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

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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: 2f0230b2f2: 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>
This commit is contained in:
Niklas Schnelle 2020-08-03 17:58:10 +02:00 committed by Heiko Carstens
parent 2f0230b2f2
commit b97bf44f99
3 changed files with 32 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/s390/pci/pci.c
View File

@ -678,8 +678,11 @@ void zpci_remove_device(struct zpci_dev *zdev)
struct pci_dev *pdev;
pdev = pci_get_slot(zbus->bus, zdev->devfn);
if (pdev)
if (pdev) {
if (pdev->is_virtfn)
return zpci_remove_virtfn(pdev, zdev->vfn);
pci_stop_and_remove_bus_device_locked(pdev);
}
}
int zpci_create_device(struct zpci_dev *zdev)

27
arch/s390/pci/pci_bus.c
View File

@ -189,6 +189,19 @@ static inline int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
}
#endif
void pcibios_bus_add_device(struct pci_dev *pdev)
{
struct zpci_dev *zdev = to_zpci(pdev);
/*
* With pdev->no_vf_scan the common PCI probing code does not
* perform PF/VF linking.
*/
if (zdev->vfn)
zpci_bus_setup_virtfn(zdev->zbus, pdev, zdev->vfn);
}
static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
{
struct pci_bus *bus;
@ -219,20 +232,10 @@ static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
}
pdev = pci_scan_single_device(bus, zdev->devfn);
if (pdev) {
if (!zdev->is_physfn) {
rc = zpci_bus_setup_virtfn(zbus, pdev, zdev->vfn);
if (rc)
goto failed_with_pdev;
}
if (pdev)
pci_bus_add_device(pdev);
}
return 0;
failed_with_pdev:
pci_stop_and_remove_bus_device(pdev);
pci_dev_put(pdev);
return rc;
return 0;
}
static void zpci_bus_add_devices(struct zpci_bus *zbus)

13
arch/s390/pci/pci_bus.h
View File

@ -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 */