This patchset provides support for perf event modifiers :G and :H which
allows for filtering of PMU events between host and guests when used
with KVM.
As the underlying hardware cannot distinguish between guest and host
context we must switch the performance counters upon entry/exit to the
guest.
For non-VHE the counters must be stopped and started upon entry/exit to
the guest in __kvm_vcpu_run_nvhe.
For VHE we keep the counters enabled but instead change the event type
to include/exclude EL0 as appropriate. This allows us to perform this
switch outside the critical section of world-switch code in vcpu_load.
This has been tested with VHE and non-VHE kernels with a KVM guest.
Changes from v10:
- Remove counter switch code from kvm_vcpu_run_vhe and replace with
enable/disable EL0 event type in kvm_arch_vcpu_load instead
- Reduce counter switch code in __kvm_vcpu_run_nvhe by moving some
logic to kvm_set_pmu_events (kvm_pmu_switch_needed)
- Simplify code by removing need for KVM_PMU_EVENTS_{HOST,GUEST}
- Add kvm_host helper function to let PMU determine if event should
start counting when it is enabled
- Exclude EL2 on !VHE when exclude_host (to avoid counting host events
as guest during entry/exit)
- Moved PMU switching code to its own file
- Rebased to v5.0
- Added documentation
- Removed Reviewed-By's for changed patches and updated commit messages
Changes from v9:
- Rebased to v5.0-rc2
- Ensure get_host_ctxt considers host_ctxt offset
Changes from v8:
- Added additional comments
- Fixed bisect build failure
- Renamed cpu_ctxt variable to cpu_data
Changes from v7:
- Added additional patch to encapsulate kvm_cpu_context in kvm_host_data
Changes from v6:
- Move events_host/events_guest out of kvm_cpu_context
Changes from v5:
- Tweak logic in use of kvm_set_pmu_events
Changes from v4:
- Prevent unnecessary write_sysreg calls by improving
__pmu_switch_to_xxx logic.
Changes from v3:
- Remove confusing _only suffix from bitfields in kvm_cpu_context
- Remove unnecessary condition when clearing event bits in disable
- Simplify API of KVM accessors
- Prevent unnecessary setting of pmcnten when guest/host events are
the same.
Changes from v2:
- Ensured that exclude_kernel works for guest
- Removed unnecessary exclusion of EL2 with exclude_host on !VHE
- Renamed kvm_clr_set_host_pmu_events to reflect args order
- Added additional information to isb patch
Changes from v1:
- Removed unnecessary exclusion of EL1 with exclude_guest on VHE
- Removed unnecessary isb from existing perf_event.c driver
- Folded perf_event.c patches together
- Added additional information to last patch commit message
Andrew Murray (8):
arm64: arm_pmu: remove unnecessary isb instruction
arm64: KVM: encapsulate kvm_cpu_context in kvm_host_data
arm64: KVM: add accessors to track guest/host only counters
arm64: arm_pmu: Add !VHE support for exclude_host/exclude_guest
attributes
arm64: KVM: Enable !VHE support for :G/:H perf event modifiers
arm64: KVM: Enable VHE support for :G/:H perf event modifiers
arm64: KVM: avoid isb's by using direct pmxevtyper sysreg
arm64: docs: document perf event attributes
Documentation/arm64/perf.txt | 74 ++++++++++
arch/arm/include/asm/kvm_host.h | 11 +-
arch/arm64/include/asm/kvm_asm.h | 3 +-
arch/arm64/include/asm/kvm_host.h | 37 ++++-
arch/arm64/kernel/asm-offsets.c | 1 +
arch/arm64/kernel/perf_event.c | 50 +++++--
arch/arm64/kvm/Makefile | 2 +-
arch/arm64/kvm/hyp/switch.c | 6 +
arch/arm64/kvm/pmu.c | 236 ++++++++++++++++++++++++++++++
arch/arm64/kvm/sys_regs.c | 3 +
virt/kvm/arm/arm.c | 14 +-
11 files changed, 414 insertions(+), 23 deletions(-)
create mode 100644 Documentation/arm64/perf.txt
create mode 100644 arch/arm64/kvm/pmu.c
--
2.21.0
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