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
when gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache
is set to TRUE (default value).
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@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
---
MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c | 137 ++++++++++++++++++--
1 file changed, 128 insertions(+), 9 deletions(-)
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
index 3dee05fded..d525998ae3 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
@@ -823,7 +823,7 @@ RuntimeServiceGetVariable (
}
/**
- This code Finds the Next available variable.
+ Finds the next available variable in a runtime cache variable store.
@param[in, out] VariableNameSize Size of the variable name.
@param[in, out] VariableName Pointer to variable name.
@@ -836,8 +836,81 @@ RuntimeServiceGetVariable (
**/
EFI_STATUS
-EFIAPI
-RuntimeServiceGetNextVariableName (
+GetNextVariableNameInRuntimeCache (
+ IN OUT UINTN *VariableNameSize,
+ IN OUT CHAR16 *VariableName,
+ IN OUT EFI_GUID *VendorGuid
+ )
+{
+ EFI_STATUS Status;
+ UINTN VarNameSize;
+ VARIABLE_HEADER *VariablePtr;
+ VARIABLE_STORE_HEADER *VariableStoreHeader[VariableStoreTypeMax];
+
+ Status = EFI_NOT_FOUND;
+
+ //
+ // 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);
+
+ 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 = VariableServiceGetNextVariableInternal (
+ VariableName,
+ VendorGuid,
+ VariableStoreHeader,
+ &VariablePtr,
+ mVariableAuthFormat
+ );
+ if (!EFI_ERROR (Status)) {
+ VarNameSize = NameSizeOfVariable (VariablePtr, mVariableAuthFormat);
+ ASSERT (VarNameSize != 0);
+ if (VarNameSize <= *VariableNameSize) {
+ CopyMem (VariableName, GetVariableNamePtr (VariablePtr, mVariableAuthFormat), VarNameSize);
+ CopyMem (VendorGuid, GetVendorGuidPtr (VariablePtr, mVariableAuthFormat), sizeof (EFI_GUID));
+ Status = EFI_SUCCESS;
+ } else {
+ Status = EFI_BUFFER_TOO_SMALL;
+ }
+
+ *VariableNameSize = VarNameSize;
+ }
+ }
+ mVariableRuntimeCacheReadLock = FALSE;
+
+ return Status;
+}
+
+/**
+ Finds the next available variable in a SMM variable store.
+
+ @param[in, out] VariableNameSize Size of the variable name.
+ @param[in, out] VariableName Pointer to variable name.
+ @param[in, out] VendorGuid Variable Vendor Guid.
+
+ @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
+GetNextVariableNameInSmm (
IN OUT UINTN *VariableNameSize,
IN OUT CHAR16 *VariableName,
IN OUT EFI_GUID *VendorGuid
@@ -849,10 +922,6 @@ RuntimeServiceGetNextVariableName (
UINTN OutVariableNameSize;
UINTN InVariableNameSize;
- if (VariableNameSize == NULL || VariableName == NULL || VendorGuid == NULL) {
- return EFI_INVALID_PARAMETER;
- }
-
OutVariableNameSize = *VariableNameSize;
InVariableNameSize = StrSize (VariableName);
SmmGetNextVariableName = NULL;
@@ -864,8 +933,6 @@ RuntimeServiceGetNextVariableName (
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.
@@ -924,7 +991,59 @@ RuntimeServiceGetNextVariableName (
CopyMem (VariableName, SmmGetNextVariableName->Name, SmmGetNextVariableName->NameSize);
Done:
+ return Status;
+}
+
+/**
+ This code Finds the Next available variable.
+
+ @param[in, out] VariableNameSize Size of the variable name.
+ @param[in, out] VariableName Pointer to variable name.
+ @param[in, out] VendorGuid Variable Vendor Guid.
+
+ @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
+RuntimeServiceGetNextVariableName (
+ IN OUT UINTN *VariableNameSize,
+ IN OUT CHAR16 *VariableName,
+ IN OUT EFI_GUID *VendorGuid
+ )
+{
+ EFI_STATUS Status;
+ UINTN MaxLen;
+
+ Status = EFI_NOT_FOUND;
+
+ if (VariableNameSize == NULL || VariableName == NULL || VendorGuid == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // Calculate the possible maximum length of name string, including the Null terminator.
+ //
+ 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);
+ if (FeaturePcdGet (PcdEnableVariableRuntimeCache)) {
+ Status = GetNextVariableNameInRuntimeCache (VariableNameSize, VariableName, VendorGuid);
+ } else {
+ Status = GetNextVariableNameInSmm (VariableNameSize, VariableName, VendorGuid);
+ }
ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
+
return Status;
}
--
2.16.2.windows.1
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