[PATCH RESEND 1/2] tools/perf: Add arch neutral function to choose event for perf kvm record

[Ravi Bangoria]

On 6/10/19 8:46 PM, Arnaldo Carvalho de Melo wrote:
> Em Mon, Jun 10, 2019 at 12:15:17PM +0530, Anju T Sudhakar escreveu:
>> 'perf kvm record' uses 'cycles'(if the user did not specify any event) as
>> the default event to profile the guest.
>> This will not provide any proper samples from the guest incase of
>> powerpc architecture, since in powerpc the PMUs are controlled by
>> the guest rather than the host.
>>
>> Patch adds a function to pick an arch specific event for 'perf kvm record',
>> instead of selecting 'cycles' as a default event for all architectures.
>>
>> For powerpc this function checks for any user specified event, and if there
>> isn't any it returns invalid instead of proceeding with 'cycles' event.
> 
> Michael, Ravi, Maddy, could you please provide an Acked-by, Reviewed-by
> or Tested-by?

Code looks fine to me but cross-build fails for aarch64:

  builtin-kvm.c:1513:12: error: no previous prototype for 'kvm_add_default_arch_event' [-Werror=missing-prototypes]
   int __weak kvm_add_default_arch_event(int *argc __maybe_unused,
              ^~~~~~~~~~~~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors
  mv: cannot stat './.builtin-kvm.o.tmp': No such file or directory

With the build fix:
Acked-by: Ravi Bangoria <ravi.bangoria at linux.ibm.com>