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;------------------------------------------------------------------------------
;
; Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
; Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
;
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
;------------------------------------------------------------------------------
DEFAULT REL
SECTION .text
;------------------------------------------------------------------------------
; Check whether we need to unroll the String I/O in SEV guest
;
; Return // eax (1 - unroll, 0 - no unroll)
;------------------------------------------------------------------------------
global ASM_PFX(SevNoRepIo)
ASM_PFX(SevNoRepIo):
; CPUID clobbers ebx, ecx and edx
push rbx
push rcx
push rdx
; Check if we are runing under hypervisor
; CPUID(1).ECX Bit 31
mov eax, 1
cpuid
bt ecx, 31
jnc @UseRepIo
; Check if we have Memory encryption CPUID leaf
mov eax, 0x80000000
cpuid
cmp eax, 0x8000001f
jl @UseRepIo
; Check for memory encryption feature:
; CPUID Fn8000_001F[EAX] - Bit 1
;
mov eax, 0x8000001f
cpuid
bt eax, 1
jnc @UseRepIo
; Check if memory encryption is enabled
; MSR_0xC0010131 - Bit 0 (SEV enabled)
; MSR_0xC0010131 - Bit 1 (SEV-ES enabled)
mov ecx, 0xc0010131
rdmsr
; Check for (SevEsEnabled == 0 && SevEnabled == 1)
and eax, 3
cmp eax, 1
je @SevNoRepIo_Done
@UseRepIo:
xor eax, eax
@SevNoRepIo_Done:
pop rdx
pop rcx
pop rbx
ret
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; SevIoReadFifo8 (
; IN UINTN Port, // rcx
; IN UINTN Size, // rdx
; OUT VOID *Buffer // r8
; );
;------------------------------------------------------------------------------
global ASM_PFX(SevIoReadFifo8)
ASM_PFX(SevIoReadFifo8):
xchg rcx, rdx
xchg rdi, r8 ; rdi: buffer address; r8: save rdi
; Check if we need to unroll String I/O
call ASM_PFX(SevNoRepIo)
test eax, eax
jnz @IoReadFifo8_NoRep
cld
rep insb
jmp @IoReadFifo8_Done
@IoReadFifo8_NoRep:
jrcxz @IoReadFifo8_Done
@IoReadFifo8_Loop:
in al, dx
mov byte [rdi], al
inc rdi
loop @IoReadFifo8_Loop
@IoReadFifo8_Done:
mov rdi, r8 ; restore rdi
ret
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; SevIoReadFifo16 (
; IN UINTN Port, // rcx
; IN UINTN Size, // rdx
; OUT VOID *Buffer // r8
; );
;------------------------------------------------------------------------------
global ASM_PFX(SevIoReadFifo16)
ASM_PFX(SevIoReadFifo16):
xchg rcx, rdx
xchg rdi, r8 ; rdi: buffer address; r8: save rdi
; Check if we need to unroll String I/O
call ASM_PFX(SevNoRepIo)
test eax, eax
jnz @IoReadFifo16_NoRep
cld
rep insw
jmp @IoReadFifo16_Done
@IoReadFifo16_NoRep:
jrcxz @IoReadFifo16_Done
@IoReadFifo16_Loop:
in ax, dx
mov word [rdi], ax
add rdi, 2
loop @IoReadFifo16_Loop
@IoReadFifo16_Done:
mov rdi, r8 ; restore rdi
ret
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; SevIoReadFifo32 (
; IN UINTN Port, // rcx
; IN UINTN Size, // rdx
; OUT VOID *Buffer // r8
; );
;------------------------------------------------------------------------------
global ASM_PFX(SevIoReadFifo32)
ASM_PFX(SevIoReadFifo32):
xchg rcx, rdx
xchg rdi, r8 ; rdi: buffer address; r8: save rdi
; Check if we need to unroll String I/O
call ASM_PFX(SevNoRepIo)
test eax, eax
jnz @IoReadFifo32_NoRep
cld
rep insd
jmp @IoReadFifo32_Done
@IoReadFifo32_NoRep:
jrcxz @IoReadFifo32_Done
@IoReadFifo32_Loop:
in eax, dx
mov dword [rdi], eax
add rdi, 4
loop @IoReadFifo32_Loop
@IoReadFifo32_Done:
mov rdi, r8 ; restore rdi
ret
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; IoWriteFifo8 (
; IN UINTN Port, // rcx
; IN UINTN Size, // rdx
; IN VOID *Buffer // r8
; );
;------------------------------------------------------------------------------
global ASM_PFX(SevIoWriteFifo8)
ASM_PFX(SevIoWriteFifo8):
xchg rcx, rdx
xchg rsi, r8 ; rsi: buffer address; r8: save rsi
; Check if we need to unroll String I/O
call ASM_PFX(SevNoRepIo)
test eax, eax
jnz @IoWriteFifo8_NoRep
cld
rep outsb
jmp @IoWriteFifo8_Done
@IoWriteFifo8_NoRep:
jrcxz @IoWriteFifo8_Done
@IoWriteFifo8_Loop:
mov al, byte [rsi]
out dx, al
inc rsi
loop @IoWriteFifo8_Loop
@IoWriteFifo8_Done:
mov rsi, r8 ; restore rsi
ret
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; SevIoWriteFifo16 (
; IN UINTN Port, // rcx
; IN UINTN Size, // rdx
; IN VOID *Buffer // r8
; );
;------------------------------------------------------------------------------
global ASM_PFX(SevIoWriteFifo16)
ASM_PFX(SevIoWriteFifo16):
xchg rcx, rdx
xchg rsi, r8 ; rsi: buffer address; r8: save rsi
; Check if we need to unroll String I/O
call ASM_PFX(SevNoRepIo)
test eax, eax
jnz @IoWriteFifo16_NoRep
cld
rep outsw
jmp @IoWriteFifo16_Done
@IoWriteFifo16_NoRep:
jrcxz @IoWriteFifo16_Done
@IoWriteFifo16_Loop:
mov ax, word [rsi]
out dx, ax
add rsi, 2
loop @IoWriteFifo16_Loop
@IoWriteFifo16_Done:
mov rsi, r8 ; restore rsi
ret
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; SevIoWriteFifo32 (
; IN UINTN Port, // rcx
; IN UINTN Size, // rdx
; IN VOID *Buffer // r8
; );
;------------------------------------------------------------------------------
global ASM_PFX(SevIoWriteFifo32)
ASM_PFX(SevIoWriteFifo32):
xchg rcx, rdx
xchg rsi, r8 ; rsi: buffer address; r8: save rsi
; Check if we need to unroll String I/O
call ASM_PFX(SevNoRepIo)
test eax, eax
jnz @IoWriteFifo32_NoRep
cld
rep outsd
jmp @IoWriteFifo32_Done
@IoWriteFifo32_NoRep:
jrcxz @IoWriteFifo32_Done
@IoWriteFifo32_Loop:
mov eax, dword [rsi]
out dx, eax
add rsi, 4
loop @IoWriteFifo32_Loop
@IoWriteFifo32_Done:
mov rsi, r8 ; restore rsi
ret
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