[PATCH v4 4/4] OvmfPkg/PlatformDxe: Add support for SEV live migration.


Ashish Kalra
 

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

Detect for KVM hypervisor and check for SEV live migration
feature support via KVM_FEATURE_CPUID, if detected setup a new
UEFI enviroment variable to indicate OVMF support for SEV
live migration.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
OvmfPkg/Include/Guid/MemEncryptLib.h | 20 ++++
OvmfPkg/OvmfPkg.dec | 1 +
OvmfPkg/PlatformDxe/AmdSev.c | 108 ++++++++++++++++++++
OvmfPkg/PlatformDxe/Platform.c | 5 +
OvmfPkg/PlatformDxe/Platform.inf | 2 +
OvmfPkg/PlatformDxe/PlatformConfig.h | 5 +
6 files changed, 141 insertions(+)

diff --git a/OvmfPkg/Include/Guid/MemEncryptLib.h b/OvmfPkg/Include/Guid/MemEncryptLib.h
new file mode 100644
index 0000000000..4c046ba439
--- /dev/null
+++ b/OvmfPkg/Include/Guid/MemEncryptLib.h
@@ -0,0 +1,20 @@
+/** @file
+
+ AMD Memory Encryption GUID, define a new GUID for defining
+ new UEFI enviroment variables assocaiated with SEV Memory Encryption.
+
+ Copyright (c) 2020, AMD Inc. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef __MEMENCRYPT_LIB_H__
+#define __MEMENCRYPT_LIB_H__
+
+#define MEMENCRYPT_GUID \
+{0x0cf29b71, 0x9e51, 0x433a, {0xa3, 0xb7, 0x81, 0xf3, 0xab, 0x16, 0xb8, 0x75}}
+
+extern EFI_GUID gMemEncryptGuid;
+
+#endif
diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 6ae733f6e3..e452dc8494 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -122,6 +122,7 @@
gQemuKernelLoaderFsMediaGuid = {0x1428f772, 0xb64a, 0x441e, {0xb8, 0xc3, 0x9e, 0xbd, 0xd7, 0xf8, 0x93, 0xc7}}
gGrubFileGuid = {0xb5ae312c, 0xbc8a, 0x43b1, {0x9c, 0x62, 0xeb, 0xb8, 0x26, 0xdd, 0x5d, 0x07}}
gConfidentialComputingSecretGuid = {0xadf956ad, 0xe98c, 0x484c, {0xae, 0x11, 0xb5, 0x1c, 0x7d, 0x33, 0x64, 0x47}}
+ gMemEncryptGuid = {0x0cf29b71, 0x9e51, 0x433a, {0xa3, 0xb7, 0x81, 0xf3, 0xab, 0x16, 0xb8, 0x75}}

[Ppis]
# PPI whose presence in the PPI database signals that the TPM base address
diff --git a/OvmfPkg/PlatformDxe/AmdSev.c b/OvmfPkg/PlatformDxe/AmdSev.c
new file mode 100644
index 0000000000..3dbf17a8cd
--- /dev/null
+++ b/OvmfPkg/PlatformDxe/AmdSev.c
@@ -0,0 +1,108 @@
+/**@file
+ Detect KVM hypervisor support for SEV live migration and if
+ detected, setup a new UEFI enviroment variable indicating
+ OVMF support for SEV live migration.
+
+ Copyright (c) 2020, Advanced Micro Devices. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+//
+// The package level header files this module uses
+//
+
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/DebugLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+#include <Guid/MemEncryptLib.h>
+
+#define KVM_FEATURE_MIGRATION_CONTROL 17
+
+/**
+ Figures out if we are running inside KVM HVM and
+ KVM HVM supports SEV Live Migration feature.
+
+ @retval TRUE KVM was detected and Live Migration supported
+ @retval FALSE KVM was not detected or Live Migration not supported
+
+**/
+BOOLEAN
+KvmDetectSevLiveMigrationFeature(
+ VOID
+ )
+{
+ UINT8 Signature[13];
+ UINT32 mKvmLeaf = 0;
+ UINT32 RegEax, RegEbx, RegEcx, 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 ((CHAR8 *) Signature, "KVMKVMKVM\0\0\0")) {
+ DEBUG ((
+ DEBUG_ERROR,
+ "%a: KVM Detected, signature = %s\n",
+ __FUNCTION__,
+ Signature
+ ));
+
+ RegEax = 0x40000001;
+ RegEcx = 0;
+ AsmCpuid (0x40000001, &RegEax, &RegEbx, &RegEcx, &RegEdx);
+ if (RegEax & (1 << KVM_FEATURE_MIGRATION_CONTROL)) {
+ DEBUG ((
+ DEBUG_ERROR,
+ "%a: Live Migration feature supported\n",
+ __FUNCTION__
+ ));
+ return TRUE;
+ }
+ }
+ }
+
+ return FALSE;
+}
+
+/**
+
+ Function checks if SEV Live Migration support is available, if present then it sets
+ a UEFI enviroment variable to be queried later using Runtime services.
+
+ **/
+VOID
+AmdSevSetConfig(
+ VOID
+ )
+{
+ EFI_STATUS Status;
+ BOOLEAN SevLiveMigrationEnabled;
+
+ SevLiveMigrationEnabled = KvmDetectSevLiveMigrationFeature();
+
+ if (SevLiveMigrationEnabled) {
+ Status = gRT->SetVariable (
+ L"SevLiveMigrationEnabled",
+ &gMemEncryptGuid,
+ EFI_VARIABLE_NON_VOLATILE |
+ EFI_VARIABLE_BOOTSERVICE_ACCESS |
+ EFI_VARIABLE_RUNTIME_ACCESS,
+ sizeof (BOOLEAN),
+ &SevLiveMigrationEnabled
+ );
+
+ DEBUG ((
+ DEBUG_ERROR,
+ "%a: Setting SevLiveMigrationEnabled variable, status = %lx\n",
+ __FUNCTION__,
+ Status
+ ));
+ }
+}
diff --git a/OvmfPkg/PlatformDxe/Platform.c b/OvmfPkg/PlatformDxe/Platform.c
index f2e51960ce..f61302d98b 100644
--- a/OvmfPkg/PlatformDxe/Platform.c
+++ b/OvmfPkg/PlatformDxe/Platform.c
@@ -763,6 +763,11 @@ PlatformInit (
{
EFI_STATUS Status;

+ //
+ // Set Amd Sev configuation
+ //
+ AmdSevSetConfig();
+
ExecutePlatformConfig ();

mConfigAccess.ExtractConfig = &ExtractConfig;
diff --git a/OvmfPkg/PlatformDxe/Platform.inf b/OvmfPkg/PlatformDxe/Platform.inf
index 14727c1220..2896f0a1d1 100644
--- a/OvmfPkg/PlatformDxe/Platform.inf
+++ b/OvmfPkg/PlatformDxe/Platform.inf
@@ -24,6 +24,7 @@
PlatformConfig.c
PlatformConfig.h
PlatformForms.vfr
+ AmdSev.c

[Packages]
MdePkg/MdePkg.dec
@@ -56,6 +57,7 @@
[Guids]
gEfiIfrTianoGuid
gOvmfPlatformConfigGuid
+ gMemEncryptGuid

[Depex]
gEfiHiiConfigRoutingProtocolGuid AND
diff --git a/OvmfPkg/PlatformDxe/PlatformConfig.h b/OvmfPkg/PlatformDxe/PlatformConfig.h
index 716514da21..4f662aafa4 100644
--- a/OvmfPkg/PlatformDxe/PlatformConfig.h
+++ b/OvmfPkg/PlatformDxe/PlatformConfig.h
@@ -44,6 +44,11 @@ PlatformConfigLoad (
OUT UINT64 *OptionalElements
);

+VOID
+AmdSevSetConfig(
+ VOID
+ );
+
//
// Feature flags for OptionalElements.
//
--
2.17.1

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