[PATCH v6 4/4] UefiCpuPkg: PiSmmCpuDxeSmm skip MSR_IA32_MISC_ENABLE manipulation on AMD

["Kirkendall, Garrett" <garrett.kirkendall@amd.com>]

AMD does not support MSR_IA32_MISC_ENABLE.  Accessing that register
causes and exception on AMD processors.  If Execution Disable is
supported, but if the processor is an AMD processor, skip manipulating
MSR_IA32_MISC_ENABLE[34] XD Disable bit.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Garrett Kirkendall <garrett.kirkendall@amd.com>
---

Notes:
    Tested on Intel hardware with Laszlo Ersek's help
    
    (1) downloaded two Linux images from provided links.
    (2) Test using a 32-bit guest on an Intel host (standing in your edk2 tree, with the patches applied):
    
    $ build -a IA32 -b DEBUG -p OvmfPkg/OvmfPkgIa32.dsc -t GCC5 -D SMM_REQUIRE
    
    $ qemu-system-i386 \
        -cpu coreduo,-nx \
        -machine q35,smm=on,accel=kvm \
        -m 4096 \
        -smp 4 \
        -global driver=cfi.pflash01,property=secure,value=on \
        -drive if=pflash,format=raw,unit=0,readonly=on,file=Build/OvmfIa32/DEBUG_GCC5/FV/OVMF_CODE.fd \
        -drive if=pflash,format=raw,unit=1,snapshot=on,file=Build/OvmfIa32/DEBUG_GCC5/FV/OVMF_VARS.fd \
        -drive id=hdd,if=none,format=qcow2,snapshot=on,file=fedora-30-efi-systemd-i686.qcow2 \
        -device virtio-scsi-pci,id=scsi0 \
        -device scsi-hd,drive=hdd,bus=scsi0.0,bootindex=1
    
    (Once you get a login prompt, feel free to interrupt QEMU with Ctrl-C.)
    
    (3) Test using a 64-bit guest on an Intel host:
    
    $ build -a IA32 -a X64 -b DEBUG -p OvmfPkg/OvmfPkgIa32X64.dsc -t GCC5 -D SMM_REQUIRE
    
    $ qemu-system-x86_64 \
        -cpu host \
        -machine q35,smm=on,accel=kvm \
        -m 4096 \
        -smp 4 \
        -global driver=cfi.pflash01,property=secure,value=on \
        -drive if=pflash,format=raw,unit=0,readonly=on,file=Build/Ovmf3264/DEBUG_GCC5/FV/OVMF_CODE.fd \
        -drive if=pflash,format=raw,unit=1,snapshot=on,file=Build/Ovmf3264/DEBUG_GCC5/FV/OVMF_VARS.fd \
        -drive id=hdd,if=none,format=qcow2,snapshot=on,file=fedora-31-efi-grub2-x86_64.qcow2 \
        -device virtio-scsi-pci,id=scsi0 \
        -device scsi-hd,drive=hdd,bus=scsi0.0,bootindex=1
    
    Tested on real AMD Hardware

 UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfileInternal.h |  3 +++
 UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c         |  9 ++++++++-
 UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm   | 19 +++++++++++++++++--
 UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm    | 20 ++++++++++++++++++--
 4 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfileInternal.h b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfileInternal.h
index 43f6935cf9dc..993360a8a8c1 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfileInternal.h
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfileInternal.h
@@ -2,6 +2,7 @@
 SMM profile internal header file.
 
 Copyright (c) 2012 - 2018, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2020, AMD Incorporated. All rights reserved.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -13,6 +14,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/UefiRuntimeServicesTableLib.h>
 #include <Library/DxeServicesTableLib.h>
 #include <Library/CpuLib.h>
+#include <Library/UefiCpuLib.h>
 #include <IndustryStandard/Acpi.h>
 
 #include "SmmProfileArch.h"
@@ -99,6 +101,7 @@ extern SMM_S3_RESUME_STATE       *mSmmS3ResumeState;
 extern UINTN                     gSmiExceptionHandlers[];
 extern BOOLEAN                   mXdSupported;
 X86_ASSEMBLY_PATCH_LABEL         gPatchXdSupported;
+X86_ASSEMBLY_PATCH_LABEL         gPatchMsrIa32MiscEnableSupported;
 extern UINTN                     *mPFEntryCount;
 extern UINT64                    (*mLastPFEntryValue)[MAX_PF_ENTRY_COUNT];
 extern UINT64                    *(*mLastPFEntryPointer)[MAX_PF_ENTRY_COUNT];
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
index c47b5573e366..d7ed9ab7a770 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmProfile.c
@@ -2,7 +2,7 @@
 Enable SMM profile.
 
 Copyright (c) 2012 - 2019, Intel Corporation. All rights reserved.<BR>
-Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
+Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
 
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
@@ -1015,6 +1015,13 @@ CheckFeatureSupported (
       mXdSupported = FALSE;
       PatchInstructionX86 (gPatchXdSupported, mXdSupported, 1);
     }
+
+    if (StandardSignatureIsAuthenticAMD ()) {
+      //
+      // AMD processors do not support MSR_IA32_MISC_ENABLE
+      //
+      PatchInstructionX86 (gPatchMsrIa32MiscEnableSupported, FALSE, 1);
+    }
   }
 
   if (mBtsSupported) {
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
index f96de9bdeb43..167f5e14dbd4 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
@@ -1,5 +1,6 @@
 ;------------------------------------------------------------------------------ ;
 ; Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2020, AMD Incorporated. All rights reserved.<BR>
 ; SPDX-License-Identifier: BSD-2-Clause-Patent
 ;
 ; Module Name:
@@ -59,6 +60,7 @@ global ASM_PFX(gPatchSmiStack)
 global ASM_PFX(gPatchSmbase)
 extern ASM_PFX(mXdSupported)
 global ASM_PFX(gPatchXdSupported)
+global ASM_PFX(gPatchMsrIa32MiscEnableSupported)
 extern ASM_PFX(gSmiHandlerIdtr)
 
 extern ASM_PFX(mCetSupported)
@@ -153,17 +155,30 @@ ASM_PFX(gPatchSmiCr3):
 ASM_PFX(gPatchXdSupported):
     cmp     al, 0
     jz      @SkipXd
+
+; If MSR_IA32_MISC_ENABLE is supported, clear XD Disable bit
+    mov     al, strict byte 1           ; source operand may be patched
+ASM_PFX(gPatchMsrIa32MiscEnableSupported):
+    cmp     al, 1
+    jz      MsrIa32MiscEnableSupported
+
+; MSR_IA32_MISC_ENABLE not supported
+    xor     edx, edx
+    push    edx                         ; don't try to restore the XD Disable bit just before RSM
+    jmp     EnableNxe
+
 ;
 ; Check XD disable bit
 ;
+MsrIa32MiscEnableSupported:
     mov     ecx, MSR_IA32_MISC_ENABLE
     rdmsr
     push    edx                        ; save MSR_IA32_MISC_ENABLE[63-32]
     test    edx, BIT2                  ; MSR_IA32_MISC_ENABLE[34]
-    jz      .5
+    jz      EnableNxe
     and     dx, 0xFFFB                 ; clear XD Disable bit if it is set
     wrmsr
-.5:
+EnableNxe:
     mov     ecx, MSR_EFER
     rdmsr
     or      ax, MSR_EFER_XD             ; enable NXE
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
index 8bfba55b5d08..0e154e5db949 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
@@ -1,5 +1,6 @@
 ;------------------------------------------------------------------------------ ;
 ; Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2020, AMD Incorporated. All rights reserved.<BR>
 ; SPDX-License-Identifier: BSD-2-Clause-Patent
 ;
 ; Module Name:
@@ -67,6 +68,7 @@ extern ASM_PFX(CpuSmmDebugExit)
 global ASM_PFX(gPatchSmbase)
 extern ASM_PFX(mXdSupported)
 global ASM_PFX(gPatchXdSupported)
+global ASM_PFX(gPatchMsrIa32MiscEnableSupported)
 global ASM_PFX(gPatchSmiStack)
 global ASM_PFX(gPatchSmiCr3)
 global ASM_PFX(gPatch5LevelPagingNeeded)
@@ -152,18 +154,32 @@ SkipEnable5LevelPaging:
 ASM_PFX(gPatchXdSupported):
     cmp     al, 0
     jz      @SkipXd
+
+; If MSR_IA32_MISC_ENABLE is supported, clear XD Disable bit
+    mov     al, strict byte 1           ; source operand may be patched
+ASM_PFX(gPatchMsrIa32MiscEnableSupported):
+    cmp     al, 1
+    jz      MsrIa32MiscEnableSupported
+
+; MSR_IA32_MISC_ENABLE not supported
+    sub     esp, 4
+    xor     rdx, rdx
+    push    rdx                         ; don't try to restore the XD Disable bit just before RSM
+    jmp     EnableNxe
+
 ;
 ; Check XD disable bit
 ;
+MsrIa32MiscEnableSupported:
     mov     ecx, MSR_IA32_MISC_ENABLE
     rdmsr
     sub     esp, 4
     push    rdx                        ; save MSR_IA32_MISC_ENABLE[63-32]
     test    edx, BIT2                  ; MSR_IA32_MISC_ENABLE[34]
-    jz      .0
+    jz      EnableNxe
     and     dx, 0xFFFB                 ; clear XD Disable bit if it is set
     wrmsr
-.0:
+EnableNxe:
     mov     ecx, MSR_EFER
     rdmsr
     or      ax, MSR_EFER_XD            ; enable NXE
-- 
2.27.0