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>

1 files changed, 17 insertions, 14 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d25cfc238b90..c3d071dfe504 100644
--- 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;