On Thu, Mar 31, 2011 at 11:23:28AM +0200, Avi Kivity wrote:
> On 03/30/2011 08:47 PM, Gleb Natapov wrote:
> >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<[email protected]>
> >> >
> >> >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.
>
> Could be very far in the future.
>
Next host interrupt. But with tickles host and guest yeah.
--
Gleb.
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