Mike, Thanks for explaining. You're right that the error is rare case and it won't cause big problem, and NonVolatileLastVariableOffset will be approaching the whole FV size after some time. I don't have strong opinion. Both work for me.
Regards, Jian > -----Original Message----- > From: Kubacki, Michael A <michael.a.kuba...@intel.com> > Sent: Wednesday, January 15, 2020 11:53 AM > To: Wang, Jian J <jian.j.w...@intel.com>; devel@edk2.groups.io > Cc: Gao, Liming <liming....@intel.com>; Kinney, Michael D > <michael.d.kin...@intel.com>; Michael Turner > <michael.tur...@microsoft.com>; Wu, Hao A <hao.a...@intel.com> > Subject: RE: [edk2-devel] [PATCH V1 1/1] MdeModulePkg/Variable: Fix > VarErrorFlag RT cache offset calculation > > Hi Jian, > > I considered that but these are the reasons I settled on the approach in > patch V1. > > 1. With the variable store filled, the length of mVariableModuleGlobal- > >NonVolatileLastVariableOffset will only marginally be a smaller value than > mNvVariableCache->Size (since variable writes grow the store for SPI flash > wear > leveling). In this case, it will be ~CommonRuntimeVariableSpace which is > usually > a major portion of the variable store size anyway. > 2. Since mVariableModuleGlobal->NonVolatileLastVariableOffset is a global > moving value that is more frequently manipulated than the fixed variable store > size, depending upon it increases the likelihood it will be set to an invalid > value > somewhere else. > 3. This is a relatively rare case (an error condition) and the memory copy is > within DRAM for variable stores that are typically ~128KB - ~512KB. > > To reduce the copy size, the Offset parameter can be "(UINTN) VarErrFlag - > (UINTN) mNvVariableCache" (just remove the unnecessary addition of (UINTN) > mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase) with size > "sizeof (TempFlag)". How about this in a V2? > > Thanks, > Michael > > > -----Original Message----- > > From: Wang, Jian J <jian.j.w...@intel.com> > > Sent: Monday, January 13, 2020 10:43 PM > > To: devel@edk2.groups.io; Kubacki, Michael A > > <michael.a.kuba...@intel.com> > > Cc: Gao, Liming <liming....@intel.com>; Kinney, Michael D > > <michael.d.kin...@intel.com>; Michael Turner > > <michael.tur...@microsoft.com>; Wu, Hao A <hao.a...@intel.com> > > Subject: RE: [edk2-devel] [PATCH V1 1/1] MdeModulePkg/Variable: Fix > > VarErrorFlag RT cache offset calculation > > > > Michael, > > > > I'm not sure sync-ing whole variable cache memory is an efficient operation. > > What about using mVariableModuleGlobal->NonVolatileLastVariableOffset > > as Length parameter? > > > > Status = SynchronizeRuntimeVariableCache ( > > &mVariableModuleGlobal- > > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeNvCache, > > 0, > > mVariableModuleGlobal->NonVolatileLastVariableOffset > > ); > > > > Regards, > > Jian > > > > > -----Original Message----- > > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of > > > Kubacki, Michael A > > > Sent: Tuesday, January 14, 2020 7:19 AM > > > To: devel@edk2.groups.io > > > Cc: Gao, Liming <liming....@intel.com>; Kinney, Michael D > > > <michael.d.kin...@intel.com>; Michael Turner > > > <michael.tur...@microsoft.com>; Wang, Jian J <jian.j.w...@intel.com>; > > > Wu, Hao A <hao.a...@intel.com> > > > Subject: [edk2-devel] [PATCH V1 1/1] MdeModulePkg/Variable: Fix > > > VarErrorFlag RT cache offset calculation > > > > > > REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2457 > > > > > > This commit fixes an offset calculation that is used to write the > > > VarErrorFlag UEFI variable to the UEFI variable runtime cache. > > > > > > Currently a physical address is used instead of an offset. This commit > > > changes the offset to zero with a length of the entire non-volatile > > > variable store so the entire non-volatile variable store buffer in > > > SMRAM (with the variable update modification) is copied to the runtime > > > variable cache. This follows the same pattern used in other > > > SynchronizeRuntimeVariableCache () calls for consistency. > > > > > > * Observable symptom: An exception in SMM will most likely occur > > > due to the invalid memory reference when the VarErrorFlag variable > > > is written. The variable is most commonly written when the UEFI > > > variable store is full. > > > > > > * The issue only occurs when the variable runtime cache is enabled > > > by the following PCD being set to TRUE: > > > gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache > > > > > > Fixes: aab3b9b9a1e5e1f3fa966fb1667fc3e6c47e7706 > > > > > > Cc: Liming Gao <liming....@intel.com> > > > Cc: Michael D Kinney <michael.d.kin...@intel.com> > > > Cc: Michael Turner <michael.tur...@microsoft.com> > > > Cc: Jian J Wang <jian.j.w...@intel.com> > > > Cc: Hao A Wu <hao.a...@intel.com> > > > Signed-off-by: Michael Kubacki <michael.a.kuba...@intel.com> > > > --- > > > MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c > > > b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c > > > index b0ee5e50d0..d23aea4bc7 100644 > > > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c > > > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c > > > @@ -16,7 +16,7 @@ > > > VariableServiceSetVariable() should also check authenticate data to > > > avoid buffer overflow, > > > integer overflow. It should also check attribute to avoid > > > authentication > > bypass. > > > > > > -Copyright (c) 2006 - 2019, Intel Corporation. All rights > > > reserved.<BR> > > > +Copyright (c) 2006 - 2020, Intel Corporation. All rights > > > +reserved.<BR> > > > (C) Copyright 2015-2018 Hewlett Packard Enterprise Development LP<BR> > > > SPDX-License-Identifier: BSD-2-Clause-Patent > > > > > > @@ -335,8 +335,8 @@ RecordVarErrorFlag ( > > > *VarErrFlag = TempFlag; > > > Status = SynchronizeRuntimeVariableCache ( > > > &mVariableModuleGlobal- > > > >VariableGlobal.VariableRuntimeCacheContext.VariableRuntimeNvCache, > > > - (UINTN) VarErrFlag - (UINTN) mNvVariableCache + (UINTN) > > > mVariableModuleGlobal->VariableGlobal.NonVolatileVariableBase, > > > - sizeof (TempFlag) > > > + 0, > > > + mNvVariableCache->Size > > > ); > > > ASSERT_EFI_ERROR (Status); > > > } > > > -- > > > 2.16.2.windows.1 > > > > > > > > > > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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