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UefiCpuPkg/MpInitLib: move SEV specific routines in AmdSev.c 

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275

Move all the SEV specific function in AmdSev.c.

No functional change intended.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Suggested-by: Jiewen Yao <Jiewen.yao@intel.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
This commit is contained in:
Brijesh Singh 2021-12-09 11:27:30 +08:00 committed by mergify[bot]
parent 2ddacfb6b8
commit e2289d19d8
7 changed files with 421 additions and 306 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

245
UefiCpuPkg/Library/MpInitLib/AmdSev.c Normal file
View File

@ -0,0 +1,245 @@
/** @file
CPU MP Initialize helper function for AMD SEV.
Copyright (c) 2021, AMD Inc. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "MpLib.h"
#include <Library/VmgExitLib.h>
/**
Get Protected mode code segment with 16-bit default addressing
from current GDT table.
@return Protected mode 16-bit code segment value.
**/
STATIC
UINT16
GetProtectedMode16CS (
VOID
)
{
IA32_DESCRIPTOR GdtrDesc;
IA32_SEGMENT_DESCRIPTOR *GdtEntry;
UINTN GdtEntryCount;
UINT16 Index;
Index = (UINT16)-1;
AsmReadGdtr (&GdtrDesc);
GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);
GdtEntry = (IA32_SEGMENT_DESCRIPTOR *)GdtrDesc.Base;
for (Index = 0; Index < GdtEntryCount; Index++) {
if ((GdtEntry->Bits.L == 0) &&
(GdtEntry->Bits.DB == 0) &&
(GdtEntry->Bits.Type > 8))
{
break;
}
GdtEntry++;
}
ASSERT (Index != GdtEntryCount);
return Index * 8;
}
/**
Get Protected mode code segment with 32-bit default addressing
from current GDT table.
@return Protected mode 32-bit code segment value.
**/
STATIC
UINT16
GetProtectedMode32CS (
VOID
)
{
IA32_DESCRIPTOR GdtrDesc;
IA32_SEGMENT_DESCRIPTOR *GdtEntry;
UINTN GdtEntryCount;
UINT16 Index;
Index = (UINT16)-1;
AsmReadGdtr (&GdtrDesc);
GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);
GdtEntry = (IA32_SEGMENT_DESCRIPTOR *)GdtrDesc.Base;
for (Index = 0; Index < GdtEntryCount; Index++) {
if ((GdtEntry->Bits.L == 0) &&
(GdtEntry->Bits.DB == 1) &&
(GdtEntry->Bits.Type > 8))
{
break;
}
GdtEntry++;
}
ASSERT (Index != GdtEntryCount);
return Index * 8;
}
/**
Reset an AP when in SEV-ES mode.
If successful, this function never returns.
@param[in] Ghcb Pointer to the GHCB
@param[in] CpuMpData Pointer to CPU MP Data
**/
VOID
MpInitLibSevEsAPReset (
IN GHCB *Ghcb,
IN CPU_MP_DATA *CpuMpData
)
{
EFI_STATUS Status;
UINTN ProcessorNumber;
UINT16 Code16, Code32;
AP_RESET *APResetFn;
UINTN BufferStart;
UINTN StackStart;
Status = GetProcessorNumber (CpuMpData, &ProcessorNumber);
ASSERT_EFI_ERROR (Status);
Code16 = GetProtectedMode16CS ();
Code32 = GetProtectedMode32CS ();
if (CpuMpData->WakeupBufferHigh != 0) {
APResetFn = (AP_RESET *)(CpuMpData->WakeupBufferHigh + CpuMpData->AddressMap.SwitchToRealNoNxOffset);
} else {
APResetFn = (AP_RESET *)(CpuMpData->MpCpuExchangeInfo->BufferStart + CpuMpData->AddressMap.SwitchToRealOffset);
}
BufferStart = CpuMpData->MpCpuExchangeInfo->BufferStart;
StackStart = CpuMpData->SevEsAPResetStackStart -
(AP_RESET_STACK_SIZE * ProcessorNumber);
//
// This call never returns.
//
APResetFn (BufferStart, Code16, Code32, StackStart);
}
/**
Allocate the SEV-ES AP jump table buffer.
@param[in, out] CpuMpData The pointer to CPU MP Data structure.
**/
VOID
AllocateSevEsAPMemory (
IN OUT CPU_MP_DATA *CpuMpData
)
{
if (CpuMpData->SevEsAPBuffer == (UINTN)-1) {
CpuMpData->SevEsAPBuffer =
CpuMpData->SevEsIsEnabled ? GetSevEsAPMemory () : 0;
}
}
/**
Program the SEV-ES AP jump table buffer.
@param[in] SipiVector The SIPI vector used for the AP Reset
**/
VOID
SetSevEsJumpTable (
IN UINTN SipiVector
)
{
SEV_ES_AP_JMP_FAR *JmpFar;
UINT32 Offset, InsnByte;
UINT8 LoNib, HiNib;
JmpFar = (SEV_ES_AP_JMP_FAR *)(UINTN)FixedPcdGet32 (PcdSevEsWorkAreaBase);
ASSERT (JmpFar != NULL);
//
// Obtain the address of the Segment/Rip location in the workarea.
// This will be set to a value derived from the SIPI vector and will
// be the memory address used for the far jump below.
//
Offset = FixedPcdGet32 (PcdSevEsWorkAreaBase);
Offset += sizeof (JmpFar->InsnBuffer);
LoNib = (UINT8)Offset;
HiNib = (UINT8)(Offset >> 8);
//
// Program the workarea (which is the initial AP boot address) with
// far jump to the SIPI vector (where XX and YY represent the
// address of where the SIPI vector is stored.
//
// JMP FAR [CS:XXYY] => 2E FF 2E YY XX
//
InsnByte = 0;
JmpFar->InsnBuffer[InsnByte++] = 0x2E; // CS override prefix
JmpFar->InsnBuffer[InsnByte++] = 0xFF; // JMP (FAR)
JmpFar->InsnBuffer[InsnByte++] = 0x2E; // ModRM (JMP memory location)
JmpFar->InsnBuffer[InsnByte++] = LoNib; // YY offset ...
JmpFar->InsnBuffer[InsnByte++] = HiNib; // XX offset ...
//
// Program the Segment/Rip based on the SIPI vector (always at least
// 16-byte aligned, so Rip is set to 0).
//
JmpFar->Rip = 0;
JmpFar->Segment = (UINT16)(SipiVector >> 4);
}
/**
The function puts the AP in halt loop.
@param[in] CpuMpData The pointer to CPU MP Data structure.
**/
VOID
SevEsPlaceApHlt (
CPU_MP_DATA *CpuMpData
)
{
MSR_SEV_ES_GHCB_REGISTER Msr;
GHCB *Ghcb;
UINT64 Status;
BOOLEAN DoDecrement;
BOOLEAN InterruptState;
DoDecrement = (BOOLEAN)(CpuMpData->InitFlag == ApInitConfig);
while (TRUE) {
Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
Ghcb = Msr.Ghcb;
VmgInit (Ghcb, &InterruptState);
if (DoDecrement) {
DoDecrement = FALSE;
//
// Perform the delayed decrement just before issuing the first
// VMGEXIT with AP_RESET_HOLD.
//
InterlockedDecrement ((UINT32 *)&CpuMpData->MpCpuExchangeInfo->NumApsExecuting);
}
Status = VmgExit (Ghcb, SVM_EXIT_AP_RESET_HOLD, 0, 0);
if ((Status == 0) && (Ghcb->SaveArea.SwExitInfo2 != 0)) {
VmgDone (Ghcb, InterruptState);
break;
}
VmgDone (Ghcb, InterruptState);
}
//
// Awakened in a new phase? Use the new CpuMpData
//
if (CpuMpData->NewCpuMpData != NULL) {
CpuMpData = CpuMpData->NewCpuMpData;
}
MpInitLibSevEsAPReset (Ghcb, CpuMpData);
}

1
UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
View File

@ -28,6 +28,7 @@
X64/MpFuncs.nasm
[Sources.common]
AmdSev.c
MpEqu.inc
DxeMpLib.c
MpLib.c

224
UefiCpuPkg/Library/MpInitLib/MpLib.c
View File

@ -599,123 +599,6 @@ InitializeApData (
SetApState (&CpuMpData->CpuData[ProcessorNumber], CpuStateIdle);
}
/**
Get Protected mode code segment with 16-bit default addressing
from current GDT table.
@return Protected mode 16-bit code segment value.
**/
STATIC
UINT16
GetProtectedMode16CS (
VOID
)
{
IA32_DESCRIPTOR GdtrDesc;
IA32_SEGMENT_DESCRIPTOR *GdtEntry;
UINTN GdtEntryCount;
UINT16 Index;
Index = (UINT16)-1;
AsmReadGdtr (&GdtrDesc);
GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);
GdtEntry = (IA32_SEGMENT_DESCRIPTOR *)GdtrDesc.Base;
for (Index = 0; Index < GdtEntryCount; Index++) {
if ((GdtEntry->Bits.L == 0) &&
(GdtEntry->Bits.DB == 0) &&
(GdtEntry->Bits.Type > 8))
{
break;
}
GdtEntry++;
}
ASSERT (Index != GdtEntryCount);
return Index * 8;
}
/**
Get Protected mode code segment with 32-bit default addressing
from current GDT table.
@return Protected mode 32-bit code segment value.
**/
STATIC
UINT16
GetProtectedMode32CS (
VOID
)
{
IA32_DESCRIPTOR GdtrDesc;
IA32_SEGMENT_DESCRIPTOR *GdtEntry;
UINTN GdtEntryCount;
UINT16 Index;
Index = (UINT16)-1;
AsmReadGdtr (&GdtrDesc);
GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);
GdtEntry = (IA32_SEGMENT_DESCRIPTOR *)GdtrDesc.Base;
for (Index = 0; Index < GdtEntryCount; Index++) {
if ((GdtEntry->Bits.L == 0) &&
(GdtEntry->Bits.DB == 1) &&
(GdtEntry->Bits.Type > 8))
{
break;
}
GdtEntry++;
}
ASSERT (Index != GdtEntryCount);
return Index * 8;
}
/**
Reset an AP when in SEV-ES mode.
If successful, this function never returns.
@param[in] Ghcb Pointer to the GHCB
@param[in] CpuMpData Pointer to CPU MP Data
**/
STATIC
VOID
MpInitLibSevEsAPReset (
IN GHCB *Ghcb,
IN CPU_MP_DATA *CpuMpData
)
{
EFI_STATUS Status;
UINTN ProcessorNumber;
UINT16 Code16, Code32;
AP_RESET *APResetFn;
UINTN BufferStart;
UINTN StackStart;
Status = GetProcessorNumber (CpuMpData, &ProcessorNumber);
ASSERT_EFI_ERROR (Status);
Code16 = GetProtectedMode16CS ();
Code32 = GetProtectedMode32CS ();
if (CpuMpData->WakeupBufferHigh != 0) {
APResetFn = (AP_RESET *)(CpuMpData->WakeupBufferHigh + CpuMpData->AddressMap.SwitchToRealNoNxOffset);
} else {
APResetFn = (AP_RESET *)(CpuMpData->MpCpuExchangeInfo->BufferStart + CpuMpData->AddressMap.SwitchToRealOffset);
}
BufferStart = CpuMpData->MpCpuExchangeInfo->BufferStart;
StackStart = CpuMpData->SevEsAPResetStackStart -
(AP_RESET_STACK_SIZE * ProcessorNumber);
//
// This call never returns.
//
APResetFn (BufferStart, Code16, Code32, StackStart);
}
/**
This function will be called from AP reset code if BSP uses WakeUpAP.
@ -895,47 +778,7 @@ ApWakeupFunction (
while (TRUE) {
DisableInterrupts ();
if (CpuMpData->SevEsIsEnabled) {
MSR_SEV_ES_GHCB_REGISTER Msr;
GHCB *Ghcb;
UINT64 Status;
BOOLEAN DoDecrement;
BOOLEAN InterruptState;
DoDecrement = (BOOLEAN)(CpuMpData->InitFlag == ApInitConfig);
while (TRUE) {
Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
Ghcb = Msr.Ghcb;
VmgInit (Ghcb, &InterruptState);
if (DoDecrement) {
DoDecrement = FALSE;
//
// Perform the delayed decrement just before issuing the first
// VMGEXIT with AP_RESET_HOLD.
//
InterlockedDecrement ((UINT32 *)&CpuMpData->MpCpuExchangeInfo->NumApsExecuting);
}
Status = VmgExit (Ghcb, SVM_EXIT_AP_RESET_HOLD, 0, 0);
if ((Status == 0) && (Ghcb->SaveArea.SwExitInfo2 != 0)) {
VmgDone (Ghcb, InterruptState);
break;
}
VmgDone (Ghcb, InterruptState);
}
//
// Awakened in a new phase? Use the new CpuMpData
//
if (CpuMpData->NewCpuMpData != NULL) {
CpuMpData = CpuMpData->NewCpuMpData;
}
MpInitLibSevEsAPReset (Ghcb, CpuMpData);
SevEsPlaceApHlt (CpuMpData);
} else {
CpuSleep ();
}
@ -1268,71 +1111,6 @@ FreeResetVector (
}
}
/**
Allocate the SEV-ES AP jump table buffer.
@param[in, out] CpuMpData The pointer to CPU MP Data structure.
**/
VOID
AllocateSevEsAPMemory (
IN OUT CPU_MP_DATA *CpuMpData
)
{
if (CpuMpData->SevEsAPBuffer == (UINTN)-1) {
CpuMpData->SevEsAPBuffer =
CpuMpData->SevEsIsEnabled ? GetSevEsAPMemory () : 0;
}
}
/**
Program the SEV-ES AP jump table buffer.
@param[in] SipiVector The SIPI vector used for the AP Reset
**/
VOID
SetSevEsJumpTable (
IN UINTN SipiVector
)
{
SEV_ES_AP_JMP_FAR *JmpFar;
UINT32 Offset, InsnByte;
UINT8 LoNib, HiNib;
JmpFar = (SEV_ES_AP_JMP_FAR *)(UINTN)FixedPcdGet32 (PcdSevEsWorkAreaBase);
ASSERT (JmpFar != NULL);
//
// Obtain the address of the Segment/Rip location in the workarea.
// This will be set to a value derived from the SIPI vector and will
// be the memory address used for the far jump below.
//
Offset = FixedPcdGet32 (PcdSevEsWorkAreaBase);
Offset += sizeof (JmpFar->InsnBuffer);
LoNib = (UINT8)Offset;
HiNib = (UINT8)(Offset >> 8);
//
// Program the workarea (which is the initial AP boot address) with
// far jump to the SIPI vector (where XX and YY represent the
// address of where the SIPI vector is stored.
//
// JMP FAR [CS:XXYY] => 2E FF 2E YY XX
//
InsnByte = 0;
JmpFar->InsnBuffer[InsnByte++] = 0x2E; // CS override prefix
JmpFar->InsnBuffer[InsnByte++] = 0xFF; // JMP (FAR)
JmpFar->InsnBuffer[InsnByte++] = 0x2E; // ModRM (JMP memory location)
JmpFar->InsnBuffer[InsnByte++] = LoNib; // YY offset ...
JmpFar->InsnBuffer[InsnByte++] = HiNib; // XX offset ...
//
// Program the Segment/Rip based on the SIPI vector (always at least
// 16-byte aligned, so Rip is set to 0).
//
JmpFar->Rip = 0;
JmpFar->Segment = (UINT16)(SipiVector >> 4);
}
/**
This function will be called by BSP to wakeup AP.

37
UefiCpuPkg/Library/MpInitLib/MpLib.h
View File

@ -34,6 +34,9 @@
#include <Library/PcdLib.h>
#include <Library/MicrocodeLib.h>
#include <Register/Amd/Fam17Msr.h>
#include <Register/Amd/Ghcb.h>
#include <Guid/MicrocodePatchHob.h>
#define WAKEUP_AP_SIGNAL SIGNATURE_32 ('S', 'T', 'A', 'P')
@ -321,7 +324,7 @@ typedef struct {
from long mode to real mode.
**/
typedef
VOID
VOID
(EFIAPI AP_RESET)(
IN UINTN BufferStart,
IN UINT16 Code16,
@ -346,7 +349,7 @@ extern EFI_GUID mCpuInitMpLibHobGuid;
@param[in] PmCodeSegment Protected mode code segment value.
**/
typedef
VOID
VOID
(EFIAPI *ASM_RELOCATE_AP_LOOP)(
IN BOOLEAN MwaitSupport,
IN UINTN ApTargetCState,
@ -740,4 +743,34 @@ PlatformShadowMicrocode (
IN OUT CPU_MP_DATA *CpuMpData
);
/**
Allocate the SEV-ES AP jump table buffer.
@param[in, out] CpuMpData The pointer to CPU MP Data structure.
**/
VOID
AllocateSevEsAPMemory (
IN OUT CPU_MP_DATA *CpuMpData
);
/**
Program the SEV-ES AP jump table buffer.
@param[in] SipiVector The SIPI vector used for the AP Reset
**/
VOID
SetSevEsJumpTable (
IN UINTN SipiVector
);
/**
The function puts the AP in halt loop.
@param[in] CpuMpData The pointer to CPU MP Data structure.
**/
VOID
SevEsPlaceApHlt (
CPU_MP_DATA *CpuMpData
);
#endif

1
UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
View File

@ -28,6 +28,7 @@
X64/MpFuncs.nasm
[Sources.common]
AmdSev.c
MpEqu.inc
PeiMpLib.c
MpLib.c

119
UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm Normal file
View File

@ -0,0 +1,119 @@
;------------------------------------------------------------------------------ ;
; Copyright (c) 2021, AMD Inc. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Module Name:
;
; AmdSev.nasm
;
; Abstract:
;
; This provides helper used by the MpFunc.nasm. If AMD SEV-ES is active
; then helpers perform the additional setups (such as GHCB).
;
;-------------------------------------------------------------------------------
%define SIZE_4KB 0x1000
;
; The function checks whether SEV-ES is enabled, if enabled
; then setup the GHCB page.
;
SevEsSetupGhcb:
lea edi, [esi + MP_CPU_EXCHANGE_INFO_FIELD (SevEsIsEnabled)]
cmp byte [edi], 1 ; SevEsIsEnabled
jne SevEsSetupGhcbExit
;
; program GHCB
; Each page after the GHCB is a per-CPU page, so the calculation programs
; a GHCB to be every 8KB.
;
mov eax, SIZE_4KB
shl eax, 1 ; EAX = SIZE_4K * 2
mov ecx, ebx
mul ecx ; EAX = SIZE_4K * 2 * CpuNumber
mov edi, esi
add edi, MP_CPU_EXCHANGE_INFO_FIELD (GhcbBase)
add rax, qword [edi]
mov rdx, rax
shr rdx, 32
mov rcx, 0xc0010130
wrmsr
SevEsSetupGhcbExit:
OneTimeCallRet SevEsSetupGhcb
;
; The function checks whether SEV-ES is enabled, if enabled, use
; the GHCB
;
SevEsGetApicId:
lea edi, [esi + MP_CPU_EXCHANGE_INFO_FIELD (SevEsIsEnabled)]
cmp byte [edi], 1 ; SevEsIsEnabled
jne SevEsGetApicIdExit
;
; Since we don't have a stack yet, we can't take a #VC
; exception. Use the GHCB protocol to perform the CPUID
; calls.
;
mov rcx, 0xc0010130
rdmsr
shl rdx, 32
or rax, rdx
mov rdi, rax ; RDI now holds the original GHCB GPA
mov rdx, 0 ; CPUID function 0
mov rax, 0 ; RAX register requested
or rax, 4
wrmsr
rep vmmcall
rdmsr
cmp edx, 0bh
jb NoX2ApicSevEs ; CPUID level below CPUID_EXTENDED_TOPOLOGY
mov rdx, 0bh ; CPUID function 0x0b
mov rax, 040000000h ; RBX register requested
or rax, 4
wrmsr
rep vmmcall
rdmsr
test edx, 0ffffh
jz NoX2ApicSevEs ; CPUID.0BH:EBX[15:0] is zero
mov rdx, 0bh ; CPUID function 0x0b
mov rax, 0c0000000h ; RDX register requested
or rax, 4
wrmsr
rep vmmcall
rdmsr
; Processor is x2APIC capable; 32-bit x2APIC ID is now in EDX
jmp RestoreGhcb
NoX2ApicSevEs:
; Processor is not x2APIC capable, so get 8-bit APIC ID
mov rdx, 1 ; CPUID function 1
mov rax, 040000000h ; RBX register requested
or rax, 4
wrmsr
rep vmmcall
rdmsr
shr edx, 24
RestoreGhcb:
mov rbx, rdx ; Save x2APIC/APIC ID
mov rdx, rdi ; RDI holds the saved GHCB GPA
shr rdx, 32
mov eax, edi
wrmsr
mov rdx, rbx
; x2APIC ID or APIC ID is in EDX
jmp GetProcessorNumber
SevEsGetApicIdExit:
OneTimeCallRet SevEsGetApicId

100
UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
View File

@ -15,6 +15,15 @@
%include "MpEqu.inc"
extern ASM_PFX(InitializeFloatingPointUnits)
%macro OneTimeCall 1
jmp %1
%1 %+ OneTimerCallReturn:
%endmacro
%macro OneTimeCallRet 1
jmp %1 %+ OneTimerCallReturn
%endmacro
DEFAULT REL
SECTION .text
@ -144,6 +153,12 @@ SkipEnable5LevelPaging:
jmp far [edi]
BITS 64
;
; Required for the AMD SEV helper functions
;
%include "AmdSev.nasm"
LongModeStart:
mov esi, ebx
lea edi, [esi + MP_CPU_EXCHANGE_INFO_FIELD (InitFlag)]
@ -175,94 +190,17 @@ LongModeStart:
add rax, qword [edi]
mov rsp, rax
lea edi, [esi + MP_CPU_EXCHANGE_INFO_FIELD (SevEsIsEnabled)]
cmp byte [edi], 1 ; SevEsIsEnabled
jne CProcedureInvoke
;
; program GHCB
; Each page after the GHCB is a per-CPU page, so the calculation programs
; a GHCB to be every 8KB.
; Setup the GHCB when AMD SEV-ES active.
;
mov eax, SIZE_4KB
shl eax, 1 ; EAX = SIZE_4K * 2
mov ecx, ebx
mul ecx ; EAX = SIZE_4K * 2 * CpuNumber
mov edi, esi
add edi, MP_CPU_EXCHANGE_INFO_FIELD (GhcbBase)
add rax, qword [edi]
mov rdx, rax
shr rdx, 32
mov rcx, 0xc0010130
wrmsr
OneTimeCall SevEsSetupGhcb
jmp CProcedureInvoke
GetApicId:
lea edi, [esi + MP_CPU_EXCHANGE_INFO_FIELD (SevEsIsEnabled)]
cmp byte [edi], 1 ; SevEsIsEnabled
jne DoCpuid
;
; Since we don't have a stack yet, we can't take a #VC
; exception. Use the GHCB protocol to perform the CPUID
; calls.
; Use the GHCB protocol to get the ApicId when SEV-ES is active.
;
mov rcx, 0xc0010130
rdmsr
shl rdx, 32
or rax, rdx
mov rdi, rax ; RDI now holds the original GHCB GPA
mov rdx, 0 ; CPUID function 0
mov rax, 0 ; RAX register requested
or rax, 4
wrmsr
rep vmmcall
rdmsr
cmp edx, 0bh
jb NoX2ApicSevEs ; CPUID level below CPUID_EXTENDED_TOPOLOGY
mov rdx, 0bh ; CPUID function 0x0b
mov rax, 040000000h ; RBX register requested
or rax, 4
wrmsr
rep vmmcall
rdmsr
test edx, 0ffffh
jz NoX2ApicSevEs ; CPUID.0BH:EBX[15:0] is zero
mov rdx, 0bh ; CPUID function 0x0b
mov rax, 0c0000000h ; RDX register requested
or rax, 4
wrmsr
rep vmmcall
rdmsr
; Processor is x2APIC capable; 32-bit x2APIC ID is now in EDX
jmp RestoreGhcb
NoX2ApicSevEs:
; Processor is not x2APIC capable, so get 8-bit APIC ID
mov rdx, 1 ; CPUID function 1
mov rax, 040000000h ; RBX register requested
or rax, 4
wrmsr
rep vmmcall
rdmsr
shr edx, 24
RestoreGhcb:
mov rbx, rdx ; Save x2APIC/APIC ID
mov rdx, rdi ; RDI holds the saved GHCB GPA
shr rdx, 32
mov eax, edi
wrmsr
mov rdx, rbx
; x2APIC ID or APIC ID is in EDX
jmp GetProcessorNumber
OneTimeCall SevEsGetApicId
DoCpuid:
mov eax, 0