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>

1 files changed, 5 insertions, 8 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 5da6b3619201..6eaedac7cf6a 100644
--- 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);