[RFC v3 0/7] PCI: hv: Support host bridge probing on ARM64

[Boqun Feng]

Hi Bjorn, Arnd and Marc,

This is the v3 for the preparation of virtual PCI support on Hyper-V
ARM64. Previous versions:

v1:	https://lore.kernel.org/lkml/20210319161956.2838291-1-boqun.feng@xxxxxxxxx/
v2:	https://lore.kernel.org/lkml/20210503144635.2297386-1-boqun.feng@xxxxxxxxx/

Changes since last version:

*	Use a sentinel value approach instead of calling
	pci_bus_find_domain_nr() for every CONFIG_PCI_DOMAIN_GENERIC=y
	arch as per suggestion from

*	Improve the commit log and comments for patch #6.

*	Rebase to the latest mainline.

The basic problem we need to resolve is that ARM64 is an arch with
PCI_DOMAINS_GENERIC=y, so the bus sysdata is pci_config_window. However,
Hyper-V PCI provides a paravirtualized PCI interface, so there is no
actual pci_config_window for a PCI host bridge, so no information can be
retrieve from the pci_config_window of a Hyper-V virtual PCI bus. Also
there is no corresponding ACPI device for the Hyper-V PCI root bridge.

With this patchset, we could enable the virtual PCI on Hyper-V ARM64
guest with other code under development.

Comments and suggestions are welcome.

Regards,
Boqun

Arnd Bergmann (1):
  PCI: hv: Generify PCI probing

Boqun Feng (6):
  PCI: Introduce domain_nr in pci_host_bridge
  PCI: Allow msi domain set-up at host probing time
  PCI: hv: Use pci_host_bridge::domain_nr for PCI domain
  PCI: hv: Set up msi domain at bridge probing time
  arm64: PCI: Support root bridge preparation for Hyper-V PCI
  PCI: hv: Turn on the host bridge probing on ARM64

 arch/arm64/kernel/pci.c             |  7 ++-
 drivers/pci/controller/pci-hyperv.c | 87 +++++++++++++++++------------
 drivers/pci/probe.c                 |  9 ++-
 include/linux/pci.h                 | 10 ++++
 4 files changed, 73 insertions(+), 40 deletions(-)

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2.30.2