On Mon, Aug 25, 2014 at 11:16:16AM +0200, Paolo Bonzini wrote: >Il 25/08/2014 11:08, Wanpeng Li ha scritto: >> Hi Paolo, >> On Mon, Aug 25, 2014 at 11:01:07AM +0200, Paolo Bonzini wrote: >>> Il 25/08/2014 09:58, Wanpeng Li ha scritto: >>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>>> index c10408e..b7c0073 100644 >>>> --- a/arch/x86/kvm/x86.c >>>> +++ b/arch/x86/kvm/x86.c >>>> @@ -4928,6 +4928,8 @@ static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask) >>>> if (!mask) >>>> kvm_make_request(KVM_REQ_EVENT, vcpu); >>>> } >>>> + if (!(int_shadow || mask)) >>>> + kvm_make_request(KVM_REQ_EVENT, vcpu); >>>> } >>>> >>>> static void inject_emulated_exception(struct kvm_vcpu *vcpu) >>> >>> No, this patch undoes the optimization in the buggy patch. >>> >>> A KVM_REQ_EVENT must be missing somewhere else. >>> >> >> Could you give some tips in order that I can figure it out? > >I have no idea right now (I was planning to debug it this week). > >(BTW, look at the original commit that introduced KVM_REQ_EVENT -- >https://git.kernel.org/cgit/virt/kvm/kvm.git/commit/?id=3842d135 -- and >compare the patch and the commit message. You can see that it was added >to the emulator because it is a "place that can set EFLAGS" and this >idea is preserved in the buggy patch). > >From xen codes which report panic: check_timer timer_irq_works local_save_flags(flags); => pushf;pop local_irq_enable(); => sti delay xxxx local_irq_restore(flags); => pushfq;andq;orq;popfq Regards, Wanpeng Li >The important thing is that (despite Xen being involved) this is not >related to nested virtualization. So I would first of all try to see if >some module parameter makes it go away (apicv and unrestricted mode >especially), then capture a trace of the panic. At least this is how I >was planning to start... :) > >Paolo -- 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
