KVM: x86 emulator: Remove byte-sized MOVSX/MOVZX hack

Currently we treat MOVSX/MOVZX with a byte source as a byte instruction,
and change the destination operand size with a hack.  Change it to be
a word instruction, so the destination receives its natural size, and
change the source to be SrcMem8.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 5da6b36192018cb717f75a0eb4ac2d19b5e31539..6eaedac7cf6aa9962298b9fc50c428718f941e28 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -860,8 +860,7 @@ static void write_sse_reg(struct x86_emulate_ctxt *ctxt, sse128_t *data,
 }
 
 static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
-                                   struct operand *op,
-                                   int inhibit_bytereg)
+                                   struct operand *op)
 {
        unsigned reg = ctxt->modrm_reg;
        int highbyte_regs = ctxt->rex_prefix == 0;
@@ -878,7 +877,7 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
        }
 
        op->type = OP_REG;
-       if ((ctxt->d & ByteOp) && !inhibit_bytereg) {
+       if (ctxt->d & ByteOp) {
                op->addr.reg = decode_register(reg, ctxt->regs, highbyte_regs);
                op->bytes = 1;
        } else {
@@ -3516,13 +3515,13 @@ static struct opcode twobyte_table[256] = {
        I(DstMem | SrcReg | ModRM | BitOp | Lock, em_btr),
        I(DstReg | SrcMemFAddr | ModRM | Src2FS, em_lseg),
        I(DstReg | SrcMemFAddr | ModRM | Src2GS, em_lseg),
-       D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
+       D(DstReg | SrcMem8 | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
        /* 0xB8 - 0xBF */
        N, N,
        G(BitOp, group8),
        I(DstMem | SrcReg | ModRM | BitOp | Lock | PageTable, em_btc),
        I(DstReg | SrcMem | ModRM, em_bsf), I(DstReg | SrcMem | ModRM, em_bsr),
-       D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
+       D(DstReg | SrcMem8 | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
        /* 0xC0 - 0xCF */
        D2bv(DstMem | SrcReg | ModRM | Lock),
        N, D(DstMem | SrcReg | ModRM | Mov),
@@ -3604,9 +3603,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
 
        switch (d) {
        case OpReg:
-               decode_register_operand(ctxt, op,
-                        op == &ctxt->dst &&
-                        ctxt->twobyte && (ctxt->b == 0xb6 || ctxt->b == 0xb7));
+               decode_register_operand(ctxt, op);
                break;
        case OpImmUByte:
                rc = decode_imm(ctxt, op, 1, false);