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Re: [Qemu-devel] [0/10] Clean up PCI code to allow for multiple root bus
From: |
Alexey Kardashevskiy |
Subject: |
Re: [Qemu-devel] [0/10] Clean up PCI code to allow for multiple root buses (v2) |
Date: |
Wed, 12 Jun 2013 17:18:46 +1000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6 |
On 06/06/2013 08:01 PM, Michael S. Tsirkin wrote:
> 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.
So, did it happen? I would be happy :) When is it expected to reach
upstream? Thanks!
> No need to repost for the lack of -M flag - I wish there was a way
> to specify that in git config.
>
--
Alexey
- [Qemu-devel] [PATCH 02/10] pci: Move pci_read_devaddr to pci-hotplug-old.c, (continued)
- [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