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Re: [Qemu-devel] [PATCH] pci: Return PCI_INTX_DISABLED when no bus INTx
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH] pci: Return PCI_INTX_DISABLED when no bus INTx routing support |
Date: |
Wed, 17 Oct 2012 21:48:52 +0200 |
On Wed, Oct 17, 2012 at 08:40:05PM +0200, Jan Kiszka wrote:
> On 2012-10-17 20:25, Alex Williamson wrote:
> > Rather than assert, simply return PCI_INTX_DISABLED when we don't
> > have a pci_route_irq_fn. PIIX already returns DISABLED for an
> > invalid pin, so users already deal with this state. Users of this
> > interface should only be acting on an ENABLED or INVERTED return
> > value (though we really have no support for INVERTED).
> >
> > Signed-off-by: Alex Williamson <address@hidden>
> > ---
> >
> > A compromise to the gridlock; defuse the assert, but don't add
> > a new state to the API. Thanks,
>
> But how do you tell "unsupported" apart from "disabled" in VFIO? If the
> chipset truly disabled the line, you must not provide it to the guest in
> some other way.
>
> Jan
vfio does not care. It merely disables irqfd and delivers irqs to qemu.
> >
> > Alex
> >
> > hw/pci.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/pci.c b/hw/pci.c
> > index 83d262a..9525220 100644
> > --- a/hw/pci.c
> > +++ b/hw/pci.c
> > @@ -1094,7 +1094,11 @@ PCIINTxRoute pci_device_route_intx_to_irq(PCIDevice
> > *dev, int pin)
> > pin = bus->map_irq(dev, pin);
> > dev = bus->parent_dev;
> > } while (dev);
> > - assert(bus->route_intx_to_irq);
> > +
> > + if (!bus->route_intx_to_irq) {
> > + return (PCIINTxRoute) { PCI_INTX_DISABLED, -1 };
> > + }
> > +
> > return bus->route_intx_to_irq(bus->irq_opaque, pin);
> > }
> >
> >
>
> --
> Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
> Corporate Competence Center Embedded Linux