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Revert "KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode"

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This reverts commit eb3df96102.

It breaks the current Android kernel abi.  It will be brought back at
the next KABI break update.

Bug: 161946584
Change-Id: Icbc6a902a085e81fb1ba72666cae32527c2479cc
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman
2023-04-23 08:14:51 +00:00
committed by Matthias Männich
parent 7ddb50fff2
commit 9d29ba9c30
2 changed files with 237 additions and 87 deletions
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322
arch/arm64/kvm/pmu-emul.c
View File

@@ -15,14 +15,16 @@
#include <kvm/arm_pmu.h>
#include <kvm/arm_vgic.h>
#define PERF_ATTR_CFG1_COUNTER_64BIT BIT(0)
DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available);
static LIST_HEAD(arm_pmus);
static DEFINE_MUTEX(arm_pmus_lock);
static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx);
static void kvm_pmu_update_pmc_chained(struct kvm_vcpu *vcpu, u64 select_idx);
static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc);
#define PERF_ATTR_CFG1_KVM_PMU_CHAINED 0x1
static u32 kvm_pmu_event_mask(struct kvm *kvm)
{
@@ -55,11 +57,6 @@ static bool kvm_pmu_idx_is_64bit(struct kvm_vcpu *vcpu, u64 select_idx)
__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_LC);
}
static bool kvm_pmu_counter_can_chain(struct kvm_vcpu *vcpu, u64 idx)
{
return (!(idx & 1) && (idx + 1) < ARMV8_PMU_CYCLE_IDX);
}
static struct kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
{
struct kvm_pmu *pmu;
@@ -72,22 +69,91 @@ static struct kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
}
/**
* kvm_pmu_get_counter_value - get PMU counter value
* kvm_pmu_pmc_is_chained - determine if the pmc is chained
* @pmc: The PMU counter pointer
*/
static bool kvm_pmu_pmc_is_chained(struct kvm_pmc *pmc)
{
struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
return test_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
}
/**
* kvm_pmu_idx_is_high_counter - determine if select_idx is a high/low counter
* @select_idx: The counter index
*/
static bool kvm_pmu_idx_is_high_counter(u64 select_idx)
{
return select_idx & 0x1;
}
/**
* kvm_pmu_get_canonical_pmc - obtain the canonical pmc
* @pmc: The PMU counter pointer
*
* When a pair of PMCs are chained together we use the low counter (canonical)
* to hold the underlying perf event.
*/
static struct kvm_pmc *kvm_pmu_get_canonical_pmc(struct kvm_pmc *pmc)
{
if (kvm_pmu_pmc_is_chained(pmc) &&
kvm_pmu_idx_is_high_counter(pmc->idx))
return pmc - 1;
return pmc;
}
static struct kvm_pmc *kvm_pmu_get_alternate_pmc(struct kvm_pmc *pmc)
{
if (kvm_pmu_idx_is_high_counter(pmc->idx))
return pmc - 1;
else
return pmc + 1;
}
/**
* kvm_pmu_idx_has_chain_evtype - determine if the event type is chain
* @vcpu: The vcpu pointer
* @select_idx: The counter index
*/
u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
static bool kvm_pmu_idx_has_chain_evtype(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];
u64 eventsel, reg;
if (!kvm_vcpu_has_pmu(vcpu))
return 0;
select_idx |= 0x1;
reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;
counter = __vcpu_sys_reg(vcpu, reg);
if (select_idx == ARMV8_PMU_CYCLE_IDX)
return false;
reg = PMEVTYPER0_EL0 + select_idx;
eventsel = __vcpu_sys_reg(vcpu, reg) & kvm_pmu_event_mask(vcpu->kvm);
return eventsel == ARMV8_PMUV3_PERFCTR_CHAIN;
}
/**
* kvm_pmu_get_pair_counter_value - get PMU counter value
* @vcpu: The vcpu pointer
* @pmc: The PMU counter pointer
*/
static u64 kvm_pmu_get_pair_counter_value(struct kvm_vcpu *vcpu,
struct kvm_pmc *pmc)
{
u64 counter, counter_high, reg, enabled, running;
if (kvm_pmu_pmc_is_chained(pmc)) {
pmc = kvm_pmu_get_canonical_pmc(pmc);
reg = PMEVCNTR0_EL0 + pmc->idx;
counter = __vcpu_sys_reg(vcpu, reg);
counter_high = __vcpu_sys_reg(vcpu, reg + 1);
counter = lower_32_bits(counter) | (counter_high << 32);
} else {
reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
? PMCCNTR_EL0 : PMEVCNTR0_EL0 + pmc->idx;
counter = __vcpu_sys_reg(vcpu, reg);
}
/*
* The real counter value is equal to the value of counter register plus
@@ -97,7 +163,29 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
counter += perf_event_read_value(pmc->perf_event, &enabled,
&running);
if (select_idx != ARMV8_PMU_CYCLE_IDX)
return counter;
}
/**
* 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;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc = &pmu->pmc[select_idx];
if (!kvm_vcpu_has_pmu(vcpu))
return 0;
counter = kvm_pmu_get_pair_counter_value(vcpu, pmc);
if (kvm_pmu_pmc_is_chained(pmc) &&
kvm_pmu_idx_is_high_counter(select_idx))
counter = upper_32_bits(counter);
else if (select_idx != ARMV8_PMU_CYCLE_IDX)
counter = lower_32_bits(counter);
return counter;
@@ -130,6 +218,7 @@ void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val)
*/
static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc)
{
pmc = kvm_pmu_get_canonical_pmc(pmc);
if (pmc->perf_event) {
perf_event_disable(pmc->perf_event);
perf_event_release_kernel(pmc->perf_event);
@@ -147,10 +236,11 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
{
u64 counter, reg, val;
pmc = kvm_pmu_get_canonical_pmc(pmc);
if (!pmc->perf_event)
return;
counter = kvm_pmu_get_counter_value(vcpu, pmc->idx);
counter = kvm_pmu_get_pair_counter_value(vcpu, pmc);
if (pmc->idx == ARMV8_PMU_CYCLE_IDX) {
reg = PMCCNTR_EL0;
@@ -162,6 +252,9 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
__vcpu_sys_reg(vcpu, reg) = val;
if (kvm_pmu_pmc_is_chained(pmc))
__vcpu_sys_reg(vcpu, reg + 1) = upper_32_bits(counter);
kvm_pmu_release_perf_event(pmc);
}
@@ -192,6 +285,8 @@ void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
for_each_set_bit(i, &mask, 32)
kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]);
bitmap_zero(vcpu->arch.pmu.chained, ARMV8_PMU_MAX_COUNTER_PAIRS);
}
/**
@@ -245,9 +340,12 @@ void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
pmc = &pmu->pmc[i];
if (!pmc->perf_event) {
kvm_pmu_create_perf_event(vcpu, i);
} else {
/* A change in the enable state may affect the chain state */
kvm_pmu_update_pmc_chained(vcpu, i);
kvm_pmu_create_perf_event(vcpu, i);
/* At this point, pmc must be the canonical */
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");
@@ -277,6 +375,11 @@ void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
pmc = &pmu->pmc[i];
/* A change in the enable state may affect the chain state */
kvm_pmu_update_pmc_chained(vcpu, i);
kvm_pmu_create_perf_event(vcpu, i);
/* At this point, pmc must be the canonical */
if (pmc->perf_event)
perf_event_disable(pmc->perf_event);
}
@@ -381,48 +484,6 @@ static void kvm_pmu_perf_overflow_notify_vcpu(struct irq_work *work)
kvm_vcpu_kick(vcpu);
}
/*
* Perform an increment on any of the counters described in @mask,
* generating the overflow if required, and propagate it as a chained
* event if possible.
*/
static void kvm_pmu_counter_increment(struct kvm_vcpu *vcpu,
unsigned long mask, u32 event)
{
int i;
if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
return;
/* Weed out disabled counters */
mask &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
for_each_set_bit(i, &mask, ARMV8_PMU_CYCLE_IDX) {
u64 type, reg;
/* Filter on event type */
type = __vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + i);
type &= kvm_pmu_event_mask(vcpu->kvm);
if (type != event)
continue;
/* Increment this counter */
reg = __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) + 1;
reg = lower_32_bits(reg);
__vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = reg;
if (reg) /* No overflow? move on */
continue;
/* Mark overflow */
__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(i);
if (kvm_pmu_counter_can_chain(vcpu, i))
kvm_pmu_counter_increment(vcpu, BIT(i + 1),
ARMV8_PMUV3_PERFCTR_CHAIN);
}
}
/**
* When the perf event overflows, set the overflow status and inform the vcpu.
*/
@@ -453,10 +514,6 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(idx);
if (kvm_pmu_counter_can_chain(vcpu, idx))
kvm_pmu_counter_increment(vcpu, BIT(idx + 1),
ARMV8_PMUV3_PERFCTR_CHAIN);
if (kvm_pmu_overflow_status(vcpu)) {
kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
@@ -476,7 +533,50 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
*/
void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
{
kvm_pmu_counter_increment(vcpu, val, ARMV8_PMUV3_PERFCTR_SW_INCR);
struct kvm_pmu *pmu = &vcpu->arch.pmu;
int i;
if (!kvm_vcpu_has_pmu(vcpu))
return;
if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
return;
/* Weed out disabled counters */
val &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++) {
u64 type, reg;
if (!(val & BIT(i)))
continue;
/* PMSWINC only applies to ... SW_INC! */
type = __vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + i);
type &= kvm_pmu_event_mask(vcpu->kvm);
if (type != ARMV8_PMUV3_PERFCTR_SW_INCR)
continue;
/* increment this even SW_INC counter */
reg = __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) + 1;
reg = lower_32_bits(reg);
__vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = reg;
if (reg) /* no overflow on the low part */
continue;
if (kvm_pmu_pmc_is_chained(&pmu->pmc[i])) {
/* increment the high counter */
reg = __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i + 1) + 1;
reg = lower_32_bits(reg);
__vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i + 1) = reg;
if (!reg) /* mark overflow on the high counter */
__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(i + 1);
} else {
/* mark overflow on low counter */
__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= BIT(i);
}
}
}
/**
@@ -525,11 +625,18 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
{
struct arm_pmu *arm_pmu = vcpu->kvm->arch.arm_pmu;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc = &pmu->pmc[select_idx];
struct kvm_pmc *pmc;
struct perf_event *event;
struct perf_event_attr attr;
u64 eventsel, counter, reg, data;
/*
* For chained counters the event type and filtering attributes are
* obtained from the low/even counter. We also use this counter to
* determine if the event is enabled/disabled.
*/
pmc = kvm_pmu_get_canonical_pmc(&pmu->pmc[select_idx]);
reg = (pmc->idx == ARMV8_PMU_CYCLE_IDX)
? PMCCFILTR_EL0 : PMEVTYPER0_EL0 + pmc->idx;
data = __vcpu_sys_reg(vcpu, reg);
@@ -540,12 +647,8 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
else
eventsel = data & kvm_pmu_event_mask(vcpu->kvm);
/*
* Neither SW increment nor chained events need to be backed
* by a perf event.
*/
if (eventsel == ARMV8_PMUV3_PERFCTR_SW_INCR ||
eventsel == ARMV8_PMUV3_PERFCTR_CHAIN)
/* Software increment event doesn't need to be backed by a perf event */
if (eventsel == ARMV8_PMUV3_PERFCTR_SW_INCR)
return;
/*
@@ -567,21 +670,30 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
attr.exclude_host = 1; /* Don't count host events */
attr.config = eventsel;
counter = kvm_pmu_get_counter_value(vcpu, select_idx);
counter = kvm_pmu_get_pair_counter_value(vcpu, pmc);
/*
* If counting with a 64bit counter, advertise it to the perf
* code, carefully dealing with the initial sample period.
*/
if (kvm_pmu_idx_is_64bit(vcpu, select_idx)) {
attr.config1 |= PERF_ATTR_CFG1_COUNTER_64BIT;
if (kvm_pmu_pmc_is_chained(pmc)) {
/**
* The initial sample period (overflow count) of an event. For
* chained counters we only support overflow interrupts on the
* high counter.
*/
attr.sample_period = (-counter) & GENMASK(63, 0);
} else {
attr.sample_period = (-counter) & GENMASK(31, 0);
}
attr.config1 |= PERF_ATTR_CFG1_KVM_PMU_CHAINED;
event = perf_event_create_kernel_counter(&attr, -1, current,
event = perf_event_create_kernel_counter(&attr, -1, current,
kvm_pmu_perf_overflow,
pmc + 1);
} else {
/* The initial sample period (overflow count) of an event. */
if (kvm_pmu_idx_is_64bit(vcpu, pmc->idx))
attr.sample_period = (-counter) & GENMASK(63, 0);
else
attr.sample_period = (-counter) & GENMASK(31, 0);
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",
@@ -592,6 +704,41 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
pmc->perf_event = event;
}
/**
* kvm_pmu_update_pmc_chained - update chained bitmap
* @vcpu: The vcpu pointer
* @select_idx: The number of selected counter
*
* Update the chained bitmap based on the event type written in the
* typer register and the enable state of the odd register.
*/
static void kvm_pmu_update_pmc_chained(struct kvm_vcpu *vcpu, u64 select_idx)
{
struct kvm_pmu *pmu = &vcpu->arch.pmu;
struct kvm_pmc *pmc = &pmu->pmc[select_idx], *canonical_pmc;
bool new_state, old_state;
old_state = kvm_pmu_pmc_is_chained(pmc);
new_state = kvm_pmu_idx_has_chain_evtype(vcpu, pmc->idx) &&
kvm_pmu_counter_is_enabled(vcpu, pmc->idx | 0x1);
if (old_state == new_state)
return;
canonical_pmc = kvm_pmu_get_canonical_pmc(pmc);
kvm_pmu_stop_counter(vcpu, canonical_pmc);
if (new_state) {
/*
* During promotion from !chained to chained we must ensure
* the adjacent counter is stopped and its event destroyed
*/
kvm_pmu_stop_counter(vcpu, kvm_pmu_get_alternate_pmc(pmc));
set_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
return;
}
clear_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
}
/**
* kvm_pmu_set_counter_event_type - set selected counter to monitor some event
* @vcpu: The vcpu pointer
@@ -619,6 +766,7 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
__vcpu_sys_reg(vcpu, reg) = data & mask;
kvm_pmu_update_pmc_chained(vcpu, select_idx);
kvm_pmu_create_perf_event(vcpu, select_idx);
}

2
include/kvm/arm_pmu.h
View File

@@ -11,6 +11,7 @@
#include <asm/perf_event.h>
#define ARMV8_PMU_CYCLE_IDX (ARMV8_PMU_MAX_COUNTERS - 1)
#define ARMV8_PMU_MAX_COUNTER_PAIRS ((ARMV8_PMU_MAX_COUNTERS + 1) >> 1)
#ifdef CONFIG_HW_PERF_EVENTS
@@ -28,6 +29,7 @@ struct kvm_pmu {
struct irq_work overflow_work;
struct kvm_pmu_events events;
struct kvm_pmc pmc[ARMV8_PMU_MAX_COUNTERS];
DECLARE_BITMAP(chained, ARMV8_PMU_MAX_COUNTER_PAIRS);
int irq_num;
bool created;
bool irq_level;