Hi Sean,
Not sure if you have bandwidth to review this mediated vPMU v4 patchset?
All your comments in v3 patchset have been addressed.
Thanks.
Dapeng Mi
On 3/25/2025 1:30 AM, Mingwei Zhang wrote:
> With joint effort from the upstream KVM community, we come up with the
> 4th version of mediated vPMU for x86. We have made the following changes
> on top of the previous RFC v3.
>
> v3 -> v4
> - Rebase whole patchset on 6.14-rc3 base.
> - Address Peter's comments on Perf part.
> - Address Sean's comments on KVM part.
> * Change key word "passthrough" to "mediated" in all patches
> * Change static enabling to user space dynamic enabling via KVM_CAP_PMU_CAPABILITY.
> * Only support GLOBAL_CTRL save/restore with VMCS exec_ctrl, drop the MSR
> save/retore list support for GLOBAL_CTRL, thus the support of mediated
> vPMU is constrained to SapphireRapids and later CPUs on Intel side.
> * Merge some small changes into a single patch.
> - Address Sandipan's comment on invalid pmu pointer.
> - Add back "eventsel_hw" and "fixed_ctr_ctrl_hw" to avoid to directly
> manipulate pmc->eventsel and pmu->fixed_ctr_ctrl.
>
>
> Testing (Intel side):
> - Perf-based legacy vPMU (force emulation on/off)
> * Kselftests pmu_counters_test, pmu_event_filter_test and
> vmx_pmu_caps_test pass.
> * KUT PMU tests pmu, pmu_lbr, pmu_pebs pass.
> * Basic perf counting/sampling tests in 3 scenarios, guest-only,
> host-only and host-guest coexistence all pass.
>
> - Mediated vPMU (force emulation on/off)
> * Kselftests pmu_counters_test, pmu_event_filter_test and
> vmx_pmu_caps_test pass.
> * KUT PMU tests pmu, pmu_lbr, pmu_pebs pass.
> * Basic perf counting/sampling tests in 3 scenarios, guest-only,
> host-only and host-guest coexistence all pass.
>
> - Failures. All above tests passed on Intel Granite Rapids as well
> except a failure on KUT/pmu_pebs.
> * GP counter 0 (0xfffffffffffe): PEBS record (written seq 0)
> is verified (including size, counters and cfg).
> * The pebs_data_cfg (0xb500000000) doesn't match with the
> effective MSR_PEBS_DATA_CFG (0x0).
> * This failure has nothing to do with this mediated vPMU patch set. The
> failure is caused by Granite Rapids supported timed PEBS which needs
> extra support on Qemu and KUT/pmu_pebs. These extra support would be
> sent in separate patches later.
>
>
> Testing (AMD side):
> - Kselftests pmu_counters_test, pmu_event_filter_test and
> vmx_pmu_caps_test all pass
>
> - legacy guest with KUT/pmu:
> * qmeu option: -cpu host, -perfctr-core
> * when set force_emulation_prefix=1, passes
> * when set force_emulation_prefix=0, passes
> - perfmon-v1 guest with KUT/pmu:
> * qmeu option: -cpu host, -perfmon-v2
> * when set force_emulation_prefix=1, passes
> * when set force_emulation_prefix=0, passes
> - perfmon-v2 guest with KUT/pmu:
> * qmeu option: -cpu host
> * when set force_emulation_prefix=1, passes
> * when set force_emulation_prefix=0, passes
>
> - perf_fuzzer (perfmon-v2):
> * fails with soft lockup in guest in current version.
> * culprit could be between 6.13 ~ 6.14-rc3 within KVM
> * Series tested on 6.12 and 6.13 without issue.
>
> Note: a QEMU series is needed to run mediated vPMU v4:
> - https://lore.kernel.org/all/20250324123712.34096-1-dapeng1.mi@linux.intel.com/
>
> History:
> - RFC v3: https://lore.kernel.org/all/20240801045907.4010984-1-mizhang@google.com/
> - RFC v2: https://lore.kernel.org/all/20240506053020.3911940-1-mizhang@google.com/
> - RFC v1: https://lore.kernel.org/all/20240126085444.324918-1-xiong.y.zhang@linux.intel.com/
>
>
> Dapeng Mi (18):
> KVM: x86/pmu: Introduce enable_mediated_pmu global parameter
> KVM: x86/pmu: Check PMU cpuid configuration from user space
> KVM: x86: Rename vmx_vmentry/vmexit_ctrl() helpers
> KVM: x86/pmu: Add perf_capabilities field in struct kvm_host_values{}
> KVM: x86/pmu: Move PMU_CAP_{FW_WRITES,LBR_FMT} into msr-index.h header
> KVM: VMX: Add macros to wrap around
> {secondary,tertiary}_exec_controls_changebit()
> KVM: x86/pmu: Check if mediated vPMU can intercept rdpmc
> KVM: x86/pmu/vmx: Save/load guest IA32_PERF_GLOBAL_CTRL with
> vm_exit/entry_ctrl
> KVM: x86/pmu: Optimize intel/amd_pmu_refresh() helpers
> KVM: x86/pmu: Setup PMU MSRs' interception mode
> KVM: x86/pmu: Handle PMU MSRs interception and event filtering
> KVM: x86/pmu: Switch host/guest PMU context at vm-exit/vm-entry
> KVM: x86/pmu: Handle emulated instruction for mediated vPMU
> KVM: nVMX: Add macros to simplify nested MSR interception setting
> KVM: selftests: Add mediated vPMU supported for pmu tests
> KVM: Selftests: Support mediated vPMU for vmx_pmu_caps_test
> KVM: Selftests: Fix pmu_counters_test error for mediated vPMU
> KVM: x86/pmu: Expose enable_mediated_pmu parameter to user space
>
> Kan Liang (8):
> perf: Support get/put mediated PMU interfaces
> perf: Skip pmu_ctx based on event_type
> perf: Clean up perf ctx time
> perf: Add a EVENT_GUEST flag
> perf: Add generic exclude_guest support
> perf: Add switch_guest_ctx() interface
> perf/x86: Support switch_guest_ctx interface
> perf/x86/intel: Support PERF_PMU_CAP_MEDIATED_VPMU
>
> Mingwei Zhang (5):
> perf/x86: Forbid PMI handler when guest own PMU
> perf/x86/core: Plumb mediated PMU capability from x86_pmu to
> x86_pmu_cap
> KVM: x86/pmu: Exclude PMU MSRs in vmx_get_passthrough_msr_slot()
> KVM: x86/pmu: introduce eventsel_hw to prepare for pmu event filtering
> KVM: nVMX: Add nested virtualization support for mediated PMU
>
> Sandipan Das (4):
> perf/x86/core: Do not set bit width for unavailable counters
> KVM: x86/pmu: Add AMD PMU registers to direct access list
> KVM: x86/pmu/svm: Set GuestOnly bit and clear HostOnly bit when guest
> write to event selectors
> perf/x86/amd: Support PERF_PMU_CAP_MEDIATED_VPMU for AMD host
>
> Xiong Zhang (3):
> x86/irq: Factor out common code for installing kvm irq handler
> perf: core/x86: Register a new vector for KVM GUEST PMI
> KVM: x86/pmu: Register KVM_GUEST_PMI_VECTOR handler
>
> arch/x86/events/amd/core.c | 2 +
> arch/x86/events/core.c | 40 +-
> arch/x86/events/intel/core.c | 5 +
> arch/x86/include/asm/hardirq.h | 1 +
> arch/x86/include/asm/idtentry.h | 1 +
> arch/x86/include/asm/irq.h | 2 +-
> arch/x86/include/asm/irq_vectors.h | 5 +-
> arch/x86/include/asm/kvm-x86-pmu-ops.h | 2 +
> arch/x86/include/asm/kvm_host.h | 10 +
> arch/x86/include/asm/msr-index.h | 18 +-
> arch/x86/include/asm/perf_event.h | 1 +
> arch/x86/include/asm/vmx.h | 1 +
> arch/x86/kernel/idt.c | 1 +
> arch/x86/kernel/irq.c | 39 +-
> arch/x86/kvm/cpuid.c | 15 +
> arch/x86/kvm/pmu.c | 254 ++++++++-
> arch/x86/kvm/pmu.h | 45 ++
> arch/x86/kvm/svm/pmu.c | 148 ++++-
> arch/x86/kvm/svm/svm.c | 26 +
> arch/x86/kvm/svm/svm.h | 2 +-
> arch/x86/kvm/vmx/capabilities.h | 11 +-
> arch/x86/kvm/vmx/nested.c | 68 ++-
> arch/x86/kvm/vmx/pmu_intel.c | 224 ++++++--
> arch/x86/kvm/vmx/vmx.c | 89 +--
> arch/x86/kvm/vmx/vmx.h | 11 +-
> arch/x86/kvm/x86.c | 63 ++-
> arch/x86/kvm/x86.h | 2 +
> include/linux/perf_event.h | 47 +-
> kernel/events/core.c | 519 ++++++++++++++----
> .../beauty/arch/x86/include/asm/irq_vectors.h | 5 +-
> .../selftests/kvm/include/kvm_test_harness.h | 13 +
> .../testing/selftests/kvm/include/kvm_util.h | 3 +
> .../selftests/kvm/include/x86/processor.h | 8 +
> tools/testing/selftests/kvm/lib/kvm_util.c | 23 +
> .../selftests/kvm/x86/pmu_counters_test.c | 24 +-
> .../selftests/kvm/x86/pmu_event_filter_test.c | 8 +-
> .../selftests/kvm/x86/vmx_pmu_caps_test.c | 2 +-
> 37 files changed, 1480 insertions(+), 258 deletions(-)
>
>
> base-commit: 0ad2507d5d93f39619fc42372c347d6006b64319