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

[Richard Henderson <rth@twiddle.net>]

On 07/25/2013 06:54 AM, Peter Maydell wrote:
> Ping!
> 
> (patchwork url: http://patchwork.ozlabs.org/patch/259148/)

Reviewed-by: Richard Henderson <rth@twiddle.net>


r~

> 
> thanks
> -- PMM
> 
> On 15 July 2013 18:21, Peter Maydell <peter.maydell@linaro.org> wrote:
>> 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 <peter.maydell@linaro.org>
>> ---
>>  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
>>
>>