Currently there are four places in which a PCI function is scanned
and made available to drivers:
1. In pci_scan_root_bus() as part of the initial zbus
creation.
2. In zpci_bus_add_devices() when registering
a device in configured state on a zbus that has already been
scanned.
3. When a function is already known to zPCI (in reserved/standby state)
and configuration is triggered through firmware by PEC 0x301.
4. When a device is already known to zPCI (in standby/reserved state)
and configuration is triggered from within Linux using
enable_slot().
The PF/VF linking step and setting of pdev->is_virtfn introduced with
commit e5794cf1a2 ("s390/pci: create links between PFs and VFs") was
only triggered for the second case, which is where VFs created through
sriov_numvfs usually land. However unlike some other platforms but like
POWER VFs can be individually enabled/disabled through
/sys/bus/pci/slots.
Fix this by doing VF setup as part of pcibios_bus_add_device() which is
called in all of the above cases.
Finally to remove the PF/VF links call the common code
pci_iov_remove_virtfn() function to remove linked VFs.
This takes care of the necessary sysfs cleanup.
Fixes: e5794cf1a2 ("s390/pci: create links between PFs and VFs")
Cc: <stable@vger.kernel.org> # 5.8: 2f0230b2f2d5: s390/pci: re-introduce zpci_remove_device()
Cc: <stable@vger.kernel.org> # 5.8
Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
b97bf44f99