Re: [Xen-devel] [Qemu-devel] [PATCH v3] xen/pt: allow passthrough of devices with bogus interrupt pin

[Zhao Yan <yan.y.zhao@xxxxxxxxx>]

On Tue, Dec 04, 2018 at 10:30:18AM +0100, Roger Pau Monné wrote:
> On Tue, Dec 04, 2018 at 02:50:49AM -0500, Zhao Yan wrote:
> > For some pci device, even its PCI_INTERRUPT_PIN is not 0, it actually
> > doesn't support INTx mode, so its machine irq read from host sysfs is 0.
> > In that case, report PCI_INTERRUPT_PIN as 0 to guest and let passthrough
> > continue.
> > 
> > Cc: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> > Cc: Jan Beulich <JBeulich@xxxxxxxx>
> > Signed-off-by: Zhao Yan <yan.y.zhao@xxxxxxxxx>
> 
> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> 
> One nit below.
Got it. Thank you!
:)
> 
> > 
> > ---
> > v2: fix some coding style issue
> > v3:
> >    1. let subject be more descriptive (roger)
> >    2. disable INTx assertion if machine irq is 0.(roger)
> >    3. in xen_pt_irqpin_reg_init(), drop the else branch as the default
> > value for *data is 0. (roger)
> > ---
> >  hw/xen/xen_pt.c             | 7 +++++++
> >  hw/xen/xen_pt_config_init.c | 4 +++-
> >  2 files changed, 10 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
> > index e5a6eff..b563837 100644
> > --- a/hw/xen/xen_pt.c
> > +++ b/hw/xen/xen_pt.c
> > @@ -847,6 +847,13 @@ static void xen_pt_realize(PCIDevice *d, Error **errp)
> >      }
> >  
> >      machine_irq = s->real_device.irq;
> > +    if (machine_irq == 0) {
> > +        XEN_PT_LOG(d, "machine irq is 0\n");
> > +        cmd |= PCI_COMMAND_INTX_DISABLE;
> > +        s->machine_irq = 0;
> 
> AFAICT this is already initialized to 0, so you can drop setting
> machine_irq.
> 
> Thanks, Roger.

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