linux/virt/kvm/arm/pmu.c
Christoffer Dall 8d404c4c24 KVM: arm64: Rewrite system register accessors to read/write functions
Currently we access the system registers array via the vcpu_sys_reg()
macro.  However, we are about to change the behavior to some times
modify the register file directly, so let's change this to two
primitives:

 * Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg()
 * Direct array access macro __vcpu_sys_reg()

The accessor macros should be used in places where the code needs to
access the currently loaded VCPU's state as observed by the guest.  For
example, when trapping on cache related registers, a write to a system
register should go directly to the VCPU version of the register.

The direct array access macro can be used in places where the VCPU is
known to never be running (for example userspace access) or for
registers which are never context switched (for example all the PMU
system registers).

This rewrites all users of vcpu_sys_regs to one of the macros described
above.

No functional change.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-03-19 10:53:16 +00:00

607 lines
15 KiB
C

/*
* Copyright (C) 2015 Linaro Ltd.
* Author: Shannon Zhao <shannon.zhao@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/cpu.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/perf_event.h>
#include <linux/uaccess.h>
#include <asm/kvm_emulate.h>
#include <kvm/arm_pmu.h>
#include <kvm/arm_vgic.h>
/**
* kvm_pmu_get_counter_value - get PMU counter value
* @vcpu: The vcpu pointer
* @select_idx: The counter index
*/
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
{
u64 counter, reg, enabled, running;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc = &pmu->pmc[select_idx];
reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
counter = __vcpu_sys_reg(vcpu, reg);
/* The real counter value is equal to the value of counter register plus
* the value perf event counts.
*/
if (pmc->perf_event)
counter += perf_event_read_value(pmc->perf_event, &enabled,
&running);
return counter & pmc->bitmask;
}
/**
* kvm_pmu_set_counter_value - set PMU counter value
* @vcpu: The vcpu pointer
* @select_idx: The counter index
* @val: The counter value
*/
void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
{
u64 reg;
reg = (select_idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + select_idx;
__vcpu_sys_reg(vcpu, reg) += (s64)val - kvm_pmu_get_counter_value(vcpu, select_idx);
}
/**
* kvm_pmu_stop_counter - stop PMU counter
* @pmc: The PMU counter pointer
*
* If this counter has been configured to monitor some event, release it here.
*/
static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
{
u64 counter, reg;
if (pmc->perf_event) {
counter = kvm_pmu_get_counter_value(vcpu, pmc->idx);
reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;
__vcpu_sys_reg(vcpu, reg) = counter;
perf_event_disable(pmc->perf_event);
perf_event_release_kernel(pmc->perf_event);
pmc->perf_event = NULL;
}
}
/**
* kvm_pmu_vcpu_reset - reset pmu state for cpu
* @vcpu: The vcpu pointer
*
*/
void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]);
pmu->pmc[i].idx = i;
pmu->pmc[i].bitmask = 0xffffffffUL;
}
}
/**
* kvm_pmu_vcpu_destroy - free perf event of PMU for cpu
* @vcpu: The vcpu pointer
*
*/
void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
struct kvm_pmc *pmc = &pmu->pmc[i];
if (pmc->perf_event) {
perf_event_disable(pmc->perf_event);
perf_event_release_kernel(pmc->perf_event);
pmc->perf_event = NULL;
}
}
}
u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
{
u64 val = __vcpu_sys_reg(vcpu, PMCR_EL0) >> ARMV8_PMU_PMCR_N_SHIFT;
val &= ARMV8_PMU_PMCR_N_MASK;
if (val == 0)
return BIT(ARMV8_PMU_CYCLE_IDX);
else
return GENMASK(val - 1, 0) | BIT(ARMV8_PMU_CYCLE_IDX);
}
/**
* kvm_pmu_enable_counter - enable selected PMU counter
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENSET register
*
* Call perf_event_enable to start counting the perf event
*/
void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) || !val)
return;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
if (!(val & BIT(i)))
continue;
pmc = &pmu->pmc[i];
if (pmc->perf_event) {
perf_event_enable(pmc->perf_event);
if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE)
kvm_debug("fail to enable perf event\n");
}
}
}
/**
* kvm_pmu_disable_counter - disable selected PMU counter
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCNTENCLR register
*
* Call perf_event_disable to stop counting the perf event
*/
void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val)
{
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
if (!val)
return;
for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
if (!(val & BIT(i)))
continue;
pmc = &pmu->pmc[i];
if (pmc->perf_event)
perf_event_disable(pmc->perf_event);
}
}
static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
{
u64 reg = 0;
if ((__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E)) {
reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
reg &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
reg &= __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
reg &= kvm_pmu_valid_counter_mask(vcpu);
}
return reg;
}
static void kvm_pmu_update_state(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
bool overflow;
if (!kvm_arm_pmu_v3_ready(vcpu))
return;
overflow = !!kvm_pmu_overflow_status(vcpu);
if (pmu->irq_level == overflow)
return;
pmu->irq_level = overflow;
if (likely(irqchip_in_kernel(vcpu->kvm))) {
int ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
pmu->irq_num, overflow, pmu);
WARN_ON(ret);
}
}
bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_sync_regs *sregs = &vcpu->run->s.regs;
bool run_level = sregs->device_irq_level & KVM_ARM_DEV_PMU;
if (likely(irqchip_in_kernel(vcpu->kvm)))
return false;
return pmu->irq_level != run_level;
}
/*
* Reflect the PMU overflow interrupt output level into the kvm_run structure
*/
void kvm_pmu_update_run(struct kvm_vcpu *vcpu)
{
struct kvm_sync_regs *regs = &vcpu->run->s.regs;
/* Populate the timer bitmap for user space */
regs->device_irq_level &= ~KVM_ARM_DEV_PMU;
if (vcpu->arch.pmu.irq_level)
regs->device_irq_level |= KVM_ARM_DEV_PMU;
}
/**
* kvm_pmu_flush_hwstate - flush pmu state to cpu
* @vcpu: The vcpu pointer
*
* Check if the PMU has overflowed while we were running in the host, and inject
* an interrupt if that was the case.
*/
void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu)
{
kvm_pmu_update_state(vcpu);
}
/**
* kvm_pmu_sync_hwstate - sync pmu state from cpu
* @vcpu: The vcpu pointer
*
* Check if the PMU has overflowed while we were running in the guest, and
* inject an interrupt if that was the case.
*/
void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu)
{
kvm_pmu_update_state(vcpu);
}
static inline struct kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
{
struct kvm_pmu *pmu;
struct kvm_vcpu_arch *vcpu_arch;
pmc -= pmc->idx;
pmu = container_of(pmc, struct kvm_pmu, pmc[0]);
vcpu_arch = container_of(pmu, struct kvm_vcpu_arch, pmu);
return container_of(vcpu_arch, struct kvm_vcpu, arch);
}
/**
* When the perf event overflows, set the overflow status and inform the vcpu.
*/
static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct kvm_pmc *pmc = perf_event->overflow_handler_context;
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
int idx = pmc->idx;
__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(idx);
if (kvm_pmu_overflow_status(vcpu)) {
kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
kvm_vcpu_kick(vcpu);
}
}
/**
* kvm_pmu_software_increment - do software increment
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMSWINC register
*/
void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
{
int i;
u64 type, enable, reg;
if (val == 0)
return;
enable = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++) {
if (!(val & BIT(i)))
continue;
type = __vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + i)
& ARMV8_PMU_EVTYPE_EVENT;
if ((type == ARMV8_PMUV3_PERFCTR_SW_INCR)
&& (enable & BIT(i))) {
reg = __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) + 1;
reg = lower_32_bits(reg);
__vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = reg;
if (!reg)
__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(i);
}
}
}
/**
* kvm_pmu_handle_pmcr - handle PMCR register
* @vcpu: The vcpu pointer
* @val: the value guest writes to PMCR register
*/
void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc;
u64 mask;
int i;
mask = kvm_pmu_valid_counter_mask(vcpu);
if (val & ARMV8_PMU_PMCR_E) {
kvm_pmu_enable_counter(vcpu,
__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask);
} else {
kvm_pmu_disable_counter(vcpu, mask);
}
if (val & ARMV8_PMU_PMCR_C)
kvm_pmu_set_counter_value(vcpu, ARMV8_PMU_CYCLE_IDX, 0);
if (val & ARMV8_PMU_PMCR_P) {
for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++)
kvm_pmu_set_counter_value(vcpu, i, 0);
}
if (val & ARMV8_PMU_PMCR_LC) {
pmc = &pmu->pmc[ARMV8_PMU_CYCLE_IDX];
pmc->bitmask = 0xffffffffffffffffUL;
}
}
static bool kvm_pmu_counter_is_enabled(struct kvm_vcpu *vcpu, u64 select_idx)
{
return (__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) &&
(__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & BIT(select_idx));
}
/**
* kvm_pmu_set_counter_event_type - set selected counter to monitor some event
* @vcpu: The vcpu pointer
* @data: The data guest writes to PMXEVTYPER_EL0
* @select_idx: The number of selected counter
*
* When OS accesses PMXEVTYPER_EL0, that means it wants to set a PMC to count an
* event with given hardware event number. Here we call perf_event API to
* emulate this action and create a kernel perf event for it.
*/
void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
u64 select_idx)
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc = &pmu->pmc[select_idx];
struct perf_event *event;
struct perf_event_attr attr;
u64 eventsel, counter;
kvm_pmu_stop_counter(vcpu, pmc);
eventsel = data & ARMV8_PMU_EVTYPE_EVENT;
/* Software increment event does't need to be backed by a perf event */
if (eventsel == ARMV8_PMUV3_PERFCTR_SW_INCR &&
select_idx != ARMV8_PMU_CYCLE_IDX)
return;
memset(&attr, 0, sizeof(struct perf_event_attr));
attr.type = PERF_TYPE_RAW;
attr.size = sizeof(attr);
attr.pinned = 1;
attr.disabled = !kvm_pmu_counter_is_enabled(vcpu, select_idx);
attr.exclude_user = data & ARMV8_PMU_EXCLUDE_EL0 ? 1 : 0;
attr.exclude_kernel = data & ARMV8_PMU_EXCLUDE_EL1 ? 1 : 0;
attr.exclude_hv = 1; /* Don't count EL2 events */
attr.exclude_host = 1; /* Don't count host events */
attr.config = (select_idx == ARMV8_PMU_CYCLE_IDX) ?
ARMV8_PMUV3_PERFCTR_CPU_CYCLES : eventsel;
counter = kvm_pmu_get_counter_value(vcpu, select_idx);
/* The initial sample period (overflow count) of an event. */
attr.sample_period = (-counter) & pmc->bitmask;
event = perf_event_create_kernel_counter(&attr, -1, current,
kvm_pmu_perf_overflow, pmc);
if (IS_ERR(event)) {
pr_err_once("kvm: pmu event creation failed %ld\n",
PTR_ERR(event));
return;
}
pmc->perf_event = event;
}
bool kvm_arm_support_pmu_v3(void)
{
/*
* Check if HW_PERF_EVENTS are supported by checking the number of
* hardware performance counters. This could ensure the presence of
* a physical PMU and CONFIG_PERF_EVENT is selected.
*/
return (perf_num_counters() > 0);
}
int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu)
{
if (!vcpu->arch.pmu.created)
return 0;
/*
* A valid interrupt configuration for the PMU is either to have a
* properly configured interrupt number and using an in-kernel
* irqchip, or to not have an in-kernel GIC and not set an IRQ.
*/
if (irqchip_in_kernel(vcpu->kvm)) {
int irq = vcpu->arch.pmu.irq_num;
if (!kvm_arm_pmu_irq_initialized(vcpu))
return -EINVAL;
/*
* If we are using an in-kernel vgic, at this point we know
* the vgic will be initialized, so we can check the PMU irq
* number against the dimensions of the vgic and make sure
* it's valid.
*/
if (!irq_is_ppi(irq) && !vgic_valid_spi(vcpu->kvm, irq))
return -EINVAL;
} else if (kvm_arm_pmu_irq_initialized(vcpu)) {
return -EINVAL;
}
kvm_pmu_vcpu_reset(vcpu);
vcpu->arch.pmu.ready = true;
return 0;
}
static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu)
{
if (!kvm_arm_support_pmu_v3())
return -ENODEV;
if (!test_bit(KVM_ARM_VCPU_PMU_V3, vcpu->arch.features))
return -ENXIO;
if (vcpu->arch.pmu.created)
return -EBUSY;
if (irqchip_in_kernel(vcpu->kvm)) {
int ret;
/*
* If using the PMU with an in-kernel virtual GIC
* implementation, we require the GIC to be already
* initialized when initializing the PMU.
*/
if (!vgic_initialized(vcpu->kvm))
return -ENODEV;
if (!kvm_arm_pmu_irq_initialized(vcpu))
return -ENXIO;
ret = kvm_vgic_set_owner(vcpu, vcpu->arch.pmu.irq_num,
&vcpu->arch.pmu);
if (ret)
return ret;
}
vcpu->arch.pmu.created = true;
return 0;
}
/*
* For one VM the interrupt type must be same for each vcpu.
* As a PPI, the interrupt number is the same for all vcpus,
* while as an SPI it must be a separate number per vcpu.
*/
static bool pmu_irq_is_valid(struct kvm *kvm, int irq)
{
int i;
struct kvm_vcpu *vcpu;
kvm_for_each_vcpu(i, vcpu, kvm) {
if (!kvm_arm_pmu_irq_initialized(vcpu))
continue;
if (irq_is_ppi(irq)) {
if (vcpu->arch.pmu.irq_num != irq)
return false;
} else {
if (vcpu->arch.pmu.irq_num == irq)
return false;
}
}
return true;
}
int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
switch (attr->attr) {
case KVM_ARM_VCPU_PMU_V3_IRQ: {
int __user *uaddr = (int __user *)(long)attr->addr;
int irq;
if (!irqchip_in_kernel(vcpu->kvm))
return -EINVAL;
if (!test_bit(KVM_ARM_VCPU_PMU_V3, vcpu->arch.features))
return -ENODEV;
if (get_user(irq, uaddr))
return -EFAULT;
/* The PMU overflow interrupt can be a PPI or a valid SPI. */
if (!(irq_is_ppi(irq) || irq_is_spi(irq)))
return -EINVAL;
if (!pmu_irq_is_valid(vcpu->kvm, irq))
return -EINVAL;
if (kvm_arm_pmu_irq_initialized(vcpu))
return -EBUSY;
kvm_debug("Set kvm ARM PMU irq: %d\n", irq);
vcpu->arch.pmu.irq_num = irq;
return 0;
}
case KVM_ARM_VCPU_PMU_V3_INIT:
return kvm_arm_pmu_v3_init(vcpu);
}
return -ENXIO;
}
int kvm_arm_pmu_v3_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
switch (attr->attr) {
case KVM_ARM_VCPU_PMU_V3_IRQ: {
int __user *uaddr = (int __user *)(long)attr->addr;
int irq;
if (!irqchip_in_kernel(vcpu->kvm))
return -EINVAL;
if (!test_bit(KVM_ARM_VCPU_PMU_V3, vcpu->arch.features))
return -ENODEV;
if (!kvm_arm_pmu_irq_initialized(vcpu))
return -ENXIO;
irq = vcpu->arch.pmu.irq_num;
return put_user(irq, uaddr);
}
}
return -ENXIO;
}
int kvm_arm_pmu_v3_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
switch (attr->attr) {
case KVM_ARM_VCPU_PMU_V3_IRQ:
case KVM_ARM_VCPU_PMU_V3_INIT:
if (kvm_arm_support_pmu_v3() &&
test_bit(KVM_ARM_VCPU_PMU_V3, vcpu->arch.features))
return 0;
}
return -ENXIO;
}