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Message-Id: <20220302111334.12689-12-likexu@tencent.com>
Date: Wed, 2 Mar 2022 19:13:33 +0800
From: Like Xu <like.xu.linux@...il.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Jim Mattson <jmattson@...gle.com>, kvm@...r.kernel.org,
Sean Christopherson <seanjc@...gle.com>,
Wanpeng Li <wanpengli@...cent.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org,
Like Xu <likexu@...cent.com>
Subject: [PATCH v2 11/12] KVM: x86/pmu: Protect kvm->arch.pmu_event_filter with SRCU
From: Like Xu <likexu@...cent.com>
Similar to "kvm->arch.msr_filter", KVM should guarantee that vCPUs will
see either the previous filter or the new filter when user space calls
KVM_SET_PMU_EVENT_FILTER ioctl with the vCPU running so that guest
pmu events with identical settings in both the old and new filter have
deterministic behavior.
Fixes: 66bb8a065f5a ("KVM: x86: PMU Event Filter")
Signed-off-by: Like Xu <likexu@...cent.com>
Reviewed-by: Wanpeng Li <wanpengli@...cent.com>
---
arch/x86/kvm/pmu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 60f44252540a..17c61c990282 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -185,11 +185,12 @@ static bool check_pmu_event_filter(struct kvm_pmc *pmc)
struct kvm *kvm = pmc->vcpu->kvm;
bool allow_event = true;
__u64 key;
- int idx;
+ int idx, srcu_idx;
if (kvm_x86_ops.pmu_ops->hw_event_is_unavail(pmc))
return false;
+ srcu_idx = srcu_read_lock(&kvm->srcu);
filter = srcu_dereference(kvm->arch.pmu_event_filter, &kvm->srcu);
if (!filter)
goto out;
@@ -212,6 +213,7 @@ static bool check_pmu_event_filter(struct kvm_pmc *pmc)
}
out:
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
return allow_event;
}
--
2.35.1
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