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 7e5ea00bf96b061f6804d6e714a6b8efb4f5da4f..dbebd36b18530dbebac6f7fc1e7a1ea4fd4c2966 100644 (file)
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
@@ -1,6 +1,8 @@
 /** @file\r
 \r
   Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>\r
 /** @file\r
 \r
   Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>\r

+  Copyright (C) 2013, Red Hat, Inc.\r
+  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>\r

 \r
   This program and the accompanying materials\r
   are licensed and made available under the terms and conditions of the BSD License\r
 \r
   This program and the accompanying materials\r
   are licensed and made available under the terms and conditions of the BSD License\r


@@ -21,97 +23,150 @@
 #include <Library/MemoryAllocationLib.h>\r
 #include <Library/UefiBootServicesTableLib.h>\r
 \r
 #include <Library/MemoryAllocationLib.h>\r
 #include <Library/UefiBootServicesTableLib.h>\r
 \r

-STATIC BOOLEAN mQemuFwCfgSupported = FALSE;\r
+#include "QemuFwCfgLibInternal.h"\r

 \r
 \r
 /**\r
 \r
 \r
 /**\r

-  Reads an 8-bit I/O port fifo into a block of memory.\r
-\r
-  Reads the 8-bit I/O fifo port specified by Port.\r
-\r
-  The port is read Count times, and the read data is\r
-  stored in the provided Buffer.\r
-\r
-  This function must guarantee that all I/O read and write operations are\r
-  serialized.\r
-\r
-  If 8-bit I/O port operations are not supported, then ASSERT().\r
+  Selects a firmware configuration item for reading.\r
+  \r
+  Following this call, any data read from this item will start from\r
+  the beginning of the configuration item's data.\r

 \r
 \r

-  @param  Port    The I/O port to read.\r
-  @param  Count   The number of times to read I/O port.\r
-  @param  Buffer  The buffer to store the read data into.\r
+  @param[in] QemuFwCfgItem - Firmware Configuration item to read\r

 \r
 **/\r
 VOID\r
 EFIAPI\r
 \r
 **/\r
 VOID\r
 EFIAPI\r

-IoReadFifo8 (\r
-  IN      UINTN                     Port,\r
-  IN      UINTN                     Count,\r
-  OUT     VOID                      *Buffer\r
-  );\r
+QemuFwCfgSelectItem (\r
+  IN FIRMWARE_CONFIG_ITEM   QemuFwCfgItem\r
+  )\r
+{\r
+  DEBUG ((EFI_D_INFO, "Select Item: 0x%x\n", (UINT16)(UINTN) QemuFwCfgItem));\r
+  IoWrite16 (FW_CFG_IO_SELECTOR, (UINT16)(UINTN) QemuFwCfgItem);\r
+}\r
+\r

 \r
 /**\r
 \r
 /**\r

-  Writes an 8-bit I/O port fifo from a block of memory.\r
+  Transfer an array of bytes, or skip a number of bytes, using the DMA\r
+  interface.\r

 \r
 \r

-  Writes the 8-bit I/O fifo port specified by Port.\r
+  @param[in]     Size     Size in bytes to transfer or skip.\r

 \r
 \r

-  The port is written Count times, and the data are obtained\r
-  from the provided Buffer.\r
+  @param[in,out] Buffer   Buffer to read data into or write data from. Ignored,\r
+                          and may be NULL, if Size is zero, or Control is\r
+                          FW_CFG_DMA_CTL_SKIP.\r

 \r
 \r

-  This function must guarantee that all I/O read and write operations are\r
-  serialized.\r
+  @param[in]     Control  One of the following:\r
+                          FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.\r
+                          FW_CFG_DMA_CTL_READ  - read from fw_cfg into Buffer.\r
+                          FW_CFG_DMA_CTL_SKIP  - skip bytes in fw_cfg.\r
+**/\r
+VOID\r
+InternalQemuFwCfgDmaBytes (\r
+  IN     UINT32   Size,\r
+  IN OUT VOID     *Buffer OPTIONAL,\r
+  IN     UINT32   Control\r
+  )\r
+{\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
+\r
+  if (Size == 0) {\r
+    return;\r
+  }\r

 \r
 \r

-  If 8-bit I/O port operations are not supported, then ASSERT().\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

-  @param  Port    The I/O port to read.\r
-  @param  Count   The number of times to read I/O port.\r
-  @param  Buffer  The buffer to store the read data into.\r
+    //\r
+    // Allocate SEV DMA buffer\r
+    //\r
+    NumPages = (UINT32)EFI_SIZE_TO_PAGES (TotalSize);\r
+    InternalQemuFwCfgSevDmaAllocateBuffer (&BounceBuffer, NumPages);\r

 \r
 \r

-**/\r
-VOID\r
-EFIAPI\r
-IoWriteFifo8 (\r
-  IN      UINTN                     Port,\r
-  IN      UINTN                     Count,\r
-  OUT     VOID                      *Buffer\r
-  );\r
+    Access = BounceBuffer;\r
+    DmaBuffer = (UINT8*)BounceBuffer + sizeof (*Access);\r

 \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
 \r

-/**\r
-  Returns a boolean indicating if the firmware configuration interface\r
-  is available or not.\r
+  Access->Control = SwapBytes32 (Control);\r
+  Access->Length  = SwapBytes32 (Size);\r
+  Access->Address = SwapBytes64 ((UINTN)DmaBuffer);\r

 \r
 \r

-  @retval    TRUE   The interface is available\r
-  @retval    FALSE  The interface is not available\r
+  //\r
+  // Delimit the transfer from (a) modifications to Access, (b) in case of a\r
+  // write, from writes to Buffer by the caller.\r
+  //\r
+  MemoryFence ();\r

 \r
 \r

-**/\r
-BOOLEAN\r
-EFIAPI\r
-QemuFwCfgIsAvailable (\r
-  VOID\r
-  )\r
-{\r
-  return mQemuFwCfgSupported;\r
-}\r
+  //\r
+  // Start the transfer.\r
+  //\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
 \r

+  //\r
+  // Don't look at Access.Control before starting the transfer.\r
+  //\r
+  MemoryFence ();\r

 \r
 \r

-/**\r
-  Selects a firmware configuration item for reading.\r
-  \r
-  Following this call, any data read from this item will start from\r
-  the beginning of the configuration item's data.\r
+  //\r
+  // Wait for the transfer to complete.\r
+  //\r
+  do {\r
+    Status = SwapBytes32 (Access->Control);\r
+    ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);\r
+  } while (Status != 0);\r

 \r
 \r

-  @param[in] QemuFwCfgItem - Firmware Configuration item to read\r
+  //\r
+  // After a read, the caller will want to use Buffer.\r
+  //\r
+  MemoryFence ();\r

 \r
 \r

-**/\r
-VOID\r
-EFIAPI\r
-QemuFwCfgSelectItem (\r
-  IN FIRMWARE_CONFIG_ITEM   QemuFwCfgItem\r
-  )\r
-{\r
-  DEBUG ((EFI_D_INFO, "Select Item: 0x%x\n", (UINT16)(UINTN) QemuFwCfgItem));\r
-  IoWrite16 (0x510, (UINT16)(UINTN) QemuFwCfgItem);\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
 }\r
 \r
 \r


@@ -129,7 +184,11 @@ InternalQemuFwCfgReadBytes (
   IN VOID                   *Buffer  OPTIONAL\r
   )\r
 {\r
   IN VOID                   *Buffer  OPTIONAL\r
   )\r
 {\r

-  IoReadFifo8 (0x511, Size, Buffer);\r
+  if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
+    InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_READ);\r
+    return;\r
+  }\r
+  IoReadFifo8 (FW_CFG_IO_DATA, Size, Buffer);\r

 }\r
 \r
 \r
 }\r
 \r
 \r


@@ -151,7 +210,7 @@ QemuFwCfgReadBytes (
   IN VOID                   *Buffer\r
   )\r
 {\r
   IN VOID                   *Buffer\r
   )\r
 {\r

-  if (mQemuFwCfgSupported) {\r
+  if (InternalQemuFwCfgIsAvailable ()) {\r

     InternalQemuFwCfgReadBytes (Size, Buffer);\r
   } else {\r
     ZeroMem (Buffer, Size);\r
     InternalQemuFwCfgReadBytes (Size, Buffer);\r
   } else {\r
     ZeroMem (Buffer, Size);\r


@@ -176,8 +235,56 @@ QemuFwCfgWriteBytes (
   IN VOID                   *Buffer\r
   )\r
 {\r
   IN VOID                   *Buffer\r
   )\r
 {\r

-  if (mQemuFwCfgSupported) {\r
-    IoWriteFifo8 (0x511, Size, Buffer);\r
+  if (InternalQemuFwCfgIsAvailable ()) {\r
+    if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
+      InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_WRITE);\r
+      return;\r
+    }\r
+    IoWriteFifo8 (FW_CFG_IO_DATA, Size, Buffer);\r
+  }\r
+}\r
+\r
+\r
+/**\r
+  Skip bytes in the firmware configuration item.\r
+\r
+  Increase the offset of the firmware configuration item without transferring\r
+  bytes between the item and a caller-provided buffer. Subsequent read, write\r
+  or skip operations will commence at the increased offset.\r
+\r
+  @param[in] Size  Number of bytes to skip.\r
+**/\r
+VOID\r
+EFIAPI\r
+QemuFwCfgSkipBytes (\r
+  IN UINTN                  Size\r
+  )\r
+{\r
+  UINTN ChunkSize;\r
+  UINT8 SkipBuffer[256];\r
+\r
+  if (!InternalQemuFwCfgIsAvailable ()) {\r
+    return;\r
+  }\r
+\r
+  if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
+    InternalQemuFwCfgDmaBytes ((UINT32)Size, NULL, FW_CFG_DMA_CTL_SKIP);\r
+    return;\r
+  }\r
+\r
+  //\r
+  // Emulate the skip by reading data in chunks, and throwing it away. The\r
+  // implementation below is suitable even for phases where RAM or dynamic\r
+  // allocation is not available or appropriate. It also doesn't affect the\r
+  // static data footprint for client modules. Large skips are not expected,\r
+  // therefore this fallback is not performance critical. The size of\r
+  // SkipBuffer is thought not to exert a large pressure on the stack in any\r
+  // phase.\r
+  //\r
+  while (Size > 0) {\r
+    ChunkSize = MIN (Size, sizeof SkipBuffer);\r
+    IoReadFifo8 (FW_CFG_IO_DATA, ChunkSize, SkipBuffer);\r
+    Size -= ChunkSize;\r

   }\r
 }\r
 \r
   }\r
 }\r
 \r


@@ -262,39 +369,6 @@ QemuFwCfgRead64 (
 }\r
 \r
 \r
 }\r
 \r
 \r

-RETURN_STATUS\r
-EFIAPI\r
-QemuFwCfgInitialize (\r
-  VOID\r
-  )\r
-{\r
-  UINT32 Signature;\r
-  UINT32 Revision;\r
-\r
-  //\r
-  // Enable the access routines while probing to see if it is supported.\r
-  //\r
-  mQemuFwCfgSupported = TRUE;\r
-\r
-  QemuFwCfgSelectItem (QemuFwCfgItemSignature);\r
-  Signature = QemuFwCfgRead32 ();\r
-  DEBUG ((EFI_D_INFO, "FW CFG Signature: 0x%x\n", Signature));\r
-  QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);\r
-  Revision = QemuFwCfgRead32 ();\r
-  DEBUG ((EFI_D_INFO, "FW CFG Revision: 0x%x\n", Revision));\r
-  if ((Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) ||\r
-      (Revision < 1)\r
-     ) {\r
-    DEBUG ((EFI_D_INFO, "QemuFwCfg interface not supported.\n"));\r
-    mQemuFwCfgSupported = FALSE;\r
-    return RETURN_SUCCESS;\r
-  }\r
-\r
-  DEBUG ((EFI_D_INFO, "QemuFwCfg interface is supported.\n"));\r
-  return RETURN_SUCCESS;\r
-}\r
-\r
-\r

 /**\r
   Find the configuration item corresponding to the firmware configuration file.\r
 \r
 /**\r
   Find the configuration item corresponding to the firmware configuration file.\r
 \r


@@ -319,7 +393,7 @@ QemuFwCfgFindFile (
   UINT32 Count;\r
   UINT32 Idx;\r
 \r
   UINT32 Count;\r
   UINT32 Idx;\r
 \r

-  if (!mQemuFwCfgSupported) {\r
+  if (!InternalQemuFwCfgIsAvailable ()) {\r

     return RETURN_UNSUPPORTED;\r
   }\r
 \r
     return RETURN_UNSUPPORTED;\r
   }\r
 \r


@@ -330,11 +404,12 @@ QemuFwCfgFindFile (
     UINT32 FileSize;\r
     UINT16 FileSelect;\r
     UINT16 FileReserved;\r
     UINT32 FileSize;\r
     UINT16 FileSelect;\r
     UINT16 FileReserved;\r

-    CHAR8  FName[56];\r
+    CHAR8  FName[QEMU_FW_CFG_FNAME_SIZE];\r

 \r
     FileSize     = QemuFwCfgRead32 ();\r
     FileSelect   = QemuFwCfgRead16 ();\r
     FileReserved = QemuFwCfgRead16 ();\r
 \r
     FileSize     = QemuFwCfgRead32 ();\r
     FileSelect   = QemuFwCfgRead16 ();\r
     FileReserved = QemuFwCfgRead16 ();\r

+    (VOID) FileReserved; /* Force a do-nothing reference. */\r

     InternalQemuFwCfgReadBytes (sizeof (FName), FName);\r
 \r
     if (AsciiStrCmp (Name, FName) == 0) {\r
     InternalQemuFwCfgReadBytes (sizeof (FName), FName);\r
 \r
     if (AsciiStrCmp (Name, FName) == 0) {\r