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Re: [Qemu-devel] [0/10] Clean up PCI code to allow for multiple root bus
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [0/10] Clean up PCI code to allow for multiple root buses (v2) |
Date: |
Fri, 7 Jun 2013 10:45:36 +1000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
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
pgpMMxWz73tY2.pgp
Description: PGP signature
- [Qemu-devel] [PATCH 09/10] pci: Remove domain from PCIHostBus, (continued)
- [Qemu-devel] [PATCH 09/10] pci: Remove domain from PCIHostBus, David Gibson, 2013/06/06
- [Qemu-devel] [PATCH 02/10] pci: Move pci_read_devaddr to pci-hotplug-old.c, David Gibson, 2013/06/06
- [Qemu-devel] [PATCH 03/10] pci: Abolish pci_find_root_bus(), David Gibson, 2013/06/06
- [Qemu-devel] [PATCH 01/10] pci: Cleanup configuration for pci-hotplug.c, David Gibson, 2013/06/06
- [Qemu-devel] [PATCH 10/10] pci: Fold host_buses list into PCIHostState functionality, David Gibson, 2013/06/06
- [Qemu-devel] [PATCH 07/10] pci: Add root bus parameter to pci_nic_init(), David Gibson, 2013/06/06
- [Qemu-devel] [PATCH 05/10] pci: Replace pci_find_domain() with more general pci_root_bus_path(), David Gibson, 2013/06/06
- Re: [Qemu-devel] [0/10] Clean up PCI code to allow for multiple root buses (v2), Michael S. Tsirkin, 2013/06/06
- Re: [Qemu-devel] [0/10] Clean up PCI code to allow for multiple root buses (v2), Michael S. Tsirkin, 2013/06/17