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authorLaszlo Ersek <lersek@redhat.com>2017-09-04 17:09:18 +0200
committerLaszlo Ersek <lersek@redhat.com>2017-09-11 22:28:05 +0200
commit98a4d04e8fda7c23c0cce1ac65597e8144bcb5b8 (patch)
tree4872c4780296664f3af756a921dd13e54e77115d /MdePkg/Library/BaseIoLibIntrinsic
parentaa9aa47e06ac0082948b880c226c8bdf2a12102b (diff)
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MdePkg/BaseIoLibIntrinsic: fix SEV (=unrolled) variants of IoWriteFifoXX()
In commit b6d11d7c4678 ("MdePkg: BaseIoLibIntrinsic (IoLib class) library", 2017-04-12), the MOV instructions in the write loops were probably copied from the read loops. However, the operand order was not adjusted. As a result, the IoWriteFifoXX() routines, when invoked in SEV guests, now overwrite the source buffer with value 0x01 / 0x0001 / 0x00000001 -- the SevNoRepIo() function returns value 1 in EAX, in SEV guests --, and write the same value to the target IO port. Fix this by putting the target operand (AL / AX / EAX) first, and the source operand (BYTE / WORD / DWORD [ESI/RSI]) second. Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Liming Gao <liming.gao@intel.com> Cc: Michael D Kinney <michael.d.kinney@intel.com> Fixes: b6d11d7c467810ea7f2e2eda46ef0bdc57bf1475 Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Liming Gao <liming.gao@intel.com> Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Diffstat (limited to 'MdePkg/Library/BaseIoLibIntrinsic')
-rw-r--r--MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifoSev.nasm6
-rw-r--r--MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifoSev.nasm6
2 files changed, 6 insertions, 6 deletions
diff --git a/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifoSev.nasm b/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifoSev.nasm
index 3e80c17d04..4b2af807cf 100644
--- a/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifoSev.nasm
+++ b/MdePkg/Library/BaseIoLibIntrinsic/Ia32/IoFifoSev.nasm
@@ -212,7 +212,7 @@ ASM_PFX(IoWriteFifo8):
jecxz @IoWriteFifo8_Done
@IoWriteFifo8_Loop:
- mov byte [esi], al
+ mov al, byte [esi]
out dx, al
inc esi
loop @IoWriteFifo8_Loop
@@ -250,7 +250,7 @@ ASM_PFX(IoWriteFifo16):
jecxz @IoWriteFifo16_Done
@IoWriteFifo16_Loop:
- mov word [esi], ax
+ mov ax, word [esi]
out dx, ax
add esi, 2
loop @IoWriteFifo16_Loop
@@ -288,7 +288,7 @@ ASM_PFX(IoWriteFifo32):
jecxz @IoWriteFifo32_Done
@IoWriteFifo32_Loop:
- mov dword [esi], eax
+ mov eax, dword [esi]
out dx, eax
add esi, 4
loop @IoWriteFifo32_Loop
diff --git a/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifoSev.nasm b/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifoSev.nasm
index 26e016625b..4d86a6cd53 100644
--- a/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifoSev.nasm
+++ b/MdePkg/Library/BaseIoLibIntrinsic/X64/IoFifoSev.nasm
@@ -205,7 +205,7 @@ ASM_PFX(IoWriteFifo8):
jrcxz @IoWriteFifo8_Done
@IoWriteFifo8_Loop:
- mov byte [rsi], al
+ mov al, byte [rsi]
out dx, al
inc rsi
loop @IoWriteFifo8_Loop
@@ -241,7 +241,7 @@ ASM_PFX(IoWriteFifo16):
jrcxz @IoWriteFifo16_Done
@IoWriteFifo16_Loop:
- mov word [rsi], ax
+ mov ax, word [rsi]
out dx, ax
add rsi, 2
loop @IoWriteFifo16_Loop
@@ -277,7 +277,7 @@ ASM_PFX(IoWriteFifo32):
jrcxz @IoWriteFifo32_Done
@IoWriteFifo32_Loop:
- mov dword [rsi], eax
+ mov eax, dword [rsi]
out dx, eax
add rsi, 4
loop @IoWriteFifo32_Loop