OvmfPkg:Fix VS2012 build failure

Initialize local variable to suppress warning C4701/C4703:
potentially uninitialized local variable/pointer variable.

1.In VirtualMemory.c:
Read of "PageMapLevel4Entry" in SetMemoryEncDe() is only
reached when "PageMapLevel4Entry" is got correctly.

2.In VirtioBlk.c:
Reads (dereferences) of "BufferMapping" and "BufferDeviceAddress"
in SynchronousRequest() are only reached if "BufferSize > 0" *and*
we map the data buffer successfully.

3.In VirtioScsi.c:
Reads (dereferences) of "InDataMapping" and "InDataDeviceAddress",
in VirtioScsiPassThru() are only reached if
"Packet->InTransferLength > 0" on input, *and* we map the
input buffer successfully. The similar reason for "OutDataMapping"
and "OutDataDeviceAddress".

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

3 files changed, 24 insertions, 3 deletions

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.c
index c1bfa35d7a..5d6289df10 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.c
@@ -2,7 +2,7 @@
 

   Virtual Memory Management Services to set or clear the memory encryption bit

 

-  Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>

+  Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>

   Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>

 

   This program and the accompanying materials are licensed and made available

@@ -596,6 +596,11 @@ SetMemoryEncDec (
   BOOLEAN                        IsWpEnabled;

   RETURN_STATUS                  Status;

 

+  //

+  // Set PageMapLevel4Entry to suppress incorrect compiler/analyzer warnings.

+  //

+  PageMapLevel4Entry = NULL;

+

   DEBUG ((

     DEBUG_VERBOSE,

     "%a:%a: Cr3Base=0x%Lx Physical=0x%Lx Length=0x%Lx Mode=%a CacheFlush=%u\n",

diff --git a/OvmfPkg/VirtioBlkDxe/VirtioBlk.c b/OvmfPkg/VirtioBlkDxe/VirtioBlk.c
index 5559884345..95e42ef3dc 100644
--- a/OvmfPkg/VirtioBlkDxe/VirtioBlk.c
+++ b/OvmfPkg/VirtioBlkDxe/VirtioBlk.c
@@ -11,7 +11,7 @@
     synchronous requests and EFI_BLOCK_IO_PROTOCOL for now.

 

   Copyright (C) 2012, Red Hat, Inc.

-  Copyright (c) 2012 - 2016, Intel Corporation. All rights reserved.<BR>

+  Copyright (c) 2012 - 2018, Intel Corporation. All rights reserved.<BR>

   Copyright (c) 2017, AMD Inc, All rights reserved.<BR>

 

   This program and the accompanying materials are licensed and made available

@@ -265,6 +265,13 @@ SynchronousRequest (
   BlockSize = Dev->BlockIoMedia.BlockSize;

 

   //

+  // Set BufferMapping and BufferDeviceAddress to suppress incorrect

+  // compiler/analyzer warnings.

+  //

+  BufferMapping       = NULL;

+  BufferDeviceAddress = 0;

+

+  //

   // ensured by VirtioBlkInit()

   //

   ASSERT (BlockSize > 0);

diff --git a/OvmfPkg/VirtioScsiDxe/VirtioScsi.c b/OvmfPkg/VirtioScsiDxe/VirtioScsi.c
index 1a68f06210..e773ecf7cc 100644
--- a/OvmfPkg/VirtioScsiDxe/VirtioScsi.c
+++ b/OvmfPkg/VirtioScsiDxe/VirtioScsi.c
@@ -26,7 +26,7 @@
     unreasonable for now.

 

   Copyright (C) 2012, Red Hat, Inc.

-  Copyright (c) 2012 - 2014, Intel Corporation. All rights reserved.<BR>

+  Copyright (c) 2012 - 2018, Intel Corporation. All rights reserved.<BR>

   Copyright (c) 2017, AMD Inc, All rights reserved.<BR>

 

   This program and the accompanying materials are licensed and made available

@@ -455,6 +455,15 @@ VirtioScsiPassThru (
   UINTN                     InDataNumPages;

   BOOLEAN                   OutDataBufferIsMapped;

 

+  //

+  // Set InDataMapping,OutDataMapping,InDataDeviceAddress and OutDataDeviceAddress to

+  // suppress incorrect compiler/analyzer warnings.

+  //

+  InDataMapping        = NULL;

+  OutDataMapping       = NULL;

+  InDataDeviceAddress  = 0;

+  OutDataDeviceAddress = 0;

+

   ZeroMem ((VOID*) &Request, sizeof (Request));

 

   Dev = VIRTIO_SCSI_FROM_PASS_THRU (This);