On 03/12/14 21:40, Konrad Rzeszutek Wilk wrote:
> From: Jan Beulich <JBeulich@xxxxxxxx>
>
> When a PF driver unloads, it may find it necessary to leave the VFs
> around simply because of pciback having marked them as assigned to a
> guest. Utilize a suitable notification to let go of the VFs, thus
> allowing the PF to go back into the state it was before its driver
> loaded (which in particular allows the driver to be loaded again with
> it being able to create the VFs anew, but which also allows to then
> pass through the PF instead of the VFs).
>
> Don't do this however for any VFs currently in active use by a guest.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> [v2: Removed the switch statement, moved it about]
> [v3: Redid it a bit differently]
Jan, are you happy with Konrad's change now?
David
> --- a/drivers/xen/xen-pciback/pci_stub.c
> +++ b/drivers/xen/xen-pciback/pci_stub.c
> @@ -1518,6 +1518,53 @@ parse_error:
> fs_initcall(pcistub_init);
> #endif
>
> +#ifdef CONFIG_PCI_IOV
> +static struct pcistub_device *find_vfs(const struct pci_dev *pdev)
> +{
> + struct pcistub_device *psdev = NULL;
> + unsigned long flags;
> + bool found = false;
> +
> + spin_lock_irqsave(&pcistub_devices_lock, flags);
> + list_for_each_entry(psdev, &pcistub_devices, dev_list) {
> + if (!psdev->pdev && psdev->dev != pdev
> + && pci_physfn(psdev->dev) == pdev) {
> + found = true;
> + break;
> + }
> + }
> + spin_unlock_irqrestore(&pcistub_devices_lock, flags);
> + if (found)
> + return psdev;
> + return NULL;
> +}
> +
> +static int pci_stub_notifier(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct device *dev = data;
> + const struct pci_dev *pdev = to_pci_dev(dev);
> +
> + if (action != BUS_NOTIFY_UNBIND_DRIVER)
> + return NOTIFY_DONE;
> +
> + if (!pdev->is_physfn)
> + return NOTIFY_DONE;
> +
> + for (;;) {
> + struct pcistub_device *psdev = find_vfs(pdev);
> + if (!psdev)
> + break;
> + device_release_driver(&psdev->dev->dev);
> + }
> + return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block pci_stub_nb = {
> + .notifier_call = pci_stub_notifier,
> +};
> +#endif
> +
> static int __init xen_pcibk_init(void)
> {
> int err;
> @@ -1539,12 +1586,19 @@ static int __init xen_pcibk_init(void)
> err = xen_pcibk_xenbus_register();
> if (err)
> pcistub_exit();
> +#ifdef CONFIG_PCI_IOV
> + else
> + bus_register_notifier(&pci_bus_type, &pci_stub_nb);
> +#endif
>
> return err;
> }
>
> static void __exit xen_pcibk_cleanup(void)
> {
> +#ifdef CONFIG_PCI_IOV
> + bus_unregister_notifier(&pci_bus_type, &pci_stub_nb);
> +#endif
> xen_pcibk_xenbus_unregister();
> pcistub_exit();
> }
>
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