From 30cd8604323dbaf20a80e797fe7057f5b02e394d Mon Sep 17 00:00:00 2001 From: Eric Hankland Date: Thu, 18 Jul 2019 11:38:18 -0700 Subject: [PATCH] KVM: x86: Add fixed counters to PMU filter Updates KVM_CAP_PMU_EVENT_FILTER so it can also whitelist or blacklist fixed counters. Signed-off-by: Eric Hankland [No need to check padding fields for zero. - Paolo] Signed-off-by: Paolo Bonzini --- Documentation/virtual/kvm/api.txt | 15 ++++++++++----- arch/x86/include/uapi/asm/kvm.h | 9 ++++++--- arch/x86/kvm/pmu.c | 23 +++++++++++++++++++---- 3 files changed, 35 insertions(+), 12 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 2cd6250..e54a3f5 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -4090,17 +4090,22 @@ Parameters: struct kvm_pmu_event_filter (in) Returns: 0 on success, -1 on error struct kvm_pmu_event_filter { - __u32 action; - __u32 nevents; - __u64 events[0]; + __u32 action; + __u32 nevents; + __u32 fixed_counter_bitmap; + __u32 flags; + __u32 pad[4]; + __u64 events[0]; }; This ioctl restricts the set of PMU events that the guest can program. The argument holds a list of events which will be allowed or denied. The eventsel+umask of each event the guest attempts to program is compared against the events field to determine whether the guest should have access. -This only affects general purpose counters; fixed purpose counters can -be disabled by changing the perfmon CPUID leaf. +The events field only controls general purpose counters; fixed purpose +counters are controlled by the fixed_counter_bitmap. + +No flags are defined yet, the field must be zero. Valid values for 'action': #define KVM_PMU_EVENT_ALLOW 0 diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index e901b0a..503d3f4 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -435,9 +435,12 @@ struct kvm_nested_state { /* for KVM_CAP_PMU_EVENT_FILTER */ struct kvm_pmu_event_filter { - __u32 action; - __u32 nevents; - __u64 events[0]; + __u32 action; + __u32 nevents; + __u32 fixed_counter_bitmap; + __u32 flags; + __u32 pad[4]; + __u64 events[0]; }; #define KVM_PMU_EVENT_ALLOW 0 diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index cedaa01..46875bb 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -19,8 +19,8 @@ #include "lapic.h" #include "pmu.h" -/* This keeps the total size of the filter under 4k. */ -#define KVM_PMU_EVENT_FILTER_MAX_EVENTS 63 +/* This is enough to filter the vast majority of currently defined events. */ +#define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300 /* NOTE: * - Each perf counter is defined as "struct kvm_pmc"; @@ -206,12 +206,24 @@ void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx) { unsigned en_field = ctrl & 0x3; bool pmi = ctrl & 0x8; + struct kvm_pmu_event_filter *filter; + struct kvm *kvm = pmc->vcpu->kvm; pmc_stop_counter(pmc); if (!en_field || !pmc_is_enabled(pmc)) return; + filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu); + if (filter) { + if (filter->action == KVM_PMU_EVENT_DENY && + test_bit(idx, (ulong *)&filter->fixed_counter_bitmap)) + return; + if (filter->action == KVM_PMU_EVENT_ALLOW && + !test_bit(idx, (ulong *)&filter->fixed_counter_bitmap)) + return; + } + pmc_reprogram_counter(pmc, PERF_TYPE_HARDWARE, kvm_x86_ops->pmu_ops->find_fixed_event(idx), !(en_field & 0x2), /* exclude user */ @@ -385,6 +397,9 @@ int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp) tmp.action != KVM_PMU_EVENT_DENY) return -EINVAL; + if (tmp.flags != 0) + return -EINVAL; + if (tmp.nevents > KVM_PMU_EVENT_FILTER_MAX_EVENTS) return -E2BIG; @@ -406,8 +421,8 @@ int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp) mutex_unlock(&kvm->lock); synchronize_srcu_expedited(&kvm->srcu); - r = 0; + r = 0; cleanup: kfree(filter); - return r; + return r; } -- 2.7.4