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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);
}
#define PMEVTYPER_READ_CASE(idx) \
case idx: \
return read_sysreg(pmevtyper##idx##_el0)
#define PMEVTYPER_WRITE_CASE(idx) \
case idx: \
write_sysreg(val, pmevtyper##idx##_el0); \
break
#define PMEVTYPER_CASES(readwrite) \
PMEVTYPER_##readwrite##_CASE(0); \
PMEVTYPER_##readwrite##_CASE(1); \
PMEVTYPER_##readwrite##_CASE(2); \
PMEVTYPER_##readwrite##_CASE(3); \
PMEVTYPER_##readwrite##_CASE(4); \
PMEVTYPER_##readwrite##_CASE(5); \
PMEVTYPER_##readwrite##_CASE(6); \
PMEVTYPER_##readwrite##_CASE(7); \
PMEVTYPER_##readwrite##_CASE(8); \
PMEVTYPER_##readwrite##_CASE(9); \
PMEVTYPER_##readwrite##_CASE(10); \
PMEVTYPER_##readwrite##_CASE(11); \
PMEVTYPER_##readwrite##_CASE(12); \
PMEVTYPER_##readwrite##_CASE(13); \
PMEVTYPER_##readwrite##_CASE(14); \
PMEVTYPER_##readwrite##_CASE(15); \
PMEVTYPER_##readwrite##_CASE(16); \
PMEVTYPER_##readwrite##_CASE(17); \
PMEVTYPER_##readwrite##_CASE(18); \
PMEVTYPER_##readwrite##_CASE(19); \
PMEVTYPER_##readwrite##_CASE(20); \
PMEVTYPER_##readwrite##_CASE(21); \
PMEVTYPER_##readwrite##_CASE(22); \
PMEVTYPER_##readwrite##_CASE(23); \
PMEVTYPER_##readwrite##_CASE(24); \
PMEVTYPER_##readwrite##_CASE(25); \
PMEVTYPER_##readwrite##_CASE(26); \
PMEVTYPER_##readwrite##_CASE(27); \
PMEVTYPER_##readwrite##_CASE(28); \
PMEVTYPER_##readwrite##_CASE(29); \
PMEVTYPER_##readwrite##_CASE(30)
/*
* Read a value direct from PMEVTYPER<idx> where idx is 0-30
* or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
*/
static u64 kvm_vcpu_pmu_read_evtype_direct(int idx)
{
switch (idx) {
PMEVTYPER_CASES(READ);
case ARMV8_PMU_CYCLE_IDX:
return read_sysreg(pmccfiltr_el0);
default:
WARN_ON(1);
}
return 0;
}
/*
* Write a value direct to PMEVTYPER<idx> where idx is 0-30
* or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
*/
static void kvm_vcpu_pmu_write_evtype_direct(int idx, u32 val)
{
switch (idx) {
PMEVTYPER_CASES(WRITE);
case ARMV8_PMU_CYCLE_IDX:
write_sysreg(val, pmccfiltr_el0);
break;
default:
WARN_ON(1);
}
}
/*
* 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) {
typer = kvm_vcpu_pmu_read_evtype_direct(counter);
typer &= ~ARMV8_PMU_EXCLUDE_EL0;
kvm_vcpu_pmu_write_evtype_direct(counter, typer);
}
}
/*
* 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) {
typer = kvm_vcpu_pmu_read_evtype_direct(counter);
typer |= ARMV8_PMU_EXCLUDE_EL0;
kvm_vcpu_pmu_write_evtype_direct(counter, typer);
}
}
/*
* 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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