KVM: x86 emulator: Use opcode::execute for XCHG(86/87)

In addition, replace one "goto xchg" with an em_xchg() call.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d25cfc2..c3d071d 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2613,6 +2613,20 @@ static int em_test(struct x86_emulate_ctxt *ctxt)
        return X86EMUL_CONTINUE;
 }
 
+static int em_xchg(struct x86_emulate_ctxt *ctxt)
+{
+       struct decode_cache *c = &ctxt->decode;
+
+       /* Write back the register source. */
+       c->src.val = c->dst.val;
+       write_register_operand(&c->src);
+
+       /* Write back the memory destination with implicit LOCK prefix. */
+       c->dst.val = c->src.orig_val;
+       c->lock_prefix = 1;
+       return X86EMUL_CONTINUE;
+}
+
 static int em_imul(struct x86_emulate_ctxt *ctxt)
 {
        struct decode_cache *c = &ctxt->decode;
@@ -3144,7 +3158,7 @@ static struct opcode opcode_table[256] = {
        G(ByteOp | DstMem | SrcImm | ModRM | No64 | Group, group1),
        G(DstMem | SrcImmByte | ModRM | Group, group1),
        I2bv(DstMem | SrcReg | ModRM, em_test),
-       D2bv(DstMem | SrcReg | ModRM | Lock),
+       I2bv(DstMem | SrcReg | ModRM | Lock, em_xchg),
        /* 0x88 - 0x8F */
        I2bv(DstMem | SrcReg | ModRM | Mov, em_mov),
        I2bv(DstReg | SrcMem | ModRM | Mov, em_mov),
@@ -3882,18 +3896,6 @@ special_insn:
                if (test_cc(c->b, ctxt->eflags))
                        jmp_rel(c, c->src.val);
                break;
-       case 0x86 ... 0x87:     /* xchg */
-       xchg:
-               /* Write back the register source. */
-               c->src.val = c->dst.val;
-               write_register_operand(&c->src);
-               /*
-                * Write back the memory destination with implicit LOCK
-                * prefix.
-                */
-               c->dst.val = c->src.orig_val;
-               c->lock_prefix = 1;
-               break;
        case 0x8c:  /* mov r/m, sreg */
                if (c->modrm_reg > VCPU_SREG_GS) {
                        rc = emulate_ud(ctxt);
@@ -3929,7 +3931,8 @@ special_insn:
        case 0x90 ... 0x97: /* nop / xchg reg, rax */
                if (c->dst.addr.reg == &c->regs[VCPU_REGS_RAX])
                        break;
-               goto xchg;
+               rc = em_xchg(ctxt);
+               break;
        case 0x98: /* cbw/cwde/cdqe */
                switch (c->op_bytes) {
                case 2: c->dst.val = (s8)c->dst.val; break;