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From: Leo Duran <leo.duran@amd.com>
To: <edk2-devel@ml01.01.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>,
	Michael D Kinney <michael.d.kinney@intel.com>,
	Liming Gao <liming.gao@intel.com>, Leo Duran <leo.duran@amd.com>
Subject: [PATCH] MdePkg: BaseIoLibIntrinsic (IoLib class) library
Date: Mon, 20 Mar 2017 11:39:10 -0500	[thread overview]
Message-ID: <1490027950-8739-2-git-send-email-leo.duran@amd.com> (raw)
In-Reply-To: <1490027950-8739-1-git-send-email-leo.duran@amd.com>

From: Brijesh Singh <brijesh.singh@amd.com>

This patch unrolls REP INSx/OUTSx on IoRead/WriteFifo#() routines
when the SEV feature is enabled under a hypervisor environment.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Leo Duran  <leo.duran@amd.com>
---
 MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.asm  | 180 +++++++++++++++++++--
 MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.nasm | 180 +++++++++++++++++++--
 MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.asm   | 179 ++++++++++++++++++--
 MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.nasm  | 180 +++++++++++++++++++--
 4 files changed, 671 insertions(+), 48 deletions(-)

diff --git a/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.asm b/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.asm
index da767d1..d81871c 100644
--- a/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.asm
+++ b/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.asm
@@ -18,6 +18,60 @@
     .code
 
 ;------------------------------------------------------------------------------
+; Check whether we need to unroll the String I/O under SEV guest
+;
+; Return // eax   (1 - unroll, 0 - no unroll)
+;------------------------------------------------------------------------------
+SevNoRepIo PROC
+
+  ; CPUID clobbers ebx, ecx and edx
+  push      ebx
+  push      ecx
+  push      edx
+
+  ; Check if we are running 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       edx
+  pop       ecx
+  pop       ebx
+  ret
+SevNoRepIo ENDP
+
+;------------------------------------------------------------------------------
 ;  VOID
 ;  EFIAPI
 ;  IoReadFifo8 (
@@ -28,11 +82,28 @@
 ;------------------------------------------------------------------------------
 IoReadFifo8 PROC
     push    edi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     edi, [esp + 16]
-rep insb
+
+    call    SevNoRepIo            ; Check if we need to unroll the rep
+    test    eax, eax
+    jnz     @IoReadFifo8_NoRep
+
+    cld
+    rep     insb
+    jmp     @IoReadFifo8_Done
+
+@IoReadFifo8_NoRep:
+    jecxz   @IoReadFifo8_Done
+
+@IoReadFifo8_Loop:
+    in      al, dx
+    mov     byte [edi], al
+    inc     edi
+    loop    @IoReadFifo8_Loop
+
+@IoReadFifo8_Done:
     pop     edi
     ret
 IoReadFifo8 ENDP
@@ -48,11 +119,28 @@ IoReadFifo8 ENDP
 ;------------------------------------------------------------------------------
 IoReadFifo16 PROC
     push    edi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     edi, [esp + 16]
-rep insw
+
+    call    SevNoRepIo            ; Check if we need to unroll the rep
+    test    eax, eax
+    jnz     @IoReadFifo16_NoRep
+
+    cld
+    rep     insw
+    jmp     @IoReadFifo16_Done
+
+@IoReadFifo16_NoRep:
+    jecxz   @IoReadFifo16_Done
+
+@IoReadFifo16_Loop:
+    in      ax, dx
+    mov     word [edi], ax
+    add     edi, 2
+    loop    @IoReadFifo16_Loop
+
+@IoReadFifo16_Done:
     pop     edi
     ret
 IoReadFifo16 ENDP
@@ -68,11 +156,28 @@ IoReadFifo16 ENDP
 ;------------------------------------------------------------------------------
 IoReadFifo32 PROC
     push    edi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     edi, [esp + 16]
-rep insd
+
+    call    SevNoRepIo            ; Check if we need to unroll the rep
+    test    eax, eax
+    jnz     @IoReadFifo32_NoRep
+
+    cld
+    rep     insd
+    jmp     @IoReadFifo32_Done
+
+@IoReadFifo32_NoRep:
+    jecxz   @IoReadFifo32_Done
+
+@IoReadFifo32_Loop:
+    in      eax, dx
+    mov     dword [edi], eax
+    add     edi, 4
+    loop    @IoReadFifo32_Loop
+
+@IoReadFifo32_Done:
     pop     edi
     ret
 IoReadFifo32 ENDP
@@ -88,11 +193,28 @@ IoReadFifo32 ENDP
 ;------------------------------------------------------------------------------
 IoWriteFifo8 PROC
     push    esi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     esi, [esp + 16]
-rep outsb
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo8_NoRep
+
+    cld
+    rep     outsb
+    jmp     @IoWriteFifo8_Done
+
+@IoWriteFifo8_NoRep:
+    jecxz   @IoWriteFifo8_Done
+
+@IoWriteFifo8_Loop:
+    mov     byte [esi], al
+    out     dx, al
+    inc     esi
+    loop    @IoWriteFifo8_Loop
+
+@IoWriteFifo8_Done:
     pop     esi
     ret
 IoWriteFifo8 ENDP
@@ -108,11 +230,28 @@ IoWriteFifo8 ENDP
 ;------------------------------------------------------------------------------
 IoWriteFifo16 PROC
     push    esi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     esi, [esp + 16]
-rep outsw
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo16_NoRep
+
+    cld
+    rep     outsw
+    jmp     @IoWriteFifo16_Done
+
+@IoWriteFifo16_NoRep:
+    jecxz   @IoWriteFifo16_Done
+
+@IoWriteFifo16_Loop:
+    mov     word [esi], ax
+    out     dx, ax
+    add     esi, 2
+    loop    @IoWriteFifo16_Loop
+
+@IoWriteFifo16_Done:
     pop     esi
     ret
 IoWriteFifo16 ENDP
@@ -128,11 +267,28 @@ IoWriteFifo16 ENDP
 ;------------------------------------------------------------------------------
 IoWriteFifo32 PROC
     push    esi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     esi, [esp + 16]
-rep outsd
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo32_NoRep
+
+    cld
+    rep     outsd
+    jmp     @IoWriteFifo32_Done
+
+@IoWriteFifo32_NoRep:
+    jecxz   @IoWriteFifo32_Done
+
+@IoWriteFifo32_Loop:
+    mov     dword [esi], eax
+    out     dx, eax
+    add     esi, 4
+    loop    @IoWriteFifo32_Loop
+
+@IoWriteFifo32_Done:
     pop     esi
     ret
 IoWriteFifo32 ENDP
diff --git a/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.nasm b/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.nasm
index bcaa743..9adb972 100644
--- a/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.nasm
+++ b/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifo.nasm
@@ -16,6 +16,60 @@
     SECTION .text
 
 ;------------------------------------------------------------------------------
+; Check whether we need to unroll the String I/O under SEV guest
+;
+; Return // eax   (1 - unroll, 0 - no unroll)
+;------------------------------------------------------------------------------
+global ASM_PFX(SevNoRepIo)
+ASM_PFX(SevNoRepIo):
+
+  ; CPUID clobbers ebx, ecx and edx
+  push      ebx
+  push      ecx
+  push      edx
+
+  ; Check if we are running 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       edx
+  pop       ecx
+  pop       ebx
+  ret
+
+;------------------------------------------------------------------------------
 ;  VOID
 ;  EFIAPI
 ;  IoReadFifo8 (
@@ -27,11 +81,28 @@
 global ASM_PFX(IoReadFifo8)
 ASM_PFX(IoReadFifo8):
     push    edi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     edi, [esp + 16]
-rep insb
+
+    call    SevNoRepIo            ; Check if we need to unroll the rep
+    test    eax, eax
+    jnz     @IoReadFifo8_NoRep
+
+    cld
+    rep     insb
+    jmp     @IoReadFifo8_Done
+
+@IoReadFifo8_NoRep:
+    jecxz   @IoReadFifo8_Done
+
+@IoReadFifo8_Loop:
+    in      al, dx
+    mov     byte [edi], al
+    inc     edi
+    loop    @IoReadFifo8_Loop
+
+@IoReadFifo8_Done:
     pop     edi
     ret
 
@@ -47,11 +118,28 @@ rep insb
 global ASM_PFX(IoReadFifo16)
 ASM_PFX(IoReadFifo16):
     push    edi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     edi, [esp + 16]
-rep insw
+
+    call    SevNoRepIo            ; Check if we need to unroll the rep
+    test    eax, eax
+    jnz     @IoReadFifo16_NoRep
+
+    cld
+    rep     insw
+    jmp     @IoReadFifo16_Done
+
+@IoReadFifo16_NoRep:
+    jecxz   @IoReadFifo16_Done
+
+@IoReadFifo16_Loop:
+    in      ax, dx
+    mov     word [edi], ax
+    add     edi, 2
+    loop    @IoReadFifo16_Loop
+
+@IoReadFifo16_Done:
     pop     edi
     ret
 
@@ -67,11 +155,28 @@ rep insw
 global ASM_PFX(IoReadFifo32)
 ASM_PFX(IoReadFifo32):
     push    edi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     edi, [esp + 16]
-rep insd
+
+    call    SevNoRepIo            ; Check if we need to unroll the rep
+    test    eax, eax
+    jnz     @IoReadFifo32_NoRep
+
+    cld
+    rep     insd
+    jmp     @IoReadFifo32_Done
+
+@IoReadFifo32_NoRep:
+    jecxz   @IoReadFifo32_Done
+
+@IoReadFifo32_Loop:
+    in      eax, dx
+    mov     dword [edi], eax
+    add     edi, 4
+    loop    @IoReadFifo32_Loop
+
+@IoReadFifo32_Done:
     pop     edi
     ret
 
@@ -87,11 +192,28 @@ rep insd
 global ASM_PFX(IoWriteFifo8)
 ASM_PFX(IoWriteFifo8):
     push    esi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     esi, [esp + 16]
-rep outsb
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo8_NoRep
+
+    cld
+    rep     outsb
+    jmp     @IoWriteFifo8_Done
+
+@IoWriteFifo8_NoRep:
+    jecxz   @IoWriteFifo8_Done
+
+@IoWriteFifo8_Loop:
+    mov     byte [esi], al
+    out     dx, al
+    inc     esi
+    loop    @IoWriteFifo8_Loop
+
+@IoWriteFifo8_Done:
     pop     esi
     ret
 
@@ -107,11 +229,28 @@ rep outsb
 global ASM_PFX(IoWriteFifo16)
 ASM_PFX(IoWriteFifo16):
     push    esi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     esi, [esp + 16]
-rep outsw
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo16_NoRep
+
+    cld
+    rep     outsw
+    jmp     @IoWriteFifo16_Done
+
+@IoWriteFifo16_NoRep:
+    jecxz   @IoWriteFifo16_Done
+
+@IoWriteFifo16_Loop:
+    mov     word [esi], ax
+    out     dx, ax
+    add     esi, 2
+    loop    @IoWriteFifo16_Loop
+
+@IoWriteFifo16_Done:
     pop     esi
     ret
 
@@ -127,11 +266,28 @@ rep outsw
 global ASM_PFX(IoWriteFifo32)
 ASM_PFX(IoWriteFifo32):
     push    esi
-    cld
     mov     dx, [esp + 8]
     mov     ecx, [esp + 12]
     mov     esi, [esp + 16]
-rep outsd
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo32_NoRep
+
+    cld
+    rep     outsd
+    jmp     @IoWriteFifo32_Done
+
+@IoWriteFifo32_NoRep:
+    jecxz   @IoWriteFifo32_Done
+
+@IoWriteFifo32_Loop:
+    mov     dword [esi], eax
+    out     dx, eax
+    add     esi, 4
+    loop    @IoWriteFifo32_Loop
+
+@IoWriteFifo32_Done:
     pop     esi
     ret
 
diff --git a/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.asm b/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.asm
index 87c6107..fe9e171 100644
--- a/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.asm
+++ b/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.asm
@@ -16,6 +16,59 @@
     .code
 
 ;------------------------------------------------------------------------------
+; Check whether we need to unroll the String I/O in SEV guest
+;
+; Return // eax   (1 - unroll, 0 - no unroll)
+;------------------------------------------------------------------------------
+SevNoRepIo PROC
+  ; 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
+SevNoRepIo  ENDP
+
+;------------------------------------------------------------------------------
 ;  VOID
 ;  EFIAPI
 ;  IoReadFifo8 (
@@ -25,10 +78,27 @@
 ;    );
 ;------------------------------------------------------------------------------
 IoReadFifo8 PROC
-    cld
     xchg    rcx, rdx
     xchg    rdi, r8             ; rdi: buffer address; r8: save rdi
-rep insb
+
+    call    SevNoRepIo          ; Check if we need to unroll String I/O
+    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
 IoReadFifo8 ENDP
@@ -43,10 +113,27 @@ IoReadFifo8 ENDP
 ;    );
 ;------------------------------------------------------------------------------
 IoReadFifo16 PROC
-    cld
     xchg    rcx, rdx
     xchg    rdi, r8             ; rdi: buffer address; r8: save rdi
-rep insw
+
+    call    SevNoRepIo          ; Check if we need to unroll String I/O
+    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
 IoReadFifo16 ENDP
@@ -61,10 +148,27 @@ IoReadFifo16 ENDP
 ;    );
 ;------------------------------------------------------------------------------
 IoReadFifo32 PROC
-    cld
     xchg    rcx, rdx
     xchg    rdi, r8             ; rdi: buffer address; r8: save rdi
-rep insd
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    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
 IoReadFifo32 ENDP
@@ -79,10 +183,27 @@ IoReadFifo32 ENDP
 ;    );
 ;------------------------------------------------------------------------------
 IoWriteFifo8 PROC
-    cld
     xchg    rcx, rdx
     xchg    rsi, r8             ; rsi: buffer address; r8: save rsi
-rep outsb
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo8_NoRep
+
+    cld
+    rep     outsb
+    jmp     @IoWriteFifo8_Done
+
+@IoWriteFifo8_NoRep:
+    jrcxz   @IoWriteFifo8_Done
+
+@IoWriteFifo8_Loop:
+    mov     byte [rsi], al
+    out     dx, al
+    inc     rsi
+    loop    @IoWriteFifo8_Loop
+
+@IoWriteFifo8_Done:
     mov     rsi, r8             ; restore rsi
     ret
 IoWriteFifo8 ENDP
@@ -97,10 +218,27 @@ IoWriteFifo8 ENDP
 ;    );
 ;------------------------------------------------------------------------------
 IoWriteFifo16 PROC
-    cld
     xchg    rcx, rdx
     xchg    rsi, r8             ; rsi: buffer address; r8: save rsi
-rep outsw
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo16_NoRep
+
+    cld
+    rep     outsw
+    jmp     @IoWriteFifo16_Done
+
+@IoWriteFifo16_NoRep:
+    jrcxz   @IoWriteFifo16_Done
+
+@IoWriteFifo16_Loop:
+    mov     word [rsi], ax
+    out     dx, ax
+    add     rsi, 2
+    loop    @IoWriteFifo16_Loop
+
+@IoWriteFifo16_Done:
     mov     rsi, r8             ; restore rsi
     ret
 IoWriteFifo16 ENDP
@@ -115,10 +253,27 @@ IoWriteFifo16 ENDP
 ;    );
 ;------------------------------------------------------------------------------
 IoWriteFifo32 PROC
-    cld
     xchg    rcx, rdx
     xchg    rsi, r8             ; rsi: buffer address; r8: save rsi
-rep outsd
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo32_NoRep
+
+    cld
+    rep     outsd
+    jmp     @IoWriteFifo32_Done
+
+@IoWriteFifo32_NoRep:
+    jrcxz   @IoWriteFifo32_Done
+
+@IoWriteFifo32_Loop:
+    mov     dword [rsi], eax
+    out     dx, eax
+    add     rsi, 4
+    loop    @IoWriteFifo32_Loop
+
+@IoWriteFifo32_Done:
     mov     rsi, r8             ; restore rsi
     ret
 IoWriteFifo32 ENDP
diff --git a/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.nasm b/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.nasm
index 7bd72d0..20e3e64 100644
--- a/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.nasm
+++ b/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifo.nasm
@@ -17,6 +17,60 @@
     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
 ;  IoReadFifo8 (
@@ -27,10 +81,27 @@
 ;------------------------------------------------------------------------------
 global ASM_PFX(IoReadFifo8)
 ASM_PFX(IoReadFifo8):
-    cld
     xchg    rcx, rdx
     xchg    rdi, r8             ; rdi: buffer address; r8: save rdi
-rep insb
+
+    call    SevNoRepIo          ; Check if we need to unroll String I/O
+    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
 
@@ -45,10 +116,27 @@ rep insb
 ;------------------------------------------------------------------------------
 global ASM_PFX(IoReadFifo16)
 ASM_PFX(IoReadFifo16):
-    cld
     xchg    rcx, rdx
     xchg    rdi, r8             ; rdi: buffer address; r8: save rdi
-rep insw
+
+    call    SevNoRepIo          ; Check if we need to unroll String I/O
+    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
 
@@ -63,10 +151,27 @@ rep insw
 ;------------------------------------------------------------------------------
 global ASM_PFX(IoReadFifo32)
 ASM_PFX(IoReadFifo32):
-    cld
     xchg    rcx, rdx
     xchg    rdi, r8             ; rdi: buffer address; r8: save rdi
-rep insd
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    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
 
@@ -81,10 +186,27 @@ rep insd
 ;------------------------------------------------------------------------------
 global ASM_PFX(IoWriteFifo8)
 ASM_PFX(IoWriteFifo8):
-    cld
     xchg    rcx, rdx
     xchg    rsi, r8             ; rsi: buffer address; r8: save rsi
-rep outsb
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo8_NoRep
+
+    cld
+    rep     outsb
+    jmp     @IoWriteFifo8_Done
+
+@IoWriteFifo8_NoRep:
+    jrcxz   @IoWriteFifo8_Done
+
+@IoWriteFifo8_Loop:
+    mov     byte [rsi], al
+    out     dx, al
+    inc     rsi
+    loop    @IoWriteFifo8_Loop
+
+@IoWriteFifo8_Done:
     mov     rsi, r8             ; restore rsi
     ret
 
@@ -99,10 +221,27 @@ rep outsb
 ;------------------------------------------------------------------------------
 global ASM_PFX(IoWriteFifo16)
 ASM_PFX(IoWriteFifo16):
-    cld
     xchg    rcx, rdx
     xchg    rsi, r8             ; rsi: buffer address; r8: save rsi
-rep outsw
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo16_NoRep
+
+    cld
+    rep     outsw
+    jmp     @IoWriteFifo16_Done
+
+@IoWriteFifo16_NoRep:
+    jrcxz   @IoWriteFifo16_Done
+
+@IoWriteFifo16_Loop:
+    mov     word [rsi], ax
+    out     dx, ax
+    add     rsi, 2
+    loop    @IoWriteFifo16_Loop
+
+@IoWriteFifo16_Done:
     mov     rsi, r8             ; restore rsi
     ret
 
@@ -117,10 +256,27 @@ rep outsw
 ;------------------------------------------------------------------------------
 global ASM_PFX(IoWriteFifo32)
 ASM_PFX(IoWriteFifo32):
-    cld
     xchg    rcx, rdx
     xchg    rsi, r8             ; rsi: buffer address; r8: save rsi
-rep outsd
+
+    call    SevNoRepIo     	; Check if we need to unroll String I/O
+    test    eax, eax
+    jnz     @IoWriteFifo32_NoRep
+
+    cld
+    rep     outsd
+    jmp     @IoWriteFifo32_Done
+
+@IoWriteFifo32_NoRep:
+    jrcxz   @IoWriteFifo32_Done
+
+@IoWriteFifo32_Loop:
+    mov     dword [rsi], eax
+    out     dx, eax
+    add     rsi, 4
+    loop    @IoWriteFifo32_Loop
+
+@IoWriteFifo32_Done:
     mov     rsi, r8             ; restore rsi
     ret
 
-- 
2.7.4



      reply	other threads:[~2017-03-20 16:39 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-20 16:39 [PATCH] MdePkg: BaseIoLibIntrinsic (IoLib class) library Leo Duran
2017-03-20 16:39 ` Leo Duran [this message]

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