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>
We allow multiple functions on a single bus.
We suppress the ZPCI_DEVFN definition and replace its
occurences with zpci->devfn.
We verify the number of device during the registration.
There can never be more domains in use than existing
devices, so we do not need to verify the count of domain
after having verified the count of devices.
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The zPCI bus is in charge to handle common zPCI resources for
zPCI devices.
Creating the zPCI bus, the PCI bus, the zPCI devices and the
PCI devices and hotplug slots
done in a specific order:
- PCI hotplug slot creation needs a PCI bus
- PCI bus needs a PCI domain
which is reported by the pci_domain_nr() when setting up the
host bridge
- PCI domain is set from the zPCI with devfn 0
this is necessary to have a reproducible enumeration
Therefore we can not create devices or hotplug slots for any PCI
device associated with a zPCI device before having discovered
the function zero of the bus.
The discovery and initialization of devices can be done at several
points in the code:
- On Events, serialized in a thread context
- On initialization, in the kernel init thread context
- When powering on the hotplug slot, in a user thread context
The removal of devices and their parent bus may also be done on
events or for devices when powering down the slot.
To guarantee the existence of the bus and devices until they are
no more needed we use kref in zPCI bus and introduce a reference
count in the zPCI devices.
In this patch the zPCI bus still only accept a device with
a devfn 0.
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Niklas Schnelle