s390/pci: fix PF/VF linking on hot plug

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 e5794cf1a270 ("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: e5794cf1a270 ("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>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/s390/pci/pci_bus.h b/arch/s390/pci/pci_bus.h
index 89be3c354b7b..4972433df458 100644
--- a/arch/s390/pci/pci_bus.h
+++ b/arch/s390/pci/pci_bus.h
@@ -29,3 +29,16 @@ static inline struct zpci_dev *get_zdev_by_bus(struct pci_bus *bus,
 
 	return (devfn >= ZPCI_FUNCTIONS_PER_BUS) ? NULL : zbus->function[devfn];
 }
+
+#ifdef CONFIG_PCI_IOV
+static inline void zpci_remove_virtfn(struct pci_dev *pdev, int vfn)
+{
+
+	pci_lock_rescan_remove();
+	/* Linux' vfid's start at 0 vfn at 1 */
+	pci_iov_remove_virtfn(pdev->physfn, vfn - 1);
+	pci_unlock_rescan_remove();
+}
+#else /* CONFIG_PCI_IOV */
+static inline void zpci_remove_virtfn(struct pci_dev *pdev, int vfn) {}
+#endif /* CONFIG_PCI_IOV */