OvmfPkg/BaseMemEncryptSevLib: Use AmdSvsmSnpPvalidate() to validate pages

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

The PVALIDATE instruction is used to change the SNP validation of a page,
but that can only be done when running at VMPL0. To prepare for running at
a less priviledged VMPL, use the AmdSvsmLib library API to perform the
PVALIDATE. The AmdSvsmLib library will perform the proper operation on
behalf of the caller.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.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>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

4 files changed, 9 insertions, 74 deletions

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf
index cc24961c92..312ee73e54 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf
@@ -1,7 +1,7 @@
 ## @file

 #  Library provides the helper functions for SEV guest

 #

-# Copyright (c) 2017 - 2020, Advanced Micro Devices. All rights reserved.<BR>

+# Copyright (c) 2017 - 2024, Advanced Micro Devices. All rights reserved.<BR>

 #

 #  SPDX-License-Identifier: BSD-2-Clause-Patent

 #

@@ -52,6 +52,7 @@
   MemoryAllocationLib

   PcdLib

   CcExitLib

+  AmdSvsmLib

 

 [FeaturePcd]

   gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
index 8f56783da5..1e0b5600eb 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
@@ -1,7 +1,7 @@
 ## @file

 #  Library provides the helper functions for SEV guest

 #

-# Copyright (c) 2020 Advanced Micro Devices. All rights reserved.<BR>

+# Copyright (c) 2020 - 2024, Advanced Micro Devices. All rights reserved.<BR>

 #

 #  SPDX-License-Identifier: BSD-2-Clause-Patent

 #

@@ -52,6 +52,7 @@
   MemoryAllocationLib

   PcdLib

   CcExitLib

+  AmdSvsmLib

 

 [FeaturePcd]

   gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
index b6d76e7e63..a06ea6188e 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
@@ -1,7 +1,7 @@
 ## @file

 #  Library provides the helper functions for SEV guest

 #

-# Copyright (c) 2020 Advanced Micro Devices. All rights reserved.<BR>

+# Copyright (c) 2020 - 2024, Advanced Micro Devices. All rights reserved.<BR>

 #

 #  SPDX-License-Identifier: BSD-2-Clause-Patent

 #

@@ -49,6 +49,7 @@
   DebugLib

   PcdLib

   CcExitLib

+  AmdSvsmLib

 

 [FixedPcd]

   gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
index f1883239a6..c8c0c4ef0e 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
@@ -14,14 +14,13 @@
 #include <Library/MemEncryptSevLib.h>

 #include <Library/DebugLib.h>

 #include <Library/CcExitLib.h>

+#include <Library/AmdSvsmLib.h>

 

 #include <Register/Amd/Ghcb.h>

 #include <Register/Amd/Msr.h>

 

 #include "SnpPageStateChange.h"

 

-#define PAGES_PER_LARGE_ENTRY  512

-

 STATIC

 UINTN

 MemoryStateToGhcbOp (

@@ -63,73 +62,6 @@ SnpPageStateFailureTerminate (
   CpuDeadLoop ();

 }

 

-/**

- This function issues the PVALIDATE instruction to validate or invalidate the memory

- range specified. If PVALIDATE returns size mismatch then it retry validating with

- smaller page size.

-

- */

-STATIC

-VOID

-PvalidateRange (

-  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_LARGE_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

-        ));

-      SnpPageStateFailureTerminate ();

-    }

-  }

-}

-

 STATIC

 EFI_PHYSICAL_ADDRESS

 BuildPageStateBuffer (

@@ -328,7 +260,7 @@ InternalSetPageState (
     // invalidate the pages before making the page shared in the RMP table.

     //

     if (State == SevSnpPageShared) {

-      PvalidateRange (Info);

+      AmdSvsmSnpPvalidate (Info);

     }

 

     //

@@ -341,7 +273,7 @@ InternalSetPageState (
     // validate the pages after it has been added in the RMP table.

     //

     if (State == SevSnpPagePrivate) {

-      PvalidateRange (Info);

+      AmdSvsmSnpPvalidate (Info);

     }

   }

 }