Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after 'msr daifclr'

[Richard Henderson]

On 06/14/2017 01:33 PM, Emilio G. Cota wrote:
> On Wed, Jun 14, 2017 at 12:48:21 -0700, Richard Henderson wrote:
> > Exit to cpu loop so we reevaluate cpu_arm_hw_interrupts.
> >
> > Cc: address@hidden
> > Cc: Peter Maydell <address@hidden>
> > Signed-off-by: Richard Henderson <address@hidden>
> > ---
> >   target/arm/translate-a64.c | 7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
> > index 860e279..e55547d 100644
> > --- a/target/arm/translate-a64.c
> > +++ b/target/arm/translate-a64.c
> > @@ -1422,7 +1422,9 @@ static void handle_msr_i(DisasContext *s, uint32_t insn,
> >           gen_helper_msr_i_pstate(cpu_env, tcg_op, tcg_imm);
> >           tcg_temp_free_i32(tcg_imm);
> >           tcg_temp_free_i32(tcg_op);
> > -        s->is_jmp = DISAS_UPDATE;
> > +        /* For DAIFClear, exit the cpu loop to re-evaluate pending IRQs.  */
> > +        gen_a64_set_pc_im(s->pc);
>
> For op != 0x1f we end up setting the pc twice (first here, then in
> the switch statement). It's still correct though.

No, that's why I switched to DISAS_JUMP.

> > +        s->is_jmp = (op == 0x1f ? DISAS_EXIT : DISAS_JUMP);
>
> Could do without the parens.

I think it's clearer.

> +        case DISAS_EXIT:
> +            gen_a64_set_pc_im(dc->pc);
> +            tcg_gen_exit_tb(0);
> +            break;

This gives translate-a64.c and translate.c different semantics for DISAS_EXIT. 
I considered that to be a bad thing.


r~