Hi, This is the v6 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/ v3: https://lore.kernel.org/lkml/20210609163211.3467449-1-boqun.feng@xxxxxxxxx/ v4: https://lore.kernel.org/lkml/20210714102737.198432-1-boqun.feng@xxxxxxxxx/ v5: https://lore.kernel.org/lkml/20210720134429.511541-1-boqun.feng@xxxxxxxxx/ Changes since last version: * Rebase to 5.14-rc3 * Comment fixes 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 | 11 ++++ 4 files changed, 93 insertions(+), 45 deletions(-) -- 2.32.0