Re: [PATCH] KVM: trace events: update list of exit reasons

[Ladi Prosek <lprosek@xxxxxxxxxx>]

On Thu, Sep 14, 2017 at 8:07 PM, Radim Krčmář <rkrcmar@xxxxxxxxxx> wrote:
> If we do not want to generate it with an external script, I think the
> simplest is to have a separate file that looks like
>
>   #define kvm_exit_reasons \
>     KVM_EXIT(UNKNOWN, 0), \
>     KVM_EXIT(EXCEPTION, 1), \
>     ...
>     KVM_EXIT(HYPERV, 27) \
>
> and include it from both places.  The current exit definitions would be
>
>   #define KVM_EXIT(reason, code)
>         KVM_EXIT_ ## reason = code
>
>   #include <the/magic/file>
>
>   enum {
>         kvm_exit_reasons
>   };
>
>   #undef kvm_exit_reasons
>
> and the trace
>
>   #define KVM_EXIT(reason, code)
>         { code, "KVM_EXIT_" # reason }
>   #include <the/magic/file>
>
>   ...
>
>         __print_symbolic(__entry->reason, kvm_exit_reasons),
>
>   ...
>
>   #undef kvm_exit_reasons
>
> (Would also work with just "KVM_EXIT(UNKNOWN), ..." and small tweaks.)

It can be done without a separate file:

#define kvm_exit_reasons \
       KVM_EXIT(UNKNOWN, 0), \
       KVM_EXIT(EXCEPTION, 1), \
       ...
       KVM_EXIT(HYPERV, 27)

#define KVM_EXIT(reason, code) \
        KVM_EXIT_ ## reason = code
enum {
        kvm_exit_reasons
};
#undef KVM_EXIT

^^^ goes in the general header


#define KVM_EXIT(reason, code) \
        { code, "KVM_EXIT_" # reason }
... _reasons[] = {
  kvm_exit_reasons
};
#undef KVM_EXIT

^^^ goes in the trace header

I.e. this is symbol manipulation, no need to have KVM_EXIT defined
when it's "used".