[PATCH v13 0/5] Simplify PCIe native ownership

[Kuppuswamy Sathyanarayanan]

This revives Bjorn's v12 from November 2020, rebased onto v7.3-rc3.

  https://lore.kernel.org/all/20201126011816.711106-1-helgaas@xxxxxxxxxx/

The goal is unchanged.  Decide who owns each PCIe port service in one
place, when we interpret the _OSC results in acpi_pci_root_create(), so
that everywhere else only has to look at host_bridge->native_X.  For AER
specifically, host_bridge->native_aer becomes the single answer to the
question "may Linux touch the AER Capability?".  Today callers each have
to remember to also test pcie_ports_native and pci_aer_available().

I posted v11.  Bjorn took it over at v12, split the _OSC changes in two
and deferred the "pcie_ports=dpc-native" work.  The v12 review comments
were agreed but never respun, and the series stalled.  v13 is that
respin.  Each patch carries its own changelog.

  https://lore.kernel.org/r/cover.1603766889.git.sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx

Bjorn suggested reviving it in response to Guixin Liu's report that
"pcie_ports=native" no longer enables DPC.  The DPC service binds on
host_bridge->native_aer, and that flag did not reflect the command line,
so DPC stayed off when firmware retained AER control.  Patch 4 fixes it
by making the flag reflect it.

  https://lore.kernel.org/linux-pci/20260901064554.2178688-1-kanie@xxxxxxxxxxxxxxxxx/

Patch 4 has a side effect worth calling out.  drivers/cxl/core/ras.c did
not exist in 2020 and tests host_bridge->native_aer with no
pcie_ports_native fallback, so it has been quietly ignoring
"pcie_ports=native".  Centralizing the check fixes that.

Two things are left for later, to keep this series a cleanup.

 * pci_aer_available() stays in the DPC arm of
   get_port_device_capability(), because "pcie_ports=dpc-native" still
   needs it there.
 * We still gate the DPC service on native_aer and ignore
   OSC_PCI_EXPRESS_DPC_CONTROL, as Bjorn noted in the v12 cover letter.
   Fixing it changes behavior, so it wants its own patch.

Bjorn Helgaas (2):
  PCI/DPC: Ignore devices with no AER Capability
  PCI: Centralize pci_aer_available() checking

Kuppuswamy Sathyanarayanan (3):
  PCI: Assume control of portdrv-related features only when portdrv
    enabled
  PCI/ACPI: Tidy _OSC control bit checking
  PCI/ACPI: Centralize pcie_ports_native checking

 drivers/acpi/pci_root.c           | 73 ++++++++++++++++++++++++-------
 drivers/pci/hotplug/pciehp_core.c |  2 +-
 drivers/pci/pci-acpi.c            |  3 --
 drivers/pci/pcie/aer.c            |  6 +--
 drivers/pci/pcie/aer_cxl_rch.c    |  2 +-
 drivers/pci/pcie/dpc.c            |  3 ++
 drivers/pci/pcie/err.c            |  2 +-
 drivers/pci/pcie/portdrv.c        |  7 ++-
 drivers/pci/probe.c               |  8 ++--
 9 files changed, 75 insertions(+), 31 deletions(-)


base-commit: fd73f4a6659897191fa0d40695fe370925dd3780
-- 
2.43.0