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>

1 files 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;

 }