[Qemu-devel] [PATCH] target-i386: Only provide CMOV and friends if feature bit set

[Peter Maydell]

The instructions CMOVcc, FCMOVcc and F[U]COMI[P] should only be
present if the CMOV feature bit is set. Add missing feature bit
checks so we correctly fault if emulating a 486 or 586.
This fixes bug LP:1201446.

Signed-off-by: Peter Maydell <address@hidden>
---
 target-i386/translate.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/target-i386/translate.c b/target-i386/translate.c
index 6550c27..f75e3b1 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -6434,12 +6434,18 @@ static target_ulong disas_insn(CPUX86State *env, 
DisasContext *s,
                 }
                 break;
             case 0x1d: /* fucomi */
+                if (!(s->cpuid_features & CPUID_CMOV)) {
+                    goto illegal_op;
+                }
                 gen_update_cc_op(s);
                 gen_helper_fmov_FT0_STN(cpu_env, tcg_const_i32(opreg));
                 gen_helper_fucomi_ST0_FT0(cpu_env);
                 set_cc_op(s, CC_OP_EFLAGS);
                 break;
             case 0x1e: /* fcomi */
+                if (!(s->cpuid_features & CPUID_CMOV)) {
+                    goto illegal_op;
+                }
                 gen_update_cc_op(s);
                 gen_helper_fmov_FT0_STN(cpu_env, tcg_const_i32(opreg));
                 gen_helper_fcomi_ST0_FT0(cpu_env);
@@ -6495,6 +6501,9 @@ static target_ulong disas_insn(CPUX86State *env, 
DisasContext *s,
                 }
                 break;
             case 0x3d: /* fucomip */
+                if (!(s->cpuid_features & CPUID_CMOV)) {
+                    goto illegal_op;
+                }
                 gen_update_cc_op(s);
                 gen_helper_fmov_FT0_STN(cpu_env, tcg_const_i32(opreg));
                 gen_helper_fucomi_ST0_FT0(cpu_env);
@@ -6502,6 +6511,9 @@ static target_ulong disas_insn(CPUX86State *env, 
DisasContext *s,
                 set_cc_op(s, CC_OP_EFLAGS);
                 break;
             case 0x3e: /* fcomip */
+                if (!(s->cpuid_features & CPUID_CMOV)) {
+                    goto illegal_op;
+                }
                 gen_update_cc_op(s);
                 gen_helper_fmov_FT0_STN(cpu_env, tcg_const_i32(opreg));
                 gen_helper_fcomi_ST0_FT0(cpu_env);
@@ -6518,6 +6530,10 @@ static target_ulong disas_insn(CPUX86State *env, 
DisasContext *s,
                         (JCC_BE << 1),
                         (JCC_P << 1),
                     };
+
+                    if (!(s->cpuid_features & CPUID_CMOV)) {
+                        goto illegal_op;
+                    }
                     op1 = fcmov_cc[op & 3] | (((op >> 3) & 1) ^ 1);
                     l1 = gen_new_label();
                     gen_jcc1_noeob(s, op1, l1);
@@ -6889,6 +6905,9 @@ static target_ulong disas_insn(CPUX86State *env, 
DisasContext *s,
         gen_ldst_modrm(env, s, modrm, OT_BYTE, OR_TMP0, 1);
         break;
     case 0x140 ... 0x14f: /* cmov Gv, Ev */
+        if (!(s->cpuid_features & CPUID_CMOV)) {
+            goto illegal_op;
+        }
         ot = dflag + OT_WORD;
         modrm = cpu_ldub_code(env, s->pc++);
         reg = ((modrm >> 3) & 7) | rex_r;
-- 
1.7.9.5