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authorZenghui Yu <yuzenghui@huawei.com>2019-07-18 08:15:10 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2019-07-23 09:23:44 +0100
commitbca031e2c8aa22a978a2452bf959e27e9fa73dc7 (patch)
treec7e80e707e3abc3d924254432f4159b36b51631f /virt
parent5f9e832c137075045d15cd6899ab0505cfb2ca4b (diff)
KVM: arm/arm64: Introduce kvm_pmu_vcpu_init() to setup PMU counter index
We use "pmc->idx" and the "chained" bitmap to determine if the pmc is chained, in kvm_pmu_pmc_is_chained(). But idx might be uninitialized (and random) when we doing this decision, through a KVM_ARM_VCPU_INIT ioctl -> kvm_pmu_vcpu_reset(). And the test_bit() against this random idx will potentially hit a KASAN BUG [1]. In general, idx is the static property of a PMU counter that is not expected to be modified across resets, as suggested by Julien. It looks more reasonable if we can setup the PMU counter idx for a vcpu in its creation time. Introduce a new function - kvm_pmu_vcpu_init() for this basic setup. Oh, and the KASAN BUG will get fixed this way. [1] https://www.spinics.net/lists/kvm-arm/msg36700.html Fixes: 80f393a23be6 ("KVM: arm/arm64: Support chained PMU counters") Suggested-by: Andrew Murray <andrew.murray@arm.com> Suggested-by: Julien Thierry <julien.thierry@arm.com> Acked-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/arm/arm.c2
-rw-r--r--virt/kvm/arm/pmu.c18
2 files changed, 17 insertions, 3 deletions
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index f645c0fbf7ec..c704fa696184 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -340,6 +340,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
/* Set up the timer */
kvm_timer_vcpu_init(vcpu);
+ kvm_pmu_vcpu_init(vcpu);
+
kvm_arm_reset_debug_ptr(vcpu);
return kvm_vgic_vcpu_init(vcpu);
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 3dd8238ed246..362a01886bab 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -215,6 +215,20 @@ static void kvm_pmu_stop_counter(struct kvm_vcpu *vcpu, struct kvm_pmc *pmc)
}
/**
+ * kvm_pmu_vcpu_init - assign pmu counter idx for cpu
+ * @vcpu: The vcpu pointer
+ *
+ */
+void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu)
+{
+ int i;
+ struct kvm_pmu *pmu = &vcpu->arch.pmu;
+
+ for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
+ pmu->pmc[i].idx = i;
+}
+
+/**
* kvm_pmu_vcpu_reset - reset pmu state for cpu
* @vcpu: The vcpu pointer
*
@@ -224,10 +238,8 @@ void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu)
int i;
struct kvm_pmu *pmu = &vcpu->arch.pmu;
- for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
+ for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++)
kvm_pmu_stop_counter(vcpu, &pmu->pmc[i]);
- pmu->pmc[i].idx = i;
- }
bitmap_zero(vcpu->arch.pmu.chained, ARMV8_PMU_MAX_COUNTER_PAIRS);
}

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