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Subject[PATCH] KVM: arm64: pmu: Don't increment SW_INCR if PMCR.E is unset
Date
commit 3837407c1aa1 upstream.

The specification says PMSWINC increments PMEVCNTR<n>_EL1 by 1
if PMEVCNTR<n>_EL0 is enabled and configured to count SW_INCR.

For PMEVCNTR<n>_EL0 to be enabled, we need both PMCNTENSET to
be set for the corresponding event counter but we also need
the PMCR.E bit to be set.

Fixes: 7a0adc7064b8 ("arm64: KVM: Add access handler for PMSWINC register")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Cc: <stable@vger.kernel.org> # 4.14 only

---

This is a backport of 3837407c1aa1 ("KVM: arm64: pmu: Don't
increment SW_INCR if PMCR.E is unset") which did not apply on
4.14-stable. Compared to the original patch
__vcpu_sys_reg() is replaced by vcpu_sys_reg().
---
virt/kvm/arm/pmu.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 8a9c42366db7..3998add436da 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -316,6 +316,9 @@ void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
if (val == 0)
return;

+ if (!(vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
+ return;
+
enable = vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++) {
if (!(val & BIT(i)))
--
2.20.1
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