Re: [PATCH v8 42/46] UefiCpuPkg: Allow AP booting under SEV-ES


Dong, Eric
 

Hi Tom,

+ //
+ // 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) (ExchangeInfo->BufferStart >> 4);
+ }
For this wake-up process, current code just handles the broadcast type. I
think it also needs to handle wake-up specific AP case. Right?

Yes, it should be. I never encountered a non-broadcast call under OVMF, but
it should be supported for error cases, etc. and for any future changes in
support.

I'll add it and make the above code a function so as not to duplicate it.
Yes, that will be good.

Thanks,
Eric

Thanks,
Tom


Thanks,
Eric
//
// Wakeup all APs
//
@@ -1669,7 +1956,7 @@ MpInitLibInitialize (
ASSERT (MaxLogicalProcessorNumber != 0);

AsmGetAddressMap (&AddressMap);
- ApResetVectorSize = AddressMap.RendezvousFunnelSize + sizeof
(MP_CPU_EXCHANGE_INFO);
+ ApResetVectorSize = GetApResetVectorSize (&AddressMap);
ApStackSize = PcdGet32(PcdCpuApStackSize);
ApLoopMode = GetApLoopMode (&MonitorFilterSize);

@@ -1728,6 +2015,8 @@ MpInitLibInitialize (
CpuMpData->CpuInfoInHob = (UINT64) (UINTN) (CpuMpData-
CpuData
+ MaxLogicalProcessorNumber);
InitializeSpinLock(&CpuMpData->MpLock);
CpuMpData->SevEsIsEnabled = PcdGetBool (PcdSevEsIsEnabled);
+ CpuMpData->SevEsAPBuffer = (UINTN) -1;
+ CpuMpData->GhcbBase = PcdGet64 (PcdGhcbBase);

//
// Make sure no memory usage outside of the allocated buffer.
@@ -1786,6 +2075,7 @@ MpInitLibInitialize (
// APs have been wakeup before, just get the CPU Information
// from HOB
//
+ OldCpuMpData->NewCpuMpData = CpuMpData;
CpuMpData->CpuCount = OldCpuMpData->CpuCount;
CpuMpData->BspNumber = OldCpuMpData->BspNumber;
CpuMpData->CpuInfoInHob = OldCpuMpData->CpuInfoInHob; diff --git
a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
index a548fed23fa7..e17a351e5cfd 100644
--- a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
@@ -280,6 +280,25 @@ GetModeTransitionBuffer (
return 0;
}

+/**
+ Return the address of the SEV-ES AP jump table.
+
+ This buffer is required in order for an SEV-ES guest to transition
+ from UEFI into an OS.
+
+ @retval other Return SEV-ES AP jump table buffer
+**/
+UINTN
+GetSevEsAPMemory (
+ VOID
+ )
+{
+ //
+ // PEI phase doesn't need to do such transition. So simply return 0.
+ //
+ return 0;
+}
+
/**
Checks APs status and updates APs status if needed.

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
index 6298571e29b2..28f8e8e133e5 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
@@ -121,7 +121,7 @@ GetProtectedModeCS (
GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;
for (Index = 0; Index < GdtEntryCount; Index++) {
if (GdtEntry->Bits.L == 0) {
- if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.L == 0) {
+ if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.DB == 1) {
break;
}
}
diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
b/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
index efb1bc2bf7cb..4f5a7c859a56 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
@@ -19,7 +19,7 @@ CPU_SWITCH_STATE_IDLE equ 0
CPU_SWITCH_STATE_STORED equ 1
CPU_SWITCH_STATE_LOADED equ 2

-LockLocation equ (RendezvousFunnelProcEnd -
RendezvousFunnelProcStart)
+LockLocation equ (SwitchToRealProcEnd -
RendezvousFunnelProcStart)
StackStartAddressLocation equ LockLocation + 04h
StackSizeLocation equ LockLocation + 08h
ApProcedureLocation equ LockLocation + 0Ch
diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
index b74046b76af3..309d53bf3b37 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
@@ -215,6 +215,16 @@ CProcedureInvoke:
jmp $ ; Never reach here
RendezvousFunnelProcEnd:

+;-------------------------------------------------------------------
+---
+---------------
+;SwitchToRealProc procedure follows.
+;NOT USED IN 32 BIT MODE.
+;-------------------------------------------------------------------
+---
+---------------
+global ASM_PFX(SwitchToRealProc)
+ASM_PFX(SwitchToRealProc):
+SwitchToRealProcStart:
+ jmp $ ; Never reach here
+SwitchToRealProcEnd:
+

;--------------------------------------------------------------------
----------------- ; AsmRelocateApLoop (MwaitSupport,
ApTargetCState, PmCodeSegment, TopOfApStack, CountTofinish);

;--------------------------------------------------------------------
----------------- @@ -263,6 +273,11 @@ ASM_PFX(AsmGetAddressMap):
mov dword [ebx + 0Ch], AsmRelocateApLoopStart
mov dword [ebx + 10h], AsmRelocateApLoopEnd -
AsmRelocateApLoopStart
mov dword [ebx + 14h], Flat32Start - RendezvousFunnelProcStart
+ mov dword [ebx + 18h], SwitchToRealProcEnd -
SwitchToRealProcStart ; SwitchToRealSize
+ mov dword [ebx + 1Ch], SwitchToRealProcStart -
RendezvousFunnelProcStart ; SwitchToRealOffset
+ mov dword [ebx + 20h], SwitchToRealProcStart - Flat32Start ;
SwitchToRealNoNxOffset
+ mov dword [ebx + 24h], 0 ;
SwitchToRealPM16ModeOffset
+ mov dword [ebx + 28h], 0 ;
SwitchToRealPM16ModeSize

popad
ret
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
b/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
index 58ef369342a7..c92daaaffd6b 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
+++ b/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
@@ -19,7 +19,7 @@ CPU_SWITCH_STATE_IDLE equ 0
CPU_SWITCH_STATE_STORED equ 1
CPU_SWITCH_STATE_LOADED equ 2

-LockLocation equ (RendezvousFunnelProcEnd -
RendezvousFunnelProcStart)
+LockLocation equ (SwitchToRealProcEnd -
RendezvousFunnelProcStart)
StackStartAddressLocation equ LockLocation + 08h
StackSizeLocation equ LockLocation + 10h
ApProcedureLocation equ LockLocation + 18h
@@ -41,3 +41,5 @@ ModeTransitionSegmentLocation equ
LockLocation +
98h
ModeHighMemoryLocation equ LockLocation + 9Ah
ModeHighSegmentLocation equ LockLocation + 9Eh
Enable5LevelPagingLocation equ LockLocation + 0A0h
+SevEsIsEnabledLocation equ LockLocation + 0A1h
+GhcbBaseLocation equ LockLocation + 0A2h
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
index 87f2523e856f..6956b408d004 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
@@ -184,9 +184,97 @@ Releaselock:
add edi, StackStartAddressLocation
add rax, qword [edi]
mov rsp, rax
+
+ lea edi, [esi + SevEsIsEnabledLocation]
+ 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.
+ ;
+ 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, GhcbBaseLocation
+ add rax, qword [edi]
+ mov rdx, rax
+ shr rdx, 32
+ mov rcx, 0xc0010130
+ wrmsr
jmp CProcedureInvoke

GetApicId:
+ lea edi, [esi + SevEsIsEnabledLocation]
+ 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.
+ ;
+ 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
+
+DoCpuid:
mov eax, 0
cpuid
cmp eax, 0bh
@@ -253,12 +341,158 @@ CProcedureInvoke:

RendezvousFunnelProcEnd:

+;-------------------------------------------------------------------
+---
+---------------
+;SwitchToRealProc procedure follows.
+;ALSO THIS PROCEDURE IS EXECUTED BY APs TRANSITIONING TO 16 BIT
MODE.
+HENCE THIS PROC ;IS IN MACHINE CODE.
+; SwitchToRealProc (UINTN BufferStart, UINT16 Code16, UINT16
+Code32, UINTN StackStart) ; rcx - Buffer Start ; rdx - Code16
+Selector Offset ; r8 - Code32 Selector Offset ; r9 - Stack Start
+;-------------------------------------------------------------------
+---
+---------------
+global ASM_PFX(SwitchToRealProc)
+ASM_PFX(SwitchToRealProc):
+SwitchToRealProcStart:
+BITS 64
+ cli
+
+ ;
+ ; Get RDX reset value before changing stacks since the
+ ; new stack won't be able to accomodate a #VC exception.
+ ;
+ push rax
+ push rbx
+ push rcx
+ push rdx
+
+ mov rax, 1
+ cpuid
+ mov rsi, rax ; Save off the reset value for RDX
+
+ pop rdx
+ pop rcx
+ pop rbx
+ pop rax
+
+ ;
+ ; Establish stack below 1MB
+ ;
+ mov rsp, r9
+
+ ;
+ ; Push ultimate Reset Vector onto the stack
+ ;
+ mov rax, rcx
+ shr rax, 4
+ push word 0x0002 ; RFLAGS
+ push ax ; CS
+ push word 0x0000 ; RIP
+ push word 0x0000 ; For alignment, will be discarded
+
+ ;
+ ; Get address of "16-bit operand size" label
+ ;
+ lea rbx, [PM16Mode]
+
+ ;
+ ; Push addresses used to change to compatibility mode
+ ;
+ lea rax, [CompatMode]
+ push r8
+ push rax
+
+ ;
+ ; Clear R8 - R15, for reset, before going into 32-bit mode
+ ;
+ xor r8, r8
+ xor r9, r9
+ xor r10, r10
+ xor r11, r11
+ xor r12, r12
+ xor r13, r13
+ xor r14, r14
+ xor r15, r15
+
+ ;
+ ; Far return into 32-bit mode
+ ;
+o64 retf
+
+BITS 32
+CompatMode:
+ ;
+ ; Set up stack to prepare for exiting protected mode
+ ;
+ push edx ; Code16 CS
+ push ebx ; PM16Mode label address
+
+ ;
+ ; Disable paging
+ ;
+ mov eax, cr0 ; Read CR0
+ btr eax, 31 ; Set PG=0
+ mov cr0, eax ; Write CR0
+
+ ;
+ ; Disable long mode
+ ;
+ mov ecx, 0c0000080h ; EFER MSR number
+ rdmsr ; Read EFER
+ btr eax, 8 ; Set LME=0
+ wrmsr ; Write EFER
+
+ ;
+ ; Disable PAE
+ ;
+ mov eax, cr4 ; Read CR4
+ btr eax, 5 ; Set PAE=0
+ mov cr4, eax ; Write CR4
+
+ mov edx, esi ; Restore RDX reset value
+
+ ;
+ ; Switch to 16-bit operand size
+ ;
+ retf
+
+BITS 16
+ ;
+ ; At entry to this label
+ ; - RDX will have its reset value
+ ; - On the top of the stack
+ ; - Alignment data (two bytes) to be discarded
+ ; - IP for Real Mode (two bytes)
+ ; - CS for Real Mode (two bytes)
+ ;
+PM16Mode:
+ mov eax, cr0 ; Read CR0
+ btr eax, 0 ; Set PE=0
+ mov cr0, eax ; Write CR0
+
+ pop ax ; Discard alignment data
+
+ ;
+ ; Clear registers (except RDX and RSP) before going into 16-bit mode
+ ;
+ xor eax, eax
+ xor ebx, ebx
+ xor ecx, ecx
+ xor esi, esi
+ xor edi, edi
+ xor ebp, ebp
+
+ iret
+
+SwitchToRealProcEnd:
+

;--------------------------------------------------------------------
----------------- ; AsmRelocateApLoop (MwaitSupport,
ApTargetCState, PmCodeSegment, TopOfApStack, CountTofinish);

;--------------------------------------------------------------------
-----------------
global ASM_PFX(AsmRelocateApLoop)
ASM_PFX(AsmRelocateApLoop):
AsmRelocateApLoopStart:
+BITS 64
cli ; Disable interrupt before switching to 32-bit mode
mov rax, [rsp + 40] ; CountTofinish
lock dec dword [rax] ; (*CountTofinish)--
@@ -324,6 +558,11 @@ ASM_PFX(AsmGetAddressMap):
mov qword [rcx + 18h], rax
mov qword [rcx + 20h], AsmRelocateApLoopEnd -
AsmRelocateApLoopStart
mov qword [rcx + 28h], Flat32Start - RendezvousFunnelProcStart
+ mov qword [rcx + 30h], SwitchToRealProcEnd -
SwitchToRealProcStart ; SwitchToRealSize
+ mov qword [rcx + 38h], SwitchToRealProcStart -
RendezvousFunnelProcStart ; SwitchToRealOffset
+ mov qword [rcx + 40h], SwitchToRealProcStart -
Flat32Start ;
SwitchToRealNoNxOffset
+ mov qword [rcx + 48h], PM16Mode -
RendezvousFunnelProcStart ; SwitchToRealPM16ModeOffset
+ mov qword [rcx + 50h], SwitchToRealProcEnd -
PM16Mode ;
SwitchToRealPM16ModeSize
ret


;--------------------------------------------------------------------
-----------------
--
2.17.1

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