On Thu, Aug 19, 2021 at 03:17:58PM +0100, Lorenzo Pieralisi wrote: > On Tue, Jul 27, 2021 at 02:06:49AM +0800, Boqun Feng wrote: > > 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(-) > > If we take this series via the PCI tree we'd need Catalin/Will ACKs on > patches 3-4. > Got it. > I need some time to look into [1] (thanks for that). > > Without [1] patch 8 is ugly, that's no news. The question is whether > it is worth waiting for a kernel cycle to integrate [1] into this series > or not. > > Is it really a problem if we postpone this series for another kernel > cycle so that we can look into it ? > Well, it's definitely better for me that we can have it in 5.15-rc1 ;-), because it's a dependency for Hyper-V virtual PCI support on ARM64 and we plan to send the rest of work in 5.15 cycle. And I can just base on hyperv-next for the rest of the work if this is in 5.15-rc1. But yes, it's not really a problem, since this one still needs to work with other patches to support virtual PCI on ARM64 Hyper-V. In fact, I personally don't think [1] is better than patch 8 (plus patch 3 & 4): playing with ->private seems dangerous and not very helpful on readiblity, but I agree that we should explore every potential solution, and that's why I send [1]. Regards, Boqun > [1] https://lore.kernel.org/lkml/20210811153619.88922-1-boqun.feng@xxxxxxxxx/
