[RFC PATCH v2 03/10] OvmfPkg/PlatformPei: Add Secure Encrypted Virutualization (SEV) support

[Brijesh Singh <brijesh.ksingh@gmail.com>]

Initialize Secure Encrypted Virtualization support and set the memory encryption mask PCD.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 OvmfPkg/OvmfPkgIa32.dsc             |    3 +
 OvmfPkg/OvmfPkgIa32X64.dsc          |    3 +
 OvmfPkg/OvmfPkgX64.dsc              |    3 +
 OvmfPkg/PlatformPei/AmdSev.c        |   97 +++++++++++++++++++++++++++++++++++
 OvmfPkg/PlatformPei/Platform.c      |    1 
 OvmfPkg/PlatformPei/Platform.h      |    5 ++
 OvmfPkg/PlatformPei/PlatformPei.inf |    2 +
 7 files changed, 114 insertions(+)
 create mode 100644 OvmfPkg/PlatformPei/AmdSev.c

diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index 546cdf7..769251d 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -506,6 +506,9 @@
   gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber|64
   gUefiCpuPkgTokenSpaceGuid.PcdCpuApInitTimeOutInMicroSeconds|50000
 
+  # Set memory encryption mask
+  gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
+
 !if $(SMM_REQUIRE) == TRUE
   gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmSyncMode|0x01
   gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmApSyncTimeout|100000
diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
index 383c8d3..3874c35 100644
--- a/OvmfPkg/OvmfPkgIa32X64.dsc
+++ b/OvmfPkg/OvmfPkgIa32X64.dsc
@@ -514,6 +514,9 @@
   gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber|64
   gUefiCpuPkgTokenSpaceGuid.PcdCpuApInitTimeOutInMicroSeconds|50000
 
+  # Set memory encryption mask
+  gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
+
 !if $(SMM_REQUIRE) == TRUE
   gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmSyncMode|0x01
   gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmApSyncTimeout|100000
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 0b7533c..fe7f086 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -513,6 +513,9 @@
   gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber|64
   gUefiCpuPkgTokenSpaceGuid.PcdCpuApInitTimeOutInMicroSeconds|50000
 
+  # Set memory encryption mask
+  gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
+
 !if $(SMM_REQUIRE) == TRUE
   gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmSyncMode|0x01
   gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmApSyncTimeout|100000
diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c
new file mode 100644
index 0000000..7f05a9a
--- /dev/null
+++ b/OvmfPkg/PlatformPei/AmdSev.c
@@ -0,0 +1,97 @@
+/**@file
+  Initialize Secure Encrypted Virtualization (SEV) support
+
+  Copyright (c) 2017, Advanced Micro Devices. All rights reserved.<BR>
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+//
+// The package level header files this module uses
+//
+#include <PiPei.h>
+
+#include <Library/DebugLib.h>
+#include <Library/PcdLib.h>
+#include <Register/Cpuid.h>
+#include <Register/AmdSevMap.h>
+
+/**
+
+  Function returns 'TRUE' when SEV is enabled otherwise FALSE
+
+  **/
+STATIC
+BOOLEAN
+SevIsEnabled (
+  VOID
+  )
+{
+  UINT32 RegEax;
+  MSR_SEV_STATUS_REGISTER Msr;
+  CPUID_MEMORY_ENCRYPTION_INFO_EAX  Eax;
+
+  //
+  // Check if memory encryption leaf exist
+  //
+  AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
+  if (RegEax >= CPUID_MEMORY_ENCRYPTION_INFO) {
+    //
+    // CPUID Fn8000_001F[EAX] Bit 1 (Sev supported)
+    //
+    AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, &Eax.Uint32, NULL, NULL, NULL);
+
+    if (Eax.Bits.SevBit) {
+      //
+      // Check MSR_0xC0010131 Bit 0 (Sev Enabled)
+      //
+      Msr.Uint32 = AsmReadMsr32 (MSR_SEV_STATUS);
+      if (Msr.Bits.SevBit) {
+        return TRUE;
+      }
+    }
+  }
+
+  return FALSE;
+}
+
+/**
+  Function checks if SEV support is available, if present then it updates
+  the dynamic PcdPteMemoryEncryptionAddressOrMask with memory encryption mask.
+
+  **/
+VOID
+EFIAPI
+AmdSevInitialize (
+  VOID
+  )
+{
+  UINT64 MeMask;
+  CPUID_MEMORY_ENCRYPTION_INFO_EBX  Ebx;
+
+  //
+  // Check if SEV is enabled
+  //
+  if (!SevIsEnabled ()) {
+    return;
+  }
+
+  //
+  // CPUID Fn8000_001F[EBX] Bit 0:5 (memory encryption bit position)
+  //
+  AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, NULL, &Ebx.Uint32, NULL, NULL);
+  MeMask = LShiftU64 (1, Ebx.Bits.PtePosBits);
+
+  //
+  // Set Memory Encryption Mask PCD
+  //
+  PcdSet64S (PcdPteMemoryEncryptionAddressOrMask, MeMask);
+
+  DEBUG ((EFI_D_INFO, "SEV support is enabled (mask 0x%lx)\n", MeMask));
+}
diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c
index 77a8a16..49e6c66 100644
--- a/OvmfPkg/PlatformPei/Platform.c
+++ b/OvmfPkg/PlatformPei/Platform.c
@@ -667,6 +667,7 @@ InitializePlatform (
     NoexecDxeInitialization ();
   }
 
+  AmdSevInitialize ();
   MiscInitialization ();
   InstallFeatureControlCallback ();
 
diff --git a/OvmfPkg/PlatformPei/Platform.h b/OvmfPkg/PlatformPei/Platform.h
index 18f42c3..a7729b9 100644
--- a/OvmfPkg/PlatformPei/Platform.h
+++ b/OvmfPkg/PlatformPei/Platform.h
@@ -88,6 +88,11 @@ XenDetect (
   VOID
   );
 
+VOID
+AmdSevInitialize (
+  VOID
+  );
+
 extern BOOLEAN mXen;
 
 VOID
diff --git a/OvmfPkg/PlatformPei/PlatformPei.inf b/OvmfPkg/PlatformPei/PlatformPei.inf
index 53c6dd4..2cf4ac876 100644
--- a/OvmfPkg/PlatformPei/PlatformPei.inf
+++ b/OvmfPkg/PlatformPei/PlatformPei.inf
@@ -35,6 +35,7 @@
   MemDetect.c
   Platform.c
   Xen.c
+  AmdSev.c
 
 [Packages]
   IntelFrameworkModulePkg/IntelFrameworkModulePkg.dec
@@ -98,6 +99,7 @@
   gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber
   gUefiCpuPkgTokenSpaceGuid.PcdCpuApInitTimeOutInMicroSeconds
   gUefiCpuPkgTokenSpaceGuid.PcdCpuApStackSize
+  gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask
 
 [FixedPcd]
   gEfiMdePkgTokenSpaceGuid.PcdPciExpressBaseAddress