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
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>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>

diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
index 3dee05fded03a76145a7a8e284cdfb490df11f8f..d525998ae301a05c43e3eb34b9d6e1a2a977fd5b 100644 (file)
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
@@ -823,7 +823,7 @@ RuntimeServiceGetVariable (
 }\r
 \r
 /**\r
-  This code Finds the Next available variable.\r
+  Finds the next available variable in a runtime cache variable store.\r
 \r
   @param[in, out] VariableNameSize   Size of the variable name.\r
   @param[in, out] VariableName       Pointer to variable name.\r
@@ -836,8 +836,81 @@ RuntimeServiceGetVariable (
 \r
 **/\r
 EFI_STATUS\r
-EFIAPI\r
-RuntimeServiceGetNextVariableName (\r
+GetNextVariableNameInRuntimeCache (\r
+  IN OUT  UINTN                             *VariableNameSize,\r
+  IN OUT  CHAR16                            *VariableName,\r
+  IN OUT  EFI_GUID                          *VendorGuid\r
+  )\r
+{\r
+  EFI_STATUS              Status;\r
+  UINTN                   VarNameSize;\r
+  VARIABLE_HEADER         *VariablePtr;\r
+  VARIABLE_STORE_HEADER   *VariableStoreHeader[VariableStoreTypeMax];\r
+\r
+  Status = EFI_NOT_FOUND;\r
+\r
+  //\r
+  // The UEFI specification restricts Runtime Services callers from invoking the same or certain other Runtime Service\r
+  // functions prior to completion and return from a previous Runtime Service call. These restrictions prevent\r
+  // a GetVariable () or GetNextVariable () call from being issued until a prior call has returned. The runtime\r
+  // cache read lock should always be free when entering this function.\r
+  //\r
+  ASSERT (!mVariableRuntimeCacheReadLock);\r
+\r
+  CheckForRuntimeCacheSync ();\r
+\r
+  mVariableRuntimeCacheReadLock = TRUE;\r
+  if (!mVariableRuntimeCachePendingUpdate) {\r
+    //\r
+    // 0: Volatile, 1: HOB, 2: Non-Volatile.\r
+    // The index and attributes mapping must be kept in this order as FindVariable\r
+    // makes use of this mapping to implement search algorithm.\r
+    //\r
+    VariableStoreHeader[VariableStoreTypeVolatile] = mVariableRuntimeVolatileCacheBuffer;\r
+    VariableStoreHeader[VariableStoreTypeHob]      = mVariableRuntimeHobCacheBuffer;\r
+    VariableStoreHeader[VariableStoreTypeNv]       = mVariableRuntimeNvCacheBuffer;\r
+\r
+    Status =  VariableServiceGetNextVariableInternal (\r
+                VariableName,\r
+                VendorGuid,\r
+                VariableStoreHeader,\r
+                &VariablePtr,\r
+                mVariableAuthFormat\r
+                );\r
+    if (!EFI_ERROR (Status)) {\r
+      VarNameSize = NameSizeOfVariable (VariablePtr, mVariableAuthFormat);\r
+      ASSERT (VarNameSize != 0);\r
+      if (VarNameSize <= *VariableNameSize) {\r
+        CopyMem (VariableName, GetVariableNamePtr (VariablePtr, mVariableAuthFormat), VarNameSize);\r
+        CopyMem (VendorGuid, GetVendorGuidPtr (VariablePtr, mVariableAuthFormat), sizeof (EFI_GUID));\r
+        Status = EFI_SUCCESS;\r
+      } else {\r
+        Status = EFI_BUFFER_TOO_SMALL;\r
+      }\r
+\r
+      *VariableNameSize = VarNameSize;\r
+    }\r
+  }\r
+  mVariableRuntimeCacheReadLock = FALSE;\r
+\r
+  return Status;\r
+}\r
+\r
+/**\r
+  Finds the next available variable in a SMM variable store.\r
+\r
+  @param[in, out] VariableNameSize   Size of the variable name.\r
+  @param[in, out] VariableName       Pointer to variable name.\r
+  @param[in, out] VendorGuid         Variable Vendor Guid.\r
+\r
+  @retval EFI_INVALID_PARAMETER      Invalid parameter.\r
+  @retval EFI_SUCCESS                Find the specified variable.\r
+  @retval EFI_NOT_FOUND              Not found.\r
+  @retval EFI_BUFFER_TO_SMALL        DataSize is too small for the result.\r
+\r
+**/\r
+EFI_STATUS\r
+GetNextVariableNameInSmm (\r
   IN OUT  UINTN                             *VariableNameSize,\r
   IN OUT  CHAR16                            *VariableName,\r
   IN OUT  EFI_GUID                          *VendorGuid\r
@@ -849,10 +922,6 @@ RuntimeServiceGetNextVariableName (
   UINTN                                           OutVariableNameSize;\r
   UINTN                                           InVariableNameSize;\r
 \r
-  if (VariableNameSize == NULL || VariableName == NULL || VendorGuid == NULL) {\r
-    return EFI_INVALID_PARAMETER;\r
-  }\r
-\r
   OutVariableNameSize   = *VariableNameSize;\r
   InVariableNameSize    = StrSize (VariableName);\r
   SmmGetNextVariableName = NULL;\r
@@ -864,8 +933,6 @@ RuntimeServiceGetNextVariableName (
     return EFI_INVALID_PARAMETER;\r
   }\r
 \r
-  AcquireLockOnlyAtBootTime(&mVariableServicesLock);\r
-\r
   //\r
   // Init the communicate buffer. The buffer data size is:\r
   // SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.\r
@@ -924,7 +991,59 @@ RuntimeServiceGetNextVariableName (
   CopyMem (VariableName, SmmGetNextVariableName->Name, SmmGetNextVariableName->NameSize);\r
 \r
 Done:\r
+  return Status;\r
+}\r
+\r
+/**\r
+  This code Finds the Next available variable.\r
+\r
+  @param[in, out] VariableNameSize   Size of the variable name.\r
+  @param[in, out] VariableName       Pointer to variable name.\r
+  @param[in, out] VendorGuid         Variable Vendor Guid.\r
+\r
+  @retval EFI_INVALID_PARAMETER      Invalid parameter.\r
+  @retval EFI_SUCCESS                Find the specified variable.\r
+  @retval EFI_NOT_FOUND              Not found.\r
+  @retval EFI_BUFFER_TO_SMALL        DataSize is too small for the result.\r
+\r
+**/\r
+EFI_STATUS\r
+EFIAPI\r
+RuntimeServiceGetNextVariableName (\r
+  IN OUT  UINTN                             *VariableNameSize,\r
+  IN OUT  CHAR16                            *VariableName,\r
+  IN OUT  EFI_GUID                          *VendorGuid\r
+  )\r
+{\r
+  EFI_STATUS              Status;\r
+  UINTN                   MaxLen;\r
+\r
+  Status = EFI_NOT_FOUND;\r
+\r
+  if (VariableNameSize == NULL || VariableName == NULL || VendorGuid == NULL) {\r
+    return EFI_INVALID_PARAMETER;\r
+  }\r
+\r
+  //\r
+  // Calculate the possible maximum length of name string, including the Null terminator.\r
+  //\r
+  MaxLen = *VariableNameSize / sizeof (CHAR16);\r
+  if ((MaxLen == 0) || (StrnLenS (VariableName, MaxLen) == MaxLen)) {\r
+    //\r
+    // Null-terminator is not found in the first VariableNameSize bytes of the input VariableName buffer,\r
+    // follow spec to return EFI_INVALID_PARAMETER.\r
+    //\r
+    return EFI_INVALID_PARAMETER;\r
+  }\r
+\r
+  AcquireLockOnlyAtBootTime (&mVariableServicesLock);\r
+  if (FeaturePcdGet (PcdEnableVariableRuntimeCache)) {\r
+    Status = GetNextVariableNameInRuntimeCache (VariableNameSize, VariableName, VendorGuid);\r
+  } else {\r
+    Status = GetNextVariableNameInSmm (VariableNameSize, VariableName, VendorGuid);\r
+  }\r
   ReleaseLockOnlyAtBootTime (&mVariableServicesLock);\r
+\r
   return Status;\r
 }\r
 \r