Re: [PATCH 4/9] vpci/header: Add and remove register handlers dynamically

[Jan Beulich <jbeulich@xxxxxxxx>]

On 03.09.2021 12:08, Oleksandr Andrushchenko wrote:
> @@ -593,6 +625,36 @@ static int init_bars(struct pci_dev *pdev)
>  }
>  REGISTER_VPCI_INIT(init_bars, VPCI_PRIORITY_MIDDLE);
>  
> +int vpci_bar_add_handlers(const struct domain *d, struct pci_dev *pdev)
> +{
> +    int rc;
> +
> +    /* Remove previously added registers. */
> +    vpci_remove_device_registers(pdev);
> +
> +    /* It only makes sense to add registers for hwdom or guest domain. */
> +    if ( d->domain_id >= DOMID_FIRST_RESERVED )
> +        return 0;
> +
> +    if ( is_hardware_domain(d) )
> +        rc = add_bar_handlers(pdev, true);
> +    else
> +        rc = add_bar_handlers(pdev, false);

    rc = add_bar_handlers(pdev, is_hardware_domain(d));

> +    if ( rc )
> +        gprintk(XENLOG_ERR,
> +            "%pp: failed to add BAR handlers for dom%d\n", &pdev->sbdf,
> +            d->domain_id);

Please use %pd and correct indentation. Logging the error code might
also help some in diagnosing issues. Further I'm not sure this is a
message we want in release builds - perhaps gdprintk()?

> +    return rc;
> +}
> +
> +int vpci_bar_remove_handlers(const struct domain *d, struct pci_dev *pdev)
> +{
> +    /* Remove previously added registers. */
> +    vpci_remove_device_registers(pdev);
> +    return 0;
> +}

Also - in how far is the goal of your work to also make vPCI work for
x86 DomU-s? If that's not a goal, I'd like to ask that you limit the
introduction of code that ends up dead there.

Jan