X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=OvmfPkg%2FLibrary%2FQemuFwCfgLib%2FQemuFwCfgLib.c;h=dbebd36b18530dbebac6f7fc1e7a1ea4fd4c2966;hp=3dd55ba5042ea4f1ef28d1895b0a4497e0504c89;hb=66c548be509d;hpb=ed1a2d42d5d54b6096b6e5121b0e5b7410b24108

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
index 3dd55ba504..dbebd36b18 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
@@ -68,9 +68,12 @@ InternalQemuFwCfgDmaBytes (
   IN     UINT32   Control
   )
 {
-  volatile FW_CFG_DMA_ACCESS Access;
+  volatile FW_CFG_DMA_ACCESS LocalAccess;
+  volatile FW_CFG_DMA_ACCESS *Access;
   UINT32                     AccessHigh, AccessLow;
   UINT32                     Status;
+  UINT32                     NumPages;
+  VOID                       *DmaBuffer, *BounceBuffer;
 
   ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ ||
     Control == FW_CFG_DMA_CTL_SKIP);
@@ -79,9 +82,44 @@ InternalQemuFwCfgDmaBytes (
     return;
   }
 
-  Access.Control = SwapBytes32 (Control);
-  Access.Length  = SwapBytes32 (Size);
-  Access.Address = SwapBytes64 ((UINTN)Buffer);
+  //
+  // When SEV is enabled then allocate DMA bounce buffer
+  //
+  if (InternalQemuFwCfgSevIsEnabled ()) {
+    UINTN  TotalSize;
+
+    TotalSize = sizeof (*Access);
+    //
+    // Skip operation does not need buffer
+    //
+    if (Control != FW_CFG_DMA_CTL_SKIP) {
+      TotalSize += Size;
+    }
+
+    //
+    // Allocate SEV DMA buffer
+    //
+    NumPages = (UINT32)EFI_SIZE_TO_PAGES (TotalSize);
+    InternalQemuFwCfgSevDmaAllocateBuffer (&BounceBuffer, NumPages);
+
+    Access = BounceBuffer;
+    DmaBuffer = (UINT8*)BounceBuffer + sizeof (*Access);
+
+    //
+    //  Decrypt data from encrypted guest buffer into DMA buffer
+    //
+    if (Control == FW_CFG_DMA_CTL_WRITE) {
+      CopyMem (DmaBuffer, Buffer, Size);
+    }
+  } else {
+    Access = &LocalAccess;
+    DmaBuffer = Buffer;
+    BounceBuffer = NULL;
+  }
+
+  Access->Control = SwapBytes32 (Control);
+  Access->Length  = SwapBytes32 (Size);
+  Access->Address = SwapBytes64 ((UINTN)DmaBuffer);
 
   //
   // Delimit the transfer from (a) modifications to Access, (b) in case of a
@@ -92,8 +130,8 @@ InternalQemuFwCfgDmaBytes (
   //
   // Start the transfer.
   //
-  AccessHigh = (UINT32)RShiftU64 ((UINTN)&Access, 32);
-  AccessLow  = (UINT32)(UINTN)&Access;
+  AccessHigh = (UINT32)RShiftU64 ((UINTN)Access, 32);
+  AccessLow  = (UINT32)(UINTN)Access;
   IoWrite32 (FW_CFG_IO_DMA_ADDRESS,     SwapBytes32 (AccessHigh));
   IoWrite32 (FW_CFG_IO_DMA_ADDRESS + 4, SwapBytes32 (AccessLow));
 
@@ -106,7 +144,7 @@ InternalQemuFwCfgDmaBytes (
   // Wait for the transfer to complete.
   //
   do {
-    Status = SwapBytes32 (Access.Control);
+    Status = SwapBytes32 (Access->Control);
     ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);
   } while (Status != 0);
 
@@ -114,6 +152,21 @@ InternalQemuFwCfgDmaBytes (
   // After a read, the caller will want to use Buffer.
   //
   MemoryFence ();
+
+  //
+  // If Bounce buffer was allocated then copy the data into guest buffer and
+  // free the bounce buffer
+  //
+  if (BounceBuffer != NULL) {
+    //
+    //  Encrypt the data from DMA buffer into guest buffer
+    //
+    if (Control == FW_CFG_DMA_CTL_READ) {
+      CopyMem (Buffer, DmaBuffer, Size);
+    }
+
+    InternalQemuFwCfgSevDmaFreeBuffer (BounceBuffer, NumPages);
+  }
 }
 
 
@@ -368,31 +421,3 @@ QemuFwCfgFindFile (
 
   return RETURN_NOT_FOUND;
 }
-
-
-/**
-  Determine if S3 support is explicitly enabled.
-
-  @retval  TRUE   if S3 support is explicitly enabled.
-           FALSE  otherwise. This includes unavailability of the firmware
-                  configuration interface.
-**/
-BOOLEAN
-EFIAPI
-QemuFwCfgS3Enabled (
-  VOID
-  )
-{
-  RETURN_STATUS        Status;
-  FIRMWARE_CONFIG_ITEM FwCfgItem;
-  UINTN                FwCfgSize;
-  UINT8                SystemStates[6];
-
-  Status = QemuFwCfgFindFile ("etc/system-states", &FwCfgItem, &FwCfgSize);
-  if (Status != RETURN_SUCCESS || FwCfgSize != sizeof SystemStates) {
-    return FALSE;
-  }
-  QemuFwCfgSelectItem (FwCfgItem);
-  QemuFwCfgReadBytes (sizeof SystemStates, SystemStates);
-  return (BOOLEAN) (SystemStates[3] & BIT7);
-}