Re: dom0 PVH: 'entry->arch.pirq != INVALID_PIRQ' failed at vmsi.c:843

[Jan Beulich <jbeulich@xxxxxxxx>]

On 12.11.2020 17:32, Roger Pau Monné wrote:
> --- a/xen/drivers/vpci/msix.c
> +++ b/xen/drivers/vpci/msix.c
> @@ -371,7 +371,12 @@ static int msix_write(struct vcpu *v, unsigned long 
> addr, unsigned int len,
>              entry->updated = false;
>          }
>          else
> +        {
> +            printk("%pp offset %u len %u new_masked %d enabled %d masked %d 
> updated %d\n",
> +                   &pdev->sbdf, offset, len, new_masked, msix->enabled, 
> msix->masked,
> +                   entry->updated);
>              vpci_msix_arch_mask_entry(entry, pdev, entry->masked);
> +        }

What about a write of all zero as the very first write we
get to see, while msix->masked is true? I'm getting the
impression we would never have come through update_entry()
in this case, and hence vpci_msix_arch_enable_entry() - the
only function setting entry->arch.pirq to a valid value
afaics - would never have been called.

Jan