSpaceGuid.PcdRtcIndexRegister64|0x0
@@ -263,7 +277,9 @@ [Components.common]
   MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf {
     <LibraryClasses>
       NULL|MdeModulePkg/Library/VarCheckUefiLib/VarCheckUefiLib.inf
+!ifdef ENABLE_CFI_FLASH
       NULL|EmbeddedPkg/Library/NvVarStoreFormattedLib/NvVarStoreFormattedLib.inf
+!endif
       BaseMemoryLib|MdePkg/Library/BaseMemoryLib/BaseMemoryLib.inf
   }
 
@@ -271,7 +287,9 @@ [Components.common]
   MdeModulePkg/Universal/CapsuleRuntimeDxe/CapsuleRuntimeDxe.inf
   MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteDxe.inf {
     <LibraryClasses>
+!ifdef ENABLE_CFI_FLASH
       NULL|ArmVirtPkg/Library/NorFlashKvmtoolLib/NorFlashKvmtoolLib.inf
+!endif
   }
 
   MdeModulePkg/Universal/MonotonicCounterRuntimeDxe/MonotonicCounterRuntimeDxe.inf
@@ -296,11 +314,13 @@ [Components.common]
       NULL|ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf
   }
 
+!ifdef ENABLE_CFI_FLASH
   OvmfPkg/VirtNorFlashDxe/VirtNorFlashDxe.inf {
     <LibraryClasses>
       # don't use unaligned CopyMem () on the UEFI varstore NOR flash region
       BaseMemoryLib|MdePkg/Library/BaseMemoryLib/BaseMemoryLib.inf
   }
+!endif
 
   MdeModulePkg/Universal/WatchdogTimerDxe/WatchdogTimer.inf
 
diff --git a/ArmVirtPkg/ArmVirtKvmTool.fdf b/ArmVirtPkg/ArmVirtKvmTool.fdf
index 82aff47673cb3085c91c1dd7431683c8353c16e6..8ccbccd71e134e0ea97d49380293687aca43e8b9 100644
--- a/ArmVirtPkg/ArmVirtKvmTool.fdf
+++ b/ArmVirtPkg/ArmVirtKvmTool.fdf
@@ -1,5 +1,5 @@
 #
-#  Copyright (c) 2018 - 2022, ARM Limited. All rights reserved.
+#  Copyright (c) 2018 - 2023, ARM Limited. All rights reserved.
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
@@ -154,7 +154,9 @@ [FV.FvMain]
   INF ArmPkg/Drivers/ArmGic/ArmGicDxe.inf
   INF ArmPkg/Drivers/TimerDxe/TimerDxe.inf
   INF MdeModulePkg/Universal/WatchdogTimerDxe/WatchdogTimer.inf
+!ifdef ENABLE_CFI_FLASH
   INF OvmfPkg/VirtNorFlashDxe/VirtNorFlashDxe.inf
+!endif
 
   #
   # FAT filesystem + GPT/MBR partitioning + UDF filesystem
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'



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