[K][PATCH 0/5] Independent Usage of Secondary Physical Function (LP: 1959542)

[frank.heimes at canonical.com]

BugLink: https://bugs.launchpad.net/bugs/1959542

These commits add the ability for a Linux (s390x) running in LPAR to use the
Physical Function (PF) associated with the second port of a ConnectX-5/6 card
independent of that of the first port.
Prior to this feature, if the secondary PF was attached to an LPAR without
also attaching the primary PF, no PCI function would be visible in Linux.
The function would instead remain in a hidden and disabled state.
Conversely it has always been possible to use the primary PF without attaching
the secondary PF.
This existing behavior is confusing and needlessly restricts flexible usage of
these powerful network cards.
The new behavior of allowing independent usage is also in accordance with the
PCI SR-IOV specification which explicitly defines the dependencies between PCI
functions in the Dependency Link field which is still honored and for
ConnectX-5/6 cards allows this independent usage.

Niklas Schnelle (5):
  PCI: Clean up pci_scan_slot()
  PCI: Split out next_ari_fn() from next_fn()
  PCI: Move jailhouse's isolated function handling to pci_scan_slot()
  PCI: Extend isolated function probing to s390
  s390/pci: allow zPCI zbus without a function zero

 arch/s390/pci/pci_bus.c    | 82 +++++++++--------------------------
 drivers/pci/probe.c        | 87 ++++++++++++++++++--------------------
 include/linux/hypervisor.h |  8 ++++
 3 files changed, 69 insertions(+), 108 deletions(-)

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2.25.1