Re: [Qemu-ppc] [RFC PATCH] pseries: use qemu_irq_raise() in spapr_msi_write()

[Alexey Kardashevskiy]

On 05/10/2016 11:50 AM, Benjamin Herrenschmidt wrote:
> On Tue, 2016-05-10 at 11:31 +1000, Alexey Kardashevskiy wrote:
> > On 05/10/2016 11:18 AM, Li Zhong wrote:
> > > It seems that both ics_set_irq() and ics_kvm_set_irq() don't do
> > > anything
> > > useful for MSIs with val = 0, so maybe the pulse in
> > > spapr_msi_write()
> > > could be replaced with a single raise?
> >
> > qemu_irq_raise() needs matching qemu_irq_lower(), where is it?
>
> Does qemu require both raise & lower for edge interrupts ?

It should not and it does not. I was just afraid that something might get 
missing in the xics state machine after this change but it looks the patch 
is correct.

And also noticed that xics_set_irq_type() is a dead code which has to go.


> Ben.
>
> > > Signed-off-by: Li Zhong <address@hidden>
> > > ---
> > >  hw/ppc/spapr_pci.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> > > index 573e635..897c541 100644
> > > --- a/hw/ppc/spapr_pci.c
> > > +++ b/hw/ppc/spapr_pci.c
> > > @@ -732,7 +732,7 @@ static void spapr_msi_write(void *opaque,
> > > hwaddr addr,
> > >
> > >      trace_spapr_pci_msi_write(addr, data, irq);
> > >
> > > -    qemu_irq_pulse(xics_get_qirq(spapr->icp, irq));
> > > +    qemu_irq_raise(xics_get_qirq(spapr->icp, irq));
> > >  }
> > >
> > >  static const MemoryRegionOps spapr_msi_ops = {


--
Alexey