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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>
static DEFINE_PER_CPU(struct kvm_pmu_events, kvm_pmu_events);
/*
* 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);
}
struct kvm_pmu_events *kvm_get_pmu_events(void)
{
return this_cpu_ptr(&kvm_pmu_events);
}
/*
* 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_pmu_events *pmu = kvm_get_pmu_events();
if (!kvm_arm_support_pmu_v3() || !pmu || !kvm_pmu_switch_needed(attr))
return;
if (!attr->exclude_host)
pmu->events_host |= set;
if (!attr->exclude_guest)
pmu->events_guest |= set;
}
/*
* Stop tracking events
*/
void kvm_clr_pmu_events(u32 clr)
{
struct kvm_pmu_events *pmu = kvm_get_pmu_events();
if (!kvm_arm_support_pmu_v3() || !pmu)
return;
pmu->events_host &= ~clr;
pmu->events_guest &= ~clr;
}
#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.
* This is called from both vcpu_{load,put} and the sysreg handling.
* Since the latter is preemptible, special care must be taken to
* disable preemption.
*/
void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu)
{
struct kvm_pmu_events *pmu;
u32 events_guest, events_host;
if (!kvm_arm_support_pmu_v3() || !has_vhe())
return;
preempt_disable();
pmu = kvm_get_pmu_events();
events_guest = pmu->events_guest;
events_host = pmu->events_host;
kvm_vcpu_pmu_enable_el0(events_guest);
kvm_vcpu_pmu_disable_el0(events_host);
preempt_enable();
}
/*
* On VHE ensure that only host events have EL0 counting enabled
*/
void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu)
{
struct kvm_pmu_events *pmu;
u32 events_guest, events_host;
if (!kvm_arm_support_pmu_v3() || !has_vhe())
return;
pmu = kvm_get_pmu_events();
events_guest = pmu->events_guest;
events_host = pmu->events_host;
kvm_vcpu_pmu_enable_el0(events_host);
kvm_vcpu_pmu_disable_el0(events_guest);
}
/*
* With VHE, keep track of the PMUSERENR_EL0 value for the host EL0 on the pCPU
* where PMUSERENR_EL0 for the guest is loaded, since PMUSERENR_EL0 is switched
* to the value for the guest on vcpu_load(). The value for the host EL0
* will be restored on vcpu_put(), before returning to userspace.
* This isn't necessary for nVHE, as the register is context switched for
* every guest enter/exit.
*
* Return true if KVM takes care of the register. Otherwise return false.
*/
bool kvm_set_pmuserenr(u64 val)
{
struct kvm_cpu_context *hctxt;
struct kvm_vcpu *vcpu;
if (!kvm_arm_support_pmu_v3() || !has_vhe())
return false;
vcpu = kvm_get_running_vcpu();
if (!vcpu || !vcpu_get_flag(vcpu, PMUSERENR_ON_CPU))
return false;
hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
ctxt_sys_reg(hctxt, PMUSERENR_EL0) = val;
return true;
}
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