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[Qemu-devel] [PATCH V1 0/4] Add vPMU vPMU support under TCG mode

From: Wei Huang
Subject: [Qemu-devel] [PATCH V1 0/4] Add vPMU vPMU support under TCG mode
Date: Thu, 12 Jan 2017 02:04:14 -0500

QEMU has implemented cycle count support for guest VM under TCG mode.
But this feature is not complete. In fact using perf inside a
64-bit Linux guest VM (under TCG) can cause the following kernel panic
because some PMU registers are not implemented.

[  329.445970] [<fffffe000009e600>] armv8pmu_enable_event+0x58/0x8c
[  329.446713] [<fffffe0000621e74>] armpmu_start+0x4c/0x74

This patchset solves the problem by adding support for missing vPMU
registers. Basic perf test can work now under TCG by applying this

address@hidden ~]# perf stat ls
 Performance counter stats for 'ls':

        226.740256      task-clock (msec)         #    0.312 CPUs utilized    
                76      context-switches          #    0.335 K/sec
                 0      cpu-migrations            #    0.000 K/sec
                64      page-faults               #    0.282 K/sec
       186,031,410      cycles                    #    0.820 GHz      (36.40%)
   <not supported>      stalled-cycles-frontend
   <not supported>      stalled-cycles-backend
     <not counted>      instructions               (0.00%)
   <not supported>      branches
     <not counted>      branch-misses              (0.00%)


Wei Huang (4):
  target-arm: Add support for PMU register PMSELR_EL0
  target-arm: Add support for AArch64 PMU register PMXEVTYPER_EL0
  target-arm: Add support for PMU register PMINTENSET_EL1
  target-arm: Hook up TCG vPMU with CPU pmu option

 target/arm/cpu.c    |  2 +-
 target/arm/cpu.h    |  1 +
 target/arm/helper.c | 41 +++++++++++++++++++++++++++++++++++------
 3 files changed, 37 insertions(+), 7 deletions(-)


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