Re: [PATCH v3 01/16] Introduce probe mode for machine type none

[Eduardo Habkost <ehabkost@redhat.com>]

On Mon, Mar 02, 2015 at 01:43:53PM +0100, Michael Mueller wrote:
> QEMU now switches into "probe mode" when the selected machine is "none" and no
> specific accelerator(s) has been requested (i.e.: "-machine none").
> 
> In probe mode a by "<ARCH>_CONFIG" defines predefined list of accelerators run
> their init() methods.
> 
> Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>
> ---
[...]
>  int configure_accelerator(MachineState *ms)
>  {
> -    const char *p;
> +    const char *p, *name;
>      char buf[10];
>      int ret;
>      bool accel_initialised = false;
>      bool init_failed = false;
>      AccelClass *acc = NULL;
> +    ObjectClass *oc;
> +    bool probe_mode = false;
>  
>      p = qemu_opt_get(qemu_get_machine_opts(), "accel");
>      if (p == NULL) {
> -        /* Use the default "accelerator", tcg */
> -        p = "tcg";
> +        oc = (ObjectClass *) MACHINE_GET_CLASS(current_machine);
> +        name = object_class_get_name(oc);
> +        probe_mode = !strcmp(name, "none" TYPE_MACHINE_SUFFIX);
> +        if (probe_mode) {
> +            /* Use these accelerators in probe mode, tcg should be last */
> +            p = probe_mode_accels;

I don't fully understand the purpose of this patch yet (I will discuss
it in a reply to the cover letter). But if you really want -machine none
to trigger different behavior, why you didn't add a probe_mode field
to MachineClass, so you can set it in the mahine_none class code?

> +        } else {
> +            /* Use the default "accelerator", tcg */
> +            p = "tcg";
> +        }
>      }
[...]

-- 
Eduardo