KVM: emulator: emulate SALC
This is an almost-undocumented instruction available in 32-bit mode.
I say "almost" undocumented because AMD documents it in their opcode
maps just to say that it is unavailable in 64-bit mode (sections
"A.2.1 One-Byte Opcodes" and "B.3 Invalid and Reassigned Instructions
in 64-Bit Mode").
It is roughly equivalent to "sbb %al, %al" except it does not
set the flags. Use fastop to emulate it, but do not use the opcode
directly because it would fail if the host is 64-bit!
Reported-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@vger.kernel.org # 3.9
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a06a550..8db0010 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -535,6 +535,9 @@
FOP_SETCC(setnle)
FOP_END;
+FOP_START(salc) "pushf; sbb %al, %al; popf \n\t" FOP_RET
+FOP_END;
+
#define __emulate_1op_rax_rdx(ctxt, _op, _suffix, _ex) \
do { \
unsigned long _tmp; \
@@ -3961,7 +3964,8 @@
G(Src2One | ByteOp, group2), G(Src2One, group2),
G(Src2CL | ByteOp, group2), G(Src2CL, group2),
I(DstAcc | SrcImmUByte | No64, em_aam),
- I(DstAcc | SrcImmUByte | No64, em_aad), N,
+ I(DstAcc | SrcImmUByte | No64, em_aad),
+ F(DstAcc | ByteOp | No64, em_salc),
I(DstAcc | SrcXLat | ByteOp, em_mov),
/* 0xD8 - 0xDF */
N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N,