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3d91befbb3
Enable/disable event counters as appropriate when entering and exiting the guest to enable support for guest or host only event counting. For both VHE and non-VHE we switch the counters between host/guest at EL2. The PMU may be on when we change which counters are enabled however we avoid adding an isb as we instead rely on existing context synchronisation events: the eret to enter the guest (__guest_enter) and eret in kvm_call_hyp for __kvm_vcpu_run_nvhe on returning. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2019 Arm Limited
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* Author: Andrew Murray <Andrew.Murray@arm.com>
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*/
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#include <linux/kvm_host.h>
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#include <linux/perf_event.h>
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#include <asm/kvm_hyp.h>
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/*
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* Given the exclude_{host,guest} attributes, determine if we are going
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* to need to switch counters at guest entry/exit.
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*/
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static bool kvm_pmu_switch_needed(struct perf_event_attr *attr)
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{
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/* Only switch if attributes are different */
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return (attr->exclude_host != attr->exclude_guest);
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}
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/*
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* Add events to track that we may want to switch at guest entry/exit
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* time.
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*/
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void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
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{
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struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data);
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if (!kvm_pmu_switch_needed(attr))
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return;
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if (!attr->exclude_host)
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ctx->pmu_events.events_host |= set;
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if (!attr->exclude_guest)
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ctx->pmu_events.events_guest |= set;
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}
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/*
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* Stop tracking events
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*/
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void kvm_clr_pmu_events(u32 clr)
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{
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struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data);
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ctx->pmu_events.events_host &= ~clr;
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ctx->pmu_events.events_guest &= ~clr;
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}
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/**
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* Disable host events, enable guest events
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*/
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bool __hyp_text __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt)
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{
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struct kvm_host_data *host;
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struct kvm_pmu_events *pmu;
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host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
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pmu = &host->pmu_events;
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if (pmu->events_host)
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write_sysreg(pmu->events_host, pmcntenclr_el0);
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if (pmu->events_guest)
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write_sysreg(pmu->events_guest, pmcntenset_el0);
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return (pmu->events_host || pmu->events_guest);
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}
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/**
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* Disable guest events, enable host events
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*/
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void __hyp_text __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt)
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{
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struct kvm_host_data *host;
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struct kvm_pmu_events *pmu;
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host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
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pmu = &host->pmu_events;
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if (pmu->events_guest)
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write_sysreg(pmu->events_guest, pmcntenclr_el0);
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if (pmu->events_host)
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write_sysreg(pmu->events_host, pmcntenset_el0);
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}
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