On Sun, Sep 29, 2013 at 3:52 AM, Michael S. Tsirkin <m...@redhat.com> wrote: > On Thu, Sep 12, 2013 at 11:25:14AM +0800, Liu Ping Fan wrote: >> According to hpet spec, hpet irq is high active. But according to >> ICH spec, there is inversion before the input of ioapic. So the OS >> will expect low active on this IRQ line. > > >>(And this is observed on >> bare metal). > > How does one test this on bare metal? > If changing the func hpet_timer_set_irq() in linux's hpet driver, from acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_LOW); to ACPI_ACTIVE_HIGH, then run hpet_example.c on bare metal, the modified kernel will complain about spurious irq and disable the irq line. >> >> We fold the emulation of this inversion inside the hpet logic. >> >> Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com> > > > Doesn't this affect cross-version migration? > E.g. imagine that you migrate between systems > with/without this fix. > No. the changing only affect "route >= ISA_NUM_IRQS", For linux guest, it use IRQ2/8 for hpet0/hpet1 which is reserved by kernel. It work without this fix (I think windows is the same). But the hpet_example.c(in linux) can not work without this fix. So no such run-time instance before this bug fix.
Regards, Pingfan >> --- >> hw/timer/hpet.c | 14 ++++++++++++-- >> 1 file changed, 12 insertions(+), 2 deletions(-) >> >> diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c >> index fcd22ae..8429eb3 100644 >> --- a/hw/timer/hpet.c >> +++ b/hw/timer/hpet.c >> @@ -198,13 +198,23 @@ static void update_irq(struct HPETTimer *timer, int >> set) >> if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) { >> s->isr &= ~mask; >> if (!timer_fsb_route(timer)) { >> - qemu_irq_lower(s->irqs[route]); >> + /* fold the ICH PIRQ# pin's internal inversion logic into hpet >> */ >> + if (route >= ISA_NUM_IRQS) { >> + qemu_irq_raise(s->irqs[route]); >> + } else { >> + qemu_irq_lower(s->irqs[route]); >> + } >> } >> } else if (timer_fsb_route(timer)) { >> stl_le_phys(timer->fsb >> 32, timer->fsb & 0xffffffff); >> } else if (timer->config & HPET_TN_TYPE_LEVEL) { >> s->isr |= mask; >> - qemu_irq_raise(s->irqs[route]); >> + /* fold the ICH PIRQ# pin's internal inversion logic into hpet */ >> + if (route >= ISA_NUM_IRQS) { >> + qemu_irq_lower(s->irqs[route]); >> + } else { >> + qemu_irq_raise(s->irqs[route]); >> + } >> } else { >> s->isr &= ~mask; >> qemu_irq_pulse(s->irqs[route]); >> -- >> 1.8.1.4 >>