Re: [PATCH v2 05/10] accel/tcg: Handle -singlestep in curr_cflags

[Richard Henderson]

On 7/17/21 10:42 AM, Alex Bennée wrote:
> Richard Henderson <richard.henderson@linaro.org> writes:
>
> > Exchange the test in translator_use_goto_tb for CF_NO_GOTO_TB,
> > and the test in tb_gen_code for setting CF_COUNT_MASK to 1.
> >
> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> > ---
> >   accel/tcg/cpu-exec.c      | 8 +++++++-
> >   accel/tcg/translate-all.c | 2 +-
> >   accel/tcg/translator.c    | 2 +-
> >   3 files changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> > index 70ea3c7d68..2206c463f5 100644
> > --- a/accel/tcg/cpu-exec.c
> > +++ b/accel/tcg/cpu-exec.c
> > @@ -149,7 +149,13 @@ uint32_t curr_cflags(CPUState *cpu)
> >   {
> >       uint32_t cflags = cpu->tcg_cflags;
> >   
> > -    if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
> > +    /*
> > +     * For singlestep and -d nochain, suppress goto_tb so that
> > +     * we can log -d cpu,exec after every TB.
> > +     */
> > +    if (singlestep) {
>
> Hmm we are testing a magic global here and looking at
> cpu->singlestep_enabled lower down. We have a transient singlestep which
> is turned on an off via cpu->singlestep_enabled and a global as a debug
> option. Can we rationalise it further?

Not sure what you're asking.

cpu->singlestep_enabled raises a debug exception after one insn, whereas singlestep merely 
exits the tb after one insn.

What is it that you want me to rationalize?


r~