> From: Paolo Bonzini [mailto:pbonz...@redhat.com] > Il 27/08/2014 15:03, Pavel Dovgaluk ha scritto: > >> > Hmm, probably not. The bug would not be other timers accessing the > >> > APIC, because that would also call apic_sync_vapic and the only effect > >> > would be an extra useless synchronization. The bug would happen if the > >> > APIC is accessed by the CPU before the timer has the occasion to run. > > Sorry, but I don't understand which problem we will solve with > > apic_sync_vapic. > > Taking inspiration from what KVM does, the fix could be even simpler > than a change state handler. run_on_cpu functions do not run while the > VM is stopped, so the following should work: > > diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c > index ce3d903..81d1ad7 100644 > --- a/hw/intc/apic_common.c > +++ b/hw/intc/apic_common.c > @@ -91,13 +91,20 @@ void apic_enable_tpr_access_reporting(DeviceState > *dev, bool enable) > } > } > > +static void do_apic_enable_vapic(void *data) > +{ > + APICCommonState *s = APIC_COMMON(data); > + APICCommonClass *info = APIC_COMMON_GET_CLASS(s); > + > + info->vapic_base_update(s); > +} > + > void apic_enable_vapic(DeviceState *dev, hwaddr paddr) > { > APICCommonState *s = APIC_COMMON(dev); > - APICCommonClass *info = APIC_COMMON_GET_CLASS(s); > > s->vapic_paddr = paddr; > - info->vapic_base_update(s); > + run_on_cpu(CPU(s->cpu), do_apic_enable_vapic, s); > }
I've tried this one and it doesn't work. do_apic_enable_vapic runs on cpu, at the same time the VM state is loaded. APIC state still remains broken because of this. Pavel Dovgalyuk
