[RFC v5 0/8] PCI: hv: Support host bridge probing on ARM64

From: Boqun Feng <boqun.feng@gmail.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
	Arnd Bergmann <arnd@arndb.de>, Marc Zyngier <maz@kernel.org>
Cc: "Catalin Marinas" <catalin.marinas@arm.com>,
	"Will Deacon" <will@kernel.org>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	"Haiyang Zhang" <haiyangz@microsoft.com>,
	"Stephen Hemminger" <sthemmin@microsoft.com>,
	"Wei Liu" <wei.liu@kernel.org>,
	"Dexuan Cui" <decui@microsoft.com>,
	"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
	linux-pci@vger.kernel.org,
	"Sunil Muthuswamy" <sunilmut@microsoft.com>,
	"Mike Rapoport" <rppt@kernel.org>
Subject: [RFC v5 0/8] PCI: hv: Support host bridge probing on ARM64
Date: Tue, 20 Jul 2021 21:44:21 +0800	[thread overview]
Message-ID: <20210720134429.511541-1-boqun.feng@gmail.com> (raw)

Hi Bjorn, Arnd and Marc,

This is the v5 for the preparation of virtual PCI support on Hyper-V
ARM64, Previous versions:

v1:	https://lore.kernel.org/lkml/20210319161956.2838291-1-boqun.feng@gmail.com/
v2:	https://lore.kernel.org/lkml/20210503144635.2297386-1-boqun.feng@gmail.com/
v3:	https://lore.kernel.org/lkml/20210609163211.3467449-1-boqun.feng@gmail.com/
v4:	https://lore.kernel.org/lkml/20210714102737.198432-1-boqun.feng@gmail.com/

Changes since last version:

*	Rebase to 5.14-rc2

*	Wording changes (Capitalization and more explanation on why) as
	suggested by Bjorn.

*	Split the patch #3 in previous into two patches as suggested by
	Bjorn.

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,
which introduces a special case when trying to find the ACPI device from
the sysdata (see patch #3).

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 (7):
  PCI: Introduce domain_nr in pci_host_bridge
  PCI: Support populating MSI domains of root buses via bridges
  arm64: PCI: Restructure pcibios_root_bridge_prepare()
  arm64: PCI: Support root bridge preparation for Hyper-V
  PCI: hv: Set ->domain_nr of pci_host_bridge at probing time
  PCI: hv: Set up MSI domain at bridge probing time
  PCI: hv: Turn on the host bridge probing on ARM64

 arch/arm64/kernel/pci.c             | 29 +++++++---
 drivers/pci/controller/pci-hyperv.c | 86 +++++++++++++++++------------
 drivers/pci/probe.c                 | 12 +++-
 include/linux/pci.h                 | 10 ++++
 4 files changed, 92 insertions(+), 45 deletions(-)

-- 
2.30.2