Re: [PATCH for-10.0] docs: deprecate RISC-V default machine option

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 4/4/25 14:28, Daniel Henrique Barboza wrote:
> Commit 5b4beba124 ("RISC-V Spike Machines") added the Spike machine and
> made it default for qemu-system-riscv32/64. It was the first RISC-V
> machine added in QEMU so setting it as default was sensible.
> 
> Today we have 7 riscv64 and 6 riscv32 machines and having 'spike' as
> default machine is not intuitive. For example, [1] is a bug that was
> opened with the 'virt' board in mind, but given that the user didn't
> pass a '-machine' option, the user was using 'spike' without knowing.
> 
> Being explicit in the command line is desirable when we have a handful
> of boards available, so deprecate the default machine setting from
> RISC-V.
> 
> [1] https://gitlab.com/qemu-project/qemu/-/issues/2467
> 
> Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> ---
>   docs/about/deprecated.rst | 17 +++++++++++++++++
>   1 file changed, 17 insertions(+)
> 
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index 76291fdfd6..0f41a99c67 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -304,6 +304,23 @@ online to check that this board did not completely bitrot yet). It is
>   recommended to use another MIPS machine for future MIPS code development
>   instead.
>   
> +RISC-V default machine option (since 10.0)
> +''''''''''''''''''''''''''''''''''''''''''
> +
> +RISC-V defines ``spike`` as the default machine if no machine option is
> +given in the command line.  This happens because ``spike`` is the first
> +RISC-V machine implemented in QEMU and setting it as default was
> +convenient at that time.  Now we have 7 riscv64 and 6 riscv32 machines
> +and having ``spike`` as a default is no longer justified.  This default
> +will also promote situations where users think they're running ``virt``
> +(the most used RISC-V machine type in 10.0) when in fact they're
> +running ``spike``.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Having users specify "-M virt" doesn't seem much of a hassle IMHO,
so I'd not use 'virt' as the /new/ default in 10.2 (but we aren't
there yet).

> +
> +Removing the default machine option forces users to always set the machine
> +they want to use and avoids confusion.  Existing users of the ``spike``
> +machine must ensure that they're setting the ``spike`` machine in the
> +command line (``-M spike``).
> +