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.
v3:
* Return to using one kernel command line parameter for reserved host counters, but set the default value meaning no partitioning to -1 so 0 isn't ambiguous. Adjust checks for partitioning accordingly.
* Move the function kvm_pmu_partition_supported() back out of the driver to avoid subbing has_vhe in 32-bit ARM code.
* Fix the kernel test robot build failures, one with KVM and no PMU, and one with PMU and no KVM.
* Scan entire series to remove vestigial changes and update comments.
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 arm64: Generate sign macro for sysreg Enums KVM: arm64: Define PMI{CNTR,FILTR}_EL0 as undef_access 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: Correct kvm_arm_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() 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: Cleanup PMU includes
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 | 18 +- arch/arm64/include/asm/kvm_pmu.h | 100 +++ arch/arm64/kernel/cpufeature.c | 8 + arch/arm64/kvm/Makefile | 2 +- arch/arm64/kvm/arm.c | 22 + arch/arm64/kvm/debug.c | 24 +- arch/arm64/kvm/hyp/include/hyp/switch.h | 233 ++++++ arch/arm64/kvm/pmu-emul.c | 674 +---------------- arch/arm64/kvm/pmu-part.c | 378 ++++++++++ arch/arm64/kvm/pmu.c | 702 ++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 79 +- arch/arm64/tools/cpucaps | 1 + arch/arm64/tools/gen-sysreg.awk | 1 + arch/arm64/tools/sysreg | 6 +- drivers/perf/arm_pmuv3.c | 123 ++- include/linux/perf/arm_pmu.h | 6 + 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 +- virt/kvm/kvm_main.c | 1 + 24 files changed, 1828 insertions(+), 752 deletions(-) create mode 100644 arch/arm64/kvm/pmu-part.c
base-commit: 79150772457f4d45e38b842d786240c36bb1f97f -- 2.50.0.727.gbf7dc18ff4-goog