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UefiCpuPkg: Has APs in 64 bit long-mode before booting to OS.

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During the finalization of Mp initialization before booting into the OS,
 depending on whether Mwait is supported or not, AsmRelocateApLoop
 places Aps in MWAIT-loop or HLT-loop.

Since paging is necessary for long mode, the original implementation of
moving APs to 32-bit was to disable paging to ensure that the booting
does not crash.

The current modification creates a page table in reserved memory,
avoiding switching modes and reclaiming memory by OS. This modification
is only for 64 bit mode.

More specifically, we keep the AMD logic as the original code flow,
extract and update the Intel-related code, where the APs would stay
in 64-bit, and run in a Mwait or Hlt loop until the OS wake them up.

Signed-off-by: Ray Ni <ray.ni@intel.com>
Signed-off-by: Yuanhao Xie <yuanhao.xie@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
This commit is contained in:
Xie, Yuanhao
2022-12-20 05:40:15 +08:00
committed by mergify[bot]
parent 7bda8c6481
commit 73ccde8f6d
7 changed files with 184 additions and 200 deletions
Download Patch File Download Diff File Expand all files Collapse all files

171
UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
View File

@@ -279,120 +279,42 @@ CProcedureInvoke:
RendezvousFunnelProcEnd:
;-------------------------------------------------------------------------------------
; AsmRelocateApLoop (MwaitSupport, ApTargetCState, PmCodeSegment, TopOfApStack, CountTofinish, Pm16CodeSegment, SevEsAPJumpTable, WakeupBuffer);
; AsmRelocateApLoop (MwaitSupport, ApTargetCState, TopOfApStack, CountTofinish, Cr3);
; This function is called during the finalizaiton of Mp initialization before booting
; to OS, and aim to put Aps either in Mwait or HLT.
;-------------------------------------------------------------------------------------
; +----------------+
; | Cr3 | rsp+40
; +----------------+
; | CountTofinish | r9
; +----------------+
; | TopOfApStack | r8
; +----------------+
; | ApTargetCState | rdx
; +----------------+
; | MwaitSupport | rcx
; +----------------+
; | the return |
; +----------------+ low address
AsmRelocateApLoopStart:
BITS 64
cmp qword [rsp + 56], 0 ; SevEsAPJumpTable
je NoSevEs
;
; Perform some SEV-ES related setup before leaving 64-bit mode
;
push rcx
push rdx
;
; Get the RDX reset value using CPUID
;
mov rax, 1
cpuid
mov rsi, rax ; Save off the reset value for RDX
;
; Prepare the GHCB for the AP_HLT_LOOP VMGEXIT call
; - Must be done while in 64-bit long mode so that writes to
; the GHCB memory will be unencrypted.
; - No NAE events can be generated once this is set otherwise
; the AP_RESET_HOLD SW_EXITCODE will be overwritten.
;
mov rcx, 0xc0010130
rdmsr ; Retrieve current GHCB address
shl rdx, 32
or rdx, rax
mov rdi, rdx
xor rax, rax
mov rcx, 0x800
shr rcx, 3
rep stosq ; Clear the GHCB
mov rax, 0x80000004 ; VMGEXIT AP_RESET_HOLD
mov [rdx + 0x390], rax
mov rax, 114 ; Set SwExitCode valid bit
bts [rdx + 0x3f0], rax
inc rax ; Set SwExitInfo1 valid bit
bts [rdx + 0x3f0], rax
inc rax ; Set SwExitInfo2 valid bit
bts [rdx + 0x3f0], rax
pop rdx
pop rcx
NoSevEs:
cli ; Disable interrupt before switching to 32-bit mode
mov rax, [rsp + 40] ; CountTofinish
mov rax, r9 ; CountTofinish
lock dec dword [rax] ; (*CountTofinish)--
mov r10, [rsp + 48] ; Pm16CodeSegment
mov rax, [rsp + 56] ; SevEsAPJumpTable
mov rbx, [rsp + 64] ; WakeupBuffer
mov rsp, r9 ; TopOfApStack
push rax ; Save SevEsAPJumpTable
push rbx ; Save WakeupBuffer
push r10 ; Save Pm16CodeSegment
push rcx ; Save MwaitSupport
push rdx ; Save ApTargetCState
lea rax, [PmEntry] ; rax <- The start address of transition code
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
;
retfq
BITS 32
PmEntry:
mov eax, cr0
btr eax, 31 ; Clear CR0.PG
mov cr0, eax ; Disable paging and caches
mov ecx, 0xc0000080
rdmsr
and ah, ~ 1 ; Clear LME
wrmsr
mov eax, cr4
and al, ~ (1 << 5) ; Clear PAE
mov cr4, eax
pop edx
add esp, 4
pop ecx,
add esp, 4
mov rax, [rsp + 40] ; Cr3
; Do not push on old stack, since old stack is not mapped
; in the page table pointed by cr3
mov cr3, rax
mov rsp, r8 ; TopOfApStack
MwaitCheck:
cmp cl, 1 ; Check mwait-monitor support
jnz HltLoop
mov ebx, edx ; Save C-State to ebx
mov rbx, rdx ; Save C-State to ebx
MwaitLoop:
cli
mov eax, esp ; Set Monitor Address
mov rax, rsp ; Set Monitor Address
xor ecx, ecx ; ecx = 0
xor edx, edx ; edx = 0
monitor
@@ -402,49 +324,10 @@ MwaitLoop:
jmp MwaitLoop
HltLoop:
pop edx ; PM16CodeSegment
add esp, 4
pop ebx ; WakeupBuffer
add esp, 4
pop eax ; SevEsAPJumpTable
add esp, 4
cmp eax, 0 ; Check for SEV-ES
je DoHlt
cli
;
; SEV-ES is enabled, use VMGEXIT (GHCB information already
; set by caller)
;
BITS 64
rep vmmcall
BITS 32
;
; Back from VMGEXIT AP_HLT_LOOP
; Push the FLAGS/CS/IP values to use
;
push word 0x0002 ; EFLAGS
xor ecx, ecx
mov cx, [eax + 2] ; CS
push cx
mov cx, [eax] ; IP
push cx
push word 0x0000 ; For alignment, will be discarded
push edx
push ebx
mov edx, esi ; Restore RDX reset value
retf
DoHlt:
cli
hlt
jmp DoHlt
jmp HltLoop
BITS 64
AsmRelocateApLoopEnd:
;-------------------------------------------------------------------------------------