[PATCH v15 0/4] 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 was that
respin.

  https://lore.kernel.org/r/cover.1603766889.git.sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx [v11]

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 3 fixes it
by making the flag reflect it.

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

Patch 3 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.

Binding the DPC service on host_bridge->native_dpc, rather than on
native_aer, is left for a separate patch on top of Lukas's series that
removes the DPC/AER dependency, as agreed with Bjorn.  That change
alters behavior, so it does not belong in this cleanup.

  https://lore.kernel.org/r/cover.1790531238.git.lukas@xxxxxxxxx
  https://lore.kernel.org/r/20261001221408.GA2731929@bhelgaas

Changes since v14:
  * Patch 3: fold "pcie_ports=dpc-native" into the _OSC control mask as
    well, so host_bridge->native_dpc and the "OS native features" line
    reflect it (Bjorn).
  * Picked up Guixin's Reviewed-by on patch 3.

v14 posting
https://lore.kernel.org/r/20260922204548.3884906-1-sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx

Changes since v13:
  * Lukas suggested dropping AER cap check fix (patch 1 of v13). He has
    a series underway to fix it cleanly (removing DPC/AER dependency).
    So dropped the patch as suggested.
    https://lore.kernel.org/r/aq95LGUHL-pnmTlr@xxxxxxxxx
  * Addressed use of IS_ENABLED(CONFIG_PCIEPORTBUS) instead of #ifdef
    (Lukas).
  * Added Fixes tag in patch 3 (Guixin Liu).
  * Added Acks from Rafael.

v13 posting
https://lore.kernel.org/r/20260919162655.3499010-1-sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx

Bjorn Helgaas (1):
  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           | 78 +++++++++++++++++++++++++------
 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/err.c            |  2 +-
 drivers/pci/pcie/portdrv.c        |  7 ++-
 drivers/pci/pcie/portdrv.h        |  2 -
 drivers/pci/probe.c               | 10 ++--
 include/linux/pci.h               |  2 +
 10 files changed, 80 insertions(+), 34 deletions(-)


base-commit: fd73f4a6659897191fa0d40695fe370925dd3780
-- 
2.43.0