Hi Dongli, Since the patch 3 was merged. I think you can rebase this series.
Thanks, Zhao On Fri, Apr 25, 2025 at 02:29:57PM -0700, Dongli Zhang wrote: > Date: Fri, 25 Apr 2025 14:29:57 -0700 > From: Dongli Zhang <dongli.zh...@oracle.com> > Subject: [PATCH v5 00/10] target/i386/kvm/pmu: PMU Enhancement, Bugfix and > Cleanup > X-Mailer: git-send-email 2.43.5 > > This patchset addresses four bugs related to AMD PMU virtualization. > > 1. The PerfMonV2 is still available if PERCORE if disabled via > "-cpu host,-perfctr-core". > > 2. The VM 'cpuid' command still returns PERFCORE although "-pmu" is > configured. > > 3. The third issue is that using "-cpu host,-pmu" does not disable AMD PMU > virtualization. When using "-cpu EPYC" or "-cpu host,-pmu", AMD PMU > virtualization remains enabled. On the VM's Linux side, you might still > see: > > [ 0.510611] Performance Events: Fam17h+ core perfctr, AMD PMU driver. > > instead of: > > [ 0.596381] Performance Events: PMU not available due to virtualization, > using software events only. > [ 0.600972] NMI watchdog: Perf NMI watchdog permanently disabled > > To address this, KVM_CAP_PMU_CAPABILITY is used to set KVM_PMU_CAP_DISABLE > when "-pmu" is configured. > > 4. The fourth issue is that unreclaimed performance events (after a QEMU > system_reset) in KVM may cause random, unwanted, or unknown NMIs to be > injected into the VM. > > The AMD PMU registers are not reset during QEMU system_reset. > > (1) If the VM is reset (e.g., via QEMU system_reset or VM kdump/kexec) while > running "perf top", the PMU registers are not disabled properly. > > (2) Despite x86_cpu_reset() resetting many registers to zero, kvm_put_msrs() > does not handle AMD PMU registers, causing some PMU events to remain > enabled in KVM. > > (3) The KVM kvm_pmc_speculative_in_use() function consistently returns true, > preventing the reclamation of these events. Consequently, the > kvm_pmc->perf_event remains active. > > (4) After a reboot, the VM kernel may report the following error: > > [ 0.092011] Performance Events: Fam17h+ core perfctr, Broken BIOS > detected, complain to your hardware vendor. > [ 0.092023] [Firmware Bug]: the BIOS has corrupted hw-PMU resources (MSR > c0010200 is 530076) > > (5) In the worst case, the active kvm_pmc->perf_event may inject unknown > NMIs randomly into the VM kernel: > > [...] Uhhuh. NMI received for unknown reason 30 on CPU 0. > > To resolve these issues, we propose resetting AMD PMU registers during the > VM reset process > > > Changed since v1: > - Use feature_dependencies for CPUID_EXT3_PERFCORE and > CPUID_8000_0022_EAX_PERFMON_V2. > - Remove CPUID_EXT3_PERFCORE when !cpu->enable_pmu. > - Pick kvm_arch_pre_create_vcpu() patch from Xiaoyao Li. > - Use "-pmu" but not a global "pmu-cap-disabled" for KVM_PMU_CAP_DISABLE. > - Also use sysfs kvm.enable_pmu=N to determine if PMU is supported. > - Some changes to PMU register limit calculation. > Changed since v2: > - Change has_pmu_cap to pmu_cap. > - Use cpuid_find_entry() instead of cpu_x86_cpuid(). > - Rework the code flow of PATCH 07 related to kvm.enable_pmu=N following > Zhao's suggestion. > - Use object_property_get_int() to get CPU family. > - Add support to Zhaoxin. > Changed since v3: > - Re-base on top of Zhao's queued patch. > - Use host_cpu_vendor_fms() from Zhao's patch. > - Pick new version of kvm_arch_pre_create_vcpu() patch from Xiaoyao. > - Re-split the cases into enable_pmu and !enable_pmu, following Zhao's > suggestion. > - Check AMD directly makes the "compat" rule clear. > - Some changes on commit message and comment. > - Bring back global static variable 'kvm_pmu_disabled' read from > /sys/module/kvm/parameters/enable_pmu. > Changed since v4: > - Re-base on top of most recent mainline QEMU. > - Add more Reviewed-by. > - All patches are reviewed. > > > Xiaoyao Li (1): > kvm: Introduce kvm_arch_pre_create_vcpu() > > Dongli Zhang (9): > target/i386: disable PerfMonV2 when PERFCORE unavailable > target/i386: disable PERFCORE when "-pmu" is configured > target/i386/kvm: set KVM_PMU_CAP_DISABLE if "-pmu" is configured > target/i386/kvm: extract unrelated code out of kvm_x86_build_cpuid() > target/i386/kvm: rename architectural PMU variables > target/i386/kvm: query kvm.enable_pmu parameter > target/i386/kvm: reset AMD PMU registers during VM reset > target/i386/kvm: support perfmon-v2 for reset > target/i386/kvm: don't stop Intel PMU counters > > accel/kvm/kvm-all.c | 5 + > include/system/kvm.h | 1 + > target/arm/kvm.c | 5 + > target/i386/cpu.c | 8 + > target/i386/cpu.h | 16 ++ > target/i386/kvm/kvm.c | 360 ++++++++++++++++++++++++++++++++++------ > target/loongarch/kvm/kvm.c | 4 + > target/mips/kvm.c | 5 + > target/ppc/kvm.c | 5 + > target/riscv/kvm/kvm-cpu.c | 5 + > target/s390x/kvm/kvm.c | 5 + > 11 files changed, 372 insertions(+), 47 deletions(-) > > base-commit: 019fbfa4bcd2d3a835c241295e22ab2b5b56129b > > Thank you very much! > > Dongli Zhang >
