diff mbox series

[v2,11/12] KVM: x86/pmu: Protect kvm->arch.pmu_event_filter with SRCU

Message ID 20220302111334.12689-12-likexu@tencent.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86/pmu: Get rid of PERF_TYPE_HARDWAR and other minor fixes | expand

Commit Message

Like Xu March 2, 2022, 11:13 a.m. UTC 
From: Like Xu <likexu@tencent.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@tencent.com>
Reviewed-by: Wanpeng Li <wanpengli@tencent.com>
---
 arch/x86/kvm/pmu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

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;
 }