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Revert "Revert "KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow""

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This reverts commit 7ddb50fff2.

It was perserving the ABI, but that is not needed anymore at this point
in time.

Change-Id: Ie92c7e1fa270672698399600076ac9be1e0ac4f4
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman
2023-04-26 12:15:28 +00:00
committed by Carlos Llamas
parent 0871e23703
commit 350ced2ef1
1 changed files with 31 additions and 12 deletions
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43
arch/arm64/kvm/pmu-emul.c
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@@ -50,6 +50,11 @@ static u32 kvm_pmu_event_mask(struct kvm *kvm)
* @select_idx: The counter index
*/
static bool kvm_pmu_idx_is_64bit(struct kvm_vcpu *vcpu, u64 select_idx)
{
return (select_idx == ARMV8_PMU_CYCLE_IDX);
}
static bool kvm_pmu_idx_has_64bit_overflow(struct kvm_vcpu *vcpu, u64 select_idx)
{
return (select_idx == ARMV8_PMU_CYCLE_IDX &&
__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_LC);
@@ -57,7 +62,8 @@ static bool kvm_pmu_idx_is_64bit(struct kvm_vcpu *vcpu, u64 select_idx)
static bool kvm_pmu_counter_can_chain(struct kvm_vcpu *vcpu, u64 idx)
{
return (!(idx & 1) && (idx + 1) < ARMV8_PMU_CYCLE_IDX);
return (!(idx & 1) && (idx + 1) < ARMV8_PMU_CYCLE_IDX &&
!kvm_pmu_idx_has_64bit_overflow(vcpu, idx));
}
static struct kvm_vcpu *kvm_pmc_to_vcpu(struct kvm_pmc *pmc)
@@ -97,7 +103,7 @@ 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)
if (!kvm_pmu_idx_is_64bit(vcpu, select_idx))
counter = lower_32_bits(counter);
return counter;
@@ -423,6 +429,23 @@ static void kvm_pmu_counter_increment(struct kvm_vcpu *vcpu,
}
}
/* Compute the sample period for a given counter value */
static u64 compute_period(struct kvm_vcpu *vcpu, u64 select_idx, u64 counter)
{
u64 val;
if (kvm_pmu_idx_is_64bit(vcpu, select_idx)) {
if (!kvm_pmu_idx_has_64bit_overflow(vcpu, select_idx))
val = -(counter & GENMASK(31, 0));
else
val = (-counter) & GENMASK(63, 0);
} else {
val = (-counter) & GENMASK(31, 0);
}
return val;
}
/**
* When the perf event overflows, set the overflow status and inform the vcpu.
*/
@@ -442,10 +465,7 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
* Reset the sample period to the architectural limit,
* i.e. the point where the counter overflows.
*/
period = -(local64_read(&perf_event->count));
if (!kvm_pmu_idx_is_64bit(vcpu, pmc->idx))
period &= GENMASK(31, 0);
period = compute_period(vcpu, idx, local64_read(&perf_event->count));
local64_set(&perf_event->hw.period_left, 0);
perf_event->attr.sample_period = period;
@@ -572,14 +592,13 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu *vcpu, u64 select_idx)
/*
* If counting with a 64bit counter, advertise it to the perf
* code, carefully dealing with the initial sample period.
* code, carefully dealing with the initial sample period
* which also depends on the overflow.
*/
if (kvm_pmu_idx_is_64bit(vcpu, select_idx)) {
if (kvm_pmu_idx_is_64bit(vcpu, select_idx))
attr.config1 |= PERF_ATTR_CFG1_COUNTER_64BIT;
attr.sample_period = (-counter) & GENMASK(63, 0);
} else {
attr.sample_period = (-counter) & GENMASK(31, 0);
}
attr.sample_period = compute_period(vcpu, select_idx, counter);
event = perf_event_create_kernel_counter(&attr, -1, current,
kvm_pmu_perf_overflow, pmc);