On 04/02/2018 19:02, Peter Maydell wrote: > On 1 February 2018 at 14:23, Paolo Bonzini <[email protected]> wrote: >> On 01/02/2018 08:47, Gonglei wrote: >>> diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c >>> index 35a05a6..d9d99c5 100644 >>> --- a/hw/timer/mc146818rtc.c >>> +++ b/hw/timer/mc146818rtc.c >>> @@ -986,6 +986,7 @@ static void rtc_realizefn(DeviceState *dev, Error >>> **errp) >>> qemu_register_suspend_notifier(&s->suspend_notifier); >>> >>> memory_region_init_io(&s->io, OBJECT(s), &cmos_ops, s, "rtc", 2); >>> + memory_region_clear_global_locking(&s->io); >>> isa_register_ioport(isadev, &s->io, base); >>> >>> qdev_set_legacy_instance_id(dev, base, 3); >>> >> >> This is not enough, you need to add a new lock or something like that. >> Otherwise two vCPUs can access the RTC together and make a mess. > > Do you also need to do something to take the global lock before > raising the outbound IRQ line (since it might be connected to a device > that does need the global lock), or am I confused ?
Yes, that's a good point. Most of the time the IRQ line is raised in a timer, but not always. Paolo
