[edk2-devel] [PATCH V4 07/10] MdeModulePkg/Variable: Add RT GetVariable() cache support
Wang, Jian J
jian.j.wang at intel.com
Thu Oct 17 14:23:28 UTC 2019
>
> Again, I would like to ask for help from other reviewers to look at this patch
> (patch 7/10) and the next one (patch 8/10) (at least from the security
> perspective). Any help will be appreciated, thanks in advance.
>
I'm trying to do a simple analysis below from security perspective. Please correct me
if anything wrong.
The patch added 3 new SMI variable Functions
f(a): SMM_VARIABLE_FUNCTION_INIT_RUNTIME_VARIABLE_CACHE_CONTEXT
f(b): SMM_VARIABLE_FUNCTION_SYNC_RUNTIME_CACHE
f(c): SMM_VARIABLE_FUNCTION_GET_RUNTIME_CACHE_INFO
f(a) communication buffer is type of
SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
which is defined as
typedef struct {
BOOLEAN *ReadLock;
BOOLEAN *PendingUpdate;
BOOLEAN *HobFlushComplete;
VARIABLE_STORE_HEADER *RuntimeHobCache;
VARIABLE_STORE_HEADER *RuntimeNvCache;
VARIABLE_STORE_HEADER *RuntimeVolatileCache;
} SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT;
There're 6 fields (all pointers) in the buffer. SMM will handle them in following ways
- ReadLock and PendingUpdate are used to avoid race condition between smm and
non-smm code. I don't think there's security breach here.
- RuntimeHobCache, RuntimeNvCache and RuntimeVolatileCache are buffers passed
to smm code to simply store variable content. Smm code will not read its content.
I think this won't bring any security risk.
The SmmVariableHandler() will call VariableSmmIsBufferOutsideSmmValid()
to make sure the communication buffer is outside of smram. But the handler will
not check the above 6 pointers passed through communication buffer to see if they
are in non-smram scope. This leaves potential security hole to allow smram buffer
to be passed in from non-smm code.
f(b) doesn't use communication buffer. It's just used to flush variable cache. Then
no security risk here.
f(c) uses communication buffer with type of
typedef struct {
UINTN TotalHobStorageSize;
UINTN TotalNvStorageSize;
UINTN TotalVolatileStorageSize;
BOOLEAN AuthenticatedVariableUsage;
} SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO;
There's no pointer in the buffer and the SMI handler doesn't read its content but
just store data into it. I think there's no security risk here.
I also checked data flow newly introduced between smm and non-smm boundary.
Most of the data flow is just from smm to non-smm. The only exception is ReadLock
mentioned above. Generally speaking, I don't find security issue in this patch series
except to above pointers passed by communication buffer.
Regards,
Jian
> -----Original Message-----
> From: Wu, Hao A <hao.a.wu at intel.com>
> Sent: Wednesday, October 16, 2019 3:57 PM
> To: Kubacki, Michael A <michael.a.kubacki at intel.com>; devel at edk2.groups.io
> Cc: Bi, Dandan <dandan.bi at intel.com>; Ard Biesheuvel
> <ard.biesheuvel at linaro.org>; Dong, Eric <eric.dong at intel.com>; Laszlo Ersek
> <lersek at redhat.com>; Gao, Liming <liming.gao at intel.com>; Kinney, Michael D
> <michael.d.kinney at intel.com>; Ni, Ray <ray.ni at intel.com>; Wang, Jian J
> <jian.j.wang at intel.com>; Yao, Jiewen <jiewen.yao at intel.com>
> Subject: RE: [PATCH V4 07/10] MdeModulePkg/Variable: Add RT GetVariable()
> cache support
>
> Again, I would like to ask for help from other reviewers to look at this patch
> (patch 7/10) and the next one (patch 8/10) (at least from the security
> perspective). Any help will be appreciated, thanks in advance.
>
>
> One comment inherited from the feedback on the V2 series:
> I saw AtRuntime() is still being added in file VariableSmmRuntimeDxe.c, could
> you help to double confirm?
>
> Another general level comment is that:
> Please help to update the MdeModulePkg.uni file as well for the introduce of
> the new PCD.
>
> Inline comments below:
>
>
> > -----Original Message-----
> > From: Kubacki, Michael A
> > Sent: Tuesday, October 15, 2019 7:30 AM
> > To: devel at edk2.groups.io
> > Cc: Bi, Dandan; Ard Biesheuvel; Dong, Eric; Laszlo Ersek; Gao, Liming; Kinney,
> > Michael D; Ni, Ray; Wang, Jian J; Wu, Hao A; Yao, Jiewen
> > Subject: [PATCH V4 07/10] MdeModulePkg/Variable: Add RT GetVariable()
> > cache support
> >
> > REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2220
> >
> > This change reduces SMIs for GetVariable () by maintaining a
> > UEFI variable cache in Runtime DXE in addition to the pre-
> > existing cache in SMRAM. When the Runtime Service GetVariable()
> > is invoked, a Runtime DXE cache is used instead of triggering an
> > SMI to VariableSmm. This can improve overall system performance
> > by servicing variable read requests without rendezvousing all
> > cores into SMM.
> >
> > The runtime cache can be disabled with by setting the FeaturePCD
> > gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache
> > to FALSE. If the PCD is set to FALSE, the runtime cache will not be
> > used and an SMI will be triggered for Runtime Service
> > GetVariable () and GetNextVariableName () invocations.
> >
> > The following are important points regarding the behavior of the
> > variable drivers when the variable runtime cache is enabled.
> >
> > 1. All of the non-volatile storage contents are loaded into the
> > cache upon driver load. This one time load operation from storage
> > is preferred as opposed to building the cache on demand. An on-
> > demand cache would require a fallback SMI to load data into the
> > cache as variables are requested.
> >
> > 2. SetVariable () requests will continue to always trigger an SMI.
> > This occurs regardless of whether the variable is volatile or
> > non-volatile.
> >
> > 3. Both volatile and non-volatile variables are cached in a runtime
> > buffer. As is the case in the current EDK II variable driver, they
> > continue to be cached in separate buffers.
> >
> > 4. The cache in Runtime DXE and SMM are intended to be exact copies
> > of one another. All SMM variable accesses only return data from the
> > SMM cache. The runtime caches are only updated after the variable I/O
> > operation is successful in SMM. The runtime caches are only updated
> > from SMM.
> >
> > 5. Synchronization mechanisms are in place to ensure the runtime cache
> > content integrity with the SMM cache. These may result in updates to
> > runtime cache that are the same in content but different in offset and
> > size from updates to the SMM cache.
> >
> > When using SMM variables with runtime cache enabled, two caches will now
> > be present.
> > 1. "Runtime Cache" - Maintained in VariableSmmRuntimeDxe. Used to
> > service
> > Runtime Services GetVariable () and GetNextVariableName () callers.
> > 2. "SMM Cache" - Maintained in VariableSmm to service SMM GetVariable ()
> > and GetNextVariableName () callers.
> > a. This cache is retained so SMM modules do not operate on data outside
> > SMRAM.
> >
> > Because a race condition can occur if an SMI occurs during the execution
> > of runtime code reading from the runtime cache, a runtime cache read lock
> > is introduced that explicitly moves pending updates from SMM to the
> > runtime
> > cache if an SMM update occurs while the runtime cache is locked. Note that
> > it is not expected a Runtime services call will interrupt SMM processing
> > since all CPU cores rendezvous in SMM.
> >
> > It is possible to view UEFI variable read and write statistics by setting
> > the gEfiMdeModulePkgTokenSpaceGuid.PcdVariableCollectStatistics
> > FeaturePcd
> > to TRUE and using the VariableInfo UEFI application in MdeModulePkg to
> > dump
> > variable statistics to the console. By doing so, a user can view the number
> > of GetVariable () hits from the Runtime DXE variable driver (Runtime Cache
> > hits) and the SMM variable driver (SMM Cache hits). SMM Cache hits for
> > GetVariable () will occur when SMM modules invoke GetVariable ().
> >
> > Cc: Dandan Bi <dandan.bi at intel.com>
> > Cc: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> > Cc: Eric Dong <eric.dong at intel.com>
> > Cc: Laszlo Ersek <lersek at redhat.com>
> > Cc: Liming Gao <liming.gao at intel.com>
> > Cc: Michael D Kinney <michael.d.kinney at intel.com>
> > Cc: Ray Ni <ray.ni at intel.com>
> > Cc: Jian J Wang <jian.j.wang at intel.com>
> > Cc: Hao A Wu <hao.a.wu at intel.com>
> > Cc: Jiewen Yao <jiewen.yao at intel.com>
> > Signed-off-by: Michael Kubacki <michael.a.kubacki at intel.com>
> > ---
> > MdeModulePkg/MdeModulePkg.dec | 12 +
> > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> > | 2 +
> > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf | 2
> > +
> >
> > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.i
> > nf | 20 +-
> >
> > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.inf
> > | 2 +
> > MdeModulePkg/Include/Guid/SmmVariableCommon.h | 29 +-
> > MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.h | 32 +-
> > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeCache.h
> > | 51 ++
> > MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c | 50 +-
> > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeCache.c
> > | 153 ++++++
> > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c | 114
> > ++++-
> >
> > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.
> > c | 512 +++++++++++++++++++-
> > 12 files changed, 938 insertions(+), 41 deletions(-)
> >
> > diff --git a/MdeModulePkg/MdeModulePkg.dec
> > b/MdeModulePkg/MdeModulePkg.dec
> > index 59b8c21713..a00835cb84 100644
> > --- a/MdeModulePkg/MdeModulePkg.dec
> > +++ b/MdeModulePkg/MdeModulePkg.dec
> > @@ -641,6 +641,18 @@
> > # @Prompt Enable Device Path From Text support.
> >
> > gEfiMdeModulePkgTokenSpaceGuid.PcdDevicePathSupportDevicePathFrom
> > Text|TRUE|BOOLEAN|0x00010038
> >
> > + ## Indicates if the UEFI variable runtime cache should be enabled.
> > + # This setting only applies if SMM variables are enabled. When enabled, all
> > variable
> > + # data for Runtime Service GetVariable () and GetNextVariableName ()
> > calls is retrieved
> > + # from a runtime data buffer referred to as the "runtime cache". An SMI is
> > not triggered
> > + # at all for these requests. Variables writes still trigger an SMI. This can
> > greatly
> > + # reduce overall system SMM usage as most boots tend to issue far more
> > variable reads
> > + # than writes.<BR><BR>
> > + # TRUE - The UEFI variable runtime cache is enabled.<BR>
> > + # FALSE - The UEFI variable runtime cache is disabled.<BR>
> > + # @Prompt Enable the UEFI variable runtime cache.
> > +
> > gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache|FALS
> > E|BOOLEAN|0x00010039
> > +
> > ## Indicates if the statistics about variable usage will be collected. This
> > information is
> > # stored as a vendor configuration table into the EFI system table.
> > # Set this PCD to TRUE to use VariableInfo application in
> > MdeModulePkg\Application directory to get
> > diff --git
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> > index 08a5490787..ceea5d1ff9 100644
> > ---
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> > @@ -40,6 +40,8 @@
> > VariableNonVolatile.h
> > VariableParsing.c
> > VariableParsing.h
> > + VariableRuntimeCache.c
> > + VariableRuntimeCache.h
> > PrivilegePolymorphic.h
> > Measurement.c
> > TcgMorLockDxe.c
> > diff --git
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> > index 6dc2721b81..bc3033588d 100644
> > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> > @@ -49,6 +49,8 @@
> > VariableNonVolatile.h
> > VariableParsing.c
> > VariableParsing.h
> > + VariableRuntimeCache.c
> > + VariableRuntimeCache.h
> > VarCheck.c
> > Variable.h
> > PrivilegePolymorphic.h
> > diff --git
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> > e.inf
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> > e.inf
> > index 14894e6f13..b5a779a233 100644
> > ---
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> > e.inf
> > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> > e.inf
> > @@ -13,7 +13,7 @@
> > # may not be modified without authorization. If platform fails to protect
> > these resources,
> > # the authentication service provided in this driver will be broken, and the
> > behavior is undefined.
> > #
> > -# Copyright (c) 2010 - 2017, Intel Corporation. All rights reserved.<BR>
> > +# Copyright (c) 2010 - 2019, Intel Corporation. All rights reserved.<BR>
> > # SPDX-License-Identifier: BSD-2-Clause-Patent
> > #
> > ##
> > @@ -39,6 +39,10 @@
> > VariableSmmRuntimeDxe.c
> > PrivilegePolymorphic.h
> > Measurement.c
> > + VariableParsing.c
> > + VariableParsing.h
> > + VariableRuntimeCache.c
> > + VariableRuntimeCache.h
> >
> > [Packages]
> > MdePkg/MdePkg.dec
> > @@ -65,7 +69,21 @@
> > gEdkiiVariableLockProtocolGuid ## PRODUCES
> > gEdkiiVarCheckProtocolGuid ## PRODUCES
> >
> > +[FeaturePcd]
> > + gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache
> > ## CONSUMES
> > + gEfiMdeModulePkgTokenSpaceGuid.PcdVariableCollectStatistics ##
> > CONSUMES
> > +
> > [Guids]
> > + ## PRODUCES ## GUID # Signature of Variable store header
> > + ## CONSUMES ## GUID # Signature of Variable store header
> > + ## SOMETIMES_PRODUCES ## SystemTable
> > + gEfiAuthenticatedVariableGuid
> > +
> > + ## PRODUCES ## GUID # Signature of Variable store header
> > + ## CONSUMES ## GUID # Signature of Variable store header
> > + ## SOMETIMES_PRODUCES ## SystemTable
> > + gEfiVariableGuid
> > +
> > gEfiEventVirtualAddressChangeGuid ## CONSUMES ## Event
> > gEfiEventExitBootServicesGuid ## CONSUMES ## Event
> > ## CONSUMES ## GUID # Locate protocol
> > diff --git
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.i
> > nf
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.
> > inf
> > index f8a3742959..6e17f6cdf5 100644
> > ---
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.i
> > nf
> > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.
> > inf
> > @@ -49,6 +49,8 @@
> > VariableNonVolatile.h
> > VariableParsing.c
> > VariableParsing.h
> > + VariableRuntimeCache.c
> > + VariableRuntimeCache.h
> > VarCheck.c
> > Variable.h
> > PrivilegePolymorphic.h
> > diff --git a/MdeModulePkg/Include/Guid/SmmVariableCommon.h
> > b/MdeModulePkg/Include/Guid/SmmVariableCommon.h
> > index c527a59891..ceef44dfd2 100644
> > --- a/MdeModulePkg/Include/Guid/SmmVariableCommon.h
> > +++ b/MdeModulePkg/Include/Guid/SmmVariableCommon.h
> > @@ -1,7 +1,7 @@
> > /** @file
> > The file defined some common structures used for communicating
> > between SMM variable module and SMM variable wrapper module.
> >
> > -Copyright (c) 2011 - 2015, Intel Corporation. All rights reserved.<BR>
> > +Copyright (c) 2011 - 2019, Intel Corporation. All rights reserved.<BR>
> > SPDX-License-Identifier: BSD-2-Clause-Patent
> >
> > **/
> > @@ -9,6 +9,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > #ifndef _SMM_VARIABLE_COMMON_H_
> > #define _SMM_VARIABLE_COMMON_H_
> >
> > +#include <Guid/VariableFormat.h>
> > #include <Protocol/VarCheck.h>
> >
> > #define EFI_SMM_VARIABLE_WRITE_GUID \
> > @@ -66,6 +67,16 @@ typedef struct {
> > #define
> > SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_GET 10
> >
> > #define SMM_VARIABLE_FUNCTION_GET_PAYLOAD_SIZE 11
> > +//
> > +// The payload for this function is
> > SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> > +//
> > +#define
> > SMM_VARIABLE_FUNCTION_INIT_RUNTIME_VARIABLE_CACHE_CONTEXT
> > 12
> > +
> > +#define SMM_VARIABLE_FUNCTION_SYNC_RUNTIME_CACHE 13
> > +//
> > +// The payload for this function is
> > SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO
> > +//
> > +#define SMM_VARIABLE_FUNCTION_GET_RUNTIME_CACHE_INFO
> > 14
> >
> > ///
> > /// Size of SMM communicate header, without including the payload.
> > @@ -120,4 +131,20 @@ typedef struct {
> > UINTN VariablePayloadSize;
> > } SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE;
> >
> > +typedef struct {
> > + BOOLEAN *ReadLock;
> > + BOOLEAN *PendingUpdate;
> > + BOOLEAN *HobFlushComplete;
> > + VARIABLE_STORE_HEADER *RuntimeHobCache;
> > + VARIABLE_STORE_HEADER *RuntimeNvCache;
> > + VARIABLE_STORE_HEADER *RuntimeVolatileCache;
> > +}
> > SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT;
> > +
> > +typedef struct {
> > + UINTN TotalHobStorageSize;
> > + UINTN TotalNvStorageSize;
> > + UINTN TotalVolatileStorageSize;
> > + BOOLEAN AuthenticatedVariableUsage;
> > +} SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO;
> > +
> > #endif // _SMM_VARIABLE_COMMON_H_
> > diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.h
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.h
> > index fb574b2e32..0b2bb6ae66 100644
> > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.h
> > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.h
> > @@ -64,6 +64,21 @@ typedef enum {
> > VariableStoreTypeMax
> > } VARIABLE_STORE_TYPE;
> >
> > +typedef struct {
> > + UINT32 PendingUpdateOffset;
> > + UINT32 PendingUpdateLength;
> > + VARIABLE_STORE_HEADER *Store;
> > +} VARIABLE_RUNTIME_CACHE;
> > +
> > +typedef struct {
> > + BOOLEAN *ReadLock;
> > + BOOLEAN *PendingUpdate;
> > + BOOLEAN *HobFlushComplete;
> > + VARIABLE_RUNTIME_CACHE VariableRuntimeHobCache;
> > + VARIABLE_RUNTIME_CACHE VariableRuntimeNvCache;
> > + VARIABLE_RUNTIME_CACHE VariableRuntimeVolatileCache;
> > +} VARIABLE_RUNTIME_CACHE_CONTEXT;
> > +
> > typedef struct {
> > VARIABLE_HEADER *CurrPtr;
> > //
> > @@ -79,14 +94,15 @@ typedef struct {
> > } VARIABLE_POINTER_TRACK;
> >
> > typedef struct {
> > - EFI_PHYSICAL_ADDRESS HobVariableBase;
> > - EFI_PHYSICAL_ADDRESS VolatileVariableBase;
> > - EFI_PHYSICAL_ADDRESS NonVolatileVariableBase;
> > - EFI_LOCK VariableServicesLock;
> > - UINT32 ReentrantState;
> > - BOOLEAN AuthFormat;
> > - BOOLEAN AuthSupport;
> > - BOOLEAN EmuNvMode;
> > + EFI_PHYSICAL_ADDRESS HobVariableBase;
> > + EFI_PHYSICAL_ADDRESS VolatileVariableBase;
> > + EFI_PHYSICAL_ADDRESS NonVolatileVariableBase;
> > + VARIABLE_RUNTIME_CACHE_CONTEXT VariableRuntimeCacheContext;
> > + EFI_LOCK VariableServicesLock;
> > + UINT32 ReentrantState;
> > + BOOLEAN AuthFormat;
> > + BOOLEAN AuthSupport;
> > + BOOLEAN EmuNvMode;
> > } VARIABLE_GLOBAL;
> >
> > typedef struct {
> > diff --git
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeCache.h
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeCache.
> > h
> > new file mode 100644
> > index 0000000000..f9804a1d69
> > --- /dev/null
> > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeCache.
> > h
> > @@ -0,0 +1,51 @@
> > +/** @file
> > + The common variable volatile store routines shared by the DXE_RUNTIME
> > variable
> > + module and the DXE_SMM variable module.
> > +
> > +Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
> > +SPDX-License-Identifier: BSD-2-Clause-Patent
> > +
> > +**/
> > +
> > +#ifndef _VARIABLE_RUNTIME_CACHE_H_
> > +#define _VARIABLE_RUNTIME_CACHE_H_
> > +
> > +#include "Variable.h"
> > +
> > +/**
> > + Copies any pending updates to runtime variable caches.
> > +
> > + @retval EFI_UNSUPPORTED The volatile store to be updated is not
> > initialized properly.
> > + @retval EFI_SUCCESS The volatile store was updated successfully.
> > +
> > +**/
> > +EFI_STATUS
> > +FlushPendingRuntimeVariableCacheUpdates (
> > + VOID
> > + );
> > +
> > +/**
> > + Synchronizes the runtime variable caches with all pending updates outside
> > runtime.
> > +
> > + Ensures all conditions are met to maintain coherency for runtime cache
> > updates. This function will attempt
> > + to write the given update (and any other pending updates) if the ReadLock
> > is available. Otherwise, the
> > + update is added as a pending update for the given variable store and it will
> > be flushed to the runtime cache
> > + at the next opportunity the ReadLock is available.
> > +
> > + @param[in] VariableRuntimeCache Variable runtime cache structure for
> > the runtime cache being synchronized.
> > + @param[in] Offset Offset in bytes to apply the update.
> > + @param[in] Length Length of data in bytes of the update.
> > +
> > + @retval EFI_SUCCESS The update was added as a pending update
> > successfully. If the variable runtime
> > + cache ReadLock was available, the runtime cache was
> > updated successfully.
> > + @retval EFI_UNSUPPORTED The volatile store to be updated is not
> > initialized properly.
> > +
> > +**/
> > +EFI_STATUS
> > +SynchronizeRuntimeVariableCache (
> > + IN VARIABLE_RUNTIME_CACHE *VariableRuntimeCache,
> > + IN UINTN Offset,
> > + IN UINTN Length
> > + );
> > +
> > +#endif
> > diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > index 0bd2f22e1a..29d6aca993 100644
> > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > @@ -25,6 +25,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > #include "Variable.h"
> > #include "VariableNonVolatile.h"
> > #include "VariableParsing.h"
> > +#include "VariableRuntimeCache.h"
> >
> > VARIABLE_MODULE_GLOBAL *mVariableModuleGlobal;
> >
> > @@ -332,6 +333,12 @@ RecordVarErrorFlag (
> > // Update the data in NV cache.
> > //
> > *VarErrFlag = TempFlag;
> > + Status = SynchronizeRuntimeVariableCache (
> > + &mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeNvCache,
> > + (UINTN) VarErrFlag - (UINTN) mNvVariableCache + (UINTN)
> > mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase,
> > + sizeof (TempFlag)
> > + );
> > + ASSERT_EFI_ERROR (Status);
> > }
> > }
> > }
> > @@ -766,12 +773,24 @@ Reclaim (
> >
> > Done:
> > if (IsVolatile || mVariableModuleGlobal->VariableGlobal.EmuNvMode) {
> > + Status = SynchronizeRuntimeVariableCache (
> > + &mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeVolatileCach
> > e,
> > + 0,
> > + VariableStoreHeader->Size
> > + );
> > + ASSERT_EFI_ERROR (Status);
> > FreePool (ValidBuffer);
> > } else {
> > //
> > // For NV variable reclaim, we use mNvVariableCache as the buffer, so
> > copy the data back.
> > //
> > - CopyMem (mNvVariableCache, (UINT8 *)(UINTN)VariableBase,
> > VariableStoreHeader->Size);
> > + CopyMem (mNvVariableCache, (UINT8 *) (UINTN) VariableBase,
> > VariableStoreHeader->Size);
> > + Status = SynchronizeRuntimeVariableCache (
> > + &mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeNvCache,
> > + 0,
> > + VariableStoreHeader->Size
> > + );
> > + ASSERT_EFI_ERROR (Status);
> > }
> >
> > return Status;
> > @@ -1614,6 +1633,7 @@ UpdateVariable (
> > VARIABLE_POINTER_TRACK *Variable;
> > VARIABLE_POINTER_TRACK NvVariable;
> > VARIABLE_STORE_HEADER *VariableStoreHeader;
> > + VARIABLE_RUNTIME_CACHE *VolatileCacheInstance;
> > UINT8 *BufferForMerge;
> > UINTN MergedBufSize;
> > BOOLEAN DataReady;
> > @@ -2275,6 +2295,23 @@ UpdateVariable (
> > }
> >
> > Done:
> > + if (!EFI_ERROR (Status)) {
> > + if (Variable->Volatile) {
> > + VolatileCacheInstance = &(mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeVolatileCach
> > e);
> > + } else {
> > + VolatileCacheInstance = &(mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeNvCache);
> > + }
> > +
> > + if (VolatileCacheInstance->Store != NULL) {
> > + Status = SynchronizeRuntimeVariableCache (
> > + VolatileCacheInstance,
> > + 0,
> > + VolatileCacheInstance->Store->Size
> > + );
> > + ASSERT_EFI_ERROR (Status);
> > + }
> > + }
> > +
> > return Status;
> > }
> >
> > @@ -3200,6 +3237,14 @@ FlushHobVariableToFlash (
> > ErrorFlag = TRUE;
> > }
> > }
> > + if (mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeHobCache.S
> > tore != NULL) {
> > + Status = SynchronizeRuntimeVariableCache (
> > + &mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeHobCache,
> > + 0,
> > + mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeHobCache.S
> > tore->Size
> > + );
> > + ASSERT_EFI_ERROR (Status);
> > + }
> > if (ErrorFlag) {
> > //
> > // We still have HOB variable(s) not flushed in flash.
> > @@ -3210,6 +3255,9 @@ FlushHobVariableToFlash (
> > // All HOB variables have been flushed in flash.
> > //
> > DEBUG ((EFI_D_INFO, "Variable driver: all HOB variables have been
> > flushed in flash.\n"));
> > + if (mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.HobFlushComplete != NULL)
> > {
> > + *(mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.HobFlushComplete) = TRUE;
> > + }
> > if (!AtRuntime ()) {
> > FreePool ((VOID *) VariableStoreHeader);
> > }
> > diff --git
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeCache.c
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeCache.c
> > new file mode 100644
> > index 0000000000..bc93cc07d2
> > --- /dev/null
> > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeCache.c
> > @@ -0,0 +1,153 @@
> > +/** @file
> > + Functions related to managing the UEFI variable runtime cache. This file
> > should only include functions
> > + used by the SMM UEFI variable driver.
> > +
> > + Caution: This module requires additional review when modified.
> > + This driver will have external input - variable data. They may be input in
> > SMM mode.
> > + This external input must be validated carefully to avoid security issue like
> > + buffer overflow, integer overflow.
> > +
> > +Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
> > +SPDX-License-Identifier: BSD-2-Clause-Patent
> > +
> > +**/
> > +
> > +#include "VariableParsing.h"
> > +#include "VariableRuntimeCache.h"
> > +
> > +extern VARIABLE_MODULE_GLOBAL *mVariableModuleGlobal;
> > +extern VARIABLE_STORE_HEADER *mNvVariableCache;
> > +
> > +/**
> > + Copies any pending updates to runtime variable caches.
> > +
> > + @retval EFI_UNSUPPORTED The volatile store to be updated is not
> > initialized properly.
> > + @retval EFI_SUCCESS The volatile store was updated successfully.
> > +
> > +**/
> > +EFI_STATUS
> > +FlushPendingRuntimeVariableCacheUpdates (
> > + VOID
> > + )
> > +{
> > + VARIABLE_RUNTIME_CACHE_CONTEXT *VariableRuntimeCacheContext;
> > +
> > + VariableRuntimeCacheContext = &mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext;
> > +
> > + if (VariableRuntimeCacheContext->VariableRuntimeNvCache.Store ==
> > NULL ||
> > + VariableRuntimeCacheContext->VariableRuntimeVolatileCache.Store ==
> > NULL ||
> > + VariableRuntimeCacheContext->PendingUpdate == NULL) {
> > + return EFI_UNSUPPORTED;
> > + }
> > +
> > + if (*(VariableRuntimeCacheContext->PendingUpdate)) {
> > + if (VariableRuntimeCacheContext->VariableRuntimeHobCache.Store !=
> > NULL &&
> > + mVariableModuleGlobal->VariableGlobal.HobVariableBase > 0) {
> > + CopyMem (
> > + (VOID *) (
> > + ((UINT8 *) (UINTN) VariableRuntimeCacheContext-
> > >VariableRuntimeHobCache.Store) +
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateOffset
> > + ),
> > + (VOID *) (
> > + ((UINT8 *) (UINTN) mVariableModuleGlobal-
> > >VariableGlobal.HobVariableBase) +
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateOffset
> > + ),
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateLength
> > + );
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateLength = 0;
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateOffset = 0;
> > + }
> > +
> > + CopyMem (
> > + (VOID *) (
> > + ((UINT8 *) (UINTN) VariableRuntimeCacheContext-
> > >VariableRuntimeNvCache.Store) +
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeNvCache.PendingUpdateOffset
> > + ),
> > + (VOID *) (
> > + ((UINT8 *) (UINTN) mNvVariableCache) +
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeNvCache.PendingUpdateOffset
> > + ),
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeNvCache.PendingUpdateLength
> > + );
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeNvCache.PendingUpdateLength = 0;
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeNvCache.PendingUpdateOffset = 0;
> > +
> > + CopyMem (
> > + (VOID *) (
> > + ((UINT8 *) (UINTN) VariableRuntimeCacheContext-
> > >VariableRuntimeVolatileCache.Store) +
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeVolatileCache.PendingUpdateOffset
> > + ),
> > + (VOID *) (
> > + ((UINT8 *) (UINTN) mVariableModuleGlobal-
> > >VariableGlobal.VolatileVariableBase) +
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeVolatileCache.PendingUpdateOffset
> > + ),
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeVolatileCache.PendingUpdateLength
> > + );
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeVolatileCache.PendingUpdateLength = 0;
> > + VariableRuntimeCacheContext-
> > >VariableRuntimeVolatileCache.PendingUpdateOffset = 0;
> > + *(VariableRuntimeCacheContext->PendingUpdate) = FALSE;
> > + }
> > +
> > + return EFI_SUCCESS;
> > +}
> > +
> > +/**
> > + Synchronizes the runtime variable caches with all pending updates outside
> > runtime.
> > +
> > + Ensures all conditions are met to maintain coherency for runtime cache
> > updates. This function will attempt
> > + to write the given update (and any other pending updates) if the ReadLock
> > is available. Otherwise, the
> > + update is added as a pending update for the given variable store and it will
> > be flushed to the runtime cache
> > + at the next opportunity the ReadLock is available.
> > +
> > + @param[in] VariableRuntimeCache Variable runtime cache structure for
> > the runtime cache being synchronized.
> > + @param[in] Offset Offset in bytes to apply the update.
> > + @param[in] Length Length of data in bytes of the update.
> > +
> > + @retval EFI_SUCCESS The update was added as a pending update
> > successfully. If the variable runtime
> > + cache ReadLock was available, the runtime cache was
> > updated successfully.
> > + @retval EFI_UNSUPPORTED The volatile store to be updated is not
> > initialized properly.
> > +
> > +**/
> > +EFI_STATUS
> > +SynchronizeRuntimeVariableCache (
> > + IN VARIABLE_RUNTIME_CACHE *VariableRuntimeCache,
> > + IN UINTN Offset,
> > + IN UINTN Length
> > + )
> > +{
> > + if (VariableRuntimeCache == NULL) {
> > + return EFI_INVALID_PARAMETER;
> > + } else if (VariableRuntimeCache->Store == NULL) {
> > + // The runtime cache may not be active or allocated yet.
> > + // In either case, return EFI_SUCCESS instead of EFI_NOT_AVAILABLE_YET.
> > + return EFI_SUCCESS;
> > + }
> > +
> > + if (mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.PendingUpdate == NULL ||
> > + mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.ReadLock == NULL) {
> > + return EFI_UNSUPPORTED;
> > + }
> > +
> > + if (*(mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.PendingUpdate) &&
> > + VariableRuntimeCache->PendingUpdateLength > 0) {
> > + VariableRuntimeCache->PendingUpdateLength =
> > + (UINT32) (
> > + MAX (
> > + (UINTN) (VariableRuntimeCache->PendingUpdateOffset +
> > VariableRuntimeCache->PendingUpdateLength),
> > + Offset + Length
> > + ) - MIN ((UINTN) VariableRuntimeCache->PendingUpdateOffset, Offset)
> > + );
> > + VariableRuntimeCache->PendingUpdateOffset =
> > + (UINT32) MIN ((UINTN) VariableRuntimeCache->PendingUpdateOffset,
> > Offset);
> > + } else {
> > + VariableRuntimeCache->PendingUpdateLength = (UINT32) Length;
> > + VariableRuntimeCache->PendingUpdateOffset = (UINT32) Offset;
> > + }
> > + *(mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.PendingUpdate) = TRUE;
> > +
> > + if (*(mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext.ReadLock) == FALSE) {
> > + return FlushPendingRuntimeVariableCacheUpdates ();
> > + }
> > +
> > + return EFI_SUCCESS;
> > +}
> > diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> > index 5e24bc4a62..45814b8996 100644
> > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
> > @@ -31,6 +31,9 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > #include <Guid/SmmVariableCommon.h>
> > #include "Variable.h"
> > #include "VariableParsing.h"
> > +#include "VariableRuntimeCache.h"
> > +
> > +extern VARIABLE_STORE_HEADER *mNvVariableCache;
> >
> > BOOLEAN mAtRuntime = FALSE;
> > UINT8 *mVariableBufferPayload = NULL;
> > @@ -451,25 +454,29 @@ SmmVariableGetStatistics (
> > EFI_STATUS
> > EFIAPI
> > SmmVariableHandler (
> > - IN EFI_HANDLE DispatchHandle,
> > - IN CONST VOID *RegisterContext,
> > - IN OUT VOID *CommBuffer,
> > - IN OUT UINTN *CommBufferSize
> > + IN EFI_HANDLE DispatchHandle,
> > + IN CONST VOID *RegisterContext,
> > + IN OUT VOID *CommBuffer,
> > + IN OUT UINTN *CommBufferSize
> > )
> > {
> > - EFI_STATUS Status;
> > - SMM_VARIABLE_COMMUNICATE_HEADER
> > *SmmVariableFunctionHeader;
> > - SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE
> > *SmmVariableHeader;
> > - SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME
> > *GetNextVariableName;
> > - SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO
> > *QueryVariableInfo;
> > - SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE
> > *GetPayloadSize;
> > - VARIABLE_INFO_ENTRY *VariableInfo;
> > - SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE *VariableToLock;
> > - SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY
> > *CommVariableProperty;
> > - UINTN InfoSize;
> > - UINTN NameBufferSize;
> > - UINTN CommBufferPayloadSize;
> > - UINTN TempCommBufferSize;
> > + EFI_STATUS Status;
> > + SMM_VARIABLE_COMMUNICATE_HEADER
> > *SmmVariableFunctionHeader;
> > + SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE
> > *SmmVariableHeader;
> > + SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME
> > *GetNextVariableName;
> > + SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO
> > *QueryVariableInfo;
> > + SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE
> > *GetPayloadSize;
> > +
> > SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> > *RuntimeVariableCacheContext;
> > + SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO
> > *GetRuntimeCacheInfo;
> > + SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE
> > *VariableToLock;
> > + SMM_VARIABLE_COMMUNICATE_VAR_CHECK_VARIABLE_PROPERTY
> > *CommVariableProperty;
> > + VARIABLE_INFO_ENTRY *VariableInfo;
> > + VARIABLE_RUNTIME_CACHE_CONTEXT
> > *VariableCacheContext;
> > + VARIABLE_STORE_HEADER *VariableCache;
> > + UINTN InfoSize;
> > + UINTN NameBufferSize;
> > + UINTN CommBufferPayloadSize;
> > + UINTN TempCommBufferSize;
> >
> > //
> > // If input is invalid, stop processing this SMI
> > @@ -789,6 +796,79 @@ SmmVariableHandler (
> > );
> > CopyMem (SmmVariableFunctionHeader->Data, mVariableBufferPayload,
> > CommBufferPayloadSize);
> > break;
> > + case
> > SMM_VARIABLE_FUNCTION_INIT_RUNTIME_VARIABLE_CACHE_CONTEXT:
> > + if (CommBufferPayloadSize < sizeof
> > (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT))
> > {
> > + DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: SMM
> > communication buffer size invalid!\n"));
> > + } else if (mEndOfDxe) {
> > + DEBUG ((DEBUG_ERROR, "InitRuntimeVariableCacheContext: Cannot
> > init context after end of DXE!\n"));
> > + } else {
> > + RuntimeVariableCacheContext =
> > (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> > *) SmmVariableFunctionHeader->Data;
> > + VariableCacheContext = &mVariableModuleGlobal-
> > >VariableGlobal.VariableRuntimeCacheContext;
> > +
> > + ASSERT (RuntimeVariableCacheContext->RuntimeVolatileCache !=
> > NULL);
> > + ASSERT (RuntimeVariableCacheContext->RuntimeNvCache != NULL);
> > + ASSERT (RuntimeVariableCacheContext->PendingUpdate != NULL);
> > + ASSERT (RuntimeVariableCacheContext->ReadLock != NULL);
> > + ASSERT (RuntimeVariableCacheContext->HobFlushComplete != NULL);
> > +
> > + VariableCacheContext->VariableRuntimeHobCache.Store =
> > RuntimeVariableCacheContext->RuntimeHobCache;
> > + VariableCacheContext->VariableRuntimeVolatileCache.Store =
> > RuntimeVariableCacheContext->RuntimeVolatileCache;
> > + VariableCacheContext->VariableRuntimeNvCache.Store =
> > RuntimeVariableCacheContext->RuntimeNvCache;
> > + VariableCacheContext->PendingUpdate =
> > RuntimeVariableCacheContext->PendingUpdate;
> > + VariableCacheContext->ReadLock =
> > RuntimeVariableCacheContext->ReadLock;
> > + VariableCacheContext->HobFlushComplete =
> > RuntimeVariableCacheContext->HobFlushComplete;
> > +
> > + // Set up the intial pending request since the RT cache needs to be in
> > sync with SMM cache
> > + if (mVariableModuleGlobal->VariableGlobal.HobVariableBase == 0) {
> > + VariableCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateOffset = 0;
> > + VariableCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateLength = 0;
> > + } else {
> > + VariableCache = (VARIABLE_STORE_HEADER *) (UINTN)
> > mVariableModuleGlobal->VariableGlobal.HobVariableBase;
> > + VariableCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateOffset = 0;
> > + VariableCacheContext-
> > >VariableRuntimeHobCache.PendingUpdateLength = (UINT32) ((UINTN)
> > GetEndPointer (VariableCache) - (UINTN) VariableCache);
> > + CopyGuid (&(VariableCacheContext-
> > >VariableRuntimeHobCache.Store->Signature), &(VariableCache-
> > >Signature));
> > + }
> > + VariableCache = (VARIABLE_STORE_HEADER *) (UINTN)
> > mVariableModuleGlobal->VariableGlobal.VolatileVariableBase;
> > + VariableCacheContext-
> > >VariableRuntimeVolatileCache.PendingUpdateOffset = 0;
> > + VariableCacheContext-
> > >VariableRuntimeVolatileCache.PendingUpdateLength = (UINT32) ((UINTN)
> > GetEndPointer (VariableCache) - (UINTN) VariableCache);
> > + CopyGuid (&(VariableCacheContext-
> > >VariableRuntimeVolatileCache.Store->Signature), &(VariableCache-
> > >Signature));
> > +
> > + VariableCache = (VARIABLE_STORE_HEADER *) (UINTN)
> > mNvVariableCache;
> > + VariableCacheContext-
> > >VariableRuntimeNvCache.PendingUpdateOffset = 0;
> > + VariableCacheContext-
> > >VariableRuntimeNvCache.PendingUpdateLength = (UINT32) ((UINTN)
> > GetEndPointer (VariableCache) - (UINTN) VariableCache);
> > + CopyGuid (&(VariableCacheContext->VariableRuntimeNvCache.Store-
> > >Signature), &(VariableCache->Signature));
> > +
> > + *(VariableCacheContext->PendingUpdate) = TRUE;
> > + *(VariableCacheContext->ReadLock) = FALSE;
> > + *(VariableCacheContext->HobFlushComplete) = FALSE;
> > + }
> > + Status = EFI_SUCCESS;
> > + break;
> > + case SMM_VARIABLE_FUNCTION_SYNC_RUNTIME_CACHE:
> > + Status = FlushPendingRuntimeVariableCacheUpdates ();
> > + break;
> > + case SMM_VARIABLE_FUNCTION_GET_RUNTIME_CACHE_INFO:
> > + if (CommBufferPayloadSize < sizeof
> > (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO)) {
> > + DEBUG ((DEBUG_ERROR, "GetRuntimeCacheInfo: SMM communication
> > buffer size invalid!\n"));
> > + return EFI_SUCCESS;
> > + }
> > + GetRuntimeCacheInfo =
> > (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO *)
> > SmmVariableFunctionHeader->Data;
> > +
> > + if (mVariableModuleGlobal->VariableGlobal.HobVariableBase > 0) {
> > + VariableCache = (VARIABLE_STORE_HEADER *) (UINTN)
> > mVariableModuleGlobal->VariableGlobal.HobVariableBase;
> > + GetRuntimeCacheInfo->TotalHobStorageSize = VariableCache->Size;
> > + } else {
> > + GetRuntimeCacheInfo->TotalHobStorageSize = 0;
> > + }
> > +
> > + VariableCache = (VARIABLE_STORE_HEADER *) (UINTN)
> > mVariableModuleGlobal->VariableGlobal.VolatileVariableBase;
> > + GetRuntimeCacheInfo->TotalVolatileStorageSize = VariableCache->Size;
> > + VariableCache = (VARIABLE_STORE_HEADER *) (UINTN)
> > mNvVariableCache;
> > + GetRuntimeCacheInfo->TotalNvStorageSize = (UINTN) VariableCache-
> > >Size;
> > + GetRuntimeCacheInfo->AuthenticatedVariableUsage =
> > mVariableModuleGlobal->VariableGlobal.AuthFormat;
> > +
> > + Status = EFI_SUCCESS;
> > + break;
> >
> > default:
> > Status = EFI_UNSUPPORTED;
> > diff --git
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> > e.c
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> > e.c
> > index 0a1888e5ef..e236ddff33 100644
> > ---
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> > e.c
> > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> > e.c
> > @@ -13,7 +13,7 @@
> >
> > InitCommunicateBuffer() is really function to check the variable data size.
> >
> > -Copyright (c) 2010 - 2017, Intel Corporation. All rights reserved.<BR>
> > +Copyright (c) 2010 - 2019, Intel Corporation. All rights reserved.<BR>
> > SPDX-License-Identifier: BSD-2-Clause-Patent
> >
> > **/
> > @@ -39,6 +39,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > #include <Guid/SmmVariableCommon.h>
> >
> > #include "PrivilegePolymorphic.h"
> > +#include "VariableParsing.h"
> >
> > EFI_HANDLE mHandle = NULL;
> > EFI_SMM_VARIABLE_PROTOCOL *mSmmVariable = NULL;
> > @@ -46,8 +47,19 @@ EFI_EVENT mVirtualAddressChangeEvent =
> > NULL;
> > EFI_SMM_COMMUNICATION_PROTOCOL *mSmmCommunication =
> > NULL;
> > UINT8 *mVariableBuffer = NULL;
> > UINT8 *mVariableBufferPhysical = NULL;
> > +VARIABLE_INFO_ENTRY *mVariableInfo = NULL;
> > +VARIABLE_STORE_HEADER *mVariableRuntimeHobCacheBuffer =
> > NULL;
> > +VARIABLE_STORE_HEADER *mVariableRuntimeNvCacheBuffer =
> > NULL;
> > +VARIABLE_STORE_HEADER *mVariableRuntimeVolatileCacheBuffer
> > = NULL;
> > UINTN mVariableBufferSize;
> > +UINTN mVariableRuntimeHobCacheBufferSize;
> > +UINTN mVariableRuntimeNvCacheBufferSize;
> > +UINTN mVariableRuntimeVolatileCacheBufferSize;
> > UINTN mVariableBufferPayloadSize;
> > +BOOLEAN mVariableRuntimeCachePendingUpdate;
> > +BOOLEAN mVariableRuntimeCacheReadLock;
> > +BOOLEAN mVariableAuthFormat;
> > +BOOLEAN mHobFlushComplete;
> > EFI_LOCK mVariableServicesLock;
> > EDKII_VARIABLE_LOCK_PROTOCOL mVariableLock;
> > EDKII_VAR_CHECK_PROTOCOL mVarCheck;
> > @@ -107,6 +119,72 @@ ReleaseLockOnlyAtBootTime (
> > }
> > }
> >
> > +/**
> > + Return TRUE if ExitBootServices () has been called.
> > +
> > + @retval TRUE If ExitBootServices () has been called. FALSE if
> > ExitBootServices () has not been called.
> > +**/
> > +BOOLEAN
> > +AtRuntime (
> > + VOID
> > + )
> > +{
> > + return EfiAtRuntime ();
> > +}
> > +
> > +/**
> > + Initialize the variable cache buffer as an empty variable store.
> > +
> > + @param[out] VariableCacheBuffer A pointer to pointer of a cache
> > variable store.
> > + @param[in,out] TotalVariableCacheSize On input, the minimum size
> > needed for the UEFI variable store cache
> > + buffer that is allocated. On output, the actual size of
> > the buffer allocated.
> > + If TotalVariableCacheSize is zero, a buffer will not be
> > allocated and the
> > + function will return with EFI_SUCCESS.
> > +
> > + @retval EFI_SUCCESS The variable cache was allocated and initialized
> > successfully.
> > + @retval EFI_INVALID_PARAMETER A given pointer is NULL or an invalid
> > variable store size was specified.
> > + @retval EFI_OUT_OF_RESOURCES Insufficient resources are available to
> > allocate the variable store cache buffer.
> > +
> > +**/
> > +EFI_STATUS
> > +InitVariableCache (
> > + OUT VARIABLE_STORE_HEADER **VariableCacheBuffer,
> > + IN OUT UINTN *TotalVariableCacheSize
> > + )
> > +{
> > + VARIABLE_STORE_HEADER *VariableCacheStorePtr;
> > +
> > + if (TotalVariableCacheSize == NULL) {
> > + return EFI_INVALID_PARAMETER;
> > + }
> > + if (*TotalVariableCacheSize == 0) {
> > + return EFI_SUCCESS;
> > + }
> > + if (VariableCacheBuffer == NULL || *TotalVariableCacheSize < sizeof
> > (VARIABLE_STORE_HEADER)) {
> > + return EFI_INVALID_PARAMETER;
> > + }
> > + *TotalVariableCacheSize = ALIGN_VALUE (*TotalVariableCacheSize, sizeof
> > (UINT32));
> > +
> > + //
> > + // Allocate NV Storage Cache and initialize it to all 1's (like an erased FV)
> > + //
> > + *VariableCacheBuffer = (VARIABLE_STORE_HEADER *)
> > AllocateRuntimePages (
> > + EFI_SIZE_TO_PAGES (*TotalVariableCacheSize)
> > + );
> > + if (*VariableCacheBuffer == NULL) {
> > + return EFI_OUT_OF_RESOURCES;
> > + }
> > + VariableCacheStorePtr = *VariableCacheBuffer;
> > + SetMem32 ((VOID *) VariableCacheStorePtr, *TotalVariableCacheSize,
> > (UINT32) 0xFFFFFFFF);
> > +
> > + ZeroMem ((VOID *) VariableCacheStorePtr, sizeof
> > (VARIABLE_STORE_HEADER));
> > + VariableCacheStorePtr->Size = (UINT32) *TotalVariableCacheSize;
> > + VariableCacheStorePtr->Format = VARIABLE_STORE_FORMATTED;
> > + VariableCacheStorePtr->State = VARIABLE_STORE_HEALTHY;
> > +
> > + return EFI_SUCCESS;
> > +}
> > +
> > /**
> > Initialize the communicate buffer using DataSize and Function.
> >
> > @@ -425,7 +503,169 @@ Done:
> > }
> >
> > /**
> > - This code finds variable in storage blocks (Volatile or Non-Volatile).
> > + Signals SMM to synchronize any pending variable updates with the
> > runtime cache(s).
> > +
> > +**/
> > +VOID
> > +SyncRuntimeCache (
> > + VOID
> > + )
> > +{
> > + //
> > + // Init the communicate buffer. The buffer data size is:
> > + // SMM_COMMUNICATE_HEADER_SIZE +
> > SMM_VARIABLE_COMMUNICATE_HEADER_SIZE.
> > + //
> > + InitCommunicateBuffer (NULL, 0,
> > SMM_VARIABLE_FUNCTION_SYNC_RUNTIME_CACHE);
> > +
> > + //
> > + // Send data to SMM.
> > + //
> > + SendCommunicateBuffer (0);
> > +}
> > +
> > +/**
> > + Check whether a SMI must be triggered to retrieve pending cache updates.
> > +
> > + If the variable HOB was finished being flushed since the last check for a
> > runtime cache update, this function
> > + will prevent the HOB cache from being used for future runtime cache hits.
> > +
> > +**/
> > +VOID
> > +CheckForRuntimeCacheSync (
> > + VOID
> > + )
> > +{
> > + if (mVariableRuntimeCachePendingUpdate) {
> > + SyncRuntimeCache ();
> > + }
> > + ASSERT (!mVariableRuntimeCachePendingUpdate);
> > +
> > + //
> > + // The HOB variable data may have finished being flushed in the runtime
> > cache sync update
> > + //
> > + if (mHobFlushComplete && mVariableRuntimeHobCacheBuffer != NULL) {
> > + if (!EfiAtRuntime ()) {
> > + FreePool (mVariableRuntimeHobCacheBuffer);
> > + }
> > + mVariableRuntimeHobCacheBuffer = NULL;
> > + }
> > +}
> > +
> > +/**
> > + Finds the given variable in a runtime cache variable store.
> > +
> > + Caution: This function may receive untrusted input.
> > + The data size is external input, so this function will validate it carefully to
> > avoid buffer overflow.
> > +
> > + @param[in] VariableName Name of Variable to be found.
> > + @param[in] VendorGuid Variable vendor GUID.
> > + @param[out] Attributes Attribute value of the variable found.
> > + @param[in, out] DataSize Size of Data found. If size is less than the
> > + data, this value contains the required size.
> > + @param[out] Data Data pointer.
> > +
> > + @retval EFI_SUCCESS Found the specified variable.
> > + @retval EFI_INVALID_PARAMETER Invalid parameter.
> > + @retval EFI_NOT_FOUND The specified variable could not be found.
> > +
> > +**/
> > +EFI_STATUS
> > +FindVariableInRuntimeCache (
> > + IN CHAR16 *VariableName,
> > + IN EFI_GUID *VendorGuid,
> > + OUT UINT32 *Attributes OPTIONAL,
> > + IN OUT UINTN *DataSize,
> > + OUT VOID *Data OPTIONAL
> > + )
> > +{
> > + EFI_STATUS Status;
> > + UINTN TempDataSize;
> > + VARIABLE_POINTER_TRACK RtPtrTrack;
> > + VARIABLE_STORE_TYPE StoreType;
> > + VARIABLE_STORE_HEADER *VariableStoreList[VariableStoreTypeMax];
> > +
> > + Status = EFI_NOT_FOUND;
> > +
> > + if (VariableName == NULL || VendorGuid == NULL || DataSize == NULL) {
> > + return EFI_INVALID_PARAMETER;
> > + }
> > +
> > + //
> > + // The UEFI specification restricts Runtime Services callers from invoking
> > the same or certain other Runtime Service
> > + // functions prior to completion and return from a previous Runtime
> > Service call. These restrictions prevent
> > + // a GetVariable () or GetNextVariable () call from being issued until a prior
> > call has returned. The runtime
> > + // cache read lock should always be free when entering this function.
> > + //
> > + ASSERT (!mVariableRuntimeCacheReadLock);
> > +
> > + mVariableRuntimeCacheReadLock = TRUE;
> > + CheckForRuntimeCacheSync ();
> > +
> > + if (!mVariableRuntimeCachePendingUpdate) {
> > + //
> > + // 0: Volatile, 1: HOB, 2: Non-Volatile.
> > + // The index and attributes mapping must be kept in this order as
> > FindVariable
> > + // makes use of this mapping to implement search algorithm.
> > + //
> > + VariableStoreList[VariableStoreTypeVolatile] =
> > mVariableRuntimeVolatileCacheBuffer;
> > + VariableStoreList[VariableStoreTypeHob] =
> > mVariableRuntimeHobCacheBuffer;
> > + VariableStoreList[VariableStoreTypeNv] =
> > mVariableRuntimeNvCacheBuffer;
> > +
> > + for (StoreType = (VARIABLE_STORE_TYPE) 0; StoreType <
> > VariableStoreTypeMax; StoreType++) {
> > + if (VariableStoreList[StoreType] == NULL) {
> > + continue;
> > + }
> > +
> > + RtPtrTrack.StartPtr = GetStartPointer (VariableStoreList[StoreType]);
> > + RtPtrTrack.EndPtr = GetEndPointer (VariableStoreList[StoreType]);
> > + RtPtrTrack.Volatile = (BOOLEAN) (StoreType ==
> > VariableStoreTypeVolatile);
> > +
> > + Status = FindVariableEx (VariableName, VendorGuid, FALSE, &RtPtrTrack,
> > mVariableAuthFormat);
> > + if (!EFI_ERROR (Status)) {
> > + break;
> > + }
> > + }
> > +
> > + if (!EFI_ERROR (Status)) {
> > + //
> > + // Get data size
> > + //
> > + TempDataSize = DataSizeOfVariable (RtPtrTrack.CurrPtr,
> > mVariableAuthFormat);
> > + ASSERT (TempDataSize != 0);
> > +
> > + if (*DataSize >= TempDataSize) {
> > + if (Data == NULL) {
> > + Status = EFI_INVALID_PARAMETER;
> > + goto Done;
> > + }
> > +
> > + CopyMem (Data, GetVariableDataPtr (RtPtrTrack.CurrPtr,
> > mVariableAuthFormat), TempDataSize);
> > + if (Attributes != NULL) {
> > + *Attributes = RtPtrTrack.CurrPtr->Attributes;
> > + }
> > +
> > + *DataSize = TempDataSize;
> > +
> > + UpdateVariableInfo (VariableName, VendorGuid, RtPtrTrack.Volatile,
> > TRUE, FALSE, FALSE, TRUE, &mVariableInfo);
> > +
> > + Status = EFI_SUCCESS;
> > + goto Done;
> > + } else {
> > + *DataSize = TempDataSize;
> > + Status = EFI_BUFFER_TOO_SMALL;
> > + goto Done;
> > + }
> > + }
> > + }
> > +
> > +Done:
> > + mVariableRuntimeCacheReadLock = FALSE;
> > +
> > + return Status;
> > +}
> > +
> > +/**
> > + Finds the given variable in a variable store in SMM.
> >
> > Caution: This function may receive untrusted input.
> > The data size is external input, so this function will validate it carefully to
> > avoid buffer overflow.
> > @@ -437,20 +677,18 @@ Done:
> > data, this value contains the required size.
> > @param[out] Data Data pointer.
> >
> > + @retval EFI_SUCCESS Found the specified variable.
> > @retval EFI_INVALID_PARAMETER Invalid parameter.
> > - @retval EFI_SUCCESS Find the specified variable.
> > - @retval EFI_NOT_FOUND Not found.
> > - @retval EFI_BUFFER_TO_SMALL DataSize is too small for the result.
> > + @retval EFI_NOT_FOUND The specified variable could not be found.
> >
> > **/
> > EFI_STATUS
> > -EFIAPI
> > -RuntimeServiceGetVariable (
> > +FindVariableInSmm (
> > IN CHAR16 *VariableName,
> > IN EFI_GUID *VendorGuid,
> > OUT UINT32 *Attributes OPTIONAL,
> > IN OUT UINTN *DataSize,
> > - OUT VOID *Data
> > + OUT VOID *Data OPTIONAL
> > )
> > {
> > EFI_STATUS Status;
> > @@ -474,8 +712,6 @@ RuntimeServiceGetVariable (
> > return EFI_INVALID_PARAMETER;
> > }
> >
> > - AcquireLockOnlyAtBootTime(&mVariableServicesLock);
> > -
> > //
> > // Init the communicate buffer. The buffer data size is:
> > // SMM_COMMUNICATE_HEADER_SIZE +
> > SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
> > @@ -488,7 +724,7 @@ RuntimeServiceGetVariable (
> > }
> > PayloadSize = OFFSET_OF
> > (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) +
> > VariableNameSize + TempDataSize;
> >
> > - Status = InitCommunicateBuffer ((VOID **)&SmmVariableHeader,
> > PayloadSize, SMM_VARIABLE_FUNCTION_GET_VARIABLE);
> > + Status = InitCommunicateBuffer ((VOID **) &SmmVariableHeader,
> > PayloadSize, SMM_VARIABLE_FUNCTION_GET_VARIABLE);
> > if (EFI_ERROR (Status)) {
> > goto Done;
> > }
> > @@ -534,11 +770,58 @@ RuntimeServiceGetVariable (
> > }
> >
> > Done:
> > + return Status;
> > +}
> > +
> > +/**
> > + This code finds variable in storage blocks (Volatile or Non-Volatile).
> > +
> > + Caution: This function may receive untrusted input.
> > + The data size is external input, so this function will validate it carefully to
> > avoid buffer overflow.
> > +
> > + @param[in] VariableName Name of Variable to be found.
> > + @param[in] VendorGuid Variable vendor GUID.
> > + @param[out] Attributes Attribute value of the variable found.
> > + @param[in, out] DataSize Size of Data found. If size is less than the
> > + data, this value contains the required size.
> > + @param[out] Data Data pointer.
> > +
> > + @retval EFI_INVALID_PARAMETER Invalid parameter.
> > + @retval EFI_SUCCESS Find the specified variable.
> > + @retval EFI_NOT_FOUND Not found.
> > + @retval EFI_BUFFER_TO_SMALL DataSize is too small for the result.
> > +
> > +**/
> > +EFI_STATUS
> > +EFIAPI
> > +RuntimeServiceGetVariable (
> > + IN CHAR16 *VariableName,
> > + IN EFI_GUID *VendorGuid,
> > + OUT UINT32 *Attributes OPTIONAL,
> > + IN OUT UINTN *DataSize,
> > + OUT VOID *Data
> > + )
> > +{
> > + EFI_STATUS Status;
> > +
> > + if (VariableName == NULL || VendorGuid == NULL || DataSize == NULL) {
> > + return EFI_INVALID_PARAMETER;
> > + }
> > + if (VariableName[0] == 0) {
> > + return EFI_NOT_FOUND;
> > + }
> > +
> > + AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> > + if (FeaturePcdGet (PcdEnableVariableRuntimeCache)) {
> > + Status = FindVariableInRuntimeCache (VariableName, VendorGuid,
> > Attributes, DataSize, Data);
> > + } else {
> > + Status = FindVariableInSmm (VariableName, VendorGuid, Attributes,
> > DataSize, Data);
> > + }
> > ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> > +
> > return Status;
> > }
> >
> > -
> > /**
> > This code Finds the Next available variable.
> >
> > @@ -870,6 +1153,17 @@ OnReadyToBoot (
> > //
> > SendCommunicateBuffer (0);
> >
> > + //
> > + // Install the system configuration table for variable info data captured
> > + //
> > + if (FeaturePcdGet (PcdEnableVariableRuntimeCache) && FeaturePcdGet
> > (PcdVariableCollectStatistics)) {
> > + if (mVariableAuthFormat) {
> > + gBS->InstallConfigurationTable (&gEfiAuthenticatedVariableGuid,
> > mVariableInfo);
> > + } else {
> > + gBS->InstallConfigurationTable (&gEfiVariableGuid, mVariableInfo);
> > + }
> > + }
> > +
> > gBS->CloseEvent (Event);
> > }
> >
> > @@ -893,6 +1187,9 @@ VariableAddressChangeEvent (
> > {
> > EfiConvertPointer (0x0, (VOID **) &mVariableBuffer);
> > EfiConvertPointer (0x0, (VOID **) &mSmmCommunication);
> > + EfiConvertPointer (0x0, (VOID **) &mVariableRuntimeHobCacheBuffer);
> > + EfiConvertPointer (0x0, (VOID **) &mVariableRuntimeNvCacheBuffer);
> > + EfiConvertPointer (0x0, (VOID **)
> > &mVariableRuntimeVolatileCacheBuffer);
> > }
> >
> > /**
> > @@ -969,6 +1266,159 @@ Done:
> > return Status;
> > }
> >
> > +/**
> > + This code gets information needed from SMM for runtime cache
> > initialization.
> > +
> > + @param[out] TotalHobStorageSize Output pointer for the total HOB
> > storage size in bytes.
> > + @param[out] TotalNvStorageSize Output pointer for the total non-
> > volatile storage size in bytes.
> > + @param[out] TotalVolatileStorageSize Output pointer for the total
> > volatile storage size in bytes.
> > + @param[out] AuthenticatedVariableUsage Output pointer that indicates if
> > authenticated variables are to be used.
> > +
> > + @retval EFI_SUCCESS Retrieved the size successfully.
> > + @retval EFI_INVALID_PARAMETER TotalNvStorageSize parameter is
> > NULL.
> > + @retval EFI_OUT_OF_RESOURCES The memory resources needed
> > for a CommBuffer are not available.
> > + @retval Others Could not retrieve the size successfully.
> > +
> > +**/
> > +EFI_STATUS
> > +GetRuntimeCacheInfo (
> > + OUT UINTN *TotalHobStorageSize,
> > + OUT UINTN *TotalNvStorageSize,
> > + OUT UINTN *TotalVolatileStorageSize,
> > + OUT BOOLEAN *AuthenticatedVariableUsage
> > + )
> > +{
> > + EFI_STATUS Status;
> > + SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO
> > *SmmGetRuntimeCacheInfo;
> > + EFI_SMM_COMMUNICATE_HEADER
> > *SmmCommunicateHeader;
> > + SMM_VARIABLE_COMMUNICATE_HEADER
> > *SmmVariableFunctionHeader;
> > + UINTN CommSize;
> > + UINT8 *CommBuffer;
> > +
> > + SmmGetRuntimeCacheInfo = NULL;
> > + CommBuffer = mVariableBuffer;
> > +
> > + if (TotalHobStorageSize == NULL || TotalNvStorageSize == NULL ||
> > TotalVolatileStorageSize == NULL || AuthenticatedVariableUsage == NULL) {
> > + return EFI_INVALID_PARAMETER;
> > + }
> > +
> > + if (CommBuffer == NULL) {
> > + return EFI_OUT_OF_RESOURCES;
> > + }
> > +
> > + AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> > +
> > + CommSize = SMM_COMMUNICATE_HEADER_SIZE +
> > SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> > (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO);
> > + ZeroMem (CommBuffer, CommSize);
>
>
> I would suggest to align with the approach of using the pre-alloacted
> communication buffer like those existing functions:
>
> VariableLockRequestToLock()
> VarCheckVariablePropertySet()
> VarCheckVariablePropertyGet()
> RuntimeServiceGetVariable()
> RuntimeServiceGetNextVariableName()
> RuntimeServiceSetVariable()
> RuntimeServiceQueryVariableInfo()
> OnExitBootServices()
> OnReadyToBoot()
>
> They will:
> 1. Use InitCommunicateBuffer() to get the communication buffer (a data size
> check will be performed in InitCommunicateBuffer);
> 2. Update the communication buffer content;
> 3. Use SendCommunicateBuffer() to send the data to SMM.
>
> There is a similar case for SendRuntimeVariableCacheContextToSmm() as well.
>
> Best Regards,
> Hao Wu
>
>
> > +
> > + SmmCommunicateHeader = (EFI_SMM_COMMUNICATE_HEADER *)
> > CommBuffer;
> > + CopyGuid (&SmmCommunicateHeader->HeaderGuid,
> > &gEfiSmmVariableProtocolGuid);
> > + SmmCommunicateHeader->MessageLength =
> > SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> > (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO);
> > +
> > + SmmVariableFunctionHeader =
> > (SMM_VARIABLE_COMMUNICATE_HEADER *) SmmCommunicateHeader-
> > >Data;
> > + SmmVariableFunctionHeader->Function =
> > SMM_VARIABLE_FUNCTION_GET_RUNTIME_CACHE_INFO;
> > + SmmGetRuntimeCacheInfo =
> > (SMM_VARIABLE_COMMUNICATE_GET_RUNTIME_CACHE_INFO *)
> > SmmVariableFunctionHeader->Data;
> > +
> > + //
> > + // Send data to SMM.
> > + //
> > + Status = mSmmCommunication->Communicate (mSmmCommunication,
> > CommBuffer, &CommSize);
> > + ASSERT_EFI_ERROR (Status);
> > + if (CommSize <= SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
> > + Status = EFI_BAD_BUFFER_SIZE;
> > + goto Done;
> > + }
> > +
> > + Status = SmmVariableFunctionHeader->ReturnStatus;
> > + if (EFI_ERROR (Status)) {
> > + goto Done;
> > + }
> > +
> > + //
> > + // Get data from SMM.
> > + //
> > + *TotalHobStorageSize = SmmGetRuntimeCacheInfo->TotalHobStorageSize;
> > + *TotalNvStorageSize = SmmGetRuntimeCacheInfo->TotalNvStorageSize;
> > + *TotalVolatileStorageSize = SmmGetRuntimeCacheInfo-
> > >TotalVolatileStorageSize;
> > + *AuthenticatedVariableUsage = SmmGetRuntimeCacheInfo-
> > >AuthenticatedVariableUsage;
> > +
> > +Done:
> > + ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> > + return Status;
> > +}
> > +
> > +/**
> > + Sends the runtime variable cache context information to SMM.
> > +
> > + @retval EFI_SUCCESS Retrieved the size successfully.
> > + @retval EFI_INVALID_PARAMETER TotalNvStorageSize parameter is
> > NULL.
> > + @retval EFI_OUT_OF_RESOURCES The memory resources needed for a
> > CommBuffer are not available.
> > + @retval Others Could not retrieve the size successfully.;
> > +
> > +**/
> > +EFI_STATUS
> > +SendRuntimeVariableCacheContextToSmm (
> > + VOID
> > + )
> > +{
> > + EFI_STATUS Status;
> > +
> > SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> > *SmmRuntimeVarCacheContext;
> > + EFI_SMM_COMMUNICATE_HEADER
> > *SmmCommunicateHeader;
> > + SMM_VARIABLE_COMMUNICATE_HEADER
> > *SmmVariableFunctionHeader;
> > + UINTN CommSize;
> > + UINT8 *CommBuffer;
> > +
> > + SmmRuntimeVarCacheContext = NULL;
> > + CommBuffer = mVariableBuffer;
> > +
> > + if (CommBuffer == NULL) {
> > + return EFI_OUT_OF_RESOURCES;
> > + }
> > +
> > + AcquireLockOnlyAtBootTime (&mVariableServicesLock);
> > +
> > + //
> > + // Init the communicate buffer. The buffer data size is:
> > + // SMM_COMMUNICATE_HEADER_SIZE +
> > SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> > (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT);
> > + //
> > + CommSize = SMM_COMMUNICATE_HEADER_SIZE +
> > SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> > (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT);
> > + ZeroMem (CommBuffer, CommSize);
> > +
> > + SmmCommunicateHeader = (EFI_SMM_COMMUNICATE_HEADER *)
> > CommBuffer;
> > + CopyGuid (&SmmCommunicateHeader->HeaderGuid,
> > &gEfiSmmVariableProtocolGuid);
> > + SmmCommunicateHeader->MessageLength =
> > SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + sizeof
> > (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT);
> > +
> > + SmmVariableFunctionHeader =
> > (SMM_VARIABLE_COMMUNICATE_HEADER *) SmmCommunicateHeader-
> > >Data;
> > + SmmVariableFunctionHeader->Function =
> > SMM_VARIABLE_FUNCTION_INIT_RUNTIME_VARIABLE_CACHE_CONTEXT;
> > + SmmRuntimeVarCacheContext =
> > (SMM_VARIABLE_COMMUNICATE_RUNTIME_VARIABLE_CACHE_CONTEXT
> > *) SmmVariableFunctionHeader->Data;
> > +
> > + SmmRuntimeVarCacheContext->RuntimeHobCache =
> > mVariableRuntimeHobCacheBuffer;
> > + SmmRuntimeVarCacheContext->RuntimeVolatileCache =
> > mVariableRuntimeVolatileCacheBuffer;
> > + SmmRuntimeVarCacheContext->RuntimeNvCache =
> > mVariableRuntimeNvCacheBuffer;
> > + SmmRuntimeVarCacheContext->PendingUpdate =
> > &mVariableRuntimeCachePendingUpdate;
> > + SmmRuntimeVarCacheContext->ReadLock =
> > &mVariableRuntimeCacheReadLock;
> > + SmmRuntimeVarCacheContext->HobFlushComplete =
> > &mHobFlushComplete;
> > +
> > + //
> > + // Send data to SMM.
> > + //
> > + Status = mSmmCommunication->Communicate (mSmmCommunication,
> > CommBuffer, &CommSize);
> > + ASSERT_EFI_ERROR (Status);
> > + if (CommSize <= SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
> > + Status = EFI_BAD_BUFFER_SIZE;
> > + goto Done;
> > + }
> > +
> > + Status = SmmVariableFunctionHeader->ReturnStatus;
> > + if (EFI_ERROR (Status)) {
> > + goto Done;
> > + }
> > +
> > +Done:
> > + ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
> > + return Status;
> > +}
> > +
> > /**
> > Initialize variable service and install Variable Architectural protocol.
> >
> > @@ -985,7 +1435,7 @@ SmmVariableReady (
> > {
> > EFI_STATUS Status;
> >
> > - Status = gBS->LocateProtocol (&gEfiSmmVariableProtocolGuid, NULL,
> > (VOID **)&mSmmVariable);
> > + Status = gBS->LocateProtocol (&gEfiSmmVariableProtocolGuid, NULL,
> > (VOID **) &mSmmVariable);
> > if (EFI_ERROR (Status)) {
> > return;
> > }
> > @@ -1007,6 +1457,42 @@ SmmVariableReady (
> > //
> > mVariableBufferPhysical = mVariableBuffer;
> >
> > + if (FeaturePcdGet (PcdEnableVariableRuntimeCache)) {
> > + DEBUG ((DEBUG_INFO, "Variable driver runtime cache is enabled.\n"));
> > + //
> > + // Allocate runtime variable cache memory buffers.
> > + //
> > + Status = GetRuntimeCacheInfo (
> > + &mVariableRuntimeHobCacheBufferSize,
> > + &mVariableRuntimeNvCacheBufferSize,
> > + &mVariableRuntimeVolatileCacheBufferSize,
> > + &mVariableAuthFormat
> > + );
> > + if (!EFI_ERROR (Status)) {
> > + Status = InitVariableCache (&mVariableRuntimeHobCacheBuffer,
> > &mVariableRuntimeHobCacheBufferSize);
> > + if (!EFI_ERROR (Status)) {
> > + Status = InitVariableCache (&mVariableRuntimeNvCacheBuffer,
> > &mVariableRuntimeNvCacheBufferSize);
> > + if (!EFI_ERROR (Status)) {
> > + Status = InitVariableCache (&mVariableRuntimeVolatileCacheBuffer,
> > &mVariableRuntimeVolatileCacheBufferSize);
> > + if (!EFI_ERROR (Status)) {
> > + Status = SendRuntimeVariableCacheContextToSmm ();
> > + if (!EFI_ERROR (Status)) {
> > + SyncRuntimeCache ();
> > + }
> > + }
> > + }
> > + }
> > + if (EFI_ERROR (Status)) {
> > + mVariableRuntimeHobCacheBuffer = NULL;
> > + mVariableRuntimeNvCacheBuffer = NULL;
> > + mVariableRuntimeVolatileCacheBuffer = NULL;
> > + }
> > + }
> > + ASSERT_EFI_ERROR (Status);
> > + } else {
> > + DEBUG ((DEBUG_INFO, "Variable driver runtime cache is disabled.\n"));
> > + }
> > +
> > gRT->GetVariable = RuntimeServiceGetVariable;
> > gRT->GetNextVariableName = RuntimeServiceGetNextVariableName;
> > gRT->SetVariable = RuntimeServiceSetVariable;
> > --
> > 2.16.2.windows.1
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