OvmfPkg/QemuFwCfgLib: Add SEV support

[mirror_edk2.git] / OvmfPkg / Library / QemuFwCfgLib / QemuFwCfgLib.c

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
index 3dd55ba5042ea4f1ef28d1895b0a4497e0504c89..dbebd36b18530dbebac6f7fc1e7a1ea4fd4c2966 100644 (file)
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
@@ -68,9 +68,12 @@ InternalQemuFwCfgDmaBytes (
   IN     UINT32   Control\r
   )\r
 {\r
-  volatile FW_CFG_DMA_ACCESS Access;\r
+  volatile FW_CFG_DMA_ACCESS LocalAccess;\r
+  volatile FW_CFG_DMA_ACCESS *Access;\r
   UINT32                     AccessHigh, AccessLow;\r
   UINT32                     Status;\r
+  UINT32                     NumPages;\r
+  VOID                       *DmaBuffer, *BounceBuffer;\r
 \r
   ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ ||\r
     Control == FW_CFG_DMA_CTL_SKIP);\r
@@ -79,9 +82,44 @@ InternalQemuFwCfgDmaBytes (
     return;\r
   }\r
 \r
-  Access.Control = SwapBytes32 (Control);\r
-  Access.Length  = SwapBytes32 (Size);\r
-  Access.Address = SwapBytes64 ((UINTN)Buffer);\r
+  //\r
+  // When SEV is enabled then allocate DMA bounce buffer\r
+  //\r
+  if (InternalQemuFwCfgSevIsEnabled ()) {\r
+    UINTN  TotalSize;\r
+\r
+    TotalSize = sizeof (*Access);\r
+    //\r
+    // Skip operation does not need buffer\r
+    //\r
+    if (Control != FW_CFG_DMA_CTL_SKIP) {\r
+      TotalSize += Size;\r
+    }\r
+\r
+    //\r
+    // Allocate SEV DMA buffer\r
+    //\r
+    NumPages = (UINT32)EFI_SIZE_TO_PAGES (TotalSize);\r
+    InternalQemuFwCfgSevDmaAllocateBuffer (&BounceBuffer, NumPages);\r
+\r
+    Access = BounceBuffer;\r
+    DmaBuffer = (UINT8*)BounceBuffer + sizeof (*Access);\r
+\r
+    //\r
+    //  Decrypt data from encrypted guest buffer into DMA buffer\r
+    //\r
+    if (Control == FW_CFG_DMA_CTL_WRITE) {\r
+      CopyMem (DmaBuffer, Buffer, Size);\r
+    }\r
+  } else {\r
+    Access = &LocalAccess;\r
+    DmaBuffer = Buffer;\r
+    BounceBuffer = NULL;\r
+  }\r
+\r
+  Access->Control = SwapBytes32 (Control);\r
+  Access->Length  = SwapBytes32 (Size);\r
+  Access->Address = SwapBytes64 ((UINTN)DmaBuffer);\r
 \r
   //\r
   // Delimit the transfer from (a) modifications to Access, (b) in case of a\r
@@ -92,8 +130,8 @@ InternalQemuFwCfgDmaBytes (
   //\r
   // Start the transfer.\r
   //\r
-  AccessHigh = (UINT32)RShiftU64 ((UINTN)&Access, 32);\r
-  AccessLow  = (UINT32)(UINTN)&Access;\r
+  AccessHigh = (UINT32)RShiftU64 ((UINTN)Access, 32);\r
+  AccessLow  = (UINT32)(UINTN)Access;\r
   IoWrite32 (FW_CFG_IO_DMA_ADDRESS,     SwapBytes32 (AccessHigh));\r
   IoWrite32 (FW_CFG_IO_DMA_ADDRESS + 4, SwapBytes32 (AccessLow));\r
 \r
@@ -106,7 +144,7 @@ InternalQemuFwCfgDmaBytes (
   // Wait for the transfer to complete.\r
   //\r
   do {\r
-    Status = SwapBytes32 (Access.Control);\r
+    Status = SwapBytes32 (Access->Control);\r
     ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);\r
   } while (Status != 0);\r
 \r
@@ -114,6 +152,21 @@ InternalQemuFwCfgDmaBytes (
   // After a read, the caller will want to use Buffer.\r
   //\r
   MemoryFence ();\r
+\r
+  //\r
+  // If Bounce buffer was allocated then copy the data into guest buffer and\r
+  // free the bounce buffer\r
+  //\r
+  if (BounceBuffer != NULL) {\r
+    //\r
+    //  Encrypt the data from DMA buffer into guest buffer\r
+    //\r
+    if (Control == FW_CFG_DMA_CTL_READ) {\r
+      CopyMem (Buffer, DmaBuffer, Size);\r
+    }\r
+\r
+    InternalQemuFwCfgSevDmaFreeBuffer (BounceBuffer, NumPages);\r
+  }\r
 }\r
 \r
 \r
@@ -368,31 +421,3 @@ QemuFwCfgFindFile (
 \r
   return RETURN_NOT_FOUND;\r
 }\r
-\r
-\r
-/**\r
-  Determine if S3 support is explicitly enabled.\r
-\r
-  @retval  TRUE   if S3 support is explicitly enabled.\r
-           FALSE  otherwise. This includes unavailability of the firmware\r
-                  configuration interface.\r
-**/\r
-BOOLEAN\r
-EFIAPI\r
-QemuFwCfgS3Enabled (\r
-  VOID\r
-  )\r
-{\r
-  RETURN_STATUS        Status;\r
-  FIRMWARE_CONFIG_ITEM FwCfgItem;\r
-  UINTN                FwCfgSize;\r
-  UINT8                SystemStates[6];\r
-\r
-  Status = QemuFwCfgFindFile ("etc/system-states", &FwCfgItem, &FwCfgSize);\r
-  if (Status != RETURN_SUCCESS || FwCfgSize != sizeof SystemStates) {\r
-    return FALSE;\r
-  }\r
-  QemuFwCfgSelectItem (FwCfgItem);\r
-  QemuFwCfgReadBytes (sizeof SystemStates, SystemStates);\r
-  return (BOOLEAN) (SystemStates[3] & BIT7);\r
-}\r