Re: [PATCH] xen/pciback: Make missing GSI non-fatal

[Jason Andryuk]

On 2025-02-27 03:23, Jan Beulich wrote:
> On 26.02.2025 21:01, Jason Andryuk wrote:
>
> > --- a/drivers/xen/acpi.c
> > +++ b/drivers/xen/acpi.c
> > @@ -101,7 +101,7 @@ int xen_acpi_get_gsi_info(struct pci_dev *dev,
> >   
> >   	pin = dev->pin;
> >   	if (!pin)
> > -		return -EINVAL;
> > +		return -ENOENT;
> >   
> >   	entry = acpi_pci_irq_lookup(dev, pin);
> >   	if (entry) {
>
> While I can understand this change, ...
>
> > @@ -116,7 +116,7 @@ int xen_acpi_get_gsi_info(struct pci_dev *dev,
> >   		gsi = -1;
> >   
> >   	if (gsi < 0)
> > -		return -EINVAL;
> > +		return -ENOENT;
> >   
> >   	*gsi_out = gsi;
> >   	*trigger_out = trigger;
>
> ... I'd expect this needs to keep using an error code other than ENOENT.
> Aiui this path means the device has a pin-based interrupt, just that it's
> not configured correctly. In which case we'd better not allow the device
> to be handed to a guest. Unless there's logic in place (somewhere) to
> make sure it then would get to see a device without pin-based interrupt.

This is actually the case that fails for me.

05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. 
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)
        Interrupt: pin A routed to IRQ -2147483648

Interrupt Pin is 0x01, and Interrupt Line is 0xff

I'll have to check the existing code to see what it does.

Also, thanks for catching the commit message typos.

Regards,
Jason