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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2019 Arm Limited
* Author: Andrew Murray <Andrew.Murray@arm.com>
*/
#include <linux/kvm_host.h>
#include <linux/perf_event.h>
#include <asm/kvm_hyp.h>
/*
* Given the perf event attributes and system type, determine
* if we are going to need to switch counters at guest entry/exit.
*/
static bool kvm_pmu_switch_needed(struct perf_event_attr *attr)
{
/**
* With VHE the guest kernel runs at EL1 and the host at EL2,
* where user (EL0) is excluded then we have no reason to switch
* counters.
*/
if (has_vhe() && attr->exclude_user)
return false;
/* Only switch if attributes are different */
return (attr->exclude_host != attr->exclude_guest);
}
/*
* Add events to track that we may want to switch at guest entry/exit
* time.
*/
void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
{
struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data);
if (!kvm_pmu_switch_needed(attr))
return;
if (!attr->exclude_host)
ctx->pmu_events.events_host |= set;
if (!attr->exclude_guest)
ctx->pmu_events.events_guest |= set;
}
/*
* Stop tracking events
*/
void kvm_clr_pmu_events(u32 clr)
{
struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data);
ctx->pmu_events.events_host &= ~clr;
ctx->pmu_events.events_guest &= ~clr;
}
/**
* Disable host events, enable guest events
*/
bool __hyp_text __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt)
{
struct kvm_host_data *host;
struct kvm_pmu_events *pmu;
host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
pmu = &host->pmu_events;
if (pmu->events_host)
write_sysreg(pmu->events_host, pmcntenclr_el0);
if (pmu->events_guest)
write_sysreg(pmu->events_guest, pmcntenset_el0);
return (pmu->events_host || pmu->events_guest);
}
/**
* Disable guest events, enable host events
*/
void __hyp_text __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt)
{
struct kvm_host_data *host;
struct kvm_pmu_events *pmu;
host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
pmu = &host->pmu_events;
if (pmu->events_guest)
write_sysreg(pmu->events_guest, pmcntenclr_el0);
if (pmu->events_host)
write_sysreg(pmu->events_host, pmcntenset_el0);
}
/*
* Modify ARMv8 PMU events to include EL0 counting
*/
static void kvm_vcpu_pmu_enable_el0(unsigned long events)
{
u64 typer;
u32 counter;
for_each_set_bit(counter, &events, 32) {
write_sysreg(counter, pmselr_el0);
isb();
typer = read_sysreg(pmxevtyper_el0) & ~ARMV8_PMU_EXCLUDE_EL0;
write_sysreg(typer, pmxevtyper_el0);
isb();
}
}
/*
* Modify ARMv8 PMU events to exclude EL0 counting
*/
static void kvm_vcpu_pmu_disable_el0(unsigned long events)
{
u64 typer;
u32 counter;
for_each_set_bit(counter, &events, 32) {
write_sysreg(counter, pmselr_el0);
isb();
typer = read_sysreg(pmxevtyper_el0) | ARMV8_PMU_EXCLUDE_EL0;
write_sysreg(typer, pmxevtyper_el0);
isb();
}
}
/*
* On VHE ensure that only guest events have EL0 counting enabled
*/
void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_host_data *host;
u32 events_guest, events_host;
if (!has_vhe())
return;
host_ctxt = vcpu->arch.host_cpu_context;
host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
events_guest = host->pmu_events.events_guest;
events_host = host->pmu_events.events_host;
kvm_vcpu_pmu_enable_el0(events_guest);
kvm_vcpu_pmu_disable_el0(events_host);
}
/*
* On VHE ensure that only host events have EL0 counting enabled
*/
void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_host_data *host;
u32 events_guest, events_host;
if (!has_vhe())
return;
host_ctxt = vcpu->arch.host_cpu_context;
host = container_of(host_ctxt, struct kvm_host_data, host_ctxt);
events_guest = host->pmu_events.events_guest;
events_host = host->pmu_events.events_host;
kvm_vcpu_pmu_enable_el0(events_host);
kvm_vcpu_pmu_disable_el0(events_guest);
}
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