> > -Done: > > + mVariableRuntimeCacheReadLock = FALSE; > > > Similar to the previous patch (7/9), > if timeout occurs when acquiring the read lock, should this flag be set to > FALSE in such case? >
Given that the runtime service can be invoked in a multi-threaded OS environment, it is possible that one thread could be stuck with the lock while another thread times out waiting to acquire the lock. In that case, I believe the global lock should not be released. I can move setting the flag to FALSE within the same conditional block in which it is set. Thanks, Michael > -----Original Message----- > From: Wu, Hao A <hao.a...@intel.com> > Sent: Thursday, October 3, 2019 1:05 AM > To: Kubacki, Michael A <michael.a.kuba...@intel.com>; > devel@edk2.groups.io > Cc: Bi, Dandan <dandan...@intel.com>; Ard Biesheuvel > <ard.biesheu...@linaro.org>; Dong, Eric <eric.d...@intel.com>; Laszlo Ersek > <ler...@redhat.com>; Gao, Liming <liming....@intel.com>; Kinney, Michael > D <michael.d.kin...@intel.com>; Ni, Ray <ray...@intel.com>; Wang, Jian J > <jian.j.w...@intel.com>; Yao, Jiewen <jiewen....@intel.com> > Subject: RE: [PATCH V2 8/9] MdeModulePkg/Variable: Add RT > GetNextVariableName() cache support > > > -----Original Message----- > > From: Kubacki, Michael A > > Sent: Saturday, September 28, 2019 9:47 AM > > To: devel@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 V2 8/9] MdeModulePkg/Variable: Add RT > > GetNextVariableName() cache support > > > > https://bugzilla.tianocore.org/show_bug.cgi?id=2220 > > > > This change implements the Runtime Service GetNextVariableName() > using > > the Runtime Cache in VariableSmmRuntimeDxe. Runtime Service calls to > > GetNextVariableName() will no longer trigger a SW SMI. > > > > Overall system performance and stability will be improved by > > eliminating an SMI for these calls as they typically result in a > > relatively large number of invocations to retrieve all variable names > > in all variable stores present. > > > > Cc: Dandan Bi <dandan...@intel.com> > > Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> > > Cc: Eric Dong <eric.d...@intel.com> > > Cc: Laszlo Ersek <ler...@redhat.com> > > Cc: Liming Gao <liming....@intel.com> > > Cc: Michael D Kinney <michael.d.kin...@intel.com> > > Cc: Ray Ni <ray...@intel.com> > > Cc: Jian J Wang <jian.j.w...@intel.com> > > Cc: Hao A Wu <hao.a...@intel.com> > > Cc: Jiewen Yao <jiewen....@intel.com> > > Signed-off-by: Michael Kubacki <michael.a.kuba...@intel.com> > > --- > > > > > MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe > > .c | 118 +++++++++----------- > > 1 file changed, 50 insertions(+), 68 deletions(-) > > > > diff --git > > > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeD > > xe.c > > > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeD > > xe.c > > index 46f69765a4..bc3b56b0ce 100644 > > --- > > > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeD > > xe.c > > +++ > > > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeD > > xe.c > > @@ -799,87 +799,69 @@ RuntimeServiceGetNextVariableName ( > > IN OUT EFI_GUID *VendorGuid > > ) > > { > > - EFI_STATUS Status; > > - UINTN PayloadSize; > > - SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME > > *SmmGetNextVariableName; > > - UINTN OutVariableNameSize; > > - UINTN InVariableNameSize; > > + EFI_STATUS Status; > > + UINTN DelayIndex; > > + UINTN MaxLen; > > + UINTN VarNameSize; > > + VARIABLE_HEADER *VariablePtr; > > + VARIABLE_STORE_HEADER > > *VariableStoreHeader[VariableStoreTypeMax]; > > + > > + Status = EFI_NOT_FOUND; > > > > if (VariableNameSize == NULL || VariableName == NULL || VendorGuid > > == > > NULL) { > > return EFI_INVALID_PARAMETER; > > } > > > > - OutVariableNameSize = *VariableNameSize; > > - InVariableNameSize = StrSize (VariableName); > > - SmmGetNextVariableName = NULL; > > - > > // > > - // If input string exceeds SMM payload limit. Return failure > > + // Calculate the possible maximum length of name string, including > > + the > > Null terminator. > > // > > - if (InVariableNameSize > mVariableBufferPayloadSize - OFFSET_OF > > (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) > { > > + MaxLen = *VariableNameSize / sizeof (CHAR16); if ((MaxLen == 0) || > > + (StrnLenS (VariableName, MaxLen) == MaxLen)) { > > + // > > + // Null-terminator is not found in the first VariableNameSize > > + bytes of the > > input VariableName buffer, > > + // follow spec to return EFI_INVALID_PARAMETER. > > + // > > return EFI_INVALID_PARAMETER; > > } > > > > - AcquireLockOnlyAtBootTime(&mVariableServicesLock); > > + AcquireLockOnlyAtBootTime (&mVariableServicesLock); > > > > - // > > - // Init the communicate buffer. The buffer data size is: > > - // SMM_COMMUNICATE_HEADER_SIZE + > > SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize. > > - // > > - if (OutVariableNameSize > mVariableBufferPayloadSize - OFFSET_OF > > (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) > { > > - // > > - // If output buffer exceed SMM payload limit. Trim output buffer to > SMM > > payload size > > - // > > - OutVariableNameSize = mVariableBufferPayloadSize - OFFSET_OF > > (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name); > > + for (DelayIndex = 0; mVariableRuntimeCacheReadLock && DelayIndex < > > VARIABLE_RT_CACHE_READ_LOCK_TIMEOUT; DelayIndex++) { > > + MicroSecondDelay (10); > > } > > - // > > - // Payload should be Guid + NameSize + MAX of Input & Output buffer > > - // > > - PayloadSize = OFFSET_OF > > (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name) > + MAX > > (OutVariableNameSize, InVariableNameSize); > > - > > - Status = InitCommunicateBuffer ((VOID > **)&SmmGetNextVariableName, > > PayloadSize, SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME); > > - if (EFI_ERROR (Status)) { > > - goto Done; > > - } > > - ASSERT (SmmGetNextVariableName != NULL); > > - > > - // > > - // SMM comm buffer->NameSize is buffer size for return string > > - // > > - SmmGetNextVariableName->NameSize = OutVariableNameSize; > > - > > - CopyGuid (&SmmGetNextVariableName->Guid, VendorGuid); > > - // > > - // Copy whole string > > - // > > - CopyMem (SmmGetNextVariableName->Name, VariableName, > > InVariableNameSize); > > - if (OutVariableNameSize > InVariableNameSize) { > > - ZeroMem ((UINT8 *) SmmGetNextVariableName->Name + > > InVariableNameSize, OutVariableNameSize - InVariableNameSize); > > - } > > - > > - // > > - // Send data to SMM > > - // > > - Status = SendCommunicateBuffer (PayloadSize); > > - > > - // > > - // Get data from SMM. > > - // > > - if (Status == EFI_SUCCESS || Status == EFI_BUFFER_TOO_SMALL) { > > - // > > - // SMM CommBuffer NameSize can be a trimed value > > - // Only update VariableNameSize when needed > > - // > > - *VariableNameSize = SmmGetNextVariableName->NameSize; > > - } > > - if (EFI_ERROR (Status)) { > > - goto Done; > > + if (DelayIndex < VARIABLE_RT_CACHE_READ_LOCK_TIMEOUT) { > > + ASSERT (!mVariableRuntimeCacheReadLock); > > + > > + CheckForRuntimeCacheSync (); > > + mVariableRuntimeCacheReadLock = TRUE; > > + > > + 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. > > + // > > + VariableStoreHeader[VariableStoreTypeVolatile] = > > mVariableRuntimeVolatileCacheBuffer; > > + VariableStoreHeader[VariableStoreTypeHob] = > > mVariableRuntimeHobCacheBuffer; > > + VariableStoreHeader[VariableStoreTypeNv] = > > mVariableRuntimeNvCacheBuffer; > > + > > + Status = GetNextVariableEx (VariableName, VendorGuid, > > VariableStoreHeader, &VariablePtr); > > + if (!EFI_ERROR (Status)) { > > + VarNameSize = NameSizeOfVariable (VariablePtr); > > + ASSERT (VarNameSize != 0); > > + if (VarNameSize <= *VariableNameSize) { > > + CopyMem (VariableName, GetVariableNamePtr (VariablePtr), > > VarNameSize); > > + CopyMem (VendorGuid, GetVendorGuidPtr (VariablePtr), sizeof > > (EFI_GUID)); > > + Status = EFI_SUCCESS; > > + } else { > > + Status = EFI_BUFFER_TOO_SMALL; > > + } > > + > > + *VariableNameSize = VarNameSize; > > + } > > + } > > } > > - > > - CopyGuid (VendorGuid, &SmmGetNextVariableName->Guid); > > - CopyMem (VariableName, SmmGetNextVariableName->Name, > > SmmGetNextVariableName->NameSize); > > - > > -Done: > > + mVariableRuntimeCacheReadLock = FALSE; > > > Similar to the previous patch (7/9), > if timeout occurs when acquiring the read lock, should this flag be set to > FALSE in such case? > > Best Regards, > Hao Wu > > > > ReleaseLockOnlyAtBootTime (&mVariableServicesLock); > > return Status; > > } > > -- > > 2.16.2.windows.1 > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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