From: Dapeng Mi <[email protected]> Explicitly zero kvm_host_pmu instead of attempting to get the perf PMU capabilities when running on a hybrid CPU to avoid running afoul of perf's sanity check.
------------[ cut here ]------------ WARNING: arch/x86/events/core.c:3089 at perf_get_x86_pmu_capability+0xd/0xc0, Call Trace: <TASK> kvm_x86_vendor_init+0x1b0/0x1a40 [kvm] vmx_init+0xdb/0x260 [kvm_intel] vt_init+0x12/0x9d0 [kvm_intel] do_one_initcall+0x60/0x3f0 do_init_module+0x97/0x2b0 load_module+0x2d08/0x2e30 init_module_from_file+0x96/0xe0 idempotent_init_module+0x117/0x330 __x64_sys_finit_module+0x73/0xe0 Always read the capabilities for non-hybrid CPUs, i.e. don't entirely revert to reading capabilities if and only if KVM wants to use a PMU, as it may be useful to have the host PMU capabilities available, e.g. if only or debug. Reported-by: Chaitanya Kumar Borah <[email protected]> Closes: https://lore.kernel.org/all/[email protected]/ Fixes: 51f34b1e650f ("KVM: x86/pmu: Snapshot host (i.e. perf's) reported PMU capabilities") Suggested-by: Sean Christopherson <[email protected]> Signed-off-by: Dapeng Mi <[email protected]> Link: https://lore.kernel.org/r/[email protected] [sean: rework changelog, call out hybrid CPUs in shortlog] References: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15122 Signed-off-by: Sean Christopherson <[email protected]> --- arch/x86/kvm/pmu.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 40ac4cb44ed2..487ad19a236e 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -108,16 +108,18 @@ void kvm_init_pmu_capability(const struct kvm_pmu_ops *pmu_ops) bool is_intel = boot_cpu_data.x86_vendor == X86_VENDOR_INTEL; int min_nr_gp_ctrs = pmu_ops->MIN_NR_GP_COUNTERS; - perf_get_x86_pmu_capability(&kvm_host_pmu); - /* * Hybrid PMUs don't play nice with virtualization without careful * configuration by userspace, and KVM's APIs for reporting supported * vPMU features do not account for hybrid PMUs. Disable vPMU support * for hybrid PMUs until KVM gains a way to let userspace opt-in. */ - if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU)) + if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU)) { enable_pmu = false; + memset(&kvm_host_pmu, 0, sizeof(kvm_host_pmu)); + } else { + perf_get_x86_pmu_capability(&kvm_host_pmu); + } if (enable_pmu) { /* -- 2.25.1
