[Qemu-devel] [PATCH V3 0/4] Add vPMU vPMU support under TCG mode

[Wei Huang <wei@redhat.com>]

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 (both ACPI and DT) now under TCG
by applying this patchset.

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%)

V2->V3:
 * Remove PMXEVCNTR_EL0 support
 * Add read access support for PMXEVTYPER and change the CONSTRAINED
   UNPREDICTABLE behavior of PMXEVTYPER to RAZ/WI.

V1->V2:
  * Change most PMU registers to 64bit and the behavior of PMXEVTYPER
  * Add support for PMXEVCNTR_EL0
  * Misc fixes (DT, ID_AA64DFR0_EL1, ...) under TCG mode

Thanks,
-Wei

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: Enable vPMU support under TCG mode

 hw/arm/virt.c       |  2 +-
 target/arm/cpu.c    |  2 +-
 target/arm/cpu.h    |  4 +--
 target/arm/helper.c | 72 ++++++++++++++++++++++++++++++++++++++++-------------
 4 files changed, 59 insertions(+), 21 deletions(-)

-- 
1.8.3.1