https://github.com/torvalds/linux
Tip revision: eb7081409f94a9a8608593d0fb63a1aa3d6f95d8 authored by Linus Torvalds on 21 November 2022, 00:02:16 UTC
Linux 6.1-rc6
Linux 6.1-rc6
Tip revision: eb70814
pmu.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Kernel-based Virtual Machine -- Performance Monitoring Unit support
*
* Copyright 2015 Red Hat, Inc. and/or its affiliates.
*
* Authors:
* Avi Kivity <avi@redhat.com>
* Gleb Natapov <gleb@redhat.com>
* Wei Huang <wei@redhat.com>
*/
#include <linux/types.h>
#include <linux/kvm_host.h>
#include <linux/perf_event.h>
#include <linux/bsearch.h>
#include <linux/sort.h>
#include <asm/perf_event.h>
#include <asm/cpu_device_id.h>
#include "x86.h"
#include "cpuid.h"
#include "lapic.h"
#include "pmu.h"
/* This is enough to filter the vast majority of currently defined events. */
#define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300
struct x86_pmu_capability __read_mostly kvm_pmu_cap;
EXPORT_SYMBOL_GPL(kvm_pmu_cap);
static const struct x86_cpu_id vmx_icl_pebs_cpu[] = {
X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, NULL),
X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, NULL),
{}
};
/* NOTE:
* - Each perf counter is defined as "struct kvm_pmc";
* - There are two types of perf counters: general purpose (gp) and fixed.
* gp counters are stored in gp_counters[] and fixed counters are stored
* in fixed_counters[] respectively. Both of them are part of "struct
* kvm_pmu";
* - pmu.c understands the difference between gp counters and fixed counters.
* However AMD doesn't support fixed-counters;
* - There are three types of index to access perf counters (PMC):
* 1. MSR (named msr): For example Intel has MSR_IA32_PERFCTRn and AMD
* has MSR_K7_PERFCTRn and, for families 15H and later,
* MSR_F15H_PERF_CTRn, where MSR_F15H_PERF_CTR[0-3] are
* aliased to MSR_K7_PERFCTRn.
* 2. MSR Index (named idx): This normally is used by RDPMC instruction.
* For instance AMD RDPMC instruction uses 0000_0003h in ECX to access
* C001_0007h (MSR_K7_PERCTR3). Intel has a similar mechanism, except
* that it also supports fixed counters. idx can be used to as index to
* gp and fixed counters.
* 3. Global PMC Index (named pmc): pmc is an index specific to PMU
* code. Each pmc, stored in kvm_pmc.idx field, is unique across
* all perf counters (both gp and fixed). The mapping relationship
* between pmc and perf counters is as the following:
* * Intel: [0 .. KVM_INTEL_PMC_MAX_GENERIC-1] <=> gp counters
* [INTEL_PMC_IDX_FIXED .. INTEL_PMC_IDX_FIXED + 2] <=> fixed
* * AMD: [0 .. AMD64_NUM_COUNTERS-1] and, for families 15H
* and later, [0 .. AMD64_NUM_COUNTERS_CORE-1] <=> gp counters
*/
static struct kvm_pmu_ops kvm_pmu_ops __read_mostly;
#define KVM_X86_PMU_OP(func) \
DEFINE_STATIC_CALL_NULL(kvm_x86_pmu_##func, \
*(((struct kvm_pmu_ops *)0)->func));
#define KVM_X86_PMU_OP_OPTIONAL KVM_X86_PMU_OP
#include <asm/kvm-x86-pmu-ops.h>
void kvm_pmu_ops_update(const struct kvm_pmu_ops *pmu_ops)
{
memcpy(&kvm_pmu_ops, pmu_ops, sizeof(kvm_pmu_ops));
#define __KVM_X86_PMU_OP(func) \
static_call_update(kvm_x86_pmu_##func, kvm_pmu_ops.func);
#define KVM_X86_PMU_OP(func) \
WARN_ON(!kvm_pmu_ops.func); __KVM_X86_PMU_OP(func)
#define KVM_X86_PMU_OP_OPTIONAL __KVM_X86_PMU_OP
#include <asm/kvm-x86-pmu-ops.h>
#undef __KVM_X86_PMU_OP
}
static inline bool pmc_is_enabled(struct kvm_pmc *pmc)
{
return static_call(kvm_x86_pmu_pmc_is_enabled)(pmc);
}
static void kvm_pmi_trigger_fn(struct irq_work *irq_work)
{
struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu, irq_work);
struct kvm_vcpu *vcpu = pmu_to_vcpu(pmu);
kvm_pmu_deliver_pmi(vcpu);
}
static inline void __kvm_perf_overflow(struct kvm_pmc *pmc, bool in_pmi)
{
struct kvm_pmu *pmu = pmc_to_pmu(pmc);
bool skip_pmi = false;
/* Ignore counters that have been reprogrammed already. */
if (test_and_set_bit(pmc->idx, pmu->reprogram_pmi))
return;
if (pmc->perf_event && pmc->perf_event->attr.precise_ip) {
if (!in_pmi) {
/*
* TODO: KVM is currently _choosing_ to not generate records
* for emulated instructions, avoiding BUFFER_OVF PMI when
* there are no records. Strictly speaking, it should be done
* as well in the right context to improve sampling accuracy.
*/
skip_pmi = true;
} else {
/* Indicate PEBS overflow PMI to guest. */
skip_pmi = __test_and_set_bit(GLOBAL_STATUS_BUFFER_OVF_BIT,
(unsigned long *)&pmu->global_status);
}
} else {
__set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
}
kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
if (!pmc->intr || skip_pmi)
return;
/*
* Inject PMI. If vcpu was in a guest mode during NMI PMI
* can be ejected on a guest mode re-entry. Otherwise we can't
* be sure that vcpu wasn't executing hlt instruction at the
* time of vmexit and is not going to re-enter guest mode until
* woken up. So we should wake it, but this is impossible from
* NMI context. Do it from irq work instead.
*/
if (in_pmi && !kvm_handling_nmi_from_guest(pmc->vcpu))
irq_work_queue(&pmc_to_pmu(pmc)->irq_work);
else
kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
}
static void kvm_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;
__kvm_perf_overflow(pmc, true);
}
static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
u64 config, bool exclude_user,
bool exclude_kernel, bool intr)
{
struct kvm_pmu *pmu = pmc_to_pmu(pmc);
struct perf_event *event;
struct perf_event_attr attr = {
.type = type,
.size = sizeof(attr),
.pinned = true,
.exclude_idle = true,
.exclude_host = 1,
.exclude_user = exclude_user,
.exclude_kernel = exclude_kernel,
.config = config,
};
bool pebs = test_bit(pmc->idx, (unsigned long *)&pmu->pebs_enable);
attr.sample_period = get_sample_period(pmc, pmc->counter);
if ((attr.config & HSW_IN_TX_CHECKPOINTED) &&
guest_cpuid_is_intel(pmc->vcpu)) {
/*
* HSW_IN_TX_CHECKPOINTED is not supported with nonzero
* period. Just clear the sample period so at least
* allocating the counter doesn't fail.
*/
attr.sample_period = 0;
}
if (pebs) {
/*
* The non-zero precision level of guest event makes the ordinary
* guest event becomes a guest PEBS event and triggers the host
* PEBS PMI handler to determine whether the PEBS overflow PMI
* comes from the host counters or the guest.
*
* For most PEBS hardware events, the difference in the software
* precision levels of guest and host PEBS events will not affect
* the accuracy of the PEBS profiling result, because the "event IP"
* in the PEBS record is calibrated on the guest side.
*
* On Icelake everything is fine. Other hardware (GLC+, TNT+) that
* could possibly care here is unsupported and needs changes.
*/
attr.precise_ip = 1;
if (x86_match_cpu(vmx_icl_pebs_cpu) && pmc->idx == 32)
attr.precise_ip = 3;
}
event = perf_event_create_kernel_counter(&attr, -1, current,
kvm_perf_overflow, pmc);
if (IS_ERR(event)) {
pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n",
PTR_ERR(event), pmc->idx);
return;
}
pmc->perf_event = event;
pmc_to_pmu(pmc)->event_count++;
clear_bit(pmc->idx, pmc_to_pmu(pmc)->reprogram_pmi);
pmc->is_paused = false;
pmc->intr = intr || pebs;
}
static void pmc_pause_counter(struct kvm_pmc *pmc)
{
u64 counter = pmc->counter;
if (!pmc->perf_event || pmc->is_paused)
return;
/* update counter, reset event value to avoid redundant accumulation */
counter += perf_event_pause(pmc->perf_event, true);
pmc->counter = counter & pmc_bitmask(pmc);
pmc->is_paused = true;
}
static bool pmc_resume_counter(struct kvm_pmc *pmc)
{
if (!pmc->perf_event)
return false;
/* recalibrate sample period and check if it's accepted by perf core */
if (perf_event_period(pmc->perf_event,
get_sample_period(pmc, pmc->counter)))
return false;
if (test_bit(pmc->idx, (unsigned long *)&pmc_to_pmu(pmc)->pebs_enable) !=
(!!pmc->perf_event->attr.precise_ip))
return false;
/* reuse perf_event to serve as pmc_reprogram_counter() does*/
perf_event_enable(pmc->perf_event);
pmc->is_paused = false;
clear_bit(pmc->idx, (unsigned long *)&pmc_to_pmu(pmc)->reprogram_pmi);
return true;
}
static int cmp_u64(const void *pa, const void *pb)
{
u64 a = *(u64 *)pa;
u64 b = *(u64 *)pb;
return (a > b) - (a < b);
}
static bool check_pmu_event_filter(struct kvm_pmc *pmc)
{
struct kvm_pmu_event_filter *filter;
struct kvm *kvm = pmc->vcpu->kvm;
bool allow_event = true;
__u64 key;
int idx;
if (!static_call(kvm_x86_pmu_hw_event_available)(pmc))
return false;
filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
if (!filter)
goto out;
if (pmc_is_gp(pmc)) {
key = pmc->eventsel & AMD64_RAW_EVENT_MASK_NB;
if (bsearch(&key, filter->events, filter->nevents,
sizeof(__u64), cmp_u64))
allow_event = filter->action == KVM_PMU_EVENT_ALLOW;
else
allow_event = filter->action == KVM_PMU_EVENT_DENY;
} else {
idx = pmc->idx - INTEL_PMC_IDX_FIXED;
if (filter->action == KVM_PMU_EVENT_DENY &&
test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
allow_event = false;
if (filter->action == KVM_PMU_EVENT_ALLOW &&
!test_bit(idx, (ulong *)&filter->fixed_counter_bitmap))
allow_event = false;
}
out:
return allow_event;
}
void reprogram_counter(struct kvm_pmc *pmc)
{
struct kvm_pmu *pmu = pmc_to_pmu(pmc);
u64 eventsel = pmc->eventsel;
u64 new_config = eventsel;
u8 fixed_ctr_ctrl;
pmc_pause_counter(pmc);
if (!pmc_speculative_in_use(pmc) || !pmc_is_enabled(pmc))
return;
if (!check_pmu_event_filter(pmc))
return;
if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL)
printk_once("kvm pmu: pin control bit is ignored\n");
if (pmc_is_fixed(pmc)) {
fixed_ctr_ctrl = fixed_ctrl_field(pmu->fixed_ctr_ctrl,
pmc->idx - INTEL_PMC_IDX_FIXED);
if (fixed_ctr_ctrl & 0x1)
eventsel |= ARCH_PERFMON_EVENTSEL_OS;
if (fixed_ctr_ctrl & 0x2)
eventsel |= ARCH_PERFMON_EVENTSEL_USR;
if (fixed_ctr_ctrl & 0x8)
eventsel |= ARCH_PERFMON_EVENTSEL_INT;
new_config = (u64)fixed_ctr_ctrl;
}
if (pmc->current_config == new_config && pmc_resume_counter(pmc))
return;
pmc_release_perf_event(pmc);
pmc->current_config = new_config;
pmc_reprogram_counter(pmc, PERF_TYPE_RAW,
(eventsel & pmu->raw_event_mask),
!(eventsel & ARCH_PERFMON_EVENTSEL_USR),
!(eventsel & ARCH_PERFMON_EVENTSEL_OS),
eventsel & ARCH_PERFMON_EVENTSEL_INT);
}
EXPORT_SYMBOL_GPL(reprogram_counter);
void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
int bit;
for_each_set_bit(bit, pmu->reprogram_pmi, X86_PMC_IDX_MAX) {
struct kvm_pmc *pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, bit);
if (unlikely(!pmc || !pmc->perf_event)) {
clear_bit(bit, pmu->reprogram_pmi);
continue;
}
reprogram_counter(pmc);
}
/*
* Unused perf_events are only released if the corresponding MSRs
* weren't accessed during the last vCPU time slice. kvm_arch_sched_in
* triggers KVM_REQ_PMU if cleanup is needed.
*/
if (unlikely(pmu->need_cleanup))
kvm_pmu_cleanup(vcpu);
}
/* check if idx is a valid index to access PMU */
bool kvm_pmu_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
{
return static_call(kvm_x86_pmu_is_valid_rdpmc_ecx)(vcpu, idx);
}
bool is_vmware_backdoor_pmc(u32 pmc_idx)
{
switch (pmc_idx) {
case VMWARE_BACKDOOR_PMC_HOST_TSC:
case VMWARE_BACKDOOR_PMC_REAL_TIME:
case VMWARE_BACKDOOR_PMC_APPARENT_TIME:
return true;
}
return false;
}
static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
{
u64 ctr_val;
switch (idx) {
case VMWARE_BACKDOOR_PMC_HOST_TSC:
ctr_val = rdtsc();
break;
case VMWARE_BACKDOOR_PMC_REAL_TIME:
ctr_val = ktime_get_boottime_ns();
break;
case VMWARE_BACKDOOR_PMC_APPARENT_TIME:
ctr_val = ktime_get_boottime_ns() +
vcpu->kvm->arch.kvmclock_offset;
break;
default:
return 1;
}
*data = ctr_val;
return 0;
}
int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
{
bool fast_mode = idx & (1u << 31);
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc;
u64 mask = fast_mode ? ~0u : ~0ull;
if (!pmu->version)
return 1;
if (is_vmware_backdoor_pmc(idx))
return kvm_pmu_rdpmc_vmware(vcpu, idx, data);
pmc = static_call(kvm_x86_pmu_rdpmc_ecx_to_pmc)(vcpu, idx, &mask);
if (!pmc)
return 1;
if (!(kvm_read_cr4(vcpu) & X86_CR4_PCE) &&
(static_call(kvm_x86_get_cpl)(vcpu) != 0) &&
(kvm_read_cr0(vcpu) & X86_CR0_PE))
return 1;
*data = pmc_read_counter(pmc) & mask;
return 0;
}
void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
{
if (lapic_in_kernel(vcpu)) {
static_call_cond(kvm_x86_pmu_deliver_pmi)(vcpu);
kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC);
}
}
bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
{
return static_call(kvm_x86_pmu_msr_idx_to_pmc)(vcpu, msr) ||
static_call(kvm_x86_pmu_is_valid_msr)(vcpu, msr);
}
static void kvm_pmu_mark_pmc_in_use(struct kvm_vcpu *vcpu, u32 msr)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc = static_call(kvm_x86_pmu_msr_idx_to_pmc)(vcpu, msr);
if (pmc)
__set_bit(pmc->idx, pmu->pmc_in_use);
}
int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
return static_call(kvm_x86_pmu_get_msr)(vcpu, msr_info);
}
int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
kvm_pmu_mark_pmc_in_use(vcpu, msr_info->index);
return static_call(kvm_x86_pmu_set_msr)(vcpu, msr_info);
}
/* refresh PMU settings. This function generally is called when underlying
* settings are changed (such as changes of PMU CPUID by guest VMs), which
* should rarely happen.
*/
void kvm_pmu_refresh(struct kvm_vcpu *vcpu)
{
static_call(kvm_x86_pmu_refresh)(vcpu);
}
void kvm_pmu_reset(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
irq_work_sync(&pmu->irq_work);
static_call(kvm_x86_pmu_reset)(vcpu);
}
void kvm_pmu_init(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
memset(pmu, 0, sizeof(*pmu));
static_call(kvm_x86_pmu_init)(vcpu);
init_irq_work(&pmu->irq_work, kvm_pmi_trigger_fn);
pmu->event_count = 0;
pmu->need_cleanup = false;
kvm_pmu_refresh(vcpu);
}
/* Release perf_events for vPMCs that have been unused for a full time slice. */
void kvm_pmu_cleanup(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc = NULL;
DECLARE_BITMAP(bitmask, X86_PMC_IDX_MAX);
int i;
pmu->need_cleanup = false;
bitmap_andnot(bitmask, pmu->all_valid_pmc_idx,
pmu->pmc_in_use, X86_PMC_IDX_MAX);
for_each_set_bit(i, bitmask, X86_PMC_IDX_MAX) {
pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i);
if (pmc && pmc->perf_event && !pmc_speculative_in_use(pmc))
pmc_stop_counter(pmc);
}
static_call_cond(kvm_x86_pmu_cleanup)(vcpu);
bitmap_zero(pmu->pmc_in_use, X86_PMC_IDX_MAX);
}
void kvm_pmu_destroy(struct kvm_vcpu *vcpu)
{
kvm_pmu_reset(vcpu);
}
static void kvm_pmu_incr_counter(struct kvm_pmc *pmc)
{
u64 prev_count;
prev_count = pmc->counter;
pmc->counter = (pmc->counter + 1) & pmc_bitmask(pmc);
reprogram_counter(pmc);
if (pmc->counter < prev_count)
__kvm_perf_overflow(pmc, false);
}
static inline bool eventsel_match_perf_hw_id(struct kvm_pmc *pmc,
unsigned int perf_hw_id)
{
return !((pmc->eventsel ^ perf_get_hw_event_config(perf_hw_id)) &
AMD64_RAW_EVENT_MASK_NB);
}
static inline bool cpl_is_matched(struct kvm_pmc *pmc)
{
bool select_os, select_user;
u64 config = pmc->current_config;
if (pmc_is_gp(pmc)) {
select_os = config & ARCH_PERFMON_EVENTSEL_OS;
select_user = config & ARCH_PERFMON_EVENTSEL_USR;
} else {
select_os = config & 0x1;
select_user = config & 0x2;
}
return (static_call(kvm_x86_get_cpl)(pmc->vcpu) == 0) ? select_os : select_user;
}
void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc;
int i;
for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) {
pmc = static_call(kvm_x86_pmu_pmc_idx_to_pmc)(pmu, i);
if (!pmc || !pmc_is_enabled(pmc) || !pmc_speculative_in_use(pmc))
continue;
/* Ignore checks for edge detect, pin control, invert and CMASK bits */
if (eventsel_match_perf_hw_id(pmc, perf_hw_id) && cpl_is_matched(pmc))
kvm_pmu_incr_counter(pmc);
}
}
EXPORT_SYMBOL_GPL(kvm_pmu_trigger_event);
int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
{
struct kvm_pmu_event_filter tmp, *filter;
size_t size;
int r;
if (copy_from_user(&tmp, argp, sizeof(tmp)))
return -EFAULT;
if (tmp.action != KVM_PMU_EVENT_ALLOW &&
tmp.action != KVM_PMU_EVENT_DENY)
return -EINVAL;
if (tmp.flags != 0)
return -EINVAL;
if (tmp.nevents > KVM_PMU_EVENT_FILTER_MAX_EVENTS)
return -E2BIG;
size = struct_size(filter, events, tmp.nevents);
filter = kmalloc(size, GFP_KERNEL_ACCOUNT);
if (!filter)
return -ENOMEM;
r = -EFAULT;
if (copy_from_user(filter, argp, size))
goto cleanup;
/* Ensure nevents can't be changed between the user copies. */
*filter = tmp;
/*
* Sort the in-kernel list so that we can search it with bsearch.
*/
sort(&filter->events, filter->nevents, sizeof(__u64), cmp_u64, NULL);
mutex_lock(&kvm->lock);
filter = rcu_replace_pointer(kvm->arch.pmu_event_filter, filter,
mutex_is_locked(&kvm->lock));
mutex_unlock(&kvm->lock);
synchronize_srcu_expedited(&kvm->srcu);
r = 0;
cleanup:
kfree(filter);
return r;
}