This series creates a new PMU scheme on ARM, a partitioned PMU that allows reserving a subset of counters for more direct guest access, significantly reducing overhead. More details, including performance benchmarks, can be read in the v1 cover letter linked below.
v4:
* Apply Mark Brown's non-UNDEF FGT control commit to the PMU FGT controls and calculate those controls with the others in kvm_calculate_traps()
* Introduce lazy context swaps for guests that only turns on for guests that have enabled partitioning and accessed PMU registers.
* Rename pmu-part.c to pmu-direct.c because future features might achieve direct PMU access without partitioning.
* Better explain certain commits, such as why the untrapped registers are safe to untrap.
* Reduce the PMU include cleanup down to only what is still necessary and explain why.
v3: https://lore.kernel.org/kvm/20250626200459.1153955-1-coltonlewis@google.com/
v2: https://lore.kernel.org/kvm/20250620221326.1261128-1-coltonlewis@google.com/
v1: https://lore.kernel.org/kvm/20250602192702.2125115-1-coltonlewis@google.com/
Colton Lewis (21): arm64: cpufeature: Add cpucap for HPMN0 KVM: arm64: Reorganize PMU functions perf: arm_pmuv3: Introduce method to partition the PMU perf: arm_pmuv3: Generalize counter bitmasks perf: arm_pmuv3: Keep out of guest counter partition KVM: arm64: Account for partitioning in kvm_pmu_get_max_counters() KVM: arm64: Set up FGT for Partitioned PMU KVM: arm64: Writethrough trapped PMEVTYPER register KVM: arm64: Use physical PMSELR for PMXEVTYPER if partitioned KVM: arm64: Writethrough trapped PMOVS register KVM: arm64: Write fast path PMU register handlers KVM: arm64: Setup MDCR_EL2 to handle a partitioned PMU KVM: arm64: Account for partitioning in PMCR_EL0 access KVM: arm64: Context swap Partitioned PMU guest registers KVM: arm64: Enforce PMU event filter at vcpu_load() KVM: arm64: Extract enum debug_owner to enum vcpu_register_owner KVM: arm64: Implement lazy PMU context swaps perf: arm_pmuv3: Handle IRQs for Partitioned PMU guest counters KVM: arm64: Inject recorded guest interrupts KVM: arm64: Add ioctl to partition the PMU when supported KVM: arm64: selftests: Add test case for partitioned PMU
Marc Zyngier (1): KVM: arm64: Reorganize PMU includes
Mark Brown (1): KVM: arm64: Introduce non-UNDEF FGT control
Documentation/virt/kvm/api.rst | 21 + arch/arm/include/asm/arm_pmuv3.h | 38 + arch/arm64/include/asm/arm_pmuv3.h | 61 +- arch/arm64/include/asm/kvm_host.h | 34 +- arch/arm64/include/asm/kvm_pmu.h | 123 +++ arch/arm64/include/asm/kvm_types.h | 7 +- arch/arm64/kernel/cpufeature.c | 8 + arch/arm64/kvm/Makefile | 2 +- arch/arm64/kvm/arm.c | 22 + arch/arm64/kvm/debug.c | 33 +- arch/arm64/kvm/hyp/include/hyp/debug-sr.h | 6 +- arch/arm64/kvm/hyp/include/hyp/switch.h | 181 ++++- arch/arm64/kvm/pmu-direct.c | 395 ++++++++++ arch/arm64/kvm/pmu-emul.c | 674 +--------------- arch/arm64/kvm/pmu.c | 725 ++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 137 +++- arch/arm64/tools/cpucaps | 1 + arch/arm64/tools/sysreg | 6 +- drivers/perf/arm_pmuv3.c | 128 +++- include/linux/perf/arm_pmu.h | 1 + include/linux/perf/arm_pmuv3.h | 14 +- include/uapi/linux/kvm.h | 4 + tools/include/uapi/linux/kvm.h | 2 + .../selftests/kvm/arm64/vpmu_counter_access.c | 62 +- 24 files changed, 1910 insertions(+), 775 deletions(-) create mode 100644 arch/arm64/kvm/pmu-direct.c
base-commit: 79150772457f4d45e38b842d786240c36bb1f97f -- 2.50.0.727.gbf7dc18ff4-goog