On 23/03/2016 06:08, Yuki Shibuya wrote:
> + /* If nmi pending > 0 and injectable interrupts exist,
> + * nmi pending counter is cleared to prevent skipping
> + * injectable pending interrupts.
> + */
> + if (vcpu->arch.nmi_pending && kvm_cpu_has_injectable_intr(vcpu)
> + && kvm_x86_ops->interrupt_allowed(vcpu))
> + vcpu->arch.nmi_pending = 0;
I am not sure I understand this. Why is it safe to drop nmi_pending?
Can we instead do something like this in vcpu_enter_guest?
It would be nice to have a testcase for this in kvm-unit-tests.
Paolo
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7236bd3a4c3d..6c73cbc8e19a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6561,10 +6561,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (inject_pending_event(vcpu, req_int_win) != 0)
req_immediate_exit = true;
/* enable NMI/IRQ window open exits if needed */
- else if (vcpu->arch.nmi_pending)
- kvm_x86_ops->enable_nmi_window(vcpu);
- else if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win)
- kvm_x86_ops->enable_irq_window(vcpu);
+ else {
+ if (vcpu->arch.nmi_pending)
+ kvm_x86_ops->enable_nmi_window(vcpu);
+ if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win)
+ kvm_x86_ops->enable_irq_window(vcpu);
+ }
if (kvm_lapic_enabled(vcpu)) {
update_cr8_intercept(vcpu);
Paolo
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