On 8/8/2025 4:28 PM, Mi, Dapeng wrote: > On 8/7/2025 3:56 AM, Sean Christopherson wrote: >> This series is based on the fastpath+PMU cleanups series[*] (which is based on >> kvm/queue), but the non-KVM changes apply cleanly on v6.16 or Linus' tree. >> I.e. if you only care about the perf changes, I would just apply on whatever >> branch is convenient and stop when you hit the KVM changes. >> >> My hope/plan is that the perf changes will go through the tip tree with a >> stable tag/branch, and the KVM changes will go the kvm-x86 tree. >> >> Non-x86 KVM folks, y'all are getting Cc'd due to minor changes in "KVM: Add a >> simplified wrapper for registering perf callbacks". >> >> The full set is also available at: >> >> https://github.com/sean-jc/linux.git tags/mediated-vpmu-v5 >> >> Add support for mediated vPMUs in KVM x86, where "mediated" aligns with the >> standard definition of intercepting control operations (e.g. event selectors), >> while allowing the guest to perform data operations (e.g. read PMCs, toggle >> counters on/off) without KVM getting involed. >> >> For an in-depth description of the what and why, please see the cover letter >> from the original RFC: >> >> https://lore.kernel.org/all/20240126085444.324918-1-xiong.y.zhang@xxxxxxxxxxxxxxx >> >> All KVM tests pass (or fail the same before and after), and I've manually >> verified MSR/PMC are passed through as expected, but I haven't done much at all >> to actually utilize the PMU in a guest. I'll be amazed if I didn't make at >> least one major goof. >> >> Similarly, I tried to address all feedback, but there are many, many changes >> relative to v4. If I missed something, I apologize in advance. >> >> In other words, please thoroughly review and test. > Went through the whole patchset, it looks good to me. > > Run all PMU related kselftests and KUT tests on Intel Sapphire Rapids, no > issue is found. We would run broader tests on more Intel platforms. Thanks. Forgot to say "all tests are run for both mediated vPMU and the legacy perf-based vPMU, no issue is found". Thanks. > > >> [*] https://lore.kernel.org/all/20250805190526.1453366-1-seanjc@xxxxxxxxxx >> >> v5: >> - Add a patch to call security_perf_event_free() from __free_event() >> instead of _free_event() (necessitated by the __cleanup() changes). >> - Add CONFIG_PERF_GUEST_MEDIATED_PMU to guard the new perf functionality. >> - Ensure the PMU is fully disabled in perf_{load,put}_guest_context() when >> when switching between guest and host context. [Kan, Namhyung] >> - Route the new system IRQ, PERF_GUEST_MEDIATED_PMI_VECTOR, through perf, >> not KVM, and play nice with FRED. >> - Rename and combine perf_{guest,host}_{enter,exit}() to a single set of >> APIs, perf_{load,put}_guest_context(). >> - Rename perf_{get,put}_mediated_pmu() to perf_{create,release}_mediated_pmu() >> to (hopefully) better differentiate them from perf_{load,put}_guest_context(). >> - Change the param to the load/put APIs from "u32 guest_lvtpc" to >> "unsigned long data" to decouple arch code as much as possible. E.g. if >> a non-x86 arch were to ever support a mediated vPMU, @data could be used >> to pass a pointer to a struct. >> - Use pmu->version to detect if a vCPU has a mediated PMU. >> - Use a kvm_x86_ops hook to check for mediated PMU support. >> - Cull "passthrough" from as many places as I could find. >> - Improve the changelog/documentation related to RDPMC interception. >> - Check harware capabilities, not KVM capabilities, when calculating >> MSR and RDPMC intercepts. >> - Rework intercept (re)calculation to use a request and the existing (well, >> will be existing as of 6.17-rc1) vendor hooks for recalculating intercepts. >> - Always read PERF_GLOBAL_CTRL on VM-Exit if writes weren't intercepted while >> running the vCPU. >> - Call setup_vmcs_config() before kvm_x86_vendor_init() so that the golden >> VMCS configuration is known before kvm_init_pmu_capability() is called. >> - Keep as much refresh/init code in common x86 as possible. >> - Context switch PMCs and event selectors in common x86, not vendor code. >> - Bail from the VM-Exit fastpath if the guest is counting instructions >> retired and the mediated PMU is enabled (because guest state hasn't yet >> been synchronized with hardware). >> - Don't require an userspace to opt-in via KVM_CAP_PMU_CAPABILITY, and instead >> automatically "create" a mediated PMU on the first KVM_CREATE_VCPU call if >> the VM has an in-kernel local APIC. >> - Add entries in kernel-parameters.txt for the PMU params. >> - Add a patch to elide PMC writes when possible. >> - Many more fixups and tweaks... >> >> v4: >> - https://lore.kernel.org/all/20250324173121.1275209-1-mizhang@xxxxxxxxxx >> - 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. >> >> v3: https://lore.kernel.org/all/20240801045907.4010984-1-mizhang@xxxxxxxxxx >> v2: https://lore.kernel.org/all/20240506053020.3911940-1-mizhang@xxxxxxxxxx >> v1: https://lore.kernel.org/all/20240126085444.324918-1-xiong.y.zhang@xxxxxxxxxxxxxxx >> >> Dapeng Mi (15): >> KVM: x86/pmu: Start stubbing in mediated PMU support >> KVM: x86/pmu: Implement Intel mediated PMU requirements and >> constraints >> KVM: x86: Rename vmx_vmentry/vmexit_ctrl() helpers >> KVM: x86/pmu: Move PMU_CAP_{FW_WRITES,LBR_FMT} into msr-index.h header >> KVM: VMX: Add helpers to toggle/change a bit in VMCS execution >> controls >> KVM: x86/pmu: Disable RDPMC interception for compatible mediated vPMU >> KVM: x86/pmu: Load/save GLOBAL_CTRL via entry/exit fields for mediated >> PMU >> KVM: x86/pmu: Use BIT_ULL() instead of open coded equivalents >> KVM: x86/pmu: Disable interception of select PMU MSRs for mediated >> vPMUs >> KVM: x86/pmu: Bypass perf checks when emulating mediated PMU counter >> accesses >> KVM: x86/pmu: Reprogram mediated PMU event selectors on event filter >> updates >> KVM: x86/pmu: Load/put mediated PMU context when entering/exiting >> guest >> KVM: x86/pmu: Handle emulated instruction for mediated vPMU >> KVM: nVMX: Add macros to simplify nested MSR interception setting >> KVM: x86/pmu: Expose enable_mediated_pmu parameter to user space >> >> Kan Liang (7): >> perf: Skip pmu_ctx based on event_type >> perf: Add generic exclude_guest support >> perf: Add APIs to create/release mediated guest vPMUs >> perf: Clean up perf ctx time >> perf: Add a EVENT_GUEST flag >> perf: Add APIs to load/put guest mediated PMU context >> perf/x86/intel: Support PERF_PMU_CAP_MEDIATED_VPMU >> >> Mingwei Zhang (3): >> perf/x86/core: Plumb mediated PMU capability from x86_pmu to >> x86_pmu_cap >> KVM: x86/pmu: Introduce eventsel_hw to prepare for pmu event filtering >> KVM: nVMX: Disable PMU MSR interception as appropriate while running >> L2 >> >> Sandipan Das (3): >> perf/x86/core: Do not set bit width for unavailable counters >> perf/x86/amd: Support PERF_PMU_CAP_MEDIATED_VPMU for AMD host >> KVM: x86/pmu: Always stuff GuestOnly=1,HostOnly=0 for mediated PMCs on >> AMD >> >> Sean Christopherson (15): >> perf: Move security_perf_event_free() call to __free_event() >> perf: core/x86: Register a new vector for handling mediated guest PMIs >> perf/x86: Switch LVTPC to/from mediated PMI vector on guest load/put >> context >> KVM: VMX: Setup canonical VMCS config prior to kvm_x86_vendor_init() >> KVM: SVM: Check pmu->version, not enable_pmu, when getting PMC MSRs >> KVM: Add a simplified wrapper for registering perf callbacks >> KVM: x86/pmu: Snapshot host (i.e. perf's) reported PMU capabilities >> KVM: x86/pmu: Implement AMD mediated PMU requirements >> KVM: x86: Rework KVM_REQ_MSR_FILTER_CHANGED into a generic >> RECALC_INTERCEPTS >> KVM: x86: Use KVM_REQ_RECALC_INTERCEPTS to react to CPUID updates >> KVM: x86/pmu: Move initialization of valid PMCs bitmask to common x86 >> KVM: x86/pmu: Restrict GLOBAL_{CTRL,STATUS}, fixed PMCs, and PEBS to >> PMU v2+ >> KVM: x86/pmu: Disallow emulation in the fastpath if mediated PMCs are >> active >> KVM: nSVM: Disable PMU MSR interception as appropriate while running >> L2 >> KVM: x86/pmu: Elide WRMSRs when loading guest PMCs if values already >> match >> >> Xiong Zhang (1): >> KVM: x86/pmu: Register PMI handler for mediated vPMU >> >> .../admin-guide/kernel-parameters.txt | 49 ++ >> arch/arm64/kvm/arm.c | 2 +- >> arch/loongarch/kvm/main.c | 2 +- >> arch/riscv/kvm/main.c | 2 +- >> arch/x86/entry/entry_fred.c | 1 + >> arch/x86/events/amd/core.c | 2 + >> arch/x86/events/core.c | 32 +- >> arch/x86/events/intel/core.c | 5 + >> arch/x86/include/asm/hardirq.h | 3 + >> arch/x86/include/asm/idtentry.h | 6 + >> arch/x86/include/asm/irq_vectors.h | 4 +- >> arch/x86/include/asm/kvm-x86-ops.h | 2 +- >> arch/x86/include/asm/kvm-x86-pmu-ops.h | 4 + >> arch/x86/include/asm/kvm_host.h | 7 +- >> arch/x86/include/asm/msr-index.h | 17 +- >> arch/x86/include/asm/perf_event.h | 1 + >> arch/x86/include/asm/vmx.h | 1 + >> arch/x86/kernel/idt.c | 3 + >> arch/x86/kernel/irq.c | 19 + >> arch/x86/kvm/Kconfig | 1 + >> arch/x86/kvm/cpuid.c | 2 + >> arch/x86/kvm/pmu.c | 272 ++++++++- >> arch/x86/kvm/pmu.h | 37 +- >> arch/x86/kvm/svm/nested.c | 18 +- >> arch/x86/kvm/svm/pmu.c | 51 +- >> arch/x86/kvm/svm/svm.c | 54 +- >> arch/x86/kvm/vmx/capabilities.h | 11 +- >> arch/x86/kvm/vmx/main.c | 14 +- >> arch/x86/kvm/vmx/nested.c | 65 ++- >> arch/x86/kvm/vmx/pmu_intel.c | 169 ++++-- >> arch/x86/kvm/vmx/pmu_intel.h | 15 + >> arch/x86/kvm/vmx/vmx.c | 143 +++-- >> arch/x86/kvm/vmx/vmx.h | 11 +- >> arch/x86/kvm/vmx/x86_ops.h | 2 +- >> arch/x86/kvm/x86.c | 69 ++- >> arch/x86/kvm/x86.h | 1 + >> include/linux/kvm_host.h | 11 +- >> include/linux/perf_event.h | 38 +- >> init/Kconfig | 4 + >> kernel/events/core.c | 521 ++++++++++++++---- >> .../beauty/arch/x86/include/asm/irq_vectors.h | 3 +- >> virt/kvm/kvm_main.c | 6 +- >> 42 files changed, 1385 insertions(+), 295 deletions(-) >> >> >> base-commit: 53d61a43a7973f812caa08fa922b607574befef4
