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

[Marc Zyngier]

On 2021-06-10 16:01, Ard Biesheuvel wrote:
> On Wed, 9 Jun 2021 at 18:32, Boqun Feng <boqun.feng@xxxxxxxxx> wrote:
> > Hi Bjorn, Arnd and Marc,
>
> Instead of cc'ing Arnd, you cc'ed me (Ard)

And I don't know if you intended to Cc me, but you definitely didn't.

Thanks,

        M.

> > 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(-)
> >
> > --
> > 2.30.2
>
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