[PATCH v2 00/22] KVM: ARM64: Add guest PMU support

[shannon.zhao@linaro.org (Shannon Zhao)]

Sorry, I forgot the changlog. Below are the main changes of this v2 
patchset.

Changes since v1->v2:
* Use switch...case for registers access handler instead of adding
   alone handler for each register
* Try to use the sys_regs to store the register value instead of adding
   new variables in struct kvm_pmc
* Fix the handle of cp15 regs
* Create a new kvm device vPMU, then userspace could choose whether to
   create PMU
* Fix the handle of PMU overflow interrupt

On 2015/9/11 16:54, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@linaro.org>
>
> This patchset adds guest PMU support for KVM on ARM64. It takes
> trap-and-emulate approach. When guest wants to monitor one event, it
> will be trapped by KVM and KVM will call perf_event API to create a perf
> event and call relevant perf_event APIs to get the count value of event.
>
> Use perf to test this patchset in guest. When using "perf list", it
> shows the list of the hardware events and hardware cache events perf
> supports. Then use "perf stat -e EVENT" to monitor some event. For
> example, use "perf stat -e cycles" to count cpu cycles and
> "perf stat -e cache-misses" to count cache misses.
>
> Below are the outputs of "perf stat -r 5 sleep 5" when running in host
> and guest.
>
> Host:
>   Performance counter stats for 'sleep 5' (5 runs):
>
>            0.551428      task-clock (msec)         #    0.000 CPUs utilized            ( +-  0.91% )
>                   1      context-switches          #    0.002 M/sec
>                   0      cpu-migrations            #    0.000 K/sec
>                  48      page-faults               #    0.088 M/sec                    ( +-  1.05% )
>             1150265      cycles                    #    2.086 GHz                      ( +-  0.92% )
>     <not supported>      stalled-cycles-frontend
>     <not supported>      stalled-cycles-backend
>              526398      instructions              #    0.46  insns per cycle          ( +-  0.89% )
>     <not supported>      branches
>                9485      branch-misses             #   17.201 M/sec                    ( +-  2.35% )
>
>         5.000831616 seconds time elapsed                                          ( +-  0.00% )
>
> Guest:
>   Performance counter stats for 'sleep 5' (5 runs):
>
>            0.730868      task-clock (msec)         #    0.000 CPUs utilized            ( +-  1.13% )
>                   1      context-switches          #    0.001 M/sec
>                   0      cpu-migrations            #    0.000 K/sec
>                  48      page-faults               #    0.065 M/sec                    ( +-  0.42% )
>             1642982      cycles                    #    2.248 GHz                      ( +-  1.04% )
>     <not supported>      stalled-cycles-frontend
>     <not supported>      stalled-cycles-backend
>              637964      instructions              #    0.39  insns per cycle          ( +-  0.65% )
>     <not supported>      branches
>               10377      branch-misses             #   14.198 M/sec                    ( +-  1.09% )
>
>         5.001289068 seconds time elapsed                                          ( +-  0.00% )
>
> This patchset can be fetched from [1] and the relevant QEMU version for
> test can be fetched from [2].
>
> Thanks,
> Shannon
>
> [1] https://git.linaro.org/people/shannon.zhao/linux-mainline.git  KVM_ARM64_PMU_v2
> [2] https://git.linaro.org/people/shannon.zhao/qemu.git  PMU_v2
>
> Shannon Zhao (22):
>    ARM64: Move PMU register related defines to asm/pmu.h
>    KVM: ARM64: Define PMU data structure for each vcpu
>    KVM: ARM64: Add offset defines for PMU registers
>    KVM: ARM64: Add reset and access handlers for PMCR_EL0 register
>    KVM: ARM64: Add a helper for CP15 registers reset to UNKNOWN
>    KVM: ARM64: Add reset and access handlers for PMSELR register
>    KVM: ARM64: Add reset and access handlers for PMCEID0 and PMCEID1
>      register
>    KVM: ARM64: PMU: Add perf event map and introduce perf event creating
>      function
>    KVM: ARM64: Add reset and access handlers for PMXEVTYPER register
>    KVM: ARM64: Add reset and access handlers for PMXEVCNTR register
>    KVM: ARM64: Add reset and access handlers for PMCCNTR register
>    KVM: ARM64: Add reset and access handlers for PMCNTENSET and
>      PMCNTENCLR register
>    KVM: ARM64: Add reset and access handlers for PMINTENSET and
>      PMINTENCLR register
>    KVM: ARM64: Add reset and access handlers for PMOVSSET and PMOVSCLR
>      register
>    KVM: ARM64: Add a helper for CP15 registers reset to specified value
>    KVM: ARM64: Add reset and access handlers for PMUSERENR register
>    KVM: ARM64: Add reset and access handlers for PMSWINC register
>    KVM: ARM64: Add access handlers for PMEVCNTRn and PMEVTYPERn register
>    KVM: ARM64: Add PMU overflow interrupt routing
>    KVM: ARM64: Reset PMU state when resetting vcpu
>    KVM: ARM64: Free perf event of PMU when destroying vcpu
>    KVM: ARM64: Add a new kvm ARM PMU device
>
>   Documentation/virtual/kvm/devices/arm-pmu.txt |  15 +
>   arch/arm/kvm/arm.c                            |   4 +
>   arch/arm64/include/asm/kvm_asm.h              |  59 ++-
>   arch/arm64/include/asm/kvm_host.h             |   2 +
>   arch/arm64/include/asm/pmu.h                  |  49 +++
>   arch/arm64/include/uapi/asm/kvm.h             |   3 +
>   arch/arm64/kernel/perf_event.c                |  35 --
>   arch/arm64/kvm/Kconfig                        |   8 +
>   arch/arm64/kvm/Makefile                       |   1 +
>   arch/arm64/kvm/reset.c                        |   3 +
>   arch/arm64/kvm/sys_regs.c                     | 490 +++++++++++++++++++++++--
>   arch/arm64/kvm/sys_regs.h                     |  16 +
>   include/kvm/arm_pmu.h                         |  66 ++++
>   include/linux/kvm_host.h                      |   1 +
>   include/uapi/linux/kvm.h                      |   2 +
>   virt/kvm/arm/pmu.c                            | 500 ++++++++++++++++++++++++++
>   virt/kvm/kvm_main.c                           |   4 +
>   17 files changed, 1188 insertions(+), 70 deletions(-)
>   create mode 100644 Documentation/virtual/kvm/devices/arm-pmu.txt
>   create mode 100644 include/kvm/arm_pmu.h
>   create mode 100644 virt/kvm/arm/pmu.c
>

-- 
Shannon