[PATCH v8 1/6] OvmfPkg/BaseMemEncryptLib: Detect SEV live migration feature.

["Ashish Kalra" <ashish.kalra@amd.com>]

From: Ashish Kalra <ashish.kalra@amd.com>

Add support to check if we are running inside KVM HVM and
KVM HVM supports SEV Live Migration feature.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 OvmfPkg/Include/Library/MemEncryptSevLib.h    | 12 ++++
 .../DxeMemEncryptSevLibInternal.c             | 49 ++++++++++++++--
 .../PeiDxeMemEncryptSevLibInternal.c          | 58 +++++++++++++++++++
 .../PeiDxeMemEncryptSevLibInternal.h          | 31 ++++++++++
 .../PeiMemEncryptSevLibInternal.c             | 42 ++++++++++++++
 .../SecMemEncryptSevLibInternal.c             | 18 ++++++
 6 files changed, 206 insertions(+), 4 deletions(-)
 create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.h

diff --git a/OvmfPkg/Include/Library/MemEncryptSevLib.h b/OvmfPkg/Include/Library/MemEncryptSevLib.h
index 4fa9c0d700..babec60df4 100644
--- a/OvmfPkg/Include/Library/MemEncryptSevLib.h
+++ b/OvmfPkg/Include/Library/MemEncryptSevLib.h
@@ -83,6 +83,18 @@ MemEncryptSevIsEnabled (
   VOID
   );
 
+/**
+  Returns a boolean to indicate whether SEV live migration is enabled.
+
+  @retval TRUE           SEV live migration is enabled
+  @retval FALSE          SEV live migration is not enabled
+**/
+BOOLEAN
+EFIAPI
+MemEncryptSevLiveMigrationIsEnabled (
+  VOID
+  );
+
 /**
   This function clears memory encryption bit for the memory region specified by
   BaseAddress and NumPages from the current page table context.
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLibInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLibInternal.c
index 4aba0075b9..d80ebe2fac 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLibInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLibInternal.c
@@ -18,10 +18,14 @@
 #include <Uefi/UefiBaseType.h>
 #include <ConfidentialComputingGuestAttr.h>
 
-STATIC UINT64   mCurrentAttr            = 0;
-STATIC BOOLEAN  mCurrentAttrRead        = FALSE;
-STATIC UINT64   mSevEncryptionMask      = 0;
-STATIC BOOLEAN  mSevEncryptionMaskSaved = FALSE;
+#include "PeiDxeMemEncryptSevLibInternal.h"
+
+STATIC UINT64   mCurrentAttr                   = 0;
+STATIC BOOLEAN  mCurrentAttrRead               = FALSE;
+STATIC UINT64   mSevEncryptionMask             = 0;
+STATIC BOOLEAN  mSevEncryptionMaskSaved        = FALSE;
+STATIC BOOLEAN  mSevLiveMigrationStatus        = FALSE;
+STATIC BOOLEAN  mSevLiveMigrationStatusChecked = FALSE;
 
 /**
   The function check if the specified Attr is set.
@@ -111,6 +115,24 @@ MemEncryptSevSnpIsEnabled (
   return ConfidentialComputingGuestHas (CCAttrAmdSevSnp);
 }
 
+/**
+  Figures out if we are running inside KVM HVM and
+  KVM HVM supports SEV Live Migration feature.
+**/
+STATIC
+VOID
+EFIAPI
+InternalDetectSevLiveMigrationFeature (
+  VOID
+  )
+{
+  if (KvmDetectSevLiveMigrationFeature ()) {
+    mSevLiveMigrationStatus = TRUE;
+  }
+
+  mSevLiveMigrationStatusChecked = TRUE;
+}
+
 /**
   Returns a boolean to indicate whether SEV-ES is enabled.
 
@@ -141,6 +163,25 @@ MemEncryptSevIsEnabled (
   return ConfidentialComputingGuestHas (CCAttrAmdSev);
 }
 
+/**
+  Returns a boolean to indicate whether SEV live migration is enabled.
+
+  @retval TRUE           SEV live migration is enabled
+  @retval FALSE          SEV live migration is not enabled
+**/
+BOOLEAN
+EFIAPI
+MemEncryptSevLiveMigrationIsEnabled (
+  VOID
+  )
+{
+  if (!mSevLiveMigrationStatusChecked) {
+    InternalDetectSevLiveMigrationFeature ();
+  }
+
+  return mSevLiveMigrationStatus;
+}
+
 /**
   Returns the SEV encryption mask.
 
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.c
index 78ea16ae06..868392f7e2 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.c
@@ -16,6 +16,8 @@
 #include <Register/SmramSaveStateMap.h>
 #include <Uefi/UefiBaseType.h>
 
+#include "PeiDxeMemEncryptSevLibInternal.h"
+
 /**
   Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
   Save State Map.
@@ -61,3 +63,59 @@ MemEncryptSevLocateInitialSmramSaveStateMapPages (
 
   return RETURN_SUCCESS;
 }
+
+/**
+  Figures out if we are running inside KVM HVM and
+  KVM HVM supports SEV Live Migration feature.
+
+  @retval TRUE           SEV live migration is supported.
+  @retval FALSE          SEV live migration is not supported.
+**/
+BOOLEAN
+EFIAPI
+KvmDetectSevLiveMigrationFeature (
+  VOID
+  )
+{
+  CHAR8   Signature[13];
+  UINT32  mKvmLeaf;
+  UINT32  RegEax;
+  UINT32  RegEbx;
+  UINT32  RegEcx;
+  UINT32  RegEdx;
+
+  Signature[12] = '\0';
+  for (mKvmLeaf = 0x40000000; mKvmLeaf < 0x40010000; mKvmLeaf += 0x100) {
+    AsmCpuid (
+      mKvmLeaf,
+      NULL,
+      (UINT32 *)&Signature[0],
+      (UINT32 *)&Signature[4],
+      (UINT32 *)&Signature[8]
+      );
+
+    if (AsciiStrCmp (Signature, "KVMKVMKVM") == 0) {
+      DEBUG ((
+        DEBUG_INFO,
+        "%a: KVM Detected, signature = %a\n",
+        __FUNCTION__,
+        Signature
+        ));
+
+      RegEax = mKvmLeaf + 1;
+      RegEcx = 0;
+      AsmCpuid (mKvmLeaf + 1, &RegEax, &RegEbx, &RegEcx, &RegEdx);
+      if ((RegEax & KVM_FEATURE_MIGRATION_CONTROL) != 0) {
+        DEBUG ((
+          DEBUG_INFO,
+          "%a: SEV Live Migration feature supported\n",
+          __FUNCTION__
+          ));
+
+        return TRUE;
+      }
+    }
+  }
+
+  return FALSE;
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.h b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.h
new file mode 100644
index 0000000000..b0ef053cd9
--- /dev/null
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiDxeMemEncryptSevLibInternal.h
@@ -0,0 +1,31 @@
+/** @file
+
+  Secure Encrypted Virtualization (SEV) library helper function
+
+  Copyright (c) 2021, AMD Incorporated. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef PEI_DXE_MEM_ENCRYPT_SEV_LIB_INTERNAL_H_
+#define PEI_DXE_MEM_ENCRYPT_SEV_LIB_INTERNAL_H_
+
+#include <Library/BaseLib.h>
+
+#define KVM_FEATURE_MIGRATION_CONTROL  BIT17
+
+/**
+  Figures out if we are running inside KVM HVM and
+  KVM HVM supports SEV Live Migration feature.
+
+  @retval TRUE           SEV live migration is supported.
+  @retval FALSE          SEV live migration is not supported.
+**/
+BOOLEAN
+EFIAPI
+KvmDetectSevLiveMigrationFeature (
+  VOID
+  );
+
+#endif // PEI_DXE_MEM_ENCRYPT_SEV_LIB_INTERNAL_H_
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLibInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLibInternal.c
index 3f8f91a5da..72bd6e98f8 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLibInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLibInternal.c
@@ -17,6 +17,11 @@
 #include <Register/Cpuid.h>
 #include <Uefi/UefiBaseType.h>
 
+#include "PeiDxeMemEncryptSevLibInternal.h"
+
+STATIC BOOLEAN  mSevLiveMigrationStatus        = FALSE;
+STATIC BOOLEAN  mSevLiveMigrationStatusChecked = FALSE;
+
 /**
    Read the workarea to determine whether SEV is enabled. If enabled,
    then return the SevEsWorkArea pointer.
@@ -83,6 +88,24 @@ MemEncryptSevSnpIsEnabled (
   return Msr.Bits.SevSnpBit ? TRUE : FALSE;
 }
 
+/**
+  Figures out if we are running inside KVM HVM and
+  KVM HVM supports SEV Live Migration feature.
+**/
+STATIC
+VOID
+EFIAPI
+InternalDetectSevLiveMigrationFeature (
+  VOID
+  )
+{
+  if (KvmDetectSevLiveMigrationFeature ()) {
+    mSevLiveMigrationStatus = TRUE;
+  }
+
+  mSevLiveMigrationStatusChecked = TRUE;
+}
+
 /**
   Returns a boolean to indicate whether SEV-ES is enabled.
 
@@ -121,6 +144,25 @@ MemEncryptSevIsEnabled (
   return Msr.Bits.SevBit ? TRUE : FALSE;
 }
 
+/**
+  Returns a boolean to indicate whether SEV live migration is enabled.
+
+  @retval TRUE           SEV live migration is enabled
+  @retval FALSE          SEV live migration is not enabled
+**/
+BOOLEAN
+EFIAPI
+MemEncryptSevLiveMigrationIsEnabled (
+  VOID
+  )
+{
+  if (!mSevLiveMigrationStatusChecked) {
+    InternalDetectSevLiveMigrationFeature ();
+  }
+
+  return mSevLiveMigrationStatus;
+}
+
 /**
   Returns the SEV encryption mask.
 
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLibInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLibInternal.c
index 80aceba01b..b05dbec02e 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLibInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLibInternal.c
@@ -121,6 +121,24 @@ MemEncryptSevIsEnabled (
   return Msr.Bits.SevBit ? TRUE : FALSE;
 }
 
+/**
+  Returns a boolean to indicate whether SEV live migration is enabled.
+
+  @retval TRUE           SEV live migration is enabled
+  @retval FALSE          SEV live migration is not enabled
+**/
+BOOLEAN
+EFIAPI
+MemEncryptSevLiveMigrationIsEnabled (
+  VOID
+  )
+{
+  //
+  // Not used in SEC phase.
+  //
+  return FALSE;
+}
+
 /**
   Returns the SEV encryption mask.
 
-- 
2.25.1