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KVM: arm64: pmu: Don't mark a counter as chained if the odd one is disabled

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At the moment we update the chain bitmap on type setting. This
does not take into account the enable state of the odd register.

Let's make sure a counter is never considered as chained if
the high counter is disabled.

We recompute the chain state on enable/disable and type changes.

Also let create_perf_event() use the chain bitmap and not use
kvm_pmu_idx_has_chain_evtype().

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200124142535.29386-3-eric.auger@redhat.com
This commit is contained in:
Eric Auger 2020-01-24 15:25:33 +01:00 committed by Marc Zyngier
parent 3837407c1a
commit 76c9fc56dd
1 changed files with 33 additions and 29 deletions
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62
virt/kvm/arm/pmu.c
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@ -15,6 +15,8 @@
#include <kvm/arm_vgic.h>
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
@ -75,6 +77,13 @@ static struct kvm_pmc *kvm_pmu_get_canonical_pmc(struct kvm_pmc *pmc)
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
@ -294,15 +303,9 @@ void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
pmc = &pmu->pmc[i];
/*
* For high counters of chained events we must recreate the
* perf event with the long (64bit) attribute set.
*/
if (kvm_pmu_pmc_is_chained(pmc) &&
kvm_pmu_idx_is_high_counter(i)) {
kvm_pmu_create_perf_event(vcpu, i);
continue;
}
/* 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) {
@ -335,15 +338,9 @@ void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
pmc = &pmu->pmc[i];
/*
* For high counters of chained events we must recreate the
* perf event with the long (64bit) attribute unset.
*/
if (kvm_pmu_pmc_is_chained(pmc) &&
kvm_pmu_idx_is_high_counter(i)) {
kvm_pmu_create_perf_event(vcpu, i);
continue;
}
/* 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)
@ -585,15 +582,14 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
counter = kvm_pmu_get_pair_counter_value(vcpu, pmc);
if (kvm_pmu_idx_has_chain_evtype(vcpu, pmc->idx)) {
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);
if (kvm_pmu_counter_is_enabled(vcpu, pmc->idx + 1))
attr.config1 |= PERF_ATTR_CFG1_KVM_PMU_CHAINED;
attr.config1 |= PERF_ATTR_CFG1_KVM_PMU_CHAINED;
event = perf_event_create_kernel_counter(&attr, -1, current,
kvm_pmu_perf_overflow,
@ -624,25 +620,33 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
* @select_idx: The number of selected counter
*
* Update the chained bitmap based on the event type written in the
* typer register.
* 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];
struct kvm_pmc *pmc = &pmu->pmc[select_idx], *canonical_pmc;
bool new_state, old_state;
if (kvm_pmu_idx_has_chain_evtype(vcpu, pmc->idx)) {
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
*/
if (!kvm_pmu_pmc_is_chained(pmc))
kvm_pmu_stop_counter(vcpu, pmc);
kvm_pmu_stop_counter(vcpu, kvm_pmu_get_alternate_pmc(pmc));
set_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
} else {
clear_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
return;
}
clear_bit(pmc->idx >> 1, vcpu->arch.pmu.chained);
}
/**