BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
An SEV-SNP guest us required to perform GHCB GPA registration before
using a GHCB. See the GHCB spec section 2.5.2 for more details.
Add a library that can be called to perform the GHCB GPA registration.
Cc: James Bottomley <j...@linux.ibm.com>
Cc: Min Xu <min.m...@intel.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: Jordan Justen <jordan.l.jus...@intel.com>
Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org>
Cc: Laszlo Ersek <ler...@redhat.com>
Cc: Erdem Aktas <erdemak...@google.com>
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
---
OvmfPkg/Include/Library/GhcbRegisterLib.h | 27 ++++++
OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.c | 97 ++++++++++++++++++++
OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf | 33 +++++++
OvmfPkg/OvmfPkg.dec | 4 +
OvmfPkg/OvmfPkgIa32.dsc | 1 +
OvmfPkg/OvmfPkgIa32X64.dsc | 1 +
OvmfPkg/OvmfPkgX64.dsc | 1 +
7 files changed, 164 insertions(+)
diff --git a/OvmfPkg/Include/Library/GhcbRegisterLib.h
b/OvmfPkg/Include/Library/GhcbRegisterLib.h
new file mode 100644
index 0000000000..7d98b6eb36
--- /dev/null
+++ b/OvmfPkg/Include/Library/GhcbRegisterLib.h
@@ -0,0 +1,27 @@
+/** @file
+
+ Declarations of utility functions used for GHCB GPA registration.
+
+ Copyright (C) 2021, AMD Inc, All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef _GHCB_REGISTER_LIB_H_
+#define _GHCB_REGISTER_LIB_H_
+
+/**
+
+ This function can be used to register the GHCB GPA.
+
+ @param[in] Address The physical address to registered.
+
+**/
+VOID
+EFIAPI
+GhcbRegister (
+ IN EFI_PHYSICAL_ADDRESS Address
+ );
+
+#endif // _GHCB_REGISTER_LIB_H_
diff --git a/OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.c
b/OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.c
new file mode 100644
index 0000000000..7fe0aad75a
--- /dev/null
+++ b/OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.c
@@ -0,0 +1,97 @@
+/** @file
+ GHCBRegister Support Library.
+
+ Copyright (C) 2021, Advanced Micro Devices, Inc. All rights reserved.<BR>
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Base.h>
+#include <Uefi.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/VmgExitLib.h>
+#include <Library/GhcbRegisterLib.h>
+#include <Register/Amd/Msr.h>
+
+/**
+ Handle an SEV-SNP/GHCB protocol check failure.
+
+ Notify the hypervisor using the VMGEXIT instruction that the SEV-SNP guest
+ wishes to be terminated.
+
+ @param[in] ReasonCode Reason code to provide to the hypervisor for the
+ termination request.
+
+**/
+STATIC
+VOID
+SevEsProtocolFailure (
+ IN UINT8 ReasonCode
+ )
+{
+ MSR_SEV_ES_GHCB_REGISTER Msr;
+
+ //
+ // Use the GHCB MSR Protocol to request termination by the hypervisor
+ //
+ Msr.GhcbPhysicalAddress = 0;
+ Msr.GhcbTerminate.Function = GHCB_INFO_TERMINATE_REQUEST;
+ Msr.GhcbTerminate.ReasonCodeSet = GHCB_TERMINATE_GHCB;
+ Msr.GhcbTerminate.ReasonCode = ReasonCode;
+ AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+ AsmVmgExit ();
+
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
+
+/**
+
+ This function can be used to register the GHCB GPA.
+
+ @param[in] Address The physical address to be registered.
+
+**/
+VOID
+EFIAPI
+GhcbRegister (
+ IN EFI_PHYSICAL_ADDRESS Address
+ )
+{
+ MSR_SEV_ES_GHCB_REGISTER Msr;
+ MSR_SEV_ES_GHCB_REGISTER CurrentMsr;
+ EFI_PHYSICAL_ADDRESS GuestFrameNumber;
+
+ GuestFrameNumber = Address >> EFI_PAGE_SHIFT;
+
+ //
+ // Save the current MSR Value
+ //
+ CurrentMsr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+
+ //
+ // Use the GHCB MSR Protocol to request to register the GPA.
+ //
+ Msr.GhcbPhysicalAddress = 0;
+ Msr.GhcbGpaRegister.Function = GHCB_INFO_GHCB_GPA_REGISTER_REQUEST;
+ Msr.GhcbGpaRegister.GuestFrameNumber = GuestFrameNumber;
+ AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+ AsmVmgExit ();
+
+ Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+
+ //
+ // If hypervisor responded with a different GPA than requested then fail.
+ //
+ if ((Msr.GhcbGpaRegister.Function != GHCB_INFO_GHCB_GPA_REGISTER_RESPONSE) ||
+ (Msr.GhcbGpaRegister.GuestFrameNumber != GuestFrameNumber)) {
+ SevEsProtocolFailure (GHCB_TERMINATE_GHCB_GENERAL);
+ }
+
+ //
+ // Restore the MSR
+ //
+ AsmWriteMsr64 (MSR_SEV_ES_GHCB, CurrentMsr.GhcbPhysicalAddress);
+}
diff --git a/OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
b/OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
new file mode 100644
index 0000000000..8cc39ef715
--- /dev/null
+++ b/OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
@@ -0,0 +1,33 @@
+## @file
+# GHCBRegisterLib Support Library.
+#
+# Copyright (C) 2021, Advanced Micro Devices, Inc. All rights reserved.<BR>
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+ INF_VERSION = 0x00010005
+ BASE_NAME = GhcbRegisterLib
+ FILE_GUID = 0e913c15-12cd-430b-8714-ffe85672a77b
+ MODULE_TYPE = BASE
+ VERSION_STRING = 1.0
+ LIBRARY_CLASS = GhcbRegisterLib
+
+#
+# The following information is for reference only and not required by the
build tools.
+#
+# VALID_ARCHITECTURES = X64
+#
+
+[Sources.common]
+ GhcbRegisterLib.c
+
+[Packages]
+ MdePkg/MdePkg.dec
+ OvmfPkg/OvmfPkg.dec
+ UefiCpuPkg/UefiCpuPkg.dec
+
+[LibraryClasses]
+ BaseLib
+ BaseMemoryLib
diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 3d5574364b..70948ab478 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -106,6 +106,10 @@
#
XenPlatformLib|Include/Library/XenPlatformLib.h
+ ## @libraryclass Register GHCB GPA
+ #
+ GhcbRegisterLib|Include/Library/GhcbRegisterLib.h
+
[Guids]
gUefiOvmfPkgTokenSpaceGuid = {0x93bb96af, 0xb9f2, 0x4eb8, {0x94,
0x62, 0xe0, 0xba, 0x74, 0x56, 0x42, 0x36}}
gEfiXenInfoGuid = {0xd3b46f3b, 0xd441, 0x1244, {0x9a,
0x12, 0x0, 0x12, 0x27, 0x3f, 0xc1, 0x4d}}
diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index 1730b6558b..f9355172d6 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -243,6 +243,7 @@
[LibraryClasses.common]
BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf
VmgExitLib|UefiCpuPkg/Library/VmgExitLibNull/VmgExitLibNull.inf
+ GhcbRegisterLib|OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
[LibraryClasses.common.SEC]
TimerLib|OvmfPkg/Library/AcpiTimerLib/BaseRomAcpiTimerLib.inf
diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
index 78a559da0d..3f27d7b90d 100644
--- a/OvmfPkg/OvmfPkgIa32X64.dsc
+++ b/OvmfPkg/OvmfPkgIa32X64.dsc
@@ -247,6 +247,7 @@
[LibraryClasses.common]
BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf
VmgExitLib|UefiCpuPkg/Library/VmgExitLibNull/VmgExitLibNull.inf
+ GhcbRegisterLib|OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
[LibraryClasses.common.SEC]
TimerLib|OvmfPkg/Library/AcpiTimerLib/BaseRomAcpiTimerLib.inf
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 593c0e69f6..92447f6a2d 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -247,6 +247,7 @@
[LibraryClasses.common]
BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf
VmgExitLib|OvmfPkg/Library/VmgExitLib/VmgExitLib.inf
+ GhcbRegisterLib|OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
[LibraryClasses.common.SEC]
TimerLib|OvmfPkg/Library/AcpiTimerLib/BaseRomAcpiTimerLib.inf
--
2.17.1
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