audk/OvmfPkg/Sec/X64/SecEntry.nasm

;------------------------------------------------------------------------------
;*
;*   Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
;*   SPDX-License-Identifier: BSD-2-Clause-Patent
;*
;*    CpuAsm.asm
;*
;*   Abstract:
;*
;------------------------------------------------------------------------------

#include <Base.h>
%include "TdxCommondefs.inc"

DEFAULT REL
SECTION .text

extern ASM_PFX(SecCoreStartupWithStack)

%macro  tdcall  0
  db  0x66, 0x0f, 0x01, 0xcc
%endmacro

;
; SecCore Entry Point
;
; Processor is in flat protected mode
;
; @param[in]  RAX   Initial value of the EAX register (BIST: Built-in Self Test)
; @param[in]  DI    'BP': boot-strap processor, or 'AP': application processor
; @param[in]  RBP   Pointer to the start of the Boot Firmware Volume
; @param[in]  DS    Selector allowing flat access to all addresses
; @param[in]  ES    Selector allowing flat access to all addresses
; @param[in]  FS    Selector allowing flat access to all addresses
; @param[in]  GS    Selector allowing flat access to all addresses
; @param[in]  SS    Selector allowing flat access to all addresses
;
; @return     None  This routine does not return
;
global ASM_PFX(_ModuleEntryPoint)
ASM_PFX(_ModuleEntryPoint):

    ;
    ; Guest type is stored in OVMF_WORK_AREA
    ;
    %define OVMF_WORK_AREA        FixedPcdGet32 (PcdOvmfWorkAreaBase)
    %define VM_GUEST_TYPE_TDX     2
    mov     eax, OVMF_WORK_AREA
    cmp     byte[eax], VM_GUEST_TYPE_TDX
    jne     InitStack

    mov     rax, TDCALL_TDINFO
    tdcall

    ;
    ; R8  [31:0]  NUM_VCPUS
    ;     [63:32] MAX_VCPUS
    ; R9  [31:0]  VCPU_INDEX
    ; Td Guest set the VCPU0 as the BSP, others are the APs
    ; APs jump to spinloop and get released by DXE's MpInitLib
    ;
    mov     rax, r9
    and     rax, 0xffff
    test    rax, rax
    jne     ParkAp

InitStack:

    ;
    ; Fill the temporary RAM with the initial stack value.
    ; The loop below will seed the heap as well, but that's harmless.
    ;
    mov     rax, (FixedPcdGet32 (PcdInitValueInTempStack) << 32) | FixedPcdGet32 (PcdInitValueInTempStack)
                                                              ; qword to store
    mov     rdi, FixedPcdGet32 (PcdOvmfSecPeiTempRamBase)     ; base address,
                                                              ;   relative to
                                                              ;   ES
    mov     rcx, FixedPcdGet32 (PcdOvmfSecPeiTempRamSize) / 8 ; qword count
    cld                                                       ; store from base
                                                              ;   up
    rep stosq

    ;
    ; Load temporary RAM stack based on PCDs
    ;
    %define SEC_TOP_OF_STACK (FixedPcdGet32 (PcdOvmfSecPeiTempRamBase) + \
                          FixedPcdGet32 (PcdOvmfSecPeiTempRamSize))
    mov     rsp, SEC_TOP_OF_STACK
    nop

    ;
    ; Setup parameters and call SecCoreStartupWithStack
    ;   rcx: BootFirmwareVolumePtr
    ;   rdx: TopOfCurrentStack
    ;
    mov     rcx, rbp
    mov     rdx, rsp
    sub     rsp, 0x20
    call    ASM_PFX(SecCoreStartupWithStack)

    ;
    ; Note: BSP never gets here. APs will be unblocked by DXE
    ;
    ; R8  [31:0]  NUM_VCPUS
    ;     [63:32] MAX_VCPUS
    ; R9  [31:0]  VCPU_INDEX
    ;
ParkAp:

    mov     rbp,  r9

.do_wait_loop:
    mov     rsp, FixedPcdGet32 (PcdOvmfSecGhcbBackupBase)

    ;
    ; register itself in [rsp + CpuArrivalOffset]
    ;
    mov       rax, 1
    lock xadd dword [rsp + CpuArrivalOffset], eax
    inc       eax

.check_arrival_cnt:
    cmp       eax, r8d
    je        .check_command
    mov       eax, dword[rsp + CpuArrivalOffset]
    jmp       .check_arrival_cnt

.check_command:
    mov     eax, dword[rsp + CommandOffset]
    cmp     eax, MpProtectedModeWakeupCommandNoop
    je      .check_command

    cmp     eax, MpProtectedModeWakeupCommandWakeup
    je      .do_wakeup

    ; Don't support this command, so ignore
    jmp     .check_command

.do_wakeup:
    ;
    ; BSP sets these variables before unblocking APs
    ;   RAX:  WakeupVectorOffset
    ;   RBX:  Relocated mailbox address
    ;   RBP:  vCpuId
    ;
    mov     rax, 0
    mov     eax, dword[rsp + WakeupVectorOffset]
    mov     rbx, [rsp + WakeupArgsRelocatedMailBox]
    nop
    jmp     rax
    jmp     $