diff options
| author | Gleb Natapov <gleb@redhat.com> | 2011-04-01 11:26:29 -0300 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-05-11 07:56:57 -0400 |
| commit | 1499e54af03ae51a937c59035bc86002deae0572 (patch) | |
| tree | 89f75af765784f573f818737e7aa3392eaabac52 /arch | |
| parent | c761e5868e6737abe0464636ebd7fcbb6814c626 (diff) | |
KVM: x86: better fix for race between nmi injection and enabling nmi window
Fix race between nmi injection and enabling nmi window in a simpler way.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/x86.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b9402d5fa0e9..692c70d6fd02 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5171,6 +5171,7 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu) static int vcpu_enter_guest(struct kvm_vcpu *vcpu) { int r; + bool nmi_pending; bool req_int_win = !irqchip_in_kernel(vcpu->kvm) && vcpu->run->request_interrupt_window; @@ -5214,11 +5215,19 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) if (unlikely(r)) goto out; + /* + * An NMI can be injected between local nmi_pending read and + * vcpu->arch.nmi_pending read inside inject_pending_event(). + * But in that case, KVM_REQ_EVENT will be set, which makes + * the race described above benign. + */ + nmi_pending = ACCESS_ONCE(vcpu->arch.nmi_pending); + if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) { inject_pending_event(vcpu); /* enable NMI/IRQ window open exits if needed */ - if (vcpu->arch.nmi_pending) + if (nmi_pending) kvm_x86_ops->enable_nmi_window(vcpu); else if (kvm_cpu_has_interrupt(vcpu) || req_int_win) kvm_x86_ops->enable_irq_window(vcpu); |