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

[Anthony Liguori <aliguori@us.ibm.com>]

"Michael S. Tsirkin" <mst@redhat.com> 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 <mst@redhat.com>
>
> 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

Regards,

Anthony Liguori

> -- 
> MST