Re: [Qemu-devel] [RFC PATCH] vl: only display available accelerators

[Eduardo Habkost <ehabkost@redhat.com>]

On Mon, Oct 30, 2017 at 01:00:56AM -0300, Philippe Mathieu-Daudé wrote:
> examples configuring with '--enable-kvm --disable-tcg'
> 
> - before
> 
>   $ qemu-system-x86_64 -accel help
>   Possible accelerators: kvm, xen, hax, tcg
> 
>   $ qemu-system-x86_64 -accel tcg
>   qemu-system-x86_64: -machine accel=tcg: No accelerator found
> 
>   # qemu-system-x86_64 -accel hax
>   qemu-system-x86_64: -machine accel=hax: No accelerator found
> 
>   # qemu-system-x86_64 -accel xen
>   xencall: error: Could not obtain handle on privileged command interface: No such file or directory
>   xen be core: xen be core: can't open xen interface
>   can't open xen interface
>   qemu-system-x86_64: failed to initialize Xen: Operation not permitted
> 
> - after
> 
>   $ qemu-system-x86_64 -accel help
>   Possible accelerators: kvm
> 
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> RFC because:
>     - I don't think this is the nicest way, too much #ifdef'fery in main()

I suggest using object_class_get_list(TYPE_ACCEL, false).


>     - I'm not sure the correct use of CONFIG_KVM_IS_POSSIBLE
>     - shouldn't CONFIG_XEN/CONFIG_HAX be as poisoned as CONFIG_KVM?
> 
>  vl.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/vl.c b/vl.c
> index ec299099ff..13fce86a6e 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3883,7 +3883,20 @@ int main(int argc, char **argv, char **envp)
>                                                       optarg, true);
>                  optarg = qemu_opt_get(accel_opts, "accel");
>                  if (!optarg || is_help_option(optarg)) {
> -                    error_printf("Possible accelerators: kvm, xen, hax, tcg\n");
> +                    error_printf("Possible accelerators: ");
> +#ifdef CONFIG_KVM_IS_POSSIBLE
> +                    error_printf("kvm ");
> +#endif
> +#ifdef CONFIG_XEN
> +                    error_printf("xen ");
> +#endif
> +#ifdef CONFIG_HAX
> +                    error_printf("hax ");
> +#endif
> +#ifdef CONFIG_TCG
> +                    error_printf("tcg ");
> +#endif
> +                    error_printf("\n");
>                      exit(0);
>                  }
>                  opts = qemu_opts_create(qemu_find_opts("machine"), NULL,
> -- 
> 2.15.0.rc2
> 

-- 
Eduardo