[Qemu-devel] [RFC v1 0/2] Add a valid_cpu_types property

[Eduardo Habkost <ehabkost@redhat.com>]

On Mon, Sep 18, 2017 at 06:57:19PM -0300, Philippe Mathieu-Daudé wrote:
> add a property to restrict the CPU for SoCs once on machine creation and avoid
> duplicate code in each board.
> 
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

The valid_cpu_types approach implemented by Alistair is more
generic:
  Subject: [Qemu-devel] [RFC v1 0/2]  Add a valid_cpu_types property
  Message-ID: <cover.1504656490.git.alistair.francis@xilinx.com>

With it, boards that don't support other CPUs just need to set
valid_cpu_types = { default_cpu_type }.

> ---
> Based-on: 1505318697-77161-6-git-send-email-imammedo@redhat.com
> 
>  include/hw/boards.h |  3 +++
>  vl.c                | 11 +++++++++++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 6b67adaef6..20dc0a0ab9 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -129,6 +129,8 @@ typedef struct {
>   *    specifies default CPU_TYPE, which will be used for parsing target
>   *    specific features and for creating CPUs if CPU name wasn't provided
>   *    explicitly at CLI
> + * @is_system_on_chip:
> + *    If true, board does not support other CPUs than default_cpu_type.
>   * @minimum_page_bits:
>   *    If non-zero, the board promises never to create a CPU with a page size
>   *    smaller than this, so QEMU can use a more efficient larger page
> @@ -182,6 +184,7 @@ struct MachineClass {
>      const char *hw_version;
>      ram_addr_t default_ram_size;
>      const char *default_cpu_type;
> +    bool is_system_on_chip;
>      bool option_rom_has_mr;
>      bool rom_file_has_mr;
>      int minimum_page_bits;
> diff --git a/vl.c b/vl.c
> index fb6a700e55..6e59ffa856 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4717,10 +4717,21 @@ int main(int argc, char **argv, char **envp)
>      current_machine->cpu_model = cpu_model;
>  
>  
> +    if (machine_class->is_system_on_chip && !machine_class->default_cpu_type) {
> +        error_report("System-on-Chip must have a default CPU type");
> +        exit(1);
> +    }
>      /* parse features once if machine provides default cpu_type */
>      if (machine_class->default_cpu_type) {
>          current_machine->cpu_type = machine_class->default_cpu_type;
>          if (cpu_model) {
> +            if (machine_class->is_system_on_chip) {
> +                if (strcmp(cpu_model, machine_class->default_cpu_type) != 0) {
> +                    error_report("This board can only be used with CPU %s",
> +                                 machine_class->default_cpu_type);
> +                    exit(1);
> +                }
> +            }
>              current_machine->cpu_type =
>                  cpu_parse_cpu_model(machine_class->default_cpu_type, cpu_model);
>          }
> -- 
> 2.14.1
> 

-- 
Eduardo