KVM: move slots_lock acquision down to vapic_exit

There is no need to grab slots_lock if the vapic_page will not
be touched.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f726ba79fd3aab9d4c8f65e15bbef29e334f1c4f..55906e4c46765b8a92998f7995b46a6fc3cc6c26 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2787,8 +2787,10 @@ static void vapic_exit(struct kvm_vcpu *vcpu)
        if (!apic || !apic->vapic_addr)
                return;
 
+       down_read(&vcpu->kvm->slots_lock);
        kvm_release_page_dirty(apic->vapic_page);
        mark_page_dirty(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
+       up_read(&vcpu->kvm->slots_lock);
 }
 
 static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
@@ -2944,9 +2946,7 @@ out:
 
        post_kvm_run_save(vcpu, kvm_run);
 
-       down_read(&vcpu->kvm->slots_lock);
        vapic_exit(vcpu);
-       up_read(&vcpu->kvm->slots_lock);
 
        return r;
 }