Re: [Qemu-devel] [0/10] Clean up PCI code to allow for multiple root buses (v2)

[David Gibson]

On Thu, Jun 06, 2013 at 10:04:58AM -0500, Anthony Liguori wrote:
> "Michael S. Tsirkin" <address@hidden> writes:
> 
> > On Thu, Jun 06, 2013 at 06:48:44PM +1000, David Gibson wrote:
> >> The current PCI subsystem has kind of half-hearted support for
> >> multiple independent root buses - aka PCI domains - in the form of the
> >> PCIHostBus structure and its domain field.  However, it doesn't quite
> >> work because pci_host_bus_register() is always called with a domain of
> >> 0.
> >> 
> >> Worse, though, the whole concept of numbered domains isn't general
> >> enough.  Many platforms can have independent root buses (usually on
> >> wholly independent host bridges), but only x86 gives them a
> >> hardware-significant domain number, essentially as a hack to allow all
> >> the separate config spaces to be accessed via the same IO ports.
> >> Linux guests on other platforms will show domain numbers in lspci, but
> >> these are purely guest assigned, so qemu won't know about them.
> >> 
> >> This patch series, therefore, removes the broken-as-is domain concept
> >> from qemu, and replaces it with a different way of handling multiple
> >> root buses, based on a host bridge class method to provide a
> >> identifier for the root bus.  This hook is designed in such a way as
> >> to allow a single bridge object to support mutiple root buses with
> >> future changes, which will allow future implementations of x86 north
> >> bridges with multiple domains to be supported correctly, and in way
> >> that matches the existing practice for all external interfaces.
> >> 
> >> v2:
> >>   * Rework concept of "primary" bus in response to Michael Tsirkin's
> >>     comments.
> >
> >
> > Looks good to me.
> >
> > Acked-by: Michael S. Tsirkin <address@hidden>
> >
> > I'll wait a bit so others have a chance to comment, then apply
> > if everyone is happy.
> >
> > No need to repost for the lack of -M flag - I wish there was a way
> > to specify that in git config.
> 
> [diff]
>         renames = true

Oh, thanks.  I was looking for a way to configure that, but hadn't
found it.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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