On Wed, Mar 30, 2011 at 07:16:34PM +0200, Avi Kivity wrote:
> On 03/30/2011 06:30 PM, Marcelo Tosatti wrote:
> >Based on Gleb's idea, fix race between nmi injection and enabling
> >nmi window in a simpler way.
> >
> >Signed-off-by: Marcelo Tosatti<mtosatti@xxxxxxxxxx>
> >
> >diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> >index a6a129f..9a7cc1be 100644
> >--- a/arch/x86/kvm/x86.c
> >+++ b/arch/x86/kvm/x86.c
> >@@ -5152,6 +5152,7 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
> > static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> > {
> > int r;
> >+ int nmi_pending;
> > bool req_int_win = !irqchip_in_kernel(vcpu->kvm)&&
> > vcpu->run->request_interrupt_window;
> >
> >@@ -5195,11 +5196,13 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> > if (unlikely(r))
> > goto out;
> >
> >+ 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);
> >
>
> What about the check in inject_pending_events()?
>
Didn't we decide that this check is not a problem? Worst that can happen
is NMI injection will be delayed till next exit.
--
Gleb.
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