OvmfPkg/BaseMemcryptSevLib: Add SEV helper library

Add Secure Encrypted Virtualization (SEV) helper library. The library provides the routines to: - set or clear memory encryption bit for a given memory region. - query whether SEV is enabled. Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Acked-by: Jordan Justen <jordan.l.justen@intel.com>
2017-07-06 09:21:12 -04:00
parent 97353a9c91
commit a1f2261425
10 changed files with 1015 additions and 0 deletions
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/MemEncryptSevLibInternal.c
@@ -0,0 +1,90 @@
+/** @file
+
+  Secure Encrypted Virtualization (SEV) library helper function
+
+  Copyright (c) 2017, AMD Incorporated. 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.
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Register/Cpuid.h>
+#include <Register/Amd/Cpuid.h>
+#include <Register/Amd/Msr.h>
+#include <Library/MemEncryptSevLib.h>
+
+STATIC BOOLEAN mSevStatus = FALSE;
+STATIC BOOLEAN mSevStatusChecked = FALSE;
+
+/**
+
+  Returns a boolean to indicate whether SEV is enabled
+
+  @retval TRUE           SEV is enabled
+  @retval FALSE          SEV is not enabled
+  **/
+STATIC
+BOOLEAN
+EFIAPI
+InternalMemEncryptSevIsEnabled (
+  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;
+}
+
+/**
+
+  Returns a boolean to indicate whether SEV is enabled
+
+  @retval TRUE           SEV is enabled
+  @retval FALSE          SEV is not enabled
+  **/
+BOOLEAN
+EFIAPI
+MemEncryptSevIsEnabled (
+  VOID
+  )
+{
+  if (mSevStatusChecked) {
+    return mSevStatus;
+  }
+
+  mSevStatus = InternalMemEncryptSevIsEnabled();
+  mSevStatusChecked = TRUE;
+
+  return mSevStatus;
+}