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Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more ge
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path() |
Date: |
Thu, 23 May 2013 22:21:09 +1000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, May 23, 2013 at 02:04:08PM +0300, Michael S. Tsirkin wrote:
> On Thu, May 09, 2013 at 10:31:09AM +1000, David Gibson wrote:
> > pci_find_domain() is used in a number of places where we want an id for a
> > whole PCI domain (i.e. the subtree under a PCI root bus). The trouble is
> > that many platforms may support multiple independent host bridges with no
> > hardware supplied notion of domain number.
> >
> > This patch, therefore, replaces calls to pci_find_domain() with calls to
> > a new pci_root_bus_path() returning a string. The new call is implemented
> > in terms of a new callback in the host bridge class, so it can be defined
> > in some way that's well defined for the platform. When no callback is
> > available we fall back on the qbus name.
> >
> > Most current uses of pci_find_domain() are for error or informational
> > messages, so the change in identifiers should be harmless. The exception
> > is pci_get_dev_path(), whose results form part of migration streams. To
> > maintain compatibility with old migration streams, the PIIX PCI host is
> > altered to always supply "0000" for this path, which matches the old domain
> > number (since the code didn't actually support domains other than 0).
> >
> > For the pseries (spapr) PCI bridge we use a different platform-unique
> > identifier (pseries machines can routinely have dozens of PCI host
> > bridges). Theoretically that breaks migration streams, but given that we
> > don't yet have migration support for pseries, it doesn't matter.
> >
> > Any other machines that have working migration support including PCI
> > devices will need to be updated to maintain migration stream compatibility.
> >
> > Signed-off-by: David Gibson <address@hidden>
>
> AFAIK PC is the only one with working migration, yes, but
> we have Q35 as well which can be migrated.
Good point, I'll add a similar hook to q35.
--
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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- Re: [Qemu-devel] [PATCH 6/8] pci: Simpler implementation of primary PCI bus, (continued)
- [Qemu-devel] [PATCH 4/8] pci: Use helper o find device's root bus in pci_find_domain(), David Gibson, 2013/05/08
- [Qemu-devel] [PATCH 3/8] pci: Abolish pci_find_root_bus(), David Gibson, 2013/05/08
- [Qemu-devel] [PATCH 7/8] pci: Remove domain from PCIHostBus, David Gibson, 2013/05/08
- [Qemu-devel] [PATCH 8/8] pci: Fold host_buses list into PCIHostState functionality, David Gibson, 2013/05/08
- [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path(), David Gibson, 2013/05/08
- Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path(), Michael S. Tsirkin, 2013/05/23
- Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path(),
David Gibson <=
- Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path(), Paolo Bonzini, 2013/05/23
- Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path(), Michael S. Tsirkin, 2013/05/23
- Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path(), Paolo Bonzini, 2013/05/23
- Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path(), Michael S. Tsirkin, 2013/05/23
- Re: [Qemu-devel] [PATCH 5/8] pci: Replace pci_find_domain() with more general pci_root_bus_path(), David Gibson, 2013/05/24
[Qemu-devel] [PATCH 1/8] pci: Cleanup configuration for pci-hotplug.c, David Gibson, 2013/05/08