[edk2-devel] [PATCH v3 15/24] Ovmfpkg/AmdSvsmLib: Create AmdSvsmLib to handle SVSM related services

["Lendacky, Thomas via groups.io" <thomas.lendacky=amd.com@groups.io>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654

Add initial support for the new AmdSvsmLib library to OvmfPkg. The initial
implementation fully implements the library interfaces.

The SVSM presence check, AmdSvsmIsSvsmPresent(), determines the presence
of an SVSM by checking if an SVSM has been advertised in the SEV-SNP
Secrets Page.

The VMPL API, AmdSvsmSnpGetVmpl(), returns the VMPL level at which OVMF is
currently running.

The CAA API, AmdSvsmSnpGetCaa(), returns the Calling Area Address when an
SVSM is present, 0 otherwise.

The PVALIDATE API, AmdSvsmSnpPvalidate(), copies the PVALIDATE logic from
the BaseMemEncryptSevLib library for the initial implementation. The
BaseMemEncryptSevLib library will be changed to use this new API so that
the decision as to whether the SVSM is needed to perform the operation
can be isolated to this library.

The VMSA API, AmdSvsmSnpVmsaRmpAdjust(), copies the RMPUPDATE logic from
the MpInitLib library for the initial implementation. The MpInitLib
library will be changed to use this new API so that the decision as to
whether the SVSM is needed to perform the operation can be isolated to
this library.

Cc: Anatol Belski <anbelski@linux.microsoft.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jianyong Wu <jianyong.wu@arm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Min Xu <min.m.xu@intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 OvmfPkg/AmdSev/AmdSevX64.dsc              |   2 +-
 OvmfPkg/CloudHv/CloudHvX64.dsc            |   2 +-
 OvmfPkg/Microvm/MicrovmX64.dsc            |   2 +-
 OvmfPkg/OvmfPkgX64.dsc                    |   2 +-
 OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.inf |  38 +++
 OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c   | 267 ++++++++++++++++++++
 6 files changed, 309 insertions(+), 4 deletions(-)

diff --git a/OvmfPkg/AmdSev/AmdSevX64.dsc b/OvmfPkg/AmdSev/AmdSevX64.dsc
index 140c4208f5b7..a7540bb6367f 100644
--- a/OvmfPkg/AmdSev/AmdSevX64.dsc
+++ b/OvmfPkg/AmdSev/AmdSevX64.dsc
@@ -204,7 +204,7 @@ [LibraryClasses]
 !include OvmfPkg/Include/Dsc/ShellLibs.dsc.inc
 
 [LibraryClasses.common]
-  AmdSvsmLib|UefiCpuPkg/Library/AmdSvsmLibNull/AmdSvsmLibNull.inf
+  AmdSvsmLib|OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.inf
   BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf
   CcExitLib|OvmfPkg/Library/CcExitLib/CcExitLib.inf
   TdxLib|MdePkg/Library/TdxLib/TdxLib.inf
diff --git a/OvmfPkg/CloudHv/CloudHvX64.dsc b/OvmfPkg/CloudHv/CloudHvX64.dsc
index 4dad0a36e757..b1911d6ab4ac 100644
--- a/OvmfPkg/CloudHv/CloudHvX64.dsc
+++ b/OvmfPkg/CloudHv/CloudHvX64.dsc
@@ -242,7 +242,7 @@ [LibraryClasses]
 !include OvmfPkg/Include/Dsc/OvmfTpmLibs.dsc.inc
 
 [LibraryClasses.common]
-  AmdSvsmLib|UefiCpuPkg/Library/AmdSvsmLibNull/AmdSvsmLibNull.inf
+  AmdSvsmLib|OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.inf
   BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf
   CcExitLib|OvmfPkg/Library/CcExitLib/CcExitLib.inf
   TdxLib|MdePkg/Library/TdxLib/TdxLib.inf
diff --git a/OvmfPkg/Microvm/MicrovmX64.dsc b/OvmfPkg/Microvm/MicrovmX64.dsc
index cc84ee3c2956..1f2f8b5bb618 100644
--- a/OvmfPkg/Microvm/MicrovmX64.dsc
+++ b/OvmfPkg/Microvm/MicrovmX64.dsc
@@ -246,7 +246,7 @@ [LibraryClasses]
 !include OvmfPkg/Include/Dsc/ShellLibs.dsc.inc
 
 [LibraryClasses.common]
-  AmdSvsmLib|UefiCpuPkg/Library/AmdSvsmLibNull/AmdSvsmLibNull.inf
+  AmdSvsmLib|OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.inf
   BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf
   CcExitLib|OvmfPkg/Library/CcExitLib/CcExitLib.inf
   SerialPortLib|MdeModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.inf
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 87e210d4409c..540c1ed8da63 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -268,7 +268,7 @@ [LibraryClasses]
 !include OvmfPkg/Include/Dsc/ShellLibs.dsc.inc
 
 [LibraryClasses.common]
-  AmdSvsmLib|UefiCpuPkg/Library/AmdSvsmLibNull/AmdSvsmLibNull.inf
+  AmdSvsmLib|OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.inf
   BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf
   CcExitLib|OvmfPkg/Library/CcExitLib/CcExitLib.inf
   TdxLib|MdePkg/Library/TdxLib/TdxLib.inf
diff --git a/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.inf b/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.inf
new file mode 100644
index 000000000000..cfd2663adc3a
--- /dev/null
+++ b/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.inf
@@ -0,0 +1,38 @@
+## @file
+#  CcExitLib Library.
+#
+#  Copyright (C) 2024, Advanced Micro Devices, Inc. All rights reserved.<BR>
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 1.29
+  BASE_NAME                      = AmdSvsmLib
+  FILE_GUID                      = 288e3588-87d8-4c2c-b568-bf900de0fb36
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = AmdSvsmLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = X64
+#
+
+[Sources.common]
+  AmdSvsmLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+  UefiCpuPkg/UefiCpuPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  BaseMemoryLib
+  DebugLib
+
+[Pcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsBase
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsSize
diff --git a/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c b/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c
new file mode 100644
index 000000000000..861bf9591ae3
--- /dev/null
+++ b/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c
@@ -0,0 +1,267 @@
+/** @file
+  SVSM Support Library.
+
+  Copyright (C) 2024, Advanced Micro Devices, Inc. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Base.h>
+#include <Uefi.h>
+#include <Library/AmdSvsmLib.h>
+#include <Register/Amd/Msr.h>
+#include <Register/Amd/Svsm.h>
+
+#define PAGES_PER_2MB_ENTRY  512
+
+/**
+  Issue a GHCB termination request for termination.
+
+  Request termination using the GHCB MSR protocol.
+
+**/
+STATIC
+VOID
+SnpTerminate (
+  VOID
+  )
+{
+  MSR_SEV_ES_GHCB_REGISTER  Msr;
+
+  //
+  // Use the GHCB MSR Protocol to request termination by the hypervisor
+  //
+  Msr.Uint64                      = 0;
+  Msr.GhcbTerminate.Function      = GHCB_INFO_TERMINATE_REQUEST;
+  Msr.GhcbTerminate.ReasonCodeSet = GHCB_TERMINATE_GHCB;
+  Msr.GhcbTerminate.ReasonCode    = GHCB_TERMINATE_GHCB_GENERAL;
+  AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.Uint64);
+
+  AsmVmgExit ();
+
+  ASSERT (FALSE);
+  CpuDeadLoop ();
+}
+
+/**
+  Report the presence of an Secure Virtual Services Module (SVSM).
+
+  Determines the presence of an SVSM.
+
+  @retval  TRUE                   An SVSM is present
+  @retval  FALSE                  An SVSM is not present
+
+**/
+BOOLEAN
+EFIAPI
+AmdSvsmIsSvsmPresent (
+  VOID
+  )
+{
+  SVSM_INFORMATION  *SvsmInfo;
+
+  SvsmInfo = (SVSM_INFORMATION *)(UINTN)PcdGet32 (PcdOvmfSnpSecretsBase);
+
+  return (SvsmInfo != NULL && SvsmInfo->SvsmSize != 0);
+}
+
+/**
+  Report the VMPL level at which the SEV-SNP guest is running.
+
+  Determines the VMPL level at which the guest is running. If an SVSM is
+  not present, then it must be VMPL0, otherwise return what is reported
+  by the SVSM.
+
+  @return                         The VMPL level
+
+**/
+UINT8
+EFIAPI
+AmdSvsmSnpGetVmpl (
+  VOID
+  )
+{
+  SVSM_INFORMATION  *SvsmInfo;
+
+  SvsmInfo = (SVSM_INFORMATION *)(UINTN)PcdGet32 (PcdOvmfSnpSecretsBase);
+
+  return AmdSvsmIsSvsmPresent () ? SvsmInfo->SvsmGuestVmpl : 0;
+}
+
+/**
+  Report the Calling Area address (CAA) for the BSP of the SEV-SNP guest.
+
+  If an SVSM is present, the CAA for the BSP is returned.
+
+  @return                         The CAA
+
+**/
+UINT64
+EFIAPI
+AmdSvsmSnpGetCaa (
+  VOID
+  )
+{
+  SVSM_INFORMATION  *SvsmInfo;
+
+  SvsmInfo = (SVSM_INFORMATION *)(UINTN)PcdGet32 (PcdOvmfSnpSecretsBase);
+
+  return AmdSvsmIsSvsmPresent () ? SvsmInfo->SvsmCaa : 0;
+}
+
+/**
+  Perform a native PVALIDATE operation for the page ranges specified.
+
+  Validate or rescind the validation of the specified pages.
+
+  @param[in]       Info           Pointer to a page state change structure
+
+**/
+STATIC
+VOID
+BasePvalidate (
+  IN  SNP_PAGE_STATE_CHANGE_INFO  *Info
+  )
+{
+  UINTN                 RmpPageSize;
+  UINTN                 StartIndex;
+  UINTN                 EndIndex;
+  UINTN                 Index;
+  UINTN                 Ret;
+  EFI_PHYSICAL_ADDRESS  Address;
+  BOOLEAN               Validate;
+
+  StartIndex = Info->Header.CurrentEntry;
+  EndIndex   = Info->Header.EndEntry;
+
+  for ( ; StartIndex <= EndIndex; StartIndex++) {
+    //
+    // Get the address and the page size from the Info.
+    //
+    Address     = ((EFI_PHYSICAL_ADDRESS)Info->Entry[StartIndex].GuestFrameNumber) << EFI_PAGE_SHIFT;
+    RmpPageSize = Info->Entry[StartIndex].PageSize;
+    Validate    = Info->Entry[StartIndex].Operation == SNP_PAGE_STATE_PRIVATE;
+
+    Ret = AsmPvalidate (RmpPageSize, Validate, Address);
+
+    //
+    // If we fail to validate due to size mismatch then try with the
+    // smaller page size. This senario will occur if the backing page in
+    // the RMP entry is 4K and we are validating it as a 2MB.
+    //
+    if ((Ret == PVALIDATE_RET_SIZE_MISMATCH) && (RmpPageSize == PvalidatePageSize2MB)) {
+      for (Index = 0; Index < PAGES_PER_2MB_ENTRY; Index++) {
+        Ret = AsmPvalidate (PvalidatePageSize4K, Validate, Address);
+        if (Ret) {
+          break;
+        }
+
+        Address = Address + EFI_PAGE_SIZE;
+      }
+    }
+
+    //
+    // If validation failed then do not continue.
+    //
+    if (Ret) {
+      DEBUG ((
+        DEBUG_ERROR,
+        "%a:%a: Failed to %a address 0x%Lx Error code %d\n",
+        gEfiCallerBaseName,
+        __func__,
+        Validate ? "Validate" : "Invalidate",
+        Address,
+        Ret
+        ));
+
+      SnpTerminate ();
+    }
+  }
+}
+
+/**
+  Perform a PVALIDATE operation for the page ranges specified.
+
+  Validate or rescind the validation of the specified pages.
+
+  @param[in]       Info           Pointer to a page state change structure
+
+**/
+VOID
+EFIAPI
+AmdSvsmSnpPvalidate (
+  IN SNP_PAGE_STATE_CHANGE_INFO  *Info
+  )
+{
+  BasePvalidate (Info);
+}
+
+/**
+  Perform a native RMPADJUST operation to alter the VMSA setting of a page.
+
+  Add or remove the VMSA attribute for a page.
+
+  @param[in]       Vmsa           Pointer to an SEV-ES save area page
+  @param[in]       SetVmsa        Boolean indicator as to whether to set or
+                                  or clear the VMSA setting for the page
+
+  @retval  EFI_SUCCESS            RMPADJUST operation successful
+  @retval  EFI_INVALID_PARAMETER  RMPADJUST operation failed, an invalid
+                                  parameter was supplied
+
+**/
+STATIC
+EFI_STATUS
+BaseVmsaRmpAdjust (
+  IN SEV_ES_SAVE_AREA  *Vmsa,
+  IN BOOLEAN           SetVmsa
+  )
+{
+  UINT64  Rdx;
+  UINT32  Ret;
+
+  //
+  // The RMPADJUST instruction is used to set or clear the VMSA bit for a
+  // page. The VMSA change is only made when running at VMPL0 and is ignored
+  // otherwise. If too low a target VMPL is specified, the instruction can
+  // succeed without changing the VMSA bit when not running at VMPL0. Using a
+  // target VMPL level of 1, RMPADJUST will return a FAIL_PERMISSION error if
+  // not running at VMPL0, thus ensuring that the VMSA bit is set appropriately
+  // when no error is returned.
+  //
+  Rdx = 1;
+  if (SetVmsa) {
+    Rdx |= RMPADJUST_VMSA_PAGE_BIT;
+  }
+
+  Ret = AsmRmpAdjust ((UINT64)(UINTN)Vmsa, 0, Rdx);
+
+  return (Ret == 0) ? EFI_SUCCESS : EFI_INVALID_PARAMETER;
+}
+
+/**
+  Perform an RMPADJUST operation to alter the VMSA setting of a page.
+
+  Add or remove the VMSA attribute for a page.
+
+  @param[in]       Vmsa           Pointer to an SEV-ES save area page
+  @param[in]       ApicId         APIC ID associated with the VMSA
+  @param[in]       SetVmsa        Boolean indicator as to whether to set or
+                                  or clear the VMSA setting for the page
+
+  @retval  EFI_SUCCESS            RMPADJUST operation successful
+  @retval  EFI_UNSUPPORTED        Operation is not supported
+  @retval  EFI_INVALID_PARAMETER  RMPADJUST operation failed, an invalid
+                                  parameter was supplied
+
+**/
+EFI_STATUS
+EFIAPI
+AmdSvsmSnpVmsaRmpAdjust (
+  IN SEV_ES_SAVE_AREA  *Vmsa,
+  IN UINT32            ApicId,
+  IN BOOLEAN           SetVmsa
+  )
+{
+  return BaseVmsaRmpAdjust (Vmsa, SetVmsa);
+}
-- 
2.43.2



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