Re: [PATCH v4 41/55] target-info: add SysEmuTarget none

[Markus Armbruster <armbru@redhat.com>]

Yonggang Luo <luoyonggang@gmail.com> writes:

> Add a none target for when no TargetInfo is selected. It is last
> so existing SYS_EMU_TARGET_* values stay put, and it is not a
> qemu-system- executable name. target_is_none() and target_none()
> report that state.

Why does it matter that existing SYS_EMU_TARGET_* stay put?

> Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>

[...]

> diff --git a/qapi/machine.json b/qapi/machine.json
> index b1be5608b61..6aaa2af709a 100644
> --- a/qapi/machine.json
> +++ b/qapi/machine.json
> @@ -22,6 +22,10 @@
>  # The individual target constants are not documented here, for the
>  # time being.
>  #
> +# @none: no TargetInfo selected.

Doc comments are reference documentation for users.  TargetInfo is an
internal thing.  Please rephrase in terms that make sense to users.

>                                    Not a qemu-system- executable name.

This barely makes sense.  I recommend to leave documenting the
qemu-system-T naming convention to the note below.

> +#     Last enumerator so existing SYS_EMU_TARGET_* values stay put.

Of no concern to users, therefore inappropriate for user documentation.

> +#     (since 11.2)
> +#
>  # @rx: since 5.0
>  #
>  # @avr: since 5.1
> @@ -30,9 +34,10 @@
>  #
>  # @hexagon: since 11.0
>  #
> -# .. note:: The resulting QMP strings can be appended to the
> -#    "qemu-system-" prefix to produce the corresponding QEMU
> -#    executable name.  This is true even for "qemu-system-x86_64".
> +# .. note:: Except for ``none``, the resulting QMP strings can be
> +#    appended to the "qemu-system-" prefix to produce the
> +#    corresponding QEMU executable name.  This is true even for
> +#    "qemu-system-x86_64".

Not this patch's concern: I don't understand what's so special about
x86_64.

>  #
>  # Since: 3.0
>  ##
> @@ -42,7 +47,7 @@
>               'mips64el', 'mipsel', 'or1k', 'ppc',
>               'ppc64', 'riscv32', 'riscv64', 'rx', 's390x', 'sh4',
>               'sh4eb', 'sparc', 'sparc64', 'tricore',
> -             'x86_64', 'xtensa', 'xtensaeb' ] }
> +             'x86_64', 'xtensa', 'xtensaeb', 'none' ] }
>  
>  ##
>  # @S390CpuState:

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