diff mbox series

[v2,1/6] KVM: x86: Optimize kvm->lock and SRCU interaction (KVM_SET_PMU_EVENT_FILTER)

Message ID 20230107001256.2365304-2-mhal@rbox.co (mailing list archive)
State New, archived
Headers show
Series kvm->lock vs. SRCU sync optimizations | expand

Commit Message

Michal Luczaj Jan. 7, 2023, 12:12 a.m. UTC 
Reduce time spent holding kvm->lock: unlock mutex before calling
synchronize_srcu_expedited().

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 arch/x86/kvm/pmu.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index eb594620dd75..18f709d3d8ba 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -633,6 +633,7 @@  int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
 	mutex_lock(&kvm->lock);
 	filter = rcu_replace_pointer(kvm->arch.pmu_event_filter, filter,
 				     mutex_is_locked(&kvm->lock));
+	mutex_unlock(&kvm->lock);
 	synchronize_srcu_expedited(&kvm->srcu);
 
 	BUILD_BUG_ON(sizeof(((struct kvm_pmu *)0)->reprogram_pmi) >
@@ -643,8 +644,6 @@  int kvm_vm_ioctl_set_pmu_event_filter(struct kvm *kvm, void __user *argp)
 
 	kvm_make_all_cpus_request(kvm, KVM_REQ_PMU);
 
-	mutex_unlock(&kvm->lock);
-
 	r = 0;
 cleanup:
 	kfree(filter);