Re: [RFC PATCH 30/34] accel/tcg: Make tcg-all.c target indpendent

[Philippe Mathieu-Daudé]

Hi Anton,

On 19/1/24 15:40, Anton Johansson wrote:
> Uses target_supports_mttcg() and target_long_bits() to turn ifdefs into
> runtime branches.
>
> Signed-off-by: Anton Johansson <anjo@rev.ng>
> ---
>   accel/tcg/tcg-all.c | 25 +++++++++----------------
>   1 file changed, 9 insertions(+), 16 deletions(-)


>   static void tcg_accel_instance_init(Object *obj)
> @@ -137,17 +129,18 @@ static char *tcg_get_thread(Object *obj, Error **errp)
>   static void tcg_set_thread(Object *obj, const char *value, Error **errp)
>   {
>       TCGState *s = TCG_STATE(obj);
> +    const bool oversized_guest = target_long_bits() > TCG_TARGET_REG_BITS;
>   
>       if (strcmp(value, "multi") == 0) {
> -        if (TCG_OVERSIZED_GUEST) {
> +        if (oversized_guest) {
>               error_setg(errp, "No MTTCG when guest word size > hosts");
>           } else if (icount_enabled()) {
>               error_setg(errp, "No MTTCG when icount is enabled");
>           } else {
> -#ifndef TARGET_SUPPORTS_MTTCG
> -            warn_report("Guest not yet converted to MTTCG - "
> -                        "you may get unexpected results");
> -#endif
> +            if (target_supports_mttcg()) {

I started smth similar but then realized this call has to be per target,
so put my work on hold. My plan is to have a single common tcg
accelerator framework, having target-specific code handled by vcpu
dispatchers. Is your plan to have each target link its own tcg?

> +                warn_report("Guest not yet converted to MTTCG - "
> +                            "you may get unexpected results");
> +            }
>               s->mttcg_enabled = true;
>           }
>       } else if (strcmp(value, "single") == 0) {