[edk2-devel] [PATCH V2 8/9] MdeModulePkg/Variable: Add RT GetNextVariableName() cache support
Wu, Hao A
hao.a.wu at intel.com
Thu Oct 3 08:04:38 UTC 2019
> -----Original Message-----
> From: Kubacki, Michael A
> Sent: Saturday, September 28, 2019 9:47 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 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.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/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
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