Re: [PATCH v2 16/16] migration/vmstate-types: move to new migration APIs

[Peter Xu <peterx@redhat.com>]

On Sat, Feb 21, 2026 at 12:02:14AM +0300, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

Reviewed-by: Peter Xu <peterx@redhat.com>

Likewise.. one trivial thing to mention below..

[...]

>  /* 32 bit int. See that the received value is the same than the one
>     in the field */
>  
> -static int get_int32_equal(QEMUFile *f, void *pv, size_t size,
> -                           const VMStateField *field)
> +static bool load_int32_equal(QEMUFile *f, void *pv, size_t size,
> +                             const VMStateField *field, Error **errp)
>  {
> +    ERRP_GUARD();
>      int32_t *v = pv;
>      int32_t v2;
>      qemu_get_sbe32s(f, &v2);
>  
>      if (*v == v2) {
> -        return 0;
> +        return true;
>      }
> -    error_report("%" PRIx32 " != %" PRIx32, *v, v2);
> +
> +    error_setg(errp, "%" PRIx32 " != %" PRIx32, *v, v2);
>      if (field->err_hint) {
> -        error_printf("%s\n", field->err_hint);
> +        error_append_hint(errp, "%s\n", field->err_hint);

According to doc for error_append_hint():

/*
 * Append a printf-style human-readable explanation to an existing error.
 * If the error is later reported to a human user with
 * error_report_err() or warn_report_err(), the hints will be shown,
 * too.  If it's reported via QMP, the hints will be ignored.
 * Intended use is adding helpful hints on the human user interface,
 * e.g. a list of valid values.  It's not for clarifying a confusing
 * error message.
 * @errp may be NULL, but not &error_fatal or &error_abort.
 * Trivially the case if you call it only after error_setg() or
 * error_propagate().
 * May be called multiple times.  The resulting hint should end with a
 * newline.
 */

It may be ignored if the errp will be finally persisted in MigrationState.

Not a huge deal because I believe we also do error_report_err()
somewhere.. but if we want, I think we could use error_append() to make the
hint available to both.

This comment applies to all 5 similar occurances in this patch.

>      }
> -    return -EINVAL;
> +    return false;
>  }

-- 
Peter Xu