On Fri, May 29, 2009 at 06:46:47PM +0200, Jan Kiszka wrote: > Gleb Natapov wrote: > > On Fri, May 29, 2009 at 04:52:41PM +0200, Jan Kiszka wrote: > >> Gleb Natapov wrote: > >>> On Fri, May 29, 2009 at 10:23:24AM +0200, Jan Kiszka wrote: > >>>> Hi Gleb, > >>>> > >>>> with latest kernel modules, namely beginning with 6bc0a1a235 (Remove > >>>> irq_pending bitmap), I'm loosing interrupts with upstream's KVM support. > >>>> After some bisecting, hair-pulling and a bit meditation I added a > >>>> WARN_ON(kvm_cpu_has_interrupt(vcpu)) to kvm_vcpu_ioctl_interrupt, and it > >>>> actually triggered right before the guest got stuck. > >>>> > >>>> This didn't trigger with qemu-kvm (and -no-kvm-irqchip) yet but, on the > >>>> other hand, I currently do not see a potential bug in upstream's > >>>> kvm_arch_pre_run. Could you have a look if you can reproduce, > >>>> specifically if this isn't a KVM kernel issue in the end? > >>>> > >>> In kvm_cpu_exec() after calling kvm_arch_pre_run() env->exit_request is > >>> tested and function can exit without calling kvm_vcpu_ioctl(KVM_RUN). > >>> Can you check if this what happens in your case? > >> This path is executed quite frequently here. No obvious correlation with > >> the lost IRQ. > >> > > If kvm_arch_pre_run() injected interrupt kvm_vcpu_ioctl(KVM_RUN) have to > > be executed before injecting another interrupt, so if on the fist call > > of kvm_cpu_exec() kvm_arch_pre_run() injected interrupt, but > > kvm_vcpu_ioctl(KVM_RUN) was not executed because of env->exit_request > > and on the next kvm_cpu_exec() other interrupt is injected the previous > > one will be lost. > > ...and kvm_run->ready_for_interrupt_injection is not updated either in > that case, right? That makes be wonder if KVM_INTERRUPT shouldn't better > return an error in case the queue is full already. > If kvm_vcpu_ioctl(KVM_RUN) is called, but exit happens before interrupt is injected kvm_run->ready_for_interrupt_injection should be update to reflect that fact. -- 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
