diff options
Diffstat (limited to 'UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm')
| -rw-r--r-- | UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm index 7c2469f9c5..b2d95adf6d 100644 --- a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm +++ b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm @@ -346,3 +346,172 @@ PM16Mode: iret
SwitchToRealProcEnd:
+;-------------------------------------------------------------------------------------
+; AsmRelocateApLoopAmd (MwaitSupport, ApTargetCState, PmCodeSegment, TopOfApStack, CountTofinish, Pm16CodeSegment, SevEsAPJumpTable, WakeupBuffer);
+;-------------------------------------------------------------------------------------
+
+AsmRelocateApLoopStartAmd:
+BITS 64
+ cmp qword [rsp + 56], 0 ; SevEsAPJumpTable
+ je NoSevEsAmd
+
+ ;
+ ; 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
+
+NoSevEsAmd:
+ cli ; Disable interrupt before switching to 32-bit mode
+ mov rax, [rsp + 40] ; 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, [PmEntryAmd] ; 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
+ ;
+o64 retf
+
+BITS 32
+PmEntryAmd:
+ 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
+
+MwaitCheckAmd:
+ cmp cl, 1 ; Check mwait-monitor support
+ jnz HltLoopAmd
+ mov ebx, edx ; Save C-State to ebx
+MwaitLoopAmd:
+ cli
+ mov eax, esp ; Set Monitor Address
+ xor ecx, ecx ; ecx = 0
+ xor edx, edx ; edx = 0
+ monitor
+ mov eax, ebx ; Mwait Cx, Target C-State per eax[7:4]
+ shl eax, 4
+ mwait
+ jmp MwaitLoopAmd
+
+HltLoopAmd:
+ 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 DoHltAmd
+
+ 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
+
+DoHltAmd:
+ cli
+ hlt
+ jmp DoHltAmd
+
+BITS 64
+AsmRelocateApLoopEndAmd:
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