OvmfPkg/QemuFwCfgLib: Implement SEV internal functions for PEI phase

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

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c
index ac05f4c347f38986ad474373dfa19bef3512b0ca..40f89c3b53e2bf0c4c8c455a972a5c24249e02f4 100644 (file)
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c
@@ -4,6 +4,7 @@
 \r
   Copyright (C) 2013, Red Hat, Inc.\r
   Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>\r
+  Copyright (c) 2017, Advanced Micro Devices. All rights reserved.<BR>\r
 \r
   This program and the accompanying materials are licensed and made available\r
   under the terms and conditions of the BSD License which accompanies this\r
@@ -14,8 +15,10 @@
   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
 **/\r
 \r
+#include <Library/BaseLib.h>\r
 #include <Library/DebugLib.h>\r
 #include <Library/QemuFwCfgLib.h>\r
+#include <Library/MemEncryptSevLib.h>\r
 \r
 #include "QemuFwCfgLibInternal.h"\r
 \r
@@ -76,8 +79,18 @@ QemuFwCfgInitialize (
   if ((Revision & FW_CFG_F_DMA) == 0) {\r
     DEBUG ((DEBUG_INFO, "QemuFwCfg interface (IO Port) is supported.\n"));\r
   } else {\r
-    mQemuFwCfgDmaSupported = TRUE;\r
-    DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n"));\r
+    //\r
+    // If SEV is enabled then we do not support DMA operations in PEI phase.\r
+    // This is mainly because DMA in SEV guest requires using bounce buffer\r
+    // (which need to allocate dynamic memory and allocating a PAGE size'd\r
+    // buffer can be challenge in PEI phase)\r
+    //\r
+    if (InternalQemuFwCfgSevIsEnabled ()) {\r
+      DEBUG ((DEBUG_INFO, "SEV: QemuFwCfg fallback to IO Port interface.\n"));\r
+    } else {\r
+      mQemuFwCfgDmaSupported = TRUE;\r
+      DEBUG ((DEBUG_INFO, "QemuFwCfg interface (DMA) is supported.\n"));\r
+    }\r
   }\r
   return RETURN_SUCCESS;\r
 }\r
@@ -114,3 +127,58 @@ InternalQemuFwCfgDmaIsAvailable (
 {\r
   return mQemuFwCfgDmaSupported;\r
 }\r
+\r
+/**\r
+\r
+ Returns a boolean indicating whether SEV is enabled\r
+\r
+ @retval    TRUE    SEV is enabled\r
+ @retval    FALSE   SEV is disabled\r
+**/\r
+BOOLEAN\r
+InternalQemuFwCfgSevIsEnabled (\r
+  VOID\r
+  )\r
+{\r
+  return MemEncryptSevIsEnabled ();\r
+}\r
+\r
+/**\r
+ Allocate a bounce buffer for SEV DMA.\r
+\r
+  @param[in]     NumPage  Number of pages.\r
+  @param[out]    Buffer   Allocated DMA Buffer pointer\r
+\r
+**/\r
+VOID\r
+InternalQemuFwCfgSevDmaAllocateBuffer (\r
+  OUT    VOID     **Buffer,\r
+  IN     UINT32   NumPages\r
+  )\r
+{\r
+  //\r
+  // We should never reach here\r
+  //\r
+  ASSERT (FALSE);\r
+  CpuDeadLoop ();\r
+}\r
+\r
+/**\r
+ Free the DMA buffer allocated using InternalQemuFwCfgSevDmaAllocateBuffer\r
+\r
+  @param[in]     NumPage  Number of pages.\r
+  @param[in]     Buffer   DMA Buffer pointer\r
+\r
+**/\r
+VOID\r
+InternalQemuFwCfgSevDmaFreeBuffer (\r
+  IN     VOID     *Buffer,\r
+  IN     UINT32   NumPages\r
+  )\r
+{\r
+  //\r
+  // We should never reach here\r
+  //\r
+  ASSERT (FALSE);\r
+  CpuDeadLoop ();\r
+}\r