Hi Lorenzo, As our previous discussion, I make a patchset showing the required effort if we want to use ->private in pci_host_bridge to store ACPI device pointer on ARM64. This patchset is mostly for discussion purpose. This patchset is based onto the v5 of my Hyper-V PCI on ARM64 patchset: https://lore.kernel.org/lkml/20210726180657.142727-1-boqun.feng@xxxxxxxxx/ , and I've tested it with other code under development to fully enable Hyper-V virtual PCI on ARM64. Regards, Boqun Boqun Feng (5): PCI: Introduce pci_create_root_bus_priv() PCI/ACPI: Store ACPI device information in the host bridge structure PCI: hv: Set NULL as the ACPI device for the PCI host bridge arm64: PCI: Retrieve ACPI device information directly from host bridges PCI: hv: Remove the dependency of pci_config_window arch/arm64/kernel/pci.c | 14 +------------- drivers/acpi/pci_root.c | 5 +++-- drivers/pci/controller/pci-hyperv.c | 20 +++++++++++++++----- drivers/pci/probe.c | 15 ++++++++++++--- include/linux/pci-acpi.h | 5 +++++ include/linux/pci.h | 3 +++ 6 files changed, 39 insertions(+), 23 deletions(-) -- 2.32.0