perf kvm/powerpc: Add support for HCALL reasons

perf kvm/powerpc: Add support for HCALL reasons

Powerpc provides hcall events that also provides insights into guest
behaviour. Enhance perf kvm stat to record and analyze hcall events.

 - To trace hcall events :
  perf kvm stat record

 - To show the results :
  perf kvm stat report --event=hcall

The result shows the number of hypervisor calls from the guest grouped
by their respective reasons displayed with the frequency.

This patch makes use of two additional tracepoints
"kvm_hv:kvm_hcall_enter" and "kvm_hv:kvm_hcall_exit". To map the hcall
codes to their respective names, it needs a mapping. Such mapping is
added in this patch in book3s_hcalls.h.

 # pgrep qemu
A sample output :
19378
60515

2 VMs running.

 # perf kvm stat record -a
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 4.153 MB perf.data.guest (39624
samples) ]

 # perf kvm stat report -p 60515 --event=hcall

Analyze events for all VMs, all VCPUs:

    HCALL-EVENT Samples Samples% Time% MinTime MaxTime  AvgTime

          H_IPI     822  66.08% 88.10% 0.63us  11.38us 2.05us (+- 1.42%)
     H_SEND_CRQ     144  11.58%  3.77% 0.41us   0.88us 0.50us (+- 1.47%)
   H_VIO_SIGNAL     118   9.49%  2.86% 0.37us   0.83us 0.47us (+- 1.43%)
H_PUT_TERM_CHAR      76   6.11%  2.07% 0.37us   0.90us 0.52us (+- 2.43%)
H_GET_TERM_CHAR      74   5.95%  2.23% 0.37us   1.70us 0.58us (+- 4.77%)
         H_RTAS       6   0.48%  0.85% 1.10us   9.25us 2.70us (+-48.57%)
      H_PERFMON       4   0.32%  0.12% 0.41us   0.96us 0.59us (+-20.92%)

Total Samples:1244, Total events handled time:1916.69us.

Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Scott  Wood <scottwood@freescale.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1453962787-15376-4-git-send-email-hemant@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>