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xen-pciback: drop SR-IOV VFs when PF driver unloads 

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@suse.com>
[v2: Removed the switch statement, moved it about]
[v3: Redid it a bit differently]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
This commit is contained in:
Jan Beulich 2014-12-03 16:40:33 -05:00 committed by David Vrabel
parent b1df4a56bf
commit 6945c59c77
1 changed files with 54 additions and 0 deletions
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54
drivers/xen/xen-pciback/pci_stub.c
View File

@ -1518,6 +1518,53 @@ static int __init pcistub_init(void)
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();
}