Re: [RFC PATCH] target/i386: terminate a tcg block on gen_RDMSR

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 10/29/26 12:17, Alex Bennée wrote:
>> End the block the same way that gen_WRMSR does so an IO access under
>> icount. While this fixes this particular case I suspect there are more
>> IO like accesses the x86 TCG front-end should take care off.
>> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/4779
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> ---
>>   target/i386/tcg/emit.c.inc | 1 +
>>   1 file changed, 1 insertion(+)
>> diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc
>> index ed56edf8a3a..911bce5f539 100644
>> --- a/target/i386/tcg/emit.c.inc
>> +++ b/target/i386/tcg/emit.c.inc
>> @@ -3783,6 +3783,7 @@ static void gen_RDMSR(DisasContext *s, X86DecodedInsn *decode)
>>       gen_update_cc_op(s);
>>       gen_update_eip_cur(s);
>>       gen_helper_rdmsr(tcg_env);
>> +    s->base.is_jmp = DISAS_EOB_NEXT;
>>   }
>>   #else
>>   #define gen_RDMSR gen_unreachable
>
> You've done nothing to update state.  I think you want
>
>     translator_io_start(&s->base);
>
> which will go though DISAS_TOO_MANY.

Should WRMSR do the same? If not why is it different?

>
>
> r~

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro