Re: [Qemu-devel] [PATCH] debugcon: support for debugging consoles (e.g. Bochs port 0xe9)

[Markus Armbruster]

Gerd Hoffmann <address@hidden> writes:

> On 11/25/09 23:31, H. Peter Anvin wrote:
>> On 11/25/2009 02:26 PM, H. Peter Anvin wrote:
>>>
>>> As such, I think there is still a place for the simple command line
>>> options like "-hda", "-serial" and my proposed "-debugcon", in addition
>>> to the full-featured connect-anything options and configuration files.
>>> That's all.
>>>
>>
>> I guess one question is if the simplified options could be better
>> implemented via some kind of builtin macros or translation submodule
>> rather than being treated as first-class options which they basically
>> are now.  Still, that's a future development task.
>
> Wouldn't be that hard I think.  Something along the lines of
>
>     case QEMU_OPTION_debugcon:
>          opts = qemu_chr_parse_compat("debugcon", optarg);
>          if (NULL == opts) {
>               fprintf(stderr, "already have a debugcon chardev\");
>               exit(1);
>          }
>          opts = qemu_opts_create(&qemu_device_opts, "debugcon", 1);
>          if (NULL == opts) {
>               fprintf(stderr, "already have a debugcon device\");
>               exit(1);
>          }
>          qemu_opt_set(opts, "driver", isa-debugcon);
>          qemu_opt_set(opts, "chardev", "debugcon");
>          break;
>
> should do the trick.  Depends on the chardev fix mentioned in this
> thread too.  Allows to define a single device with the default port
> via shortcut.

There's precedence for this method to implement convenience options;
look for uses of qemu_opts_create() / qemu_opt_set().  Expanding the
convenience option into longhand that way saves code and avoids subtle
differences between the two.  Just avoid NULL == opts kraxelism ;)

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