On Wed, May 16, 2012 at 07:32:06PM +0300, Gleb Natapov wrote: > On Wed, May 16, 2012 at 07:22:47PM +0300, Michael S. Tsirkin wrote: > > On Wed, May 16, 2012 at 12:49:40PM -0300, Marcelo Tosatti wrote: > > > > @@ -1245,9 +1306,20 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu) > > > > int vector = kvm_apic_has_interrupt(vcpu); > > > > struct kvm_lapic *apic = vcpu->arch.apic; > > > > > > > > - if (vector == -1) > > > > + /* Detect interrupt nesting and disable EOI optimization */ > > > > + if (pv_eoi_enabled(vcpu) && vector == -2) > > > > + pv_eoi_clr_pending(vcpu); > > > > + > > > > + if (vector < 0) > > > > > > With interrupt window exiting, the guest will exit: > > > > > > - as soon as it sets RFLAGS.IF=1 and there is any > > > interrupt pending in IRR. > > > - any new interrupt is set in IRR will kick vcpu > > > out of guest mode and recalculate interrupt-window-exiting. > > > > > > Doesnt this make this bit unnecessary ? > > > > Looks like we could cut it out. But I'm not sure how architectural it is > > that we exit on interrupt window. > We request exit on interrupt window only if there is pending irq that > can be delivered on a guest entry. Aha. If so what Marcelo proposed won't work I think: if we inject A then B which is lower priority, we need an exit on EOI, we can't inject immediately. > > I guess there are reasons to exit on interrupt window but > > isn't it better to make the feature independent of it? > > > > This almost never happens in my testing anyway, so > > however we handle it is unlikely to affect performance. > > > > -- > > MST > > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
